Microclimate design methods for energy-saving houses on
various site conditions in Korea
Technische Universität Berlin
Fakultät VI. Planen Bauen Umwelt
Zur Erlangung des Grade
Doktorin der Ingenieurwissenschaftler
Dr. –Ing
genehmigte Dissertation
vorgelegt von
Min Kyeong Kim
aus Süd Korea
Promotionsausschuss:
Vorsitzender:Prof. Dr. –Ing. Peter Herrle
Berichter : Prof. Dipl.-Ing. Claus Steffan
Berichter:Prof.Dr. rer. nat. Dieter Scherer
Tag der wissenschaftlichen Aussprache : 9. 7. 2008
Berlin 2008
D 83
I
Contents
List of Figures .......................................................................................................................................................................................... IV
List of Tables ............................................................................................................................................................................................ IX
Abstract ........... .......................................................................................................................................................................................... XI
Acknowledgement ............................................................................................................................................................................... XIII
1. Introduction ......................................................................................................................................................................................... １
1.1. Importance of energy-saving ................................................................................................................................................. １
1.2. Need for energy simulation .................................................................................................................................................... ５
1.3. Research objective ....................................................................................................................................................................... ７
1.4. Constraints ...................................................................................................................................................................................... ９
1.5. Structure of thesis .................................................................................................................................................................. １１
Research flowchart .......................................................................................................................................................................... １３
2. Energy-saving and climate in the Passive House ........................................................................................................... １４
2.1. Energy in Passive House ...................................................................................................................................................... １４
2.2. Human comfort factor .......................................................................................................................................................... １６
2.2.1. Psychometric comfort scale .................................................................................................................................... １７
2.2.2. Comfort zone ................................................................................................................................................................ １９
2.3. Aerodynamic and energy contents ................................................................................................................................. ２０
2.4. Design for energy gain......................................................................................................................................................... ２２
2.5. Design for heat loss ............................................................................................................................................................... ２６
2.6. Thermal insulation .................................................................................................................................................................. ３０
2.7. Thermal mass ........................................................................................................................................................................... ３ ４
3. Microclimate design for energy-saving .............................................................................................................................. ３ ９
3.1. Microclimate and building .................................................................................................................................................. ３９
3.1.1. Definition of Macro- and Microclimate ............................................................................................................. ３９
3.1.2. Microclimate design ................................................................................................................................................... ４０
3.1.3. Climate design process ............................................................................................................................................. ４１
3.2. Arrangement ............................................................................................................................................................................. ４２
3.2.1. Microclimate effects adapting wind direction ................................................................................................. ４２
3.2.2. Optimum building orientation ............................................................................................................................... ４４
3.2.3 Topography ..................................................................................................................................................................... ４５
II
3.2.4. Building attachment and courtyard ..................................................................................................................... ５０
3.3 Form ............................................................................................................................................................................................... ５３
3.3.1. Windbreak ....................................................................................................................................................................... ５３
3.3.2. Building geometry and form .................................................................................................................................. ５６
3.3.3. Internal partitioning .................................................................................................................................................... ５７
3.3.4. Courtyard roofing ........................................................................................................................................................ ５８
3.3.5. Roof opening and stack effect ............................................................................................................................... ６０
3.4. Façade elements ...................................................................................................................................................................... ６２
3.4.1. Microclimate in opening control ........................................................................................................................... ６２
3.4.2. Opening locations and shapes .............................................................................................................................. ６３
3.4.3. Projected building structure .................................................................................................................................... ６６
3.4.4. Opening slits .................................................................................................................................................................. ６８
3.5. Analysis of building microclimate .................................................................................................................................... ７０
3.5.1. Problems for energy assessment .......................................................................................................................... ７０
3.5.2. Previous methods ........................................................................................................................................................ ７１
3.5.3. Hybrid model for microclimate analysis ............................................................................................................ ７５
3.5.4. Experimental expression of models ..................................................................................................................... ７７
4. Microclimate energy simulation ............................................................................................................................................. ８１
4.1. Multi-zone energy simulation ............................................................................................................................................ ８１
4.1.1. Multi-zone simulation method using EP ........................................................................................................... ８１
4.1.2. Calculation of internal temperatures in multi-zones .................................................................................... ８３
4.2. Microclimate energy variation model ............................................................................................................................. ８６
4.2.1. Outdoor model ............................................................................................................................................................. ８７
4.2.2. Indoor model ................................................................................................................................................................. ９１
4.3. Multi-scale EP-CFD analysis ................................................................................................................................................ ９３
4.4. Graph modeling for real house analysis ....................................................................................................................... ９５
5. Microclimate design methods in S. Korea: Simulation results using unit EP-CFD ........................................... ９９
5.1. Arrangement ........................................................................................................................................................................ １０２
5.1.1. Microclimate of building orientation: the highest heating gain and small indoor airflow ..... １０２
5.1.2. Microclimate on topography: large microclimate cooling effect with high air pressure ......... １０３
5.1.3. Microclimate of courtyard cooling: thermodynamic air circulation through the house .......... １０４
5.1.4. Microclimate of courtyard roof: atrium passive heating using courtyard ..................................... １０６
5.2. Form ......................................................................................................................................................................................... １０８
5.2.1. Microclimate in roof shapes: strong shading and control of wind stream direction ................ １０８
5.2.2. Microclimate of curved roof: minimum wind resistance and small eddy current ....................... １１０
5.2.3. Microclimate in fence design: deriving small wind and airflow on the site .................................. １１１
5.2.4. Microclimate of windbreaks: cold wind protection in winter .............................................................. １１２
5.2.5. Microclimate in building over pilotis: cooling efficiency of airflow under the floor .................. １１４
5.2.6. Microclimate of heat diffusion: Indoor airflow for heat recovery ...................................................... １１６
5.3. Façade elements ................................................................................................................................................................. １１８
5.3.1. Microclimate of window shape: Fast and well-distributed cross-ventilation ................................ １１８
III
5.3.2. Microclimate of window shape: optimal inlet design for ventilation
and passive solar design ....................................................................................................................................... １２０
5.3.3. Microclimate of building projection: enhancing microclimate pressure
and protecting direct solar gain ........................................................................................................................ １２２
6. Application of microclimate simulation to a real-house design .......................................................................... １２５
6.1. A real-house in a suburb of Seoul, S. Korea ........................................................................................................... １２５
6.2. Converting Model from CAD to IFC ........................................................................................................................... １２７
6.3. Climate data and features ............................................................................................................................................... １２９
6.4. Microclimate design elements ...................................................................................................................................... １３２
6.5. Energy efficiency ................................................................................................................................................................. １３６
7. Conclusions ................................................................................................................................................................................ １４５
Appendix …. ..................................................................................................................................................................................... １５７
Bibliography .................................................................................................................................................................................... １６９
IV
List of Figures
1. Introduction
Figure 1.1. Annual changes in average surface temperature and changes of CO2 ............................................... １
Figure 1.2. Classification of 10 elements using the solar energy from passive to active level ......................... ４
Figure 1.3. Climate of local regions in S. Korea ..................................................................................................................... ６
Figure 1.4. Climate scales, (a) time and distance scales, (b) macro- and microclimate ........................................ ８
Figure 1.5. An example of S. Korean site set-up including slope areas. ................................................................. １０
2. Energy-saving and climate in the Passive House
Figure 2.1. CO2 emissions for the buildings sector including electricity
. .............................................................. １４
Figure 2.2. Energy consumption in residential sectors of some cities ................................................................... １６
Figure 2.3. Psychometric chart of Seoul .............................................................................................................................. １８
Figure 2.4. Actual temperature as perceived by a person and MRT ........................................................................ １９
Figure 2.5. Relationship between body temperature and the energy balance,
(a) the components over a range of environmental temperatures,
(b) the four modes .... ２１
Figure 2.6. Typical design approach when considering solar access by G. Watrous in Kentucky .............. ２２
Figure 2.7. Angles of visible sky for the average DF calculation .............................................................................. ２３
Figure 2.8. Outdoor heat balance of longwave radiation,
(a) the diagram, (b) an example in Berlin,
Stglitz
.................................................................................. ２４
Figure 2.9. Indoor heat balance diagram and an example of longwave radiation
from internal exchange ...................................................................................................................................... ２５
Figure 2.10. Solar shading, (a) devices by C. Scarpa, (b) overhang ........................................................................... ２７
Figure 2.11. Very large roof overhangs of Robie house by F.L. Wright ................................................................. ２８
Figure 2.12. Areas of opening required in winter and summer, volume to area ratio for stack-driven
ventilation ............................................................................................................................................................. ２９
Figure 2.13. Temperature gradient of a composite wall .............................................................................................. ３０
Figure 2.14. Calculating heat transfer .................................................................................................................................... ３１
Figure 2.15. U-value of a ground floor, (a) for solid floor and suspended floor,
(b) solid floors with all over insulation ................................................................................................... ３２
Figure 2.16. Thermal bridge ...................................................................................................................................................... ３３
Figure 2.17. Effect of position of thermal mass on the inside temperature.......................................................... ３４
Figure 2.18. The relationship between density and thermal conductivity ............................................................ ３４
V
Figure 2.19. Thermal mass in solar-air-collector by E.S. Morse in Salem, Massachusetts ............................. ３５
Figure 2.20. Thermal mass for passive cooling of Tono Inax pavilion 1998. ........................................................ ３６
3. Microclimate design for energy-saving
Figure 3.1. Wind streamlines around a building, (a) schematic distribution of wind pressure and wind
shadow, (b) the pattern for the building forms and layouts ................................................................. ４３
Figure 3.2. Wind streamlines and wind shadow by building arrangement ......................................................... ４３
Figure 3.3. House orientation considering the sun path ............................................................................................. ４４
Figure 3.4.
Schöneiche
(nearby Berlin) ecological house complex by Gölling and Schmidt .......................... ４５
Figure 3.5. Aluminum city terrace in Pennsylvania by W. Gropius and M. Breuer ........................................... ４６
Figure 3.6. Solar radiation on slope, (a) total daily direct-beam radiations,
(b) shadow range for distance between buildings ................................................................................... ４６
Figure 3.7. Slope wind systems, (a) interplay of slope and valley winds for a day,
(b) streamlines in slopes and building arrangement .............................................................................. ４８
Figure 3.8. Airflow patterns over moderate topography ............................................................................................... ４９
Figure 3.9. Utilization of topography and site condition, (a) house by Körner and Stotz in
Murrhardt
,
(b) Korean traditional architectural scheme ............................................................................................... ４９
Figure 3.10. Several types of court for wind protection .............................................................................................. ５０
Figure 3.11. Building attachment, (a) annex building against regional wind,
(b) layered structures of
Dokrak-Dang
......................................................................................................... ５１
Figure 3.12. Airflow patterns corresponding to the function of
H/W
and
L/W
.................................................. ５１
Figure 3.13. The thermal system of a courtyard house ................................................................................................ ５２
Figure 3.14. Barrier usage and the influence, (a) layered walls of Korean architecture,
(b) the wind speed in the vicinity in the open, (c) wind streamline zones ................................ ５３
Figure 3.15. Shading of backyard .......................................................................................................................................... ５５
Figure 3.16. The effects of building geometry ................................................................................................................. ５６
Figure 3.17. Energy-saving house at
Fläming Str.
in Berlin by A. Salomon & Scheidt ................................... ５６
Figure 3.18. Internal airflow patterns using several partitions, (a) the diagrams,
(b) airflow patterns of in complex partitions ............................................................................................. ５７
Figure 3.19. Ventilation parametric models for the courtyard roofing .................................................................. ５８
Figure 3.20. Public housing at
Köpeniker Str.
in Berlin by O. Steidle .................................................................... ５９
Figure 3.21. Exposed roof-ventilation holes of the gable roof of Mr. Eu’s house ............................................ ６０
Figure 3.22. Stack effect of an IHK’s office in
Karlsruhe
by C. Steffan .................................................................... ６１
Figure 3.23. Performance of different wind direction with shape and angles of opening ........................... ６４
Figure 3.24. Opening sizes control of
Janggyeong Panjeon
, (a) the structure, (b) mean airflow speed .. ６６
Figure 3.25. Horizontal projections and airflow patterns ............................................................................................. ６７
Figure 3.26. Out-standing structures, in the Korean traditional residence .......................................................... ６８
Figure 3.27. Opening slits of
Janggyeong Panjeon
on the elevation of a module .......................................... ６９
Figure 3.28. Debis tower in Berlin designed by R. Piano ............................................................................................. ６９
Figure 3.29. Airflow patterns of ventilation for several slit types ............................................................................. ７０
VI
Figure 3.30. The geometric representation of building zones and the structural component graph ........ ７２
Figure 3.31.The analyzed variable parameters as the flow in the grid network ................................................ ７４
Figure 3.32. Validity for with and without CFD in a building model ........................................................................ ７４
Figure 3.33. 3D CFD ....................................................................................................................................................................... ７５
Figure 3.34. Experimental expression, (a) predicted and observed pressure coefficients (CQ),
(b) energy balance between wall and room air ....................................................................................... ７８
4. Microclimate energy simulation
Figure 4.1. Input interface of EP ............................................................................................................................................... ８２
Figure 4.2. EP schematic and modules .................................................................................................................................. ８３
Figure 4.3. Multi-zone analytical energy simulation of EP ............................................................................................ ８３
Figure 4.4. Two layer examples for deriving the Laplace transform extension
to include sources and sinks ............................................................................................................................. ８４
Figure 4.5. Controlling temperature scheme for heating and cooling. ................................................................... ８６
Figure 4.6. Simulation model and three modules ............................................................................................................ ８６
Figure 4.7. Sloping topographical design process ............................................................................................................ ８９
Figure 4.8. Outdoor model ......................................................................................................................................................... ９０
Figure 4.9. Thermo- and aerodynamic processes, (a) thermodynamic, (b) airflow by aerodynamic
microclimate............................................................................................................................................................... ９１
Figure 4.10. Numerical solution in the Fluent ................................................................................................................... ９３
Figure 4.11. Multi-scale scheme using macroclimate and microclimate scales ................................................... ９４
Figure 4.12. Graph modeling, (a) graph model of EP method for the 3 zones, (b) relationship between
AirflowNetwork and regular EP objects ....................................................................................................... ９６
Figure 4.13. Allocating EP’s volume average value to CFD nodes of the volume .............................................. ９６
5. Microclimate design methods in S. Korea: Simulation results using unit EP-CFD
Figure 5.1. Result of orientation of the CFD, (a) 2D plot, (b) 3D plot ............................................................. １０２
Figure 5.2. Result of building in topography ............................................................................................................... １０３
Figure 5.3. Comparison of thermal condition with cooling gain ........................................................................ １０４
Figure 5.4. A cooling scheme of a Korean traditional house on topography ............................................... １０４
Figure 5.5. Result of courtyard cooling between house and courtyard,
(a) air velocity and the microclimate air circulation, (b) thermodynamic air circulation .... １０５
Figure 5.6. Air temperature of courtyard, (a) indoor and outdoor by day and night,
(b) with and without roof .............................................................................................................................. １０６
Figure 5.7. Result of courtyard roof, (a) thermal condition of courtyard in winter,
(b) comparison of airflows between courtyard with roof and without roof.............................. １０７
Figure 5.8. Result of gable roof with shading overhang and roof ventilation .............................................. １０８
Figure 5.9. Result of curved roof, (a) air-streamline comparison between gable roof and curved roof,
(b) pressure and thermal condition of curved roof ............................................................................ １０９
VII
Figure 5.10. Comparison of thermal condition (a) cooling gain between flat and gable roof,
(b) indoor and exterior wall temperatures between gable and curved roofs ....................... １０９
Figure 5.11. Result of fence design in Korean house, (a) 3D streamline plot of airflow,
(b) the present state of Mr. Jung’s house ............................................................................................. １１１
Figure 5.12. Cold wind protection, (a) using wall and projection, (b) using trees ......................................... １１２
Figure 5.13. Average indoor temperatures of no wind shelter, shelters using wall and projection
and using tree ................................................................................................................................................... １１３
Figure 5.14. Building over pilotis, (a) result of flow field and a Korean pavilion, (b) comparison of wind
pressure distribution for different porosities (%) ............................................................................... １１４
Figure 5.15. Comparison of thermal condition with cooling gain between ventilation using pilotis and
cross-ventilation of low-set building ....................................................................................................... １１５
Figure 5.16. Thermodynamic heat diffusion process using isothermal particle tracking ............................ １１６
Figure 5.17. Difficulty in visualizing thermo- and aerodynamic simultaneously, (a) simple zone,
(b) two different heating zones ................................................................................................................. １１７
Figure 5.18. Temperature of the zone-to-zone natural ventilation ...................................................................... １１８
Figure 5.19. Airflow pattern in cross-ventilation, (a) uniform window shape,
(b) non-uniform window shape, (C) 3D streamline plot of airflow ............................................ １１９
Figure 5.20. Comparison between uniform window and non-uniform window,
(a) pressure and air velocity, (b) average outdoor and indoor temperatures .................... １２０
Figure 5.21. Airflow plots of horizontal inlet with temperature ........................................................................... １２１
Figure 5.22. Cooling performance for window shape and air velocities ............................................................ １２１
Figure 5.23. Microclimate of building projection, (a) pressure difference between of horizontal
and vertical projection, (b) horizontal projection, (c) vertical projection ................................ １２３
Figure 5.24. Comparison of thermal condition of cross-ventilation with horizontal
and vertical projections and without projection ................................................................................ １２４
6. Application of microclimate simulation to a real-house design
Figure 6.1. Pine Tree House by S.Y. Choi, (a) drawings, (b) views ....................................................................... １２６
Figure 6.2. CAD model of Pine Tree House .................................................................................................................. １２７
Figure 6.3. Difference between CAD and IFC ............................................................................................................... １２８
Figure 6.4. Adaptable mesh for better analysis resolution near model edges .............................................. １２８
Figure 6.5. Heating and cooling loads by the difference of solar radiation
between Seoul and Berlin . ............................................................................................................................. １２９
Figure 6.6. Korean climate analysis using EP over 1 year ....................................................................................... １３２
Figure 6.7. Microclimate design elements of Pine Tree House ............................................................................ １３３
Figure 6.8. Heating and cooling loads, (a) by change of slope angle, (b) by change of window ratios,
(c) by change of insulation thickness ........................................................................................................ １３８
Figure 6.9. Comparison of heating and cooling loads EP-CFD method using microclimate design models
VIII
.................................................................................................................................................................................... １３９
Figure 6.10. EP-CFD simulation results of Pine Tree House .................................................................................. １４１
Figure 6.11. Zone temperature comparison between passive method and HVAC model ....................... １４２
Figure 6.12. 1 year temperature comparison between a passive method and a combination of passive
method and flow net of microclimate design ..................................................................................... １４３
7. Conclusions
Figure 7. 1 Classification by heating and cooling effects of elements in Table 7.3 ...................................... １４９
Figure 7.2. Energy simulation method using EP-CFD coupling. ............................................................................ １５０
IX
List of Tables
1. Introduction
2. Energy-saving and climate in the Passive House
Table 2.1. Thermal sensation scale for the PMV, ............................................................................................................. １８
Table 2.2. Solar heat gain through single thickness of common window glass
through an unshaded window ............................................................................................................................ ２６
Table 2.3. Comparison of global radiation of four countries .................................................................................... ２７
Table 2.4. Climate data in summer and winter in S. Korea ........................................................................................ ２７
3. Microclimate design for energy-saving
Table 3.1. The factors and related issues ........................................................................................................................... ４０
Table 3.2. Planning issues and the effects .......................................................................................................................... ４１
Table 3.3. The amount of wind reduction measured against varying heights and object shapes ........... ５４
Table 3.4. The effects of planting in Chicago .................................................................................................................. ５５
Table 3.5. Effects of clerestory on average internal airflow rates ............................................................................ ６０
Table 3.6. Airflow related to the opening location or wind direction ................................................................... ６５
Table 3.7. Effects of wing-walls on cross-ventilation and the wind direction .................................................... ６７
Table 3.8. Strategies for the coupling of the CFD and multi-zone model .......................................................... ７７
Table 3.9. Analytic method for cross-ventilation of single buildings ...................................................................... ７８
4. Microclimate energy simulation
Table 4.1. The physical properties that can be analyzed using CFD ....................................................................... ８７
Table 4.2. The advantages of CFD .......................................................................................................................................... ８９
Table 4.3. Outdoor model and indoor model concerned to chapter, (a) outdoor model,
(b) indoor model ........................................................................................................................................................ ９０
Table 4.4. The utilization of microclimate modification ................................................................................................ ９２
Table 4.5. Sub-tools of Fluent software ............................................................................................................................... ９２
Table 4.6. Procedure of Fluent solver.................................................................................................................................... ９３
Table 4.7. Process of EP-CFD coupling ............................................................................................................................... ９５
Table 4.8. Graph models of EP and CFD ............................................................................................................................. ９６
X
5. Microclimate design methods in S. Korea: Simulation results using unit EP-CFD
Table 5.1. List of Elements in classified microclimate design methods for energy-saving houses . ..... １００
6. Application of microclimate simulation to a real-house design
Table 6.1. Construction materials and outline of Pine Tree House .................................................................... １２７
Table 6.2. Construction materials and outline of Pine Tree House .................................................................... １２９
Table 6.3. Drawing of details and snapshots for design elements of Pine Tree House ........................... １３５
Table 6.4. Some of the factors that influence results ................................................................................................ １３６
Table 6.5. Heating and cooling models based on the simulation results of microclimate design elements
.................................................................................................................................................................................. １３９
Table 6.6. Part of a building and percentage of heat loss .................................................................................... １４２
7. Conclusions
Table 7.1. Comparisons between multi-zone and CFD method .......................................................................... １４６
Table 7.2. Accuracy of thermal prediction .................................................................................................................... １４６
Table 7.3. Strength of thermo- and aerodynamic microclimate for architectural design elements
.................................................................................................................................................................................... １４７
Table 7.4. The thermal effects of glazing directions in S.Korea .......................................................................... １５１
XI
Abstract
Mikroklimatische Designmethoden für energiesparende
Häuser an verschiedenen Standorten in Korea
Min Kyeong Kim
Eingereicht zum Fachgebiet Architektur, Institut für Gebäudetechnik und Entwerfen im Juni 2008 für
den Grad des Doktor Ingeniur im Fachgebiet Architektur
Thesen zur Dissertation:
Ein kleines territoriales Gebiet in Korea weist verschiedene mikroklimatische Bedingungen auf, je
nachdem, wie viel Sonne, Schatten, Feuchtigkeit und Winden es ausgesetzt ist. Diese
mikroklimatischen Bedingungen können durch zielgerichtete Betrachtung aller Elemente bei der
Entwicklung und beim Bauen beeinflusst werden, so durch die Nutzung geneigter Geländeflächen, die
Anwendung einer 3-dimensionalen Geometrie, wie die Kombination von architektonischen Elementen
des Neubaues und der Einbeziehung bereits auf der Geländefläche existierenden Gebäuden. Diese
Studie untersucht die Nutzung mikroklimatischer Veränderungen für ein effektives
Niedrigenergiedesign unter Einbeziehung der von Elementen der traditionellen koreanischen Bauweise
und des Passivhauses.
Die untersuchte Methode der mikroklimatischen Analyse kann zu zeitlichen und räumlichen
Vorhersage bezüglich der Gebäudegeometrie genutzt werden. Eine Kombination u.a. von passiver
solarer Gewinne, gezielten Schutzmassnahmen vor kalten Winden, Sicherung der Zirkulation der
Raumluft und natürlicher Belüftung sowie der Berücksichtigung der Sonnenscheindauer und der
Ausbreitung des Schattens ist eine wichtige Voraussetzung für behagliches Wohnen und Arbeiten zu
jeder Jahreszeit. Zugleich kann so eine wirkungsvolle Einflussnahme auf die Senkung des
Energieverbrauches genommen werden. Für die passive Gewinne und Kühlung ist unbedingt eine
ständige Betrachtung der Veränderungen in den mikroklimatischen Bedingungen erforderlich, um die
XII
höchstmögliche Energieeffizienz in den Gebäuden zu sichern. Die vorliegende Arbeit enthält die
Untersuchung der mikroklimatischen Veränderungen zur Nutzung der räumlichen Planung eines
Gebäudes, des effektiven Einsatzes von Niedrigenergiemethoden, des Passivhaus-Standards und
allgemeine physikalische Grundlagen in den Energiesimulationsmethoden.
Die heißen und feuchten Sommer in Korea, erfordern immer zu beachten, dass eine ausreichende
Luftzirkulation in den Gebäuden gewährleistet wird. So ist die Be- und Entlüftung eine wichtige
Voraussetzung für die konvektive Kühlung oder Verdunstungskühlung in den Gebäuden. Der
erforderliche Luftfluss in einem Gebäude wird durch die Geometrie und der Betrachtung des
Unterschieds von Lufttemperatur und des Luftdrucks erreicht. Die Betrachtung der Positionen bereits
bestehender Gebäude ist für die Führung des Luftflusses von großer Wichtigkeit. Die
Gebäudegeometrie und die Gebäudeorientierung hat eine größere Wirkung auf die Tendenz des
Luftflusses als die Luftgeschwindigkeit.
Diesen Effekt richtig genutzt, wird er zu einer wichtigen Quelle der Energieeinsparung. Eine neuartige
Simulationsmethode in der Kombination der Simulation von Multi-Zonen und CFD kann zu einer
wirkungsvollen Analyse effektiver Energiespareffekte im Bereich der passiven und mikroklimatischen
Elemente der Gestaltung von Gebäuden und Einrichtungen genutzt werden. Der Multi-Zone
Energiesimulationstools „Energie Plus“ kann für die Erlangung von Parametern zur Vereinfachung der
Energiesparprobleme für die verschiedensten Gebäudezonen (Räume, Flure usw.) genutzt werden.
Diese Methode ist aber nicht geeignet, um Variationen in der Geometrie von Gebäuden zu behandeln,
da sie in ihrer Gesamtheit nur auf Schätzungen von durchschnittlichen Werten bezogen auf
Energieverbrauch, Temperatur, Feuchtigkeit usw. beruht. Besser geeignet für Variationen in der
Gebäudegestaltung ist die CFD Methode mit unterteilender „Grid-Unit“. Sie ermöglicht genauere
Ergebnisse zu den Schätzungen des Luftflusses und der zielgerichteten Veränderung des thermischen
Zustands. Für die Gestaltung eines Hausmodells in Südkorea, sind Fallstudien und Methoden der
Energieeinsparung, immer einer gründlichen Bewertung und Analyse, bezogen auf die
vorherrschenden mikroklimatischen Bedingungen zu unterziehen.
XIII
Acknowledgement
Danksagung
Ich möchte mich bedanken
bei Prof. Claus Steffan für die Betreuung meiner Arbeit;
bei Prof. Dieter Scherer, mit dem ich lange ein Büro teilen durfte und der mir bei allen
computertechnischen Problemen eine unendliche Hilfe war;
bei Prof. Paul Uwe Thamsen des Fluidsystemdynamik Institutes, für die CFD Arbeit;
bei Anke Sippel und bei Klaus Sippel, die mir speziell in den letzten 3 Jahren in Berlin eine große Hilfe
waren;
bei Heon, Farshad und Kollen in dem Institut für Ökologie, für ihre Freundschaften und ihre aufrichtige
Kritik;
bei Gwyneth Edwards, Petra Pham und Robert Crouch, für ihre kurze aber wichtige Freundschaft und
für die Korrektur in Englisch;
Am allermeisten bedanke ich mich allerdings bei meinen Eltern, für ihre Liebe und ihre jahrelange
Unterstützung;
Vielen Dank!
Kim, Min Kyeong
Berlin, den 11. July 2008
1. I
n
1.1. Im
p
Climate h
a
of climate
i
Earth has
compositi
o
needed fo
r
such as pr
i
“Greenho
u
reflected
f
climate.
A
Increasing
events an
d
changes i
n
ranges of
d
Figure
1
n
tro
d
p
ortance
a
s constantl
y
i
s bound u
p
been disr
u
o
n of the g
l
r
human act
i
marily car
b
u
se Gases (
G
f
rom the s
u
A
popular
p
global te
m
d
change th
e
n
agricultur
a
d
isease vec
t
a. Temp
e
1
.1.
Annual
d
ucti
o
of ener
y
formed t
h
p
with the o
r
u
pted due
t
l
obal atmo
s
ivities are
o
b
on dioxide
G
HGs)”, a
r
u
rface into
p
hrase “Gl
o
m
perature w
i
e
amounts
a
a
l yields, t
r
t
ors.
e
rature
changes i
n
o
n
gy-savi
n
h
e global fe
a
r
igin and ad
a
t
o human
a
s
phere, wit
h
o
btained by
(CO
2
), me
t
r
e generate
d
the atmos
p
o
bal Warm
i
i
ll cause se
a
nd pattern
s
r
ade routes,
n
average s
u
１
n
g
a
tures of th
e
a
ptation of
l
a
ctivities
w
h
substanti
a
the combu
s
t
hane (CH
4
)
d
and act a
s
p
here. Risi
n
i
ng” is no
w
a levels to
s
of precipi
t
glacier re
t
u
rface temp
e
e
Earth sin
c
l
ife on the
E
w
hich have
a
l implicati
o
s
tion of fos
)
and nitro
u
s
a partial
b
n
g concent
r
w
adays
b
ei
n
rise, incre
a
t
ation. Oth
e
t
reat, speci
e
e
rature and
c
e the begin
n
E
arth. Rece
n
dramatica
l
o
ns for the
sil fuels. B
y
u
s oxide (N
2
b
lanket for
t
r
ations of
G
n
g used to
a
se the inte
n
e
r effects o
f
e
s extinctio
n
changes of
Panel on
C
n
ing of tim
e
n
tly, the ec
o
l
ly altered
climate. E
n
y
-products
o
2
O) etc., w
h
t
he longwa
v
G
HGs war
m
define th
e
n
sity of ext
r
f
global wa
r
n
s and the
b. CO2
CO
2
[The In
t
C
limate Chan
g
e
. The hist
o
o
syste
m
of t
h
the chemi
c
n
ergy sour
c
o
f fossil fu
e
h
ich are call
v
e radiati
o
m
the Eart
h
e
phenome
n
r
eme weat
h
r
ming inclu
spread of t
h
t
ergovernme
n
g
e (IPCC) 200
o
ry
h
e
c
al
c
es
e
ls
ed
o
n
h
’s
n
a.
h
er
de
h
e
n
tal
7].
２
For the evaluation of the risk of climate change caused by human activity, the Intergovernmental Panel
on Climate Change (IPCC) was established in 1988 by the World Meteorological Organization (WMO)
and the United Nations Environment Programme (UNEP),1 and has published several reports on topics
relevant to the implementation of the UN Framework Convention on Climate Change (UNFCCC).2 The
IPCC Fourth Assessment Report (AR4)3 provides a comparison between projections of climate change
in past reports and current observations. Fig.1.1-a indicates that the global average air temperature near
the Earth’s surface rose 0.76±0.19℃ during the 100 year period ending in 2005 and will rise a further
1.1℃ to 6.4℃ during the 21st century. The rate of warming averaged over the last 50 years is
0.13±0.03℃ per decade, which is nearly twice that for the last 100 years. The global average surface
temperature has increased, especially since about 1950. The bars and line shown in Fig.1.1-b represent
annual changes in global mean CO2 concentration and the annual increases that would occur if all fossil
fuel emissions stayed in the atmosphere. Global GHG emissions have grown with an increase of 70%
between 1970 and 2004, and the total amount of GHGs in the atmosphere has increased by about 35%.
It is clear that the problem of GHGs is related to buildings since buildings involve consumption of
energy, and thereby cause GHG emissions. The WG-III4 report of IPCC AR4 identifies that building is
one of the main contributors to global warming. Between 1970 and 1990, direct emissions from
buildings grew by 26%, and remained at approximately at 1990 levels thereafter. However, the
buildings sector has a high level of electricity use and hence the total of direct and indirect emissions in
this sector is 75% higher than direct emissions alone. The UN Economic Commission for Europe
(UNECE) also published similar statistical results,5 showing that 50% to 60% of total energy in the
world is used for building operation and maintenance.
In Asia, few low-energy houses have been developed although the international dimensions of Asian
energy insecurity have grown more difficult. The regional increases in CO2 emissions by commercial
buildings is 30% from developing Asia, 29% from North America and 18% from the OECD Pacific
region. For the regional increases in CO2 emissions in residential buildings, developing Asia accounts
for 42% and Middle East/North Africa for 19%.6 South Korea is also responsible for the large CO2
emissions due to its rapid and large-scale industrialization and automotive revolution. Although S.
Korea is the world’s 26th-largest country in population and 11th in Gross Domestic Product (GDP), S.
Korea was 10th globally in primary energy consumption in 2002, 7th in oil usage, and 5th in crude oil
1 The WMO and the UNEP are two organizations of the UN.
2 The UNFCCC is an international environmental treaty that acknowledges the possibility of harmful climate change.
3 The IPCC published the first assessment report in 1990, a supplementary report in 1992, a second assessment report in
1995, and a third assessment report in 2001. AR4 was released in 2007. The IPCC AR4 consists of four reports, WG-I: The
Scientific Basis, WG-II: Impacts, Adaptation and Vulnerability, WG-III: Mitigation and The AR4 Synthesis Report.
WG: Working Groups.
4 See footnote 3.
5 Economic Commission for Europe 1996.
6 The Intergovernmental Panel on Climate Change (IPCC) 2007.
３
imports. S. Korea confronts some of the most severe energy security issues in the world. S. Korea lacks
domestic sources of energy to fuel its remarkable, rapidly growing, and energy intensive economy. Of
the total energy supply, 84% comes from abroad and it is one of the highest levels7 in the world. To
make matters worse, it is unusually dependent on oil as a fuel source i.e. 50% of the primary energy
from oil compared with a global average of 38%. The amount of discharged
CO
2
person
-1 is close to 3.5
tons, and it is equivalent to the average of the OECD’s level. Household heating makes up 67.7% of
CO2 sources. The scale is increasing and will be in the top 5 in 2010 and over the OECD’s level in
2020.8
Governmental awareness of energy security problems furthers low-energy housing and development.
For example, the US Green Building Council (USGBC) has led to a green building rating system called
“Leadership in Energy and Environmental Design (LEED)” which provides a list of standards. The
LEED rating system 4 levels9 according to the energy performance of a building using an evaluation
checklist which addresses six major categories: Sustainable sites, Water efficiency, Energy and
atmosphere, Materials and resources, Indoor environmental quality and Innovation and design process.
Buildings can qualify for 4 levels of certification. Only 35 of all residences, public and complex
buildings in S. Korea could get the 1st or the 2nd grade by the LEED rating system until December 2005
due to the lack of S. Korean governmental policy.10 Recently, low-energy housing has started to play a
more important role in the establishment of Korea’s future energy policy.
Awareness of sustainability has shifted the concerns of engineers, architects, inventors and decision
makers towards a sustainable architectural design approach. Energy efficiency over the entire life cycle
of a building can be achieved by the concept of sustainable architecture. Architects use many different
techniques to reduce the energy needs of buildings and increase their ability to capture or generate their
own energy. For example, a passive solar design allows buildings to harness sunlight for energy
efficiently without active mechanical systems such as photovoltaic cells and solar hot water panels. It
converts sunlight into usable heat, causes air movement for ventilating, or stores heat for future use,
without the assistance of other energy sources. A passive building design generally has a very low
surface area with high thermal mass to minimize heat loss.
Fig.1.2 represents a classification between active and passive design elements. A passive design utilizes
building design elements e.g. windows, sunspace and thermal mass etc. to improve the building’s
energy performance while an active design employs some mechanics e.g. water/air collector, heat
exchanger, photovoltaic, heat pumps.
7 By comparison, Japan imports 82% of its energy, Germany 60%, and the United States only 27%.
8 Calder 2005.
9 Platinum (52-69 points), Gold (39-51 points), Silver (33-38 points), Certified (26-32 points) and non-innovation points.
10 The Korea Institute of Construction Technology (KICT) 2005.
In
ar
e
is
pr
o
si
m
Fi
g
b.
s
h.
a
R
e
e
n
ar
c
e
n
di
v
ar
c
e
n
1
9
P
a
th
e
11
P
12
T
r
e
e
13
F
r
t
r
d
c
e
b
p
t
14
I
c
l
col
d
er cli
m
e
typically
o
also impor
t
o
per mixtu
r
m
ulation.
g
ure 1.2
. C
l
s
unspace, c. t
h
a
utomatic co
n
e
ducing en
e
n
ergy are
c
c
hitectu
r
al
t
n
able impro
v
erse, gre
a
c
hitecture
w
n
vironment
a
9
90s. Low-
e
a
ssive Hous
e
world, wi
t
P
assive cooli
n
T
he term “pa
s
r
igorous, vol
u
e
nergy for s
p
e
fficient vent
i
F
rom the roo
t
r
elated to the
t
erms, howev
e
r
egardless of
h
d
esign to arc
h
c
omponents,
e
mphasizes e
f
b
uilding sitin
g
p
umps, wind
p
t
hat filter and
I
n general, th
e
c
hange in th
e
l
ow-energy st
a
m
ates, heati
n
o
ne of the l
a
t
ant to avo
i
r
e of heati
n
l
assification o
h
ermal mass,
n
trol in a ~ g,
i
e
rgy consu
m
c
alled activ
t
echnology
,
vements i
n
a
test and
m
w
as first
p
a
l architect
u
e
nergy hou
s
e has dem
o
t
hout using
n
g refers to te
c
s
sive” implie
s
u
ntary, Passi
v
p
ace heating.
i
lation and co
o
t
words “
s
ust
e
concept of “
g
er
, are often u
s
h
ow they actu
a
h
itecture and
during the c
o
f
ficiency of
h
g
, reused or
r
p
ower), rain
w
control stor
m
e
meaning of
t
e
future. Rig
h
a
ndards ment
i
n
g syste
m
d
a
rgest singl
e
i
d overhea
t
n
g and co
o
f
10 eleme
n
d. Trombe w
a
i
. water/air c
o
m
ption with
e methods
,
low-ener
g
n
the energ
y
m
ost cost
e
p
roposed,
s
u
re in the 1
9
s
e
14
has
b
e
c
o
nstrated en
any active
p
c
hnologies or
s
that mecha
n
v
haus standar
d
The designs
o
ling systems
,
e
nere” i.e.
s
u
s
g
reen building
s
ed interchan
g
a
lly function
i
attempts to r
o
nstruction p
r
h
eating and
c
r
ecycled buil
d
w
ater harvesti
n
m
water run-o
ff
t
he ter
m
“lo
w
h
t now, it is
g
i
oned below
f
d
esign is a
p
e
energy dr
t
ing. Howe
v
o
ling contr
o
n
ts using th
e
a
ll, e. fore-bu
i
o
llectors with
low energ
y
to reduce
g
y houses,
P
y
efficienc
y
e
ffective e
n
s
everal pas
9
80s and ec
o
c
ome a ne
w
ergy consu
m
p
ower gen
e
design featur
e
n
ical compon
e
d
for energy-
u
include pass
i
,
solar water
h
s
(under) + t
e
” (or “green
a
g
eably to rela
t
i
n regard to s
u
educe the co
l
r
ocess, as w
e
c
ooling syste
m
d
ing material
s
n
g for gardeni
n
ff
.
w
-energy hous
e
g
enerally con
s
f
or space heat
i
４
p
rimary fo
c
ains in buil
d
v
er, in cli
m
o
l is diffic
u
e
solar ener
g
i
lding of glas
s
heat exchang
e
p
y
control or
s
GHG em
i
P
assive Ho
u
y
of new
a
n
vironment
a
sive meth
o
o
logical/gr
e
w
paradigm
m
ption red
u
e
ration syst
e
e
s used to co
o
e
nts like pum
p
u
se in buildin
i
ve solar des
i
h
eaters, insul
a
e
nere (to hol
d
a
rchitecture”,
t
e to any buil
d
u
ch goals. Sus
t
l
lective envir
o
e
ll as during
m
s, alternativ
e
s
, on-site po
w
n
g and washi
n
e
(Niedrigen
e
s
idered to be
i
ng, typically
c
us for sust
a
d
ings. In w
a
m
ates with
f
u
lt to plan
d
g
y from pas
s
s
, f. mechanic
s
e
r, j. high-eff
i
p
hotovoltaic,
h
s
witching t
o
i
ssions fro
m
u
se
12
and s
u
a
nd existin
g
a
l solution
.
o
ds for de
s
e
en design
a
for the 21
u
ctions of
7
e
ms.
o
l buildings n
a
p
s and fans a
r
gs. It results
i
i
gn, high effi
c
a
tion material
s
d
); to keep in
“eco-design”
,
d
ing designed
w
t
ainable archi
t
o
nmental im
p
the lifecycle
e
energy sou
r
w
er generatio
n
n
g, and on-sit
e
e
rgiehaus)” h
a
one that use
in the range
3
a
inable arc
h
a
rmer clim
a
f
our season
s
d
irectly wi
t
s
ive to acti
v
s
in a ~ e, g.
a
i
cient collecto
r
h
eat pumps et
c
o
low carbo
m
b
uilding
u
stainable
a
g
buildings,
.
Since th
e
s
igns had
a
nd sustain
a
st century
b
7
0% to 90
%
a
turally.
r
e not used.
P
i
n low-energ
y
c
iency lighti
n
s
and techniq
u
existence; to
,
or “design f
o
w
ith environ
m
t
ecture ap
p
lie
s
p
acts during t
h
of the buil
d
r
ces such as
p
n
(solar techn
o
e
waste mana
g
a
s changed o
v
s around hal
f
3
0~20 kWh
m
h
itecture be
a
tes, passiv
e
s
such as
S
t
hout usin
g
v
e level,
a. s
o
a
dditional
s
to
r
r
s (e.g. vacuu
c
. in a ~ i [G
o
n fuels and
g
s. With a
d
a
rchitecture
1
to achiev
e
e
1970s,
w
b
een deve
a
ble archite
c
b
y high te
c
%
in many l
o
P
assive house
y
houses that
n
g and appli
a
u
es.
maintain or
p
o
r environme
n
m
ental goals i
n
s
techniques
o
h
e productio
n
d
ing. This de
s
p
assive solar
,
o
logy, groun
d
g
ement such a
v
er time, and
w
f
of the Ger
m
m
-2year-1.
cause they
e
cooling
11
S
. Korea, a
g
computer
o
uth window,
r
age in a ~ e,
m
collector),
o
nzalo 1994].
renewable
d
vances in
1
3
concepts
e
the most
w
hen solar
loped e.g.
c
ture in the
c
hnologies.
o
cations of
refers to the
require little
a
nces, highly
p
rolong, it is
n
t”). The two
n
mind, often
o
f sustainable
n
of building
s
ign practice
,
appropriate
d
source heat
s green roofs
w
ill certainly
m
an & Swiss
５
1.2. Need for energy simulation
Increased living standards in the developed world have increased energy consumption in the building
sector. According to reports of Santamouris and Asimakopoulos (1996), the total number of world
cooling units is more than 240 million. The reports also represent that the cooling units consume 15% of
world electricity. In S. Korea, the number of houses which have an electric air conditioner or fans has
rapidly increased and the electric consumption per person has greatly jumped from 4006 kWh person-1
in 1996 to 7191 kWh person-1 in 2006. 15 The balance between energy conservation and the distributed
point-of-use generation of renewable energy e.g. solar energy and wind energy etc. is a key factor to
achieve energy-saving in the building sector. The design significantly departs from conventional
construction practice and the energy consumption can be reduced by an appropriate passive design. For
example, in hot and dry climates, e.g. Mediterranean, solar protection can reduce 20% of the cooling
loads and air conditioning can be completely avoided since the internal heat gains are not important.
However, energy-saving in a largely varying climate is often seen for architects to be too complex or
too time consuming. A largely varying climate in S. Korea (i.e. cold and dry in winter, hot and humid in
summer) requires consideration of both heat gain and heat loss. For example, passive solar design gives
some heating gain in cold winter, but the heating gain makes the condition uncomfortable in hot
summer.
Korean climate16 is cold and dry during winter and extremely hot and humid in summer. The southern
regions are classified as subtropical zone affected by warm ocean waters including the East Korea
Warm Current. Fig.1.3-a shows the climate zones in S. Korea. The entire Korean peninsula is
influenced by the East Asian monsoon in midsummer and the frequent incidence of typhoons in autumn.
The majority of rainfall takes place during the summer months, with nearly half during the monsoon
alone. During the spring and fall seasons, the movement of high atmospheric pressures brings clear and
dry weather to the peninsula. The graphs shown in Fig.1.3-b are the local temperature and rainfall. The
yearly average temperature ranges 6℃ to 16℃ with a relatively high temperature variance throughout
the regions and the average temperature across the peninsula, with the exception of the mountainous
areas, ranges 10℃ to 16℃. In August, which is considered to be the hottest month of the year, the
average temperature ranges 26℃ to 32℃ whereas in January, which is considered to be the coldest
month of the year, it falls below freezing between -6℃ to -7℃. In this climate, the thermal interactions
between a building and its external environment are complex. To account for the complexities of the
energy transfer processes occurring between inside and outside and among its various components and
15 Korea Electric Power Corporation 2007.
16 See chapter 6.3.
sy
de
F
o
b
e
ar
c
o
p
d
u
he
o
p
Cl
a
n
17
T
18
T
f
ste
m
s, co
m
veloped.
or
a long ter
m
much hig
h
c
hitecture,
p
timization
o
u
ring the de
s
ating, cool
i
p
erate this e
q
Fi
g
ure 1
.
imate is an
n
alyzes cli
m
T
he US depar
t
T
he phrase “
b
f
rom the larg
e
m
puter simu
l
m
consider
i
h
e
r
than bui
l
for determ
i
o
f building
s
ign proces
s
i
ng and ven
t
q
uipment.
a. Clim
a
.
3.
Climate
environme
n
m
ate data t
o
t
ment of ener
g
uilt environ
m
e
-scale civic s
u
l
ation soft
w
i
ng environ
m
l
ding const
r
i
ning com
p
componen
t
s
. Energy s
i
t
ilation loa
d
a
te zones
of local re
g
n
tal factor
a
o
provide
gy
2007a.
m
en
t
” refers to
u
rroundings t
o
w
are e.g. D
O
m
ent, main
t
r
uction cost
s
p
liance wit
h
t
s. There ar
e
i
mulation a
t
d
s within a
b
g
ions in S.
K
a
ffecting ar
c
compleme
n
the man-ma
d
o
the persona
l
６
O
E-2, BL
A
t
enance an
d
s
. Hence,
bu
h
b
uilding
e
various e
c
t
tempts to
a
b
uilding, t
h
b. The te
m
K
orea
[S.H.
L
c
hitecture a
n
n
tary infor
m
d
e surroundin
g
l
places.
A
ST, TRNS
Y
d
energy co
s
u
ilding ene
r
standards
a
onomic co
n
a
ccount for
a
h
e equipme
n
m
peratures a
n
L
ee et al. 200
5
n
d its built
e
m
ation abo
u
g
s that provid
e
Y
S and En
e
s
ts etc., the
t
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gy simulat
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a
nd for the
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sequences
a
lot of fact
o
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t types an
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d rainfalls o
f
5
, Britannica
E
e
nvironmen
t
u
t the ene
r
e
the setting f
o
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rgyPlus (
E
t
otal
b
uildi
n
i
on is used
a
long term
of the deci
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rs in deter
m
d
sizes, and
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several citie
s
E
ncyclopaedi
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t
.
18
Energy
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r human acti
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P)
17
have
n
g cost will
a
s a tool in
economic
s
ions made
m
ining the
the cost to
s
a
2004].
simulation
m
ance and
v
ity, ranging
７
accurate comfort prediction. Energy simulation software can predict the energy performance of a
building with both passive designs and active building envelopes. However, the programs are based on
the zonal approach in an attempt to reduce computation time and complexity. The zonal approach
breaks down the object into zones, where each zone is considered to be in a thermal state. However, this
method is unable to give an accurate and detail prediction result since the real thermal state of a zone is
not uniform. The Computational Fluid Dynamics (CFD) approach is the quantitative process of
modeling fluid flows by the numerical solution of governing partial differential equations or other
mathematical equations of motion mass, and enthalpy conservation. The CFD approach uses
realistically representative of the true 3D environment with non-uniform energy distributions. 3D space
is divided into grids, where each node on the grid is given an initial value for different environmental
parameters. This approach represents thermo- and aerodynamic movements and more accurately than
the zonal approach. For this reason, there is a need to spend a lot more time and effort in simulation
preparation.
1.3. Research objective
A problem with energy simulation tools is that climate data is not on the scale of individual buildings.
General climate data of a region are generated by a weather station which is located across several
hundred kilometers. The simulation tools generally assume isothermal condition19 in a building zone
and set up the zones to utilize such large-scale climate data for the building energy analysis and comfort
prediction. However, a building can be placed in a local atmospheric zone where the climate differs
from the surrounding area. Such a local climate with small-scale atmospheric phenomena is called
“microclimate”. Fig.1.4 (a) shows four different climate scales i.e. micro-, local-, meso- and
macroclimate. A small area such as a garden or courtyard can have several different microclimates
depending on how much sunlight, shade, or exposure to the wind there is at a particular spot.
Microclimate within a given area is usually influenced by hills, hollows, geometric structures or
proximity to bodies of water.
Microclimate is strongly related to energy balance which is a systematic presentation of energy flows
and transformations. When energy source is concentrated at a particular spot, the energy is continuously
moved from an area of high concentration to an area of low concentration in a given volume. Similarly,
microclimate around the building can be modified by the environment and even by architect’s designs.
Microclimate is important because it can alter the building’s energy efficiency. The building thermal
condition can be modified by energy gains, leakages and distributions related to energy balance. In this
19 Zonal energy simulation methods use Finite Volume Method (FVM) which has a single node with an average temperature
value for each zone. A zone is considered as an iso-thermal condition with the average temperature.
Fi
g
st
u
co
A
i
e
n
pr
e
th
r
m
i
H
o
w
i
zo
ge
a
n
a
v
a
n
su
r
th
e
co
m
a
sp
a
m
i
la
r
R
e
-
-
-
g
ure 1.4.
C
u
dy, a nov
e
mbination
o
i
r temperat
u
n
ergy since
i
e
cipitation,
r
ough the
a
i
croclimate
o
wever, it i
s
i
th aggrega
t
nes is used
t
neral and l
a
n
d aerodyn
a
v
erage temp
n
d outside i
s
r
face elem
e
e
rmal cont
e
mbination
a
croclimat
e
a
tial varia
n
i
croclimate
r
ge area, w
h
e
search obj
e
Investigati
Extension
Establish
m
(a)
C
limate scal
e
e
l design
m
o
f zonal an
d
u
re is the
m
i
t is a meas
u
humidity
a
a
ir. Temper
a
in the stru
c
s
very diffi
c
t
ed walls an
d
t
o predict i
n
a
rge-scale c
l
a
mic flows
erature, w
h
s
inte
r
-spac
e
nts of eac
h
e
nt. Energ
y
of zonal
e
to microc
l
n
ces in th
e
in a buildi
n
h
ich are dis
t
e
ctive is su
m
on for nov
e
of the exist
m
ent of mic
r
e
s, (a) time
m
ethod wh
i
d
CFD met
h
m
ost impor
t
u
re of ther
m
a
nd wind s
p
a
ture can b
c
tures and
s
c
ult to pred
i
d
volumes
o
n
itial therm
a
l
imate data
related to
e
h
ich are the
e ventilati
o
h
room ha
v
y
balance
and CFD
l
imate. Mi
c
e
planning
n
g simulati
o
t
inguished
f
m
marized a
e
l and adva
n
ing energy
r
oclimate f
a
and distan
c
i
ch consid
e
h
ods is em
p
t
ant to pre
d
m
al content
i
p
eed and ai
r
e used as
a
s
paces e.g.
w
i
ct accurate
o
f a buildin
g
a
l state. Th
e
and differe
n
e
nergy bal
a
microclim
a
o
n which is
v
e differen
t
between a
methods
a
c
roclimate
a
. Fig.1.4
(
o
n and mac
r
f
rom the m
i
s
n
ced energ
y
simulation
s
a
ctors influ
e
８
c
e scales, (
b
e
rs microcl
p
loyed for e
n
d
ict for hu
m
i
n the air.
A
r
pressure
w
a
tracer to
d
w
alls, roof
s
air temper
a
g
. A zonal
m
e
average ai
r
n
t temperat
u
a
nce. CFD
a
a
te effects.
affected b
y
t
physical
p
djacent ro
o
a
cts a hie
r
a
nalysis in
(
b) illustra
t
r
oclimate
m
i
croclimate.
y
-saving m
e
s
, which co
n
e
ncing the l
o
b
) macro- a
n
imate for
t
n
ergy simu
l
m
an comfo
r
A
ir tempera
t
w
hich signi
f
d
etect the s
p
s
, windows,
a
ture in the
c
m
ethod whi
c
r
temperatu
r
u
res betwe
e
a
nalysis pr
e
Thermal v
a
y
different
h
p
roperties
a
o
ms gener
a
r
archical a
n
this study
t
es the re
l
m
eans gener
a
e
thods in a
h
n
si
d
ers mic
r
o
w-energy
h
(b)
n
d microcli
m
t
he energy
-
l
ation of th
e
r
t and to d
e
t
ure is mad
e
f
icantly inf
l
p
atial and t
doors, co
u
c
omplex m
o
c
h divided t
h
r
e of each z
e
n adjacent
z
e
dicts vari
a
a
riation bet
w
h
eight-to-
w
a
s well as
a
tes therm
o
n
d multi-s
c
enables to
l
ationship
b
a
l large-sca
h
ouse desig
n
r
oclimate a
r
h
ouse.
m
ate
[Oke 1
9
-
saving is
s
e
building.
e
termine t
h
e
by a joint
e
l
uences he
a
emporal v
a
u
rtyard and
o
rphologic
a
h
e structur
e
one is esti
m
z
ones deri
v
a
nces from
w
een the b
u
w
idth room
r
different e
x
o
dynamic
f
c
ale predi
c
predict te
m
b
etween
m
le climate
d
n
r
ound a ho
u
9
87, author].
s
tudied. A
h
e building
e
ffect with
a
t transport
a
riations of
rooms etc.
a
l structure
e
into small
m
ated using
v
es thermo-
the zone’s
u
ilding in-
r
atios. The
x
posure to
f
low. This
c
tion from
m
poral and
m
acro- and
d
ata for the
u
se
９
- Quantitative analysis and evaluation of the factors
To achieve the microclimate energy-saving, design elements are considered by following questions:
- What is the building microclimate?
- Which microclimate phenomena will be considerable for energy-saving in buildings?
- Why does a complex Passive House need energy simulation?
- What is missing in previous energy simulation for complex Passive House designs?
- What is the method of energy simulation?
- How can microclimate effects be analyzed?
- Is architectural design considering microclimate efficient?
This study evaluates the indoor comfort problem in a real house model and tries to improve the human
comfort condition without large energy requirements. A certain number of hypotheses are set out using
common knowledge for Passive House designs:
- West orientation of the building façade is not sufficient for assuring good thermal insulation for
whole houses in slope topography.
- Elimination of shading devices from the façade dramatically affects increasing heat entering through
the windows into the house.
- Bad insulation is partly responsible for the lack of convenient thermal comfort in the house.
- Microclimate effects can be often observed with the lack of thermal comfort.
- A suitable microclimate design improves the energy efficiency of the house in some special climate.
1.4. Constraints
(1) In this study, influences of neighboring buildings are not considered since analysis of microclimate
in and around a building increases complexity. However, this consideration enables concentration on
the accuracy of the building analysis.
(2) This study assumes that the building site is a simple slope model without deformation. A simple
slope model is useful for architects to define several site conditions with topography and makes the
geometric analysis easy. Fig.1.5 shows a normal site condition with topography in S. Korea. In Seoul,
the percentage of slope areas for building reconstruction is amounted to 66.5%.20
20 Kang 1996.
１０
Figure 1.5. An example of S. Korean site set-up including slope areas.
(3) Only 0˚ to 19˚ slopes are considered. According to data of Ministry of Construction and
Transportation (MOCT) of S. Korea, only 32.5% of the land is flat with 0˚ to 9˚ slopes which a normal
or flatland design can be applied. 10˚ to 29˚ slopes are possible to be developed by slope design.
However, slopes above 30˚ are impossible to be used for building sites. In S. Korea, 10˚ to 29˚ slopes
make up 53.2% of the total land. Within these angles, a lot of slope and flatland designs are mixed.
Above 20˚, totally different forms from flatland designs should be considered. 21
(4) This study targets high density housing in S. Korea. It is strongly related to a ratio between the
population and the total habitable land. The population of S. Korea is 48 million people, which are
about 60% of 82.43 million in Germany. The habitable land in Seoul is 606km2 and the population is
10.35 million people. The population density (people m-2) of S. Korea is 17.994, which is lower than
20.246 of Paris but higher than 13.657 of Tokyo, 9.475 of New York City and 2.093 of Hong Kong.22
(5) The study target is a detached dwelling. About 80% of residences in Seoul were detached dwellings
before the 1970s;23 developments from the detached dwellings to high rise apartments have decreased
living quality and made several environmental problems. Recently, the percentage of high rise
apartments in Seoul is 55.2% and detached dwellings and apartment units are respectively 22.8% and
17.3%. It was caused by development policy during the 1970s and the 1990s to solve the population
explosion of Seoul after the rapid industrialization. However, it is clear that an innovative design to
improve the living quality and the economic attraction for the choice of a future detached dwelling or to
propagate the low storey and high density houses widely is a continuing solution to reform the problems
of prevailing high rise apartments progressively.
In the last 15 years, an apartment is seen as an investment, with large profit margins. In recent years, the
S. Korean government policy which bans the large profits is in operation. 64% of old age people in S.
21 H.J. Kim 2001.
22 Seoul Statistical Yearbook 2007.
23 Seoul Statistical Yearbook 2007.
１１
Korea are living in detached dwellings and only 17.3% in apartments. The fact suggests that the fashion
of apartments was not for living but for profit. If no profit will be expected in the future real estate
market by efforts by the S. Korean government, actual demands will pursue the living quality or to
prepare for old age. A form of detached dwelling or the low storey and high density house in S. Korea
which are built by environmentally friendly and “well-being” concepts may be expected to be popular.
The goal of this study is to expand them and for this reason, a residence model in one suburb of Seoul
has been chosen.
1.5. Structure of thesis
Chapter 2 introduces heating and cooling in Passive House designs in various climates and the
importance of energy-saving in the designs. Advanced Passive House design methods use energy
simulation which predicts energy gain, loss and distribution of building sectors in the design procedure.
This chapter describes common physical bases in energy simulation methods.
Many aspects for an energy-saving house which can be considered for the climate response, but not all
of them can be useful for the climate. Heating and cooling in a passive design are not always efficient
for human comfort, and additional energy should be input to try to correct the climate, actively.
Therefore, it is important to establish at the early stage which elements in passive design cause the
problems. Hence, the next chapter describes the energy-saving issues and the ill-posed problems of the
existing passive designs. Energy-saving which is developed in this study is obtained by advanced
design with computer simulation which can measure thermo- and aerodynamic variations by
microclimate in the design.
Passive and dynamic control of microclimate is helpful to accomplish the energy efficiency in the
building. Chapter 3 gives the details of the high-performance novel design with microclimate
energy-saving methods including dynamic flow controls. It includes issues of site planning and general
concepts for building forms and the elements to modify the flow as well. The method can predict energy
details, distributions, gains and losses in the thermo- and aerodynamic phenomena in building sectors.
The simulation result enables to provide detail information about the energy usage and leakage in the
zones. The method plays an important role in determining the overall efficiency of a complex
architectural design with an early consideration that can be a great benefit. For example, when the
methods are applied in a difficult mixed climate i.e. seasonally hot-humid and cold-dry, it makes the
appropriate decision of an architectural design easier and economical. The numerical simulation is used
to analyze microclimate effects by several design elements.
１２
In chapter 4, a novel simulation model combining multi-zone and CFD energy simulations is introduced
for the analysis of energy-saving aspects in passive and microclimate design elements. The multi-zone
model generally uses a parameterization method to simplify the energy-saving problem for each space
in a building. However, the model is not appropriate to handle the dynamic energy variations since it
calculates the averages for each zone volume. On the contrary, the CFD method using subdivided grid
units is more suitable for the microclimate analysis. However, the main difficulty of CFD is the
convergence of the problem with the solution. These problems can be solved by a multi-scale hybrid
method combining the multi-zone and the CFD models. The several climate scales can be a volume and
the subdivision, which are adapted in units of the multi-scales.
A case study using a real Passive House model in the mixed climate of S. Korea is represented in
chapter 5 and 6. Energy-saving houses using general passive features are tested and evaluated in the
house model. The multi-zones are simulated to evaluate the energy performance of the passive designs.
If the microclimate method is tested, the difference of the energy usages can be compared by a
quantitative analysis. The comparison between one of the most famous multi-zone energy simulation
tools EnergyPlus (EP) and the simulation of microclimate energy-saving model in this study are
evaluated to prove the efficiency of the novel method.
The Conclusions and the future study are represented in chapter 7. This method can be utilized to bring
about valuation items in microclimate phenomena to accomplish the energy-saving and the prediction
possibility.
１３
Research flowchart
１４
2. Energy-saving and climate in the
Passive House
2.1. Energy in Passive House
In the field of architecture, a lot of endeavors for energy-saving, prevention against pollution and
recycling resources were made, since 50% to 60% of the total energy in the world is used for building
and maintenance of architecture.24 Fig.2.1 shows the CO2 emissions scenario for the buildings sectors
of 10 world regions produced by IPCC (2007). There will be approximately 81% increase of total CO2
emissions from 8.6 GtCO2 emissions in 2004 to 15.6 GtCO2 emissions in 2030. This scenario shows a
range of increasing buildings related CO2 emissions. Especially most increases of CO2 emissions are
produced in the developing world: Developing Asia, Middle East and North Africa, Latin America and
sub-Saharan Africa, in that order. East Asia shows increase of more than 150%.
Figure 2.1. CO2 emissions for the buildings sector including electricity [The Intergovernmental Panel on
Climate Change (IPCC) 2007].
Realizing the low-energy houses require an integrated design process which involves architects,
engineers, contractors and clients, with full consideration of opportunities in reducing building energy
24 Economic Commission for Europe 1996.
１５
demands. A lot of European countries are promoting the construction and distribution of low-energy
buildings since the largest savings in energy-use can be obtained in new buildings through building
design and operating plan. An EU project called CEPHEUS (the Cost Efficient Passive Houses as
European Standards) is an example of the largest Passive House project which has built 221 houses25
using Passive House standards.
Passive house method focuses to accomplish energy-saving by architectural planning and modeling
with minimum or without a mechanical assistance. However, it needs a lot of expertise and solutions
because a Passive House design is composed of several thousand building components. Conservation of
energy in innovations of architectural design should be checked for correspondence the Passive House
Standard and the world’s premier test of energy efficiency. The following specifications have proven to
achieve the Passive House Standard:26
- Insulation value of the envelope must be under 0.15
W
m
-2
K
-1
.
- The external envelope must be constructed without thermal bridges.
- An air leakage test must be performed, and the air exchange result must not exceed 0.6times h-1
by over and under-pressurization tests with a pressure of 50Pa.
- Windows, i.e. frame and glazing, must have total U-values under 0.8
W
m
-2
K
-1
, and glazing must
have total solar energy transmittance of at least 50% to achieve heat gains in winter.
- Ventilation systems must be designed with the highest efficiency of heat recovery and have
minimal electricity consumption.
- A domestic hot water generation and distribution system with minimal heat losses should be used.
- It is essential to use highly efficient electrical appliances and lighting and total primary energy
consumption has to be below 120 kWh m-2year-1.
Since the 1970s as solar architecture was first proposed, more advanced ideas were developed for
Passive House: environmental architecture in the 1980s, ecological/green design and sustainable
architecture in the 1990s. Nowadays they are integrated in new paradigms for the 21st century including
high technologies, e.g. “Zero Energy Building” and “Green Building”. The methods additionally utilize
natural energy, life-cycle-cost and comfortability modeling etc. to improve the energy efficiency of
building and to suppress an increment in entropy leading to a disordered state of energy. Green space or
Biotope can be also considered to recover the ecological balance. However, one of the most important
factors is the improvement in the heating and cooling consumption for the economic feasibility of these
technologies.
Ulseth et al. (1999) estimated the expected development of the heating and the cooling consumption in
25 Feist et al. 2001.
i.e. 84 houses were in Austria, 72 in Germany, 40 in France, 20 in Sweden and 5 in Switzerland.
26 Feist et al. 2001.
a
f
a
n
bu
2
0
S.
o
n
co
e
n
co
to
co
e
n
he
2.
H
u
sa
t
co
sli
su
r
b
e
e
n
te
m
ge
h
u
f
uture build
i
n
d cooling l
o
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ilding in 1
9
0
05. The si
m
K
orea, an
d
n
the nation
a
oling ener
g
n
ergy consu
m
oling energ
be energy
ntribute to
n
ergy-savin
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lping to pr
o
Fi
g
u
r
2. Hum
a
u
man com
fo
t
isfie
d
wit
h
nditions fo
r
ght tempe
r
r
roundings
determin
e
n
vironment.
m
perature i
nerally co
n
u
midity and
i
ng stoc
k
by
o
ads and th
e
9
90, and co
m
m
ulation ass
d
the local c
l
a
l building
c
g
y consump
t
m
ption was
y consump
t
efficient i
achieving
e
g
factors. E
o
duce low
e
a.
H
r
e 2.2. Ene
r
a
n comf
o
fo
rt may be
h
the com
fo
r
themselv
e
r
ature chan
through th
e
e
d by stea
d
The huma
n
s varying
w
n
trolled by
airflow. H
o
y
comparin
g
e
energy co
m
pared the
umed typic
l
imate data
c
odes in res
t
ions in res
i
50 kWh m
-
t
ion was in
c
s difficult
e
nergy-sav
i
ach of the
f
e
nergy
b
uil
d
H
eating
r
gy consu
m
o
rt fact
o
the most
i
fo
rt conditi
o
e
s. The hu
m
ge in the
e
rmodynam
i
d
y-state he
a
n
comfort l
e
w
ith inflow
s
four maj
o
o
wever, it i
s
g
to today.
F
nsumption
loads and
e
al climate s
are based
o
pective co
u
i
dential sec
t
-
2
year
-1
in 1
9
c
reased fro
m
without u
n
i
ng. Hence
,
f
ollowing
c
d
ings.
m
ption in re
s
o
r
i
mportant a
o
n of the
b
m
an body h
a
environme
n
i
c mechani
s
a
t transfer
e
vel can
b
e
s
and outfl
o
o
r factors:
a
s
clear that
h
１６
F
or the pur
p
of a “typic
a
e
nergy cons
u
ituations o
f
o
n a standa
r
u
ntries. Fig.
2
t
ors of the
c
9
90 and 44
%
m
25 kWh
m
n
derstan
d
in
g
,
the follo
w
c
hapte
r
s int
r
s
idential se
c
spect of e
n
b
uilding, t
h
a
s a comple
x
n
t. Human
sm
s such as
and the e
n
also affect
e
o
ws. In en
e
a
ir temper
a
h
uman co
m
p
ose, a sim
u
a
l” office b
u
u
mption to
f
4 countrie
s
r
dized “refe
r
2
.2 represe
n
c
ountries. I
n
%
lower th
a
m
-2
to 35 kW
g
the relati
v
w
ing chapte
r
r
oduces so
m
b.
C
c
to
r
s of so
m
n
ergy cons
u
h
ey consu
m
x
thermod
y
skin is al
w
radiation,
c
n
ergy bala
n
e
d by air m
o
e
rgy simul
a
a
ture, Mea
n
m
fort is a ve
r
u
lation tool
u
ilding and
an expecte
d
s
; No
r
way,
F
r
ence year
”
n
ts the com
p
n
the case o
f
a
n 28 kWh
m
h m
-2
year
-1
v
e importa
n
r
s focus o
n
m
e element
s
C
ooling
m
e cities
[Ul
s
u
mption. If
m
e more e
n
y
namic mec
w
ays exch
a
c
onduction
n
ce
b
etwe
e
o
tion in bu
i
a
tion studie
s
n
Radiant
r
y complex
calculated
t
a “typical”
d
“typical”
b
F
inland, Ge
”
. Building
s
p
arison of
h
f
S. Korea,
t
m
-2
year
-1
in
2
. Designin
g
n
ce of fac
t
n
setting o
u
s
and their
s
eth et al. 199
9
the occupi
e
n
ergy to
m
hanism sus
a
nging hea
t
and convec
t
e
n the bo
d
i
lding wher
e
s
, building
Temperatu
r
issue for d
e
t
he heating
residential
b
uilding in
rmany and
s
are based
h
eating and
t
he heating
2
005. 40%
g
a building
t
o
r
s which
u
t effective
features in
9
].
e
rs are not
m
ake better
ceptible to
t
with the
t
ion. It can
d
y and the
e
the room
comfort is
r
e (MRT),
e
cisions on
１７
building design policy since there is always a likelihood of some mismatch between the design intention
and the real human perception. The relationship between the factors and comfort is not necessarily
additive and practically never linear. Temperature and humidity largely affect human comfort more
than other factors, and thereby understanding these factors is very important. Psychometric measures
such as Givoni chart, Mahoney table and PMV (Predicted Mean Vote) etc. are studied for this purpose.
2.2.1. Psychometric comfort scale
Climate is a key factor for building design and it influences on the effectiveness of social activity,
human comfort, health, physical resource and energy-use etc. Psychometric comfort scale is used to
indicate measures of effectiveness, and the psychometric chart provides a graphic representation of the
comfort state and the climate at a location. The most famous psychometric measures are the Givoni
chart,27 Mahoney diagram28 and PMV. Psychometric comfort measures can be used to make building
design policy. For example, if temperature and humidity are outside of the comfort zone, ventilation
and dehumidification should be considered in building design.
Fig.2.3 shows the Givoni chart for the climate of S. Korea. The horizontal and vertical axes of the chart
respectively indicate temperature scale and moisture scale. The air temperature represented by the
horizontal axis of the chart is known as the dry bulb temperature. The vertical axis is known by a
number of names, such as specific humidity, absolute humidity and humidity ratio. They all represent
the same measure: the amount of water by weight in the air.29 If the temperature of the air is decreased
to the point at which it can hold no more moisture, the air becomes saturated. The corresponding
temperature is called “dew point”. When the air is cooled to the dew point, it is at 100% relative
humidity (RH). This saturation point is represented by the outer, curved boundary of the chart. The
brightness in the graph represents the frequency of days corresponding to the value. In Fig.2.3, the
seasonal climate of Korea can be estimated, and a lot of hot and humid days in summer and cold and dry
days in winter make uncomfortable conditions. The square area in the chart represents the psychometric
comfort condition. The Mahoney diagram30 offers a lot of design recommendations, e.g. layout,
spacing, air movement, openings, walls, roofs, protection from rain, size of opening, position of
openings, protection of openings, walls, floors, roofs and external features etc., for human comfort by
analyzing the Givoni chart. However, the Givoni chart and the Mahoney diagram are often not exact in
27 Givoni chart is also called psychometric chart.
28 Daoudi 2002.
29 The units often can be given by the moisture scale, which is represented by two other names: vapor pressure, which is the
partial pressure exerted by the moisture in the air, and dew point temperature which is an exponential temperature scale
representing the temperature at which moisture will begin to condense from a given unit of air.
30 Casey 2002.
m
e
te
m
w
i
Fi
g
T
o
ba
ba
P
h
R
a
in
d
3
7
ur
b
de
in
d
a
c
th
e
T
h
ve
31
H
32
M
T
33
w
e
asu
r
ing th
e
m
peratures
i
th solar ra
d
g
ure 2.3. P
o
solve the
a
lance to de
t
a
lance is
M
h
ysiologica
l
a
diant Tem
p
d
ices such
7
87).
32
Rec
e
b
an and reg
gree of dis
c
d
icate unco
m
c
ase study
33
e
paramete
r
h
ese param
e
ntilated cit
y
H
öppe 1993.
M
aye
r
and M
a
T
he German
V
w
ww.lohmey
e
e
real cond
i
arising fro
m
d
iant gain i
n
sychometri
c
problem,
p
t
ailed envir
o
M
unich En
e
l
ly Equival
e
p
erature (
M
as PET, S
t
e
ntly, PMV
ional clima
t
c
omfort acc
o
m
fortable f
e
for differe
n
r
s of wind,
e
ters deter
m
y
centers, e
f
a
tzarakis 199
9
V
DI-Guidelin
e
e
r.de/ai
r
-eia/c
i
tion of ho
w
m
detailed e
n
n
a cold wi
n
c
chart of S
p
hysiologi
c
o
nments w
e
e
rgy Bala
n
e
nt Tempe
r
M
RT) whic
h
t
andard Ef
f
is used fo
r
t
e which ar
e
o
rding to th
e
elings due
n
t designs
o
temperatur
e
m
ine the the
r
f
fects of th
e
9
.
e
3787,
VDI:
asestudies/
w
humans f
e
n
vironmen
t
n
ter may no
t
eoul [auth
o
c
ally relev
a
e
re establis
h
n
ce for In
d
r
ature (PE
T
h
is require
d
f
ective Te
m
r
the physi
o
e
based on t
e psycholo
g
to a hot se
n
o
f the plann
i
e
, humidit
y
r
mal comfo
r
e
air temper
Verein Deuts
c
１８
e
el
b
ecaus
e
t
s. For exa
m
t
be cold b
u
o
r]. Table
metabo
a
nt indices
h
ed.
31
A mo
d
ividuals (
M
T
). A final
o
d
in the en
e
m
perature (
S
o
logically r
e
he human
e
g
ical scales
n
sation. Zer
o
i
ng called “
S
y
and radiat
i
r
t in the co
m
ature and h
u
c
her Ingenieu
r
e
they do n
o
m
ple, the fel
t
u
t be warme
2.1. Ther
m
lite rate 80W
,
which are
del for the
t
M
EMI), w
h
o
utput of t
h
e
rgy balan
c
S
ET) and
P
e
levant eva
l
e
nergy bala
n
which are l
i
o
is the neu
t
S
tuttgart 21
i
on for 2 d
i
m
munity. In
u
midity ar
e
r
e/ German E
n
S
c
+
+
+
+
0
-
-
-
o
t consider
t
t
temperatu
r
r
than in re
a
m
al sensatio
n
,
0.9 clo [Ma
y
derived fr
o
t
hermal co
m
h
ich uses
t
h
e model i
s
c
e model f
o
P
redicted
M
l
uation of t
h
n
ce. The P
M
i
ste
d
in Ta
b
t
ral point, r
e
”, PMV an
d
i
fferent me
t
densely bu
i
e
also studi
e
n
gineering S
o
c
ale
S
+
3.5
+
2.5
+
1.5
Sl
i
+
0.5
Ne
0
.5
S
1.5
2.5
3.5
V
t
he narrow
e
r
e of a win
d
a
lity.
n
scale for
t
y
e
r
and Matza
r
o
m the hu
m
m
plex of hu
m
t
he assess
m
s
the calcu
l
o
r humans
a
M
ean Vote
(
h
ermal co
m
M
V index q
u
b
le 2.1. Neg
a
e
presenting
d
PET are d
e
t
eorologica
l
ilt up regio
n
e
d.
o
ciety.
S
ensation
Very hot
Hot
Warm
ightly warm
utral comfort
lightly cool
Cool
Cold
V
ery cold
e
r range of
d
ow façade
t
he PMV,
r
akis 1999].
m
an energ
y
m
an energ
y
m
ent inde
x
l
ated Mea
n
a
nd therma
l
(
PMV, IS
O
m
ponents o
f
u
antifies th
e
a
tive value
s
comfort. I
n
e
rive
d
fro
m
l
situations
.
n
s or poorl
y
y
y
x
n
l
O
f
e
s
n
m
.
y
１９
2.2.2. Comfort zone
A lot of statistical studies, which arrive at a quantitative description of human comfort, have been
performed on large numbers of subjects of all ages, sexes and nationalities. The results of these studies
provide a comfort zone with a relatively wide band of acceptability in which 80% of the population
experiences the sensation of thermal comfort. Psychometric charts can be used to show graphically the
condition of the comfort zone. However, only a few studies have attempted to express the additional
major comfort variables such as Mean Radiant Temperature (MRT) and air motion.
a. With a large cool window b. Without window
Figure 2.4. Actual temperature as perceived by a person and MRT [author].
The MRT of a space is really the measure of the combined effects of temperatures of surfaces within that
space. The MRT is the measure of all these surface areas and temperatures acting on a person’s location
in the room. Even in an environment with some differences between the air temperature and the surface
temperature of the walls, ceiling, windows and floor etc., a building zone which is well insulated and
does not have extensive glazing as Fig.2.4-b shows have small temperature differences between the air
and the surfaces. However, if there is a significant difference in the space as Fig.2.4-a represents, this
difference will affect the perception of comfort. For the center of a zone, each surface plays an equal part
in determining the average. However, if the person was sitting near a large window with a temperature of
10℃, the MRT would be in a region of 17℃. At the optimum level, the radiant exchange of the human
body with the surroundings can account for about 50% of the body’s ability to lose heat. Therefore, if
MRT is increased, the net radiant exchange from the body to the surroundings will decrease. Inversely, if
MRT is decreased, the net radiant exchange from the body to its surroundings will increase. This has
proven to be a very powerful passive building technique for both heating and cooling.
A large air motion across the skin can greatly increase the tolerance for higher temperature and
humidity levels. HVAC studies by Fanger (1870) showed that at least 28℃, a very large air velocity of
91.44m min-1 across the skin can maintain the human comfort even in 100% relative humidity. Ceiling
２０
fans were used to produce this air motion. At below 50% relative humidity (RH), much higher
temperatures up to 32℃ are also comfortable at this air velocity. Air motion across the skin
accomplishes cooling through both convective and latent energy, i.e. evaporation of perspiration from
the skin transfers. Since skin temperatures are relatively high, even 32℃ air temperatures can carry off
some excess heat. Additionally, at high RH, near or at 100%, if dry bulb air temperatures are lower than
skin temperatures, evaporation from the skin will occur. By the use of materials capable of storing
relatively large amounts of thermal energy, e.g. concrete and masonry products, water, and Phase
Change Materials (PCMs) etc. heat collection and rejection techniques can be effectively applied to
Passive Houses. The studies of the comfort zone in effective design were provided by Givoni (1994).
By architectural design with thermal mass and ventilation, various building zones based on exterior
climate can have additional comfort producing potentials. A research of Loxsom and Clarke (1980)
indicated that radiative night cooling in conjunction with thermal mass and air motion can extend the
results of Givoni.
2.3. Aerodynamic and energy contents
The psychometric measures are important since the total energy in temperature and vapor content (i.e.
energy content) of building air can be calculated.34 The total air energy is achieved by the sum of both
the temperature content and vaporized moisture content. The temperature content is physically called
“sensible heat”.35 The moisture content is called “latent energy” since the vapor in the air represents
approximately 334 kJ kg-1 of latent heat energy. Normally, the humidity of the air is not generally
regarded as being important since the humidity percentage usually ranges from about the mid 30s to the
upper 60s and occupants are quite able to tolerate this range.36 However, if the humidity is in the upper
60s along with high air temperatures and very little air movement this may give rise to a larger
proportion of the occupants feeling uncomfortable.
The sum of the latent energy and the sensible heat is called the air enthalpy (kJ kg-1). Air at 0℃ and 0%
RH is assumed, by convection, to have an enthalpy of 0 and is used as the base for the enthalpy scale. In
34 Fairey 1994.
35 Sensible heat is potential energy in the form of thermal energy or heat. The thermal body must have a temperature higher
than its surroundings. The thermal energy can be transported via conduction, convection, radiation or by a combination
thereof. The quantity or magnitude of the sensible heat is the product of the body’s mass, its specific heat capacity and its
temperature above a reference temperature. A transport of heat from a warm area to a cold area is affected by the sensible
heat in the form of warm air moving toward the cold air, and by latent heat as cold air moving toward the warm area.
36 Ward 2004.
Fig.2.5 (a
)
temperatu
r
air. The hi
g
be used fo
r
refrigerati
o
modify de
s
Figure 2.
5
range of e
n
The wet b
u
bulb enca
s
surface of
cools the
w
of moistu
r
theoretical
temperatu
r
air-stream.
This is als
relative h
u
climates, t
h
the sensib
l
the air), a
n
The other
m
evaporativ
such a dis
c
37 a~b zone:
metabolis
m
temperatu
r
)
, the lines
r
e that can
b
g
her the w
e
r
numerical
o
n and air c
s
igns to ma
i
(a)
5
. Relations
h
n
vironmen
t
u
lb tempera
t
s
ed in a we
t
the wick a
n
w
ick and th
e
r
e which t
h
ly, not coo
l
r
e between
t
o the meth
o
u
midity lev
h
e evaporat
i
l
e heat of t
h
n
d the air is
m
echanism
e cooling o
f
c
omfort hu
m
hypothermia,
m
, e~f zone: h
y
r
e, d: tempera
t
of constan
t
b
e simply m
e
e
t bulb tem
p
calculation
s
onditionin
g
i
ntain ther
m
h
ip betwee
n
t
al tempera
t
t
ure can be
r
t
ted wick t
h
nd
wet bulb
e
sensing
bu
h
e air-stre
a
l
the wette
d
t
he wet an
d
o
d by whic
h
els have s
u
i
ve principl
h
e ai
r
(i.e. t
e
thereby co
o
is by conv
e
f
the skin is
m
idity level
,
b~e zone: th
e
y
perthermia,
b
t
ure of marke
d
t
air entha
l
e
asure
d
by
a
p
erature, th
e
s
of the ene
r
g
. Through
u
m
al comfort
n
body tem
p
t
ures,
deep-b
r
ather easil
y
h
at is subje
c
causes mo
i
u
lb by an a
m
am
is cap
a
d
bulb by a
d
dry
b
ulb t
h
h
evaporat
i
u
ch great i
m
e can be us
e
e
mperature
o
le
d
along
a
e
ctive cool
i
reduced an
d
,
one way t
o
e
rmoregulatio
n
b
: temperatur
e
d
increase in
e
２１
l
py
37
follo
w
a
relatively
e
greater th
e
r
gy require
d
u
nderstandi
.
p
erature an
d
ody temperat
u
y
measure
d
c
ted to ai
r
m
i
sture to ev
a
m
ount whic
h
a
ble of ab
s
substantial
h
ermomete
r
i
ve cooling
m
port on t
h
e
d to advan
t
content in
t
a
line of co
n
i
ng using ai
d
eventuall
y
o
help the e
v
n
, c~d zone:
l
e
of summit
m
e
vaporative l
o
w
almost ex
accurate m
e
e
energy co
n
d
to change
ng this pro
c
(b)
d
the energ
y
u
re
T
b
,
(b) t
h
by a stand
a
m
otion acr
o
a
porate fro
m
h
is directly
p
s
orbing. In
amount. T
h
r
s, the lowe
r
of the ski
n
h
e body’s
a
t
age to cool
t
he air) wit
h
n
stant wet
b
r
velocity.
A
y
ceases w
h
v
aporation
o
l
east thermor
e
m
etabolism an
o
ss, e: temper
a
actly the li
e
asurement
n
tent of the
the conditi
o
c
ess, it will
y
balance, (
a
h
e four mo
d
a
rd thermo
m
o
ss its surfa
m
the wick.
p
roportion
a
other wo
r
h
erefore, fo
r
r
moisture
a
n
occurs an
d
a
bility to
m
the air. Th
e
h
latent he
a
b
ulb temper
a
A
s the hum
h
en very hig
h
o
f sweat fr
o
e
gulatory effe
c
d incipient h
y
a
ture of incipi
ne of cons
t
of the heat
air. Hence
,
o
ns of the a
i
be easier t
o
a
) the com
p
d
es
[Oke 198
7
R
m
eter which
ce. Air mo
t
This evap
o
a
l to the add
r
ds, saturat
e
r
the greate
a
nd energy
c
d
is the ma
j
m
aintain co
e
swamp co
o
a
t (i.e. mois
t
a
tures.
idity of the
h
humidity
o
m the bod
y
c
t, c~e zone:
m
y
pothermia, c:
ent hyperther
m
t
ant wet b
u
content of t
h
,
enthalpy c
ir
e.g. heati
n
o
evaluate a
n
p
onents ove
r
7
, modified fr
o
R
osenlund 20
0
has its sens
t
ion across
o
ration pro
c
itional amo
u
e
d ai
r
wo
u
r differenc
e
c
ontent of
t
j
or reason
t
mfort. In
a
o
ler exchan
g
t
ure conten
t
air increas
e
is reached.
A
y
is to incre
a
m
inimal
critical
m
ia.
u
lb
h
e
an
n
g,
n
d
r
a
o
m
0
0].
ing
the
c
ess
u
nt
u
ld,
e
in
t
hat
t
hat
a
rid
g
es
t
in
e
s,
A
t
a
se
th
e
T
h
T
h
sp
e
m
o
2.
E
n
se
a
g
a
ac
c
o
p
ef
f
al
t
is
a
o
n
el
i
Si
n
gr
e
o
p
ra
t
co
ra
d
af
t
w
i
a
m
e
airflow r
a
h
e faste
r
th
e
h
e cross-ve
n
e
ed is too
h
o
des of ene
r
4. Desig
n
ergy-savin
g
a
sonal dem
a
a
in from th
e
c
ess. A typ
i
p
en to the s
u
f
ect when
c
t
itudes of s
u
a
lways mo
r
n
the east a
n
i
minated.
Figure 2.6
.
n
ce windo
w
e
ate
r
gain b
p
timized by
t
ios of 30
%
oling. The
o
d
iation earl
y
t
ernoon. A
c
i
ndow size
m
ount of lig
h
a
te over the
e
air passes
n
tilation of
h
igh then
w
r
gy balanc
e
n for e
n
g
in buildi
n
a
nd for ene
e
climate.
T
i
cal solar a
c
u
n is repre
s
c
onsidering
u
n in the m
o
r
e difficult t
n
d west fa
ç
.
Typical d
e
w
s allow th
e
ut also has
t
consideri
n
%
to 50% in
o
rientation
o
y
in the mo
r
c
losely rela
t
and shape.
h
t falling o
n
body. This
over the b
o
a
b
uilding
w
e feel a dr
a
e
in the hu
m
n
ergy ga
i
n
gs is close
l
rgy. The d
e
T
he
m
ost i
m
c
cess situat
i
s
ented in F
i
solar heati
o
rning and
e
o handle th
e
ç
ade is avo
i
e
sign appro
a
e
sun to pe
n
t
he greater
h
n
g the orie
n
the region
o
f the glazi
n
r
ning and
w
t
ed term to
g
This is a s
i
n
a particul
a
is convect
i
o
dy, the mo
r
is advanta
g
a
ught and i
f
m
an body.
i
n
l
y related t
o
e
mand for e
m
portant so
i
on where t
h
i
g.2.6. Lea
v
ng. The ea
s
e
vening. L
o
e
problem t
h
i
ded or the
a
ch when c
o
n
etrate or lo
h
eat loss. T
o
n
tation, loc
a
are genera
l
n
g should
b
w
arm the sp
a
g
lazing is t
h
i
mple ratio
b
a
r surface.
T
２２
i
ve cooling
r
e its abilit
y
g
eous to ge
t
f
too low,
w
o
the climat
nergy in a
P
urce of en
e
h
e southeas
t
v
ing open
t
s
t or west
f
o
w altitudes
h
an the hig
h
south faça
d
o
nsidering
s
se the heat
o
balance b
e
a
tion, obstr
u
l
ly accepte
d
b
e carefully
a
ce. West-f
a
h
e Daylight
b
etween th
e
T
he range
o
which is e
f
y
to remov
e
t
the highe
r
w
e feel stuf
f
e since the
P
assive Ho
u
e
rgy gain i
n
t
to the sou
t
t
he south f
a
f
açade is
m
of sun con
t
h
er altitude
d
e is shade
d
s
olar acces
s
to the outs
i
e
tween the
s
u
ctions an
d
d
for buildi
n
considered
.
a
cing wind
o
Factor (D
F
)
e
amounts
o
o
f the DF is
f
ficient in t
h
e
heat
b
y co
r
air velocit
y
f
y. Fig.2.5
(
designs sh
o
u
se is depe
n
n
passive d
e
t
hwest aspe
a
çade allo
w
m
ore suscep
t
t
ributes to
l
sun during
t
d
, the over
h
s
by G. Wa
t
Kentucky
D
i
de, the lar
g
s
e energy fl
o
d
user requ
i
n
gs which
d
.
East-facin
g
o
ws may ov
e
F
)
, which is
a
o
f light av
a
0~1. The
D
h
e subtropi
o
nvection is
y
. Howeve
r
(
b
) illustrat
e
o
uld be ada
p
n
dent upon
e
sign meth
o
cts of the b
u
w
s maximiz
a
t
ible to rec
e
l
ikely over
h
t
he midday
h
eating eff
e
t
rous in Ke
n
D
ivision of E
n
g
er window
o
ws, glazin
g
i
rements. T
h
d
o not use
m
g
windows
e
rheat the s
p
a
direct fun
c
a
ilable outs
i
D
F is made
u
cal region.
increased.
r
, if the air
e
s the four
p
ted to the
the energy
o
d is solar
u
ilding are
a
tion of its
e
iving low
h
eating and
. If glazing
e
cts can be
n
tucky
[The
n
ergy 2003].
allows the
g
ratios are
h
e glazing
m
echanical
let in solar
p
ace in the
c
tion of the
de and the
u
p of three
２３
components such as direct light from the sky, reflected light from external surfaces of other buildings or
internally reflected light. The average38 for a room is estimated as
2
(1 )
g
avg
A
DF
A
R
θ
γ
=− Eq.1
where θ is the angle of visible sky measured from the center of the window shown in Fig.2.7 and ᵞ is the
transmittance of glazing, e.g. 0.85 for clear glass and 0.5 for tinted glass. A is the total area of room
surfaces such as floor, walls and ceiling, and Ag is the glazed area. R is the mean reflectance of the
surfaces, e.g. 0.7 for light finishes. The initial size of glazing area can be estimated by the ratio Ag /A.
The DF for a sun-space is estimated using a combination of transmittance T ≈ TgTmTf in the area of roof
aperture (㎥). Tg is the transmittance of the glass e.g. 0.8 for single glazing and 0.65 for double glazing.
Tm is the maintenance factor, 0.7 for horizontal glazing, 0.8 for tilted glazing and 0.9 for vertical glazing.
Tf is a correction factor for light that is trapped in the room since the angle of view is 0.5 at the edge of
the space and 0.7 in the center.
Figure 2.7. Angles of visible sky for the average DF calculation [author].
In winter, the glazing has a lower air temperature than the surrounding air which causes the air near the
surface of the glass to cool due to heat losses. In the summer, direct solar radiation by glazing causes
overheating. The direct solar gain on a surface is a combination of the absorption of direct and diffuse
solar radiation given by
cos sunlight
s
olar direct diffuse sky gnd gnd
A
GI IFIF
A
αϕ
⎛⎞
=++
⎜⎟
⎝⎠
Eq.2
where α is solar absorptance of the surface, φ is angle of incidence of the sun’s rays and Asunlight is
sunlight area. Idirect, Idiffuse and Ignd are respectively the intensities of direct radiation, sky diffuse radiation
and ground reflected diffuse radiation. The view factors to ground and sky are calculated using the tilt
angle
φ
of the surface as,39
38 Ward 2004.
39 Walton 1983.
T
h
h
o
T
h
su
r
co
g
a
co
pr
o
T
h
su
r
he
If
gr
o
40
W
h
e thermal
o
rizontal gl
a
h
e sunlight
w
r
faces, the
ntainer usi
n
a
in in solar
nvection (
u
o
cedures g
e
h
e radiative
r
roundings.
at flux into
(a)
(b)
Figure 2.
8
we let the
b
o
und surfa
c
W
alton 1983.
efficiency
o
a
zing.
w
arms up t
h
air temper
a
n
g solar ra
d
designs o
r
u
sually nat
u
e
nerally co
m
heat gain
G
G
conv
and
G
the wall.
40
8
. Outdoor
h
b
oundary c
c
e, and sky
,
o
f a cave
s
h
e walls of
a
ture increa
s
d
iation, or
u
r
systems
i
u
ral). Fig.2
.
m
bine the r
a
G
rad
is net l
o
G
cond
are res
p
h
eat balan
c
ondition as
,
the radiati
v
0.5(
1
gnd
F=
s
tyle glazin
g
a house w
h
s
es. Some
p
u
sing natur
a
i
s represen
t
.
8 illustrate
a
diation an
d
rad co
GG
+
o
ng wavele
n
p
ectively c
o
c
e of longw
a
an enclos
u
v
e gain (G
r
２４
1
cos )
φ
+ a
n
g
is better
h
ich absorb
p
assive he
a
a
l daylight t
o
t
ed by the
s the diagr
d
convectio
n
0
nv cond
G−=
n
gth (ther
m
o
nvective fl
a
ve radiati
o
u
re consisti
n
r
ad
) can be
c
d
0.5(
sky
F
=
than jut st
y
solar energ
y
a
ting syste
m
o
read or p
e
heat balan
c
am of the
o
n
terms by
u
m
al) radiati
o
ux exchan
g
o
n, (a) the d
i
n
g of build
i
c
alculated
a
1cos)
φ
+
y
le. Tilted
g
y
as well.
T
m
may incl
u
e
rform vari
o
c
e of con
d
o
utside he
a
u
sing the en
e
o
n flux exc
h
g
e with outs
i
i
agra
m
, (b)
Stgl
i
i
ng exterio
r
a
s the sum
o
g
lazing is
b
T
hrough ab
s
u
de heating
o
us tasks.
T
d
uction, ra
d
a
t balance.
e
rgy-balan
c
h
ange with
t
i
de air and
c
an exampl
e
i
tz
[author, S
c
r
surface, s
u
o
f compon
e
Eq.3
b
etter than
s
orption by
water in a
T
he energy
d
iation and
Simplified
c
e concept.
Eq.4
t
he air and
c
onduction
e
in Berlin,
c
herer 2006].
u
rrounding
e
nts due to
２５
radiation exchange with the ground, sky and air. The radiation heat flux is calculated from the surface
absorptive, surface temperature, sky and ground temperatures, and sky and ground view factors.
rad gnd sky air
GGGG
=
++
Eq.5
Applying the Stefan-Boltzmann Law to each component yields
44 44 44
()()()
rad gnd surf gnd sky surf sky air surf air
GFTT FTTFTT
σσσ
=−+−+−
Eq.6
where σ=5.67 10-8W m-2 K-4 is Stefan-Boltzmann constant. Tsurf, Tgnd, Tsky and Tair are temperatures of
outside surface, ground surface, sky and air. Fgnd, Fsky and Fair are the longwave view factors of surface
to ground surface, sky and air temperature.
Heat transfer rate due to exterior convection Gconv is calculated as
()
conv surf air
QhATT
=
− Eq.7
where Qconv is rate of exterior convective heat transfer, h is the convection coefficient related to material
roughness and local surface wind speed and A is the surface area.41
Figure 2.9. Indoor heat balance diagram and an example of longwave radiation from internal exchange
[author].
The longwave-radiation heat exchange between surfaces depends on surface temperatures, spatial
relationships between surfaces and surroundings, and material properties of the surfaces. Fig.2.9
exemplifies the indoor heat balance with longwave radiation from internal exchange. The relevant
material properties of the surface e.g. emissive and absorptive are complex functions which are related
with temperature, angle, and wavelength for each participating surface. A grey interchange model
based on the ScriptF concept42 simplifies the complexity. The method relies on a matrix of exchange
coefficients between pairs of surfaces that include all exchange paths between the surfaces. If we
assume that all surface radiation properties are grey and all radiation is diffuse, all reflections,
41 Walton 1983
42 Hottel and Sarofim 1967.
２６
absorptions and re-emissions from other surfaces in the enclosure are included in the exchange
coefficient, which is called ScriptF. The long wave radiant exchange between surfaces i and j are,
44
,,
()
ij i ij i j
QAFTT=−
Eq.8
where Fi,j is the ScriptF between surfaces i and j.
2.5. Design for heat loss
If the heat gains cannot be balanced by the loss, a space will be overheated by internal heat gains. In
order to determine the possibility of overheating occurring, a rough approximation of overheating in a
space is estimated in two divided areas of passive and non-passive zones. If the glazing area of passive
and non-passive zones is estimated, the overheating by the solar load can be estimated.
Table 2.2. Solar heat gain through single thickness of common window glass through an unshaded
window [Saini 1970].
Type of shade, finish on side exposed to the sun Heat gain (%)
Outside slatted shade, slats set to prevent direct sun falling on glass, white, cream. 15
Outside commercial bronze shading screen, consisting of narrow metal slats, solar altitude above 40˚ so
that no direct sun falls on glass, dark 15
Outside canvas awning, sides open, dark or medium color. 25
Inside Venetian blinds, slats set to prevent direct sunshine passing though, diffuse reflecting aluminum. 45
Ditto, white, cream 55
Inside roller shutter fully drawn, dark 80
To prevent overheating, the windows of the overheating area should be protected from direct solar gains.
Internal and external shading efficiently removes the gains. Since internal shading only serves to direct
the gains which are already in the space having passed through the window, external shading is more
efficient for the overheating. While solar shading must give good protection in summer, in winter when
the sun is not so strong and lower in the sky, the solar protection must be able to allow sufficient
daylight and natural ventilation to enter the building. Horizontal shading devices are appropriate to
blind south-facing windows but not appropriate with east or west facing windows. Different types of
solar shading devices have the different percentage of the external radiation protection. Table 2.2
clearly shows the effect of various types of shading devices for instantaneous solar heat gain through a
single thickness of a common window glass.
Fig.2.10 represents the external shading devices with horizontal overhang. The angle a and b
respectively determines the angle from a line perpendicular to the bottom of the window to the edge of
the overhang and from the middle of the window to the edge of the overhang. These angles represent
100% and
overcome
s
radiation
i
radiation
o
winter.
44
Table 2.3.
Table 2.4.
Korea is l
o
middle lat
i
Korea has
summer a
n
generally
b
The mons
o
43 B.S. Kim
a
44 E.J. Lee e
t
50% sha
d
s
the upper
i
tself to th
e
o
f Korea an
d
(a)
Fi
g
ure
Comparis
o
S. Korea (A
)
Central-Japan
Germany (
C
Swiss (D)
Climate d
a
o
cated on th
e
i
tude. The
c
four distin
c
nd
a dry c
o
b
elow freez
i
o
on season
a
nd K.H. Ki
m
t
al. 2004.
d
ing of the
limitation
e
window
i
d
the comp
a
2.10. Solar
o
n of global
Sprin
)
4.4
8
124
%
(B) 4.4
9
121
%
C
) 3.6
9
128
%
4.0
9
126
%
a
ta in sum
m
Mean Tempera
Relative Humi
d
Characteristi
c
e
center of
N
c
limate is
fe
c
t seasons
w
o
ld and co
n
i
ng and wi
d
begins wit
h
m
2004.
window.
T
of heat co
m
i
s 325.5w
m
a
rison with
shading, (
a
radiation
o
g Sum
m
8
4.41
%
123
%
9
4.6
7
%
132
%
9
4.8
8
%
169
%
9
5.4
6
%
168
%
m
er and win
t
S
ture
d
ity
c
s
N
ortheast
A
fe
ature
d
b
y
w
ith simila
r
n
tinental cl
i
d
ely differe
n
h
the heav
i
２７
T
he inside
e
m
fortable p
a
m
-2
. Table
four count
r
a
) devices
by
o
f four cou
n
m
e
r
A
utu
m
3.1
4
%
87
%
7
3.0
0
%
84
%
8
1.6
8
%
58
%
6
2.3
%
71
%
t
er in S. Ko
r
S
umme
r
(Jun.
~
23 ~ 26
℃
75 ~ 85%
Subtropical Cli
A
sia betwee
n
the mi
d
-la
t
r
lengths. It
i
mate in w
n
t from sum
i
est rain in
e
ffective e
q
a
rt i.e. wh
e
2.3 and 2.
4
r
ies and the
y
C. Scarp
a
n
tries
[E.J. L
e
m
n Wint
e
4
2.3
5
%
65
%
0
2.2
3
%
63
%
8
0.9
4
%
33
%
1.1
5
%
35
%
r
ea
[E.J. Lee
~
Aug.)
℃
mate
n
33˚N to 4
3
t
itudinal lo
c
has a hum
i
inter. The
m
m
er. In su
m
late June a
n
q
uivalent t
e
e
n t
ef
>26˚e
f
4
respectiv
climate dat
(b
)
a
, (b) overh
a
e
e et al. 2004]
.
er
Mea
n
5
3.6
0
%
100
%
3
3.5
5
%
100
%
4
2.8
8
%
100
%
5
3.2
5
%
100
%
et al. 2004].
Winter (Dec.
~
-5 ~ 5℃
50 ~ 75
%
Continental C
l
3
˚N and 12
4
c
ation and
p
i
d, East Asi
m
ean tem
p
m
mer it is v
e
n
d continu
e
e
mperature
f
.
43
Simulta
n
ely repres
e
t
a of Korea
n
)
a
ng
[author].
.
n
0
A
=10
0
%
5
B/A=
9
%
8
C/A=
8
%
5
D/A=
9
%
~
Feb.)
%
l
imate
4
˚E to 132˚
E
p
eninsular
c
an monsoo
n
p
erature du
r
e
ry hot, rain
e
s until Jul
y
with shadi
n
n
eously, so
l
e
nt the glo
b
n
summer a
n
0
%
9%
8
0%
9
0%
E
which is t
h
c
onfigurati
o
n
al climate
r
ing winter
y
, and hum
i
y
. The end
n
g
l
ar
b
al
n
d
h
e
o
n.
in
is
i
d.
of
S
e
T
h
Si
n
he
d
o
a
n
co
W
su
p
th
e
o
p
st
a
pr
e
sh
o
hi
g
th
r
T
h
45
L
e
ptember to
h
e winter w
e
n
ce solar r
a
at resistan
c
o
ors and wi
n
n
d humid s
u
nditioning
b
Fi
g
ure
2
W
indows are
p
plied and
e
e
more eff
e
p
enings at b
o
a
ck effect.
A
e
ssure diff
e
o
uld be as
s
g
hly partiti
o
r
ough an at
r
h
e factors
w
- The s
h
- The
w
- The
p
- The i
n
- The r
e
- Exha
u
- The e
L
echner 1991
Novembe
r
e
ather is co
a
diation is t
h
c
e. The Ro
b
n
dows that
c
u
mmers, pl
e
b
ecame av
a
2
.11. Very
l
the main
w
e
xtracted b
y
e
ctive the v
e
o
th low an
d
A
solar chi
m
e
rences an
d
s
implified a
s
o
ned space
s
r
ium, whic
h
w
hich affect
h
ape orient
a
w
indow des
i
p
rovision o
f
n
ternal lay
o
e
sistance o
f
u
st paths su
xistence of
.
is the autu
m
l
d
and dry.
h
e most im
p
b
ie house h
a
c
ould be op
e
ntiful vent
i
a
ilable.
45
l
arge roof
o
w
ays for s
o
y
wind, the
e
ntilation
w
d
high level
s
m
ney creat
e
d
so further
s
possible e
s
raise the
r
h
will addit
i
the natural
a
tion and d
e
i
gn to mak
e
f
flow paths
o
ut should
p
f
flow thro
u
ch as a sta
c
open wind
o
m
n season
w
p
ortant fact
o
a
s very lar
g
ened for ve
i
lation and
o
verhangs o
o
lar heat to
difference
i
w
ill occur.
H
s
within the
e
s a colum
n
enhances t
h
.g. open pl
a
r
esistance a
c
i
onally act
a
ventilation
e
pth of the
b
e
efficiency
for the air
–
p
ermit easy
u
gh partitio
n
c
k or windo
w
o
ws not to
i
２８
w
hich is dry
o
r in heatin
g
e roof ove
r
ntilation as
full shade
w
f Robie ho
u
enter
b
ut
a
i
n ai
r
densi
t
H
owever, t
o
building a
r
n
of air at
a
h
e stack e
ff
a
n spaces ef
f
c
ross or up
a
s a buffer
t
are set out
b
uilding.
of air distr
i
–
sun space
access to t
h
n
ed spaces
w
s.
i
nterfere wi
t
due to dry
a
g, solar sh
a
r
hangs to s
h
Fig.2.11 s
h
w
ere the m
u
se by F.L.
W
a
lso for nat
u
t
y makes b
u
o
make nat
u
r
e also nece
s
a
higher te
m
ff
ect. The i
n
f
ectively o
ff
the buildi
n
t
o reduce in
as
i
butio
n
s, stacks or
h
e windows
.
t
h the oper
a
a
ir fro
m
the
a
ding at mi
d
h
ade walls
m
h
ows. Since
ajor coolin
g
W
right
[aut
h
u
ral ventil
a
u
oyancy. T
h
u
ral ventila
t
s
sary to pr
o
m
perature.
T
n
ternal pla
n
ff
er little res
i
n
g. A stack
filtration h
e
windows.
.
a
tion of bli
n
continent t
o
d
day shoul
d
m
ade entir
e
Chicago h
a
g
strategies
h
or, Lechner
1
a
tion. Whe
n
h
e larger th
e
t
ion work
e
o
mote the b
u
T
his gener
a
n
form of t
h
istance to a
i
can also b
e
e
at loss.
n
ds
o
the north.
d
maximize
ly of glass
a
s very hot
before air
1
991].
n
the air is
e
windows,
e
ffectively,
u
oyancy or
a
tes higher
h
e building
i
rflows but
e
generated
In the typ
e
cooling is
openings
c
requireme
n
number of
slightly di
f
The openi
n
microclim
a
b
uilding c
a
C
d
is the d
i
relationshi
p
neutral pr
e
volume fl
o
smaller o
p
volume fl
o
Fi
g
ure
2
Using this
19.5℃ an
d
summer,
f
b
ecause i
n
architectu
r
46 The Chart
e
47 Ward 200
4
e
s of wind
o
required,
s
c
an be also
n
ts to a sp
a
ways in w
h
f
ferent way
s
n
g size for
n
a
te of the
s
a
n be repre
s
i
scharge co
e
p
between
t
e
ssure h
npl
(
m
o
w rate is d
e
p
ening size,
o
w rate sinc
2
.12. Areas
relationshi
p
d
24℃. Al
t
f
low-driven
n
/out temp
e
r
e, the temp
e
e
red Institute
4
.
o
ws, tilting
w
s
ome form
considere
d
a
ce, to pro
m
h
ich a wind
o
s
.
n
atural vent
i
s
ite.
46
A si
m
s
ented by v
o
e
fficient i.e.
t
he opening
m
) and the
e
pendent u
p
large diff
e
e they brin
g
a.
of openin
g
p
, Fig.2.12
g
t
hough the
effects, e.
g
e
rature dif
f
e
rature and
of Building S
w
indows g
e
of trickle
v
d
. Trickle v
m
ote natura
l
o
w can ope
n
i
lation is th
e
m
plified est
i
o
lume flow
Q
C
A
=
normally
0
size and th
e
inside tem
p
p
on the pres
s
e
rence of i
n
g
large pres
Winter
g
required i
n
g
ives the re
s
stac
k
-drive
n
g
. temperat
u
f
erence is
moisture b
a
ervice Engin
e
２９
e
nerally ar
e
v
entilation
p
entilators
a
l
cooling a
n
n
and, depe
e
most freq
u
i
mation of
rate to are
a
[2 (
dn
p
C
gh×
0
.61 and g=
9
e
temperatu
r
p
erature Tin
s
s
ure passin
g
n
/out temp
e
sure i.e. sta
n
winte
r
an
d
s
ults for S.
K
n
ventilati
o
u
re and m
o
generally l
a
lancing is
v
e
ers (CIBSE)
e
regarded
a
p
rovided ei
a
re designe
d
n
d to mini
m
n
ding on t
y
u
ently aske
d
the size of
a
of openin
g
)
ins
o
p
l
ins
T
T
hT
−
−
9
.81 m s-2 i
s
r
e is given
b
s
(K) and t
h
g
an openin
g
e
ratures an
d
c
k
-driven
v
d
summer,
v
K
orean wi
n
o
n is an es
p
o
isture
b
al
a
arger in
w
v
ery impor
t
1997.
a
s being th
e
ther by de
v
d
to provid
e
m
ize moist
u
y
pe, the air
d
d
issue. Th
e
windows
f
g
Q (m
3
s
-1
)
1
2
]
o
ut
T
s
the accele
r
b
y the heig
h
h
e outside t
e
g
and is rel
a
d
opening
h
v
entilation.
b. Sum
m
v
olume to a
r
n
ter and su
m
p
ecially effi
a
ncing can
w
inter. For
t
ant to mai
n
e
best type
v
ices or s
m
e
the mini
m
u
re buil
d
-u
p
d
istributes t
o
e
solution is
f
or a natur
a
/A (m
2
),
47
r
ation due t
o
h
t of openin
g
e
mperature
a
ted to the
s
h
eights res
u
m
e
r
r
ea ratio fo
r
vent
i
m
mer indoo
r
cient cooli
n
be conside
example,
i
n
tain the bu
i
to use. Wh
m
all clearst
o
m
um fresh
a
p
. There ar
e
o
the space
related to t
h
a
lly ventilat
E
q
o
gravity. T
h
g
h (m) and
T
out
(K). T
s
tack effect.
u
lt in a lar
g
r
stac
k
-driv
i
lation
[auth
o
r
temperatu
r
n
g concept
r
ed in win
t
i
n vernacu
l
i
lding clim
a
en
o
ry
a
ir
e
a
in
h
e
ed
q
.9
h
e
of
he
A
g
er
en
o
r].
r
e,
in
t
er
l
ar
a
te
co
bu
di
f
us
e
2.
E
n
he
th
e
m
a
gr
a
m
a
re
d
pr
o
T
h
U
-
pr
o
T
h
48
W
ntrol. Natu
r
u
ilding. Th
e
f
ference ge
n
e
, the heig
h
6. Ther
m
n
ergy tends
ating in wi
n
e
phenome
n
a
terials i.e.
a
dient. D
e
a
terials ha
v
d
uce heat
l
o
perties of
t
F
i
h
e ter
m
of
U
-
value is ca
o
perties of
t
h
e thermal
r
W
ard 2004.
r
al ventilat
i
e
neutral pr
e
n
erates ver
y
h
t differenc
e
m
al insul
to move f
r
n
ter or coo
l
n
a through
brick, cav
i
e
nse materi
a
v
e a high re
s
l
osses, and
t
he materia
l
ig
ure 2.13.
U
-value is u
lculated by
t
he materia
l
r
esistance o
f
i
on occu
r
s,
e
ssure line
y
large vari
a
e
is a more
i
ation
r
om a war
m
l
ing in sum
m
the cross-s
e
i
ty, concret
e
a
ls such as
s
istance of
the rate o
f
l
s.
Temperatu
r
sed to dete
r
a steady-s
t
l
s
48
U
T
=∑
f
each mat
e
however, t
h
should be
a
a
tion in the
v
i
mportant i
s
m
indoor ar
e
m
er throug
h
e
ction of a
e
, wood w
o
brick and
heat transf
e
f
the ener
g
r
e gradient
r
mine the r
e
t
ate heat tr
a
T
hermal resista
n
e
rial is give
n
T
h
RTherma
l
=
３０
h
e neutral
p
a
bout 0.25
m
v
olume flo
w
s
sue than te
m
e
a to a coo
l
h
walls, ro
o
composite
o
ol and pl
a
wood woo
l
e
rs. Therm
a
g
y moveme
n
of a comp
o
e
sistance of
a
nsfe
r
equa
t
1
n
ces of each el
e
n
by
()
(
h
ickness L
l
conductivity
p
ressure lin
e
m
above th
e
w
rate both i
n
m
perature
d
l
outdoor a
r
o
fs, floors
a
wall with
t
a
ster, wher
e
l
can act a
s
a
l insulatio
n
n
t is deter
m
o
site wall
[
K
heat transf
e
t
io
n
across
e
ment in the str
u
(
)K
e
is not exa
c
e
highest c
e
n
winter an
d
d
ifference d
u
r
ea, and th
e
a
nd windo
w
t
he thermal
e
the line s
h
s
thermal i
n
n
is a mec
h
m
ined by t
h
K
oenigsberger
e
rs in a co
m
the structu
r
()
u
cture R
ctly define
d
e
iling since
d
summer.
I
u
e to the la
r
e
reby a bui
l
w
s. Fig.2.13
properties
h
ows the t
e
n
sulation s
i
h
anism whi
c
h
e thermal
et al. 1974].
m
bination o
f
r
e with kno
w
d
for every
the height
I
n practical
r
ge effects.
l
ding loses
represents
of several
e
mperature
i
nce dense
c
h helps to
insulation
f
materials.
w
n certain
Eq.10
Eq.11
A rough e
s
of thermal
Thermal r
e
convectio
n
resistance
o
of the surf
a
where eac
h
Eq. 11.
For the sl
o
the heat tr
a
where R
s
i
s
R
a
is the t
h
For a stru
c
minimize
d
partially i
n
percentag
e
(a)-b give
s
levels of
v
thermal in
s
factor is b
a
s
timation o
f
resistances
e
sistance is
n
heat trans
o
f outside s
u
a
ce where
R
h
thermal r
e
o
pe roof str
u
a
nsfer from
s
the sum o
f
h
ermal resis
t
c
ture footi
n
d
since hea
t
n
sulate
d
so
l
e
of insulati
o
s
U-values
o
v
entilation
s
ulation. H
e
a
sed on the
f
energy tra
n
of n numb
e
related to
t
fer. In a h
o
u
rfaces R
ou
t
R
k
is resista
n
U
=
e
sistance R
Fi
gu
u
ctures wit
h
a room thr
o
f
the therma
l
t
ance of th
e
n
g,
b
oth los
t
losses to
t
l
id ground
o
n makes l
o
o
f uninsula
t
openings.
U
e
nce, when
U-value of
n
sfers acros
e
rs.
U
t
he heat tr
a
o
use show
n
t
and the the
r
n
ce of n nu
m
1
n
kkins
R
R
=
=
++
∑
can be rew
r
u
re 2.14. C
a
h
the angle
α
o
ugh a loft
roof
U
=
l
resistance
s
e
attic spac
e
ses throug
h
t
he ground
floors for
t
o
wer U-val
u
t
ed suspen
d
U
ninsulate
d
the floor is
the floor c
o
３１
s a structur
e
1
1
nn
kk
k
U
R
==
=
=
∑∑
a
nsfe
r
s at t
h
n
in Fig.2.1
4
r
mal resist
a
m
bers. The
1
out f
RR
=
+
+
∑
r
itten by th
e
a
lculating h
e
α
as shown
and then th
r
1
cos
s
RR
α
+
s
of the roo
f
e
and R
c
is t
h
h
the groun
can be si
g
t
he percent
a
u
es for the l
a
d
ed floors f
o
d
suspende
d
insulate
d
,
a
o
nstruction
e
with n ma
t
1
k
k
K
L
=
∑
h
e surfaces
4
, the resis
t
a
nce of floo
r
U-value is
1
n
kins
kkins
KK
LL
=
+
+
∑
e
thickness
L
e
at transfe
r
in Fig.2.1
4
r
ough the r
o
acsi
R
RR++
f
materials
a
h
e thermal
r
d below th
e
g
nificant. F
i
a
ges of gr
o
a
rge perime
t
o
r various
p
d
floors un
d
a
correctio
n
and set out
t
erials can
b
of the mat
e
t
ance of th
e
r
R
f
are dep
e
calculated
a
f
out
out f
K
K
LL
+
+
L
and the t
h
[author].
4
, the follo
w
o
of structur
a
nd the outs
i
r
esistance
o
e
building
a
i
g.2.15 (a)-
a
o
und cover
e
t
ers to floo
r
p
erimeters t
o
d
er ventila
t
n
factor is n
e
as
b
e establish
e
e
rials and t
a
e
inside su
r
e
ndent upo
n
a
s
h
ermal con
d
w
ing equati
o
r
e as
i
de surface
r
o
f the ceilin
g
a
nd the ed
g
a
compare
s
e
d by insul
r
area ratios
.
o area rati
o
t
ion reduce
e
cessary. T
h
ed
b
y the s
u
Eq.
a
kes place
b
r
face R
ins
, t
h
n
the expos
u
Eq.
d
uctivity K
o
n determi
n
Eq.
r
esistance
R
g
.
g
es should
b
s
U-values
ation. Hig
h
.
The Fig.2.
o
s and for t
w
the value
h
is correcti
o
u
m
12
b
y
h
e
u
re
13
as
n
es
14
R
si
,
b
e
of
h
e
r
15
w
o
of
o
n
w
h
co
th
e
p
o
(
b)
Fi
g
M
o
su
r
-
-
-
-
49
W
h
ere U
insula
t
nstruction
a
e
upper an
d
o
sitioned ei
t
)
.
(a)
a
(b)
a
g
ure 2.15.
U
o
st buildin
g
r
face. The
m
Conductio
n
Convectio
n
Radiation
t
Moisture t
r
W
ard 2004.
t
ed floo
r
is t
h
a
nd R
f
is th
e
d
undersid
e
t
her vertica
l
a
. Solid grou
n
a
. Horizontal
U
-value of
g
materials
a
m
echanism
s
n
through t
h
n
at the sur
f
t
o or from t
r
ansmissio
n
h
e U-value
e
thermal r
e
e
of the fl
o
l
ly or ho
r
iz
o
n
d floor with
e
insulation
a ground fl
o
a
re able to
a
s
at play in
h
h
e solid pa
r
f
aces –
b
ot
h
he surfaces
n
through t
h
insulated floor
U
=
of the in
s
e
sistance o
f
o
or i.e. no
r
o
ntally aro
u
e
dge insulatio
o
o
r
, (a) for
a
bsorb moi
s
h
eat and m
o
r
ts of the m
a
h
inside an
d
h
e surface
３２
1
(1/ ) 0.2
o
U
=
−
s
ulated sus
p
f
the floor c
o
r
mally 0.1
7
u
nd the edg
e
n
solid floor
a
s
ture in the
o
isture tran
s
a
terial
d
outside su
r
f
R+
p
ended flo
o
o
nstruction
.
7
. The corr
e
e
of the bu
i
b. Unins
u
b.Verti
c
a
nd suspen
d
form of va
p
s
fer across
a
r
faces inclu
or
,
49
U
o
is
.
1/U
o
is th
e
e
ction fact
o
i
lding are r
e
u
lated suspen
d
c
al insulation
d
ed floor, (
b
over
p
or and thi
s
a
surface a
r
ding any c
a
the U-val
u
e
surface re
s
o
rs for the
e
presented
i
d
ed floo
r
b
) solid flo
o
insulation
[
s
can pass t
h
r
e:
a
vities
Eq.15
u
e of floor
s
istance on
insulation
i
n Fig.2.15
o
rs with all
Ward 2004].
h
rough the
In winter,
lower tem
p
condensat
i
temperatu
r
results in
i
conductivi
insulator,
a
the ability
it feels dri
e
into the ai
r
wall.
A thermal
flow throu
due to the
r
materials
t
b
ridges oc
c
heat flow
r
shows a t
h
Gonzalo (
1
moisture h
o
p
erature th
a
i
on. The te
m
r
e of the m
a
i
nterstitial
c
ty is affec
t
a
nd other m
o
of the air t
o
er
since the
r
r
. These si
t
a. An ex
a
bridge is c
gh the path
r
mal bridgi
n
t
hat have b
e
c
ur where
m
r
ates. It res
u
h
ermal bri
d
1
994).
o
lding abil
i
a
n the roo
m
m
perature
w
a
terial is be
l
c
o
n
densatio
t
ed. The o
v
o
re detrime
o
hold mois
t
r
elative hu
m
t
uations sh
o
a
mple o
f
a th
e
Fi
g
reated whe
n
created. In
n
g; the brid
e
tter insula
t
m
aterials of
u
lts in part
s
d
ge at the l
i
i
ty of the a
i
m
, moistur
e
w
hich mois
t
l
ow the de
w
n in the m
a
v
erall resul
t
ntal effects
t
ure also in
c
m
idity decr
e
o
uld be tak
e
e
rmal bridge
g
ure 2.16.
T
n
materials
sulation ar
o
ging has to
t
ing proper
t
different t
h
s
of the str
u
i
ntel of a
w
３３
i
r decrease.
e
for
m
s eit
h
t
ure occurs
w
point tem
p
a
terials. If
a
t
is that th
e
may occur.
c
reases at a
e
ases. The
m
e
n into acc
o
T
hermal bri
d
that are p
o
o
und a brid
g
be elimina
t
t
ies, or wit
h
h
ermal prop
e
u
cture bein
g
w
indow an
d
If the air i
s
h
er on the
is known
a
p
erature, m
o
a
material t
a
e
material
b
When the
a
faster rate.
I
m
oisture in
t
o
unt when
c
b
d
ge
[Gonzal
o
o
or insulato
g
e is of littl
e
t
ed, rebuilt
h
an additi
o
e
rties are u
s
g
significan
t
d
the soluti
o
s
saturated
surface or
a
s the dew
p
o
isture in t
h
a
kes up m
o
b
ecomes le
a
ir tempe
r
a
t
I
f air enabl
e
t
he material
c
alculating
b
. The solutio
n
o
1994].
rs come in
e
help in pr
with a red
u
o
nal insula
t
s
e
d
, the res
u
t
ly cooler t
h
o
n using a
at a surfac
e
within the
p
oint temp
e
h
e air is con
d
o
re moistur
e
ss efficien
t
t
ure increas
e
e
s to hold
m
is evapora
t
the overall
n
contact, al
l
eventing h
e
u
ced cross-
s
t
ing comp
o
u
lt is show
n
h
an anothe
r
wind shiel
d
e
which ha
s
structure i
e
rature. If t
h
d
ensed, an
d
e
, the ther
m
t
to act as
e
s in summ
e
m
ore moistu
r
t
ed and mo
v
U-value o
f
l
owing hea
t
e
at loss or
g
s
ection or
w
nent. Ther
m
n
in differen
t
r
part. Fig.2
d
proposed
s
a
.e.
h
e
d
it
m
al
an
er
,
r
e,
v
es
f
a
t
to
g
ain
w
ith
m
al
t
ial
.16
by
2.
Si
n
in
s
ye
th
e
in
s
m
a
A
n
Fi
g
si
m
T
h
T
h
7. Ther
m
n
ce a ther
m
s
ulation is
n
ar with hi
g
e
rmal ener
g
s
ulation, th
e
a
ss is coop
e
n
installatio
g
.2.17. a a
n
m
ultaneous
l
h
e space wi
t
h
ermal mas
Fi
g
u
F
i
m
al mas
s
m
al insulati
o
n
ecessary t
o
g
h, mediu
m
g
y is referr
e
e
internal t
e
e
ratively us
e
n of therm
a
n
d b respe
c
l
y with the
t
h the ther
m
s has an a
b
a. Ma
s
re 2.17. Ef
f
ig
ure 2.18.
s
o
n reduces
t
o
most pass
i
m
and low
o
e
d to as a
m
e
mperature
ed
to avoid
a
l mass con
s
c
tively hav
e
same sourc
m
al mass ou
t
b
ility to st
o
s
s outside
f
ect of posi
t
The relatio
n
t
he heat lo
s
i
ve house d
e
o
utside te
m
m
aterial wit
h
will easily
the proble
m
s
tructed of
i
e
the polyst
e, and the i
t
side the
bu
o
re thermal
t
ion of ther
m
n
ship betw
e
３４
s
s in winter
e
sign. How
m
peratures,
a
h
low ther
m
rise or dro
p
m
of insulat
i
i
dentical m
a
yrene to th
nside temp
e
u
ilding is m
o
energy for
m
al mass o
n
e
en density
and avoid
s
ever,
a
b
uil
a
n
d
insulat
i
m
al mass. I
n
p
with the
h
i
on.
a
terials of
b
e inside an
e
ratures ar
e
o
re balance
heating o
r
n
the inside
and therm
a
s
excessive
ding is ope
r
i
on materi
a
n
a building
h
eat gain o
r
b
rick and p
o
d the outsi
d
e
differentl
y
d than insi
d
r
cooling a
n
b. Mass ins
i
temperatu
r
a
l conducti
v
heat gain i
n
r
ated for th
e
a
l which c
a
with large
r
loss. Hen
c
o
lystyrene i
s
d
e. If both
y
varied ov
e
d
e the
b
uild
i
nd
high the
i
de
r
e
[Ward 200
4
v
ity
[author].
n
summe
r
,
e
complete
a
nnot store
amount of
c
e, thermal
s
shown in
are heated
e
r a period.
i
ng.
rmal mass
4
].
materials
a
significant
represents
relationshi
p
conductivi
In a cold
s
desirable i
n
the night.
I
occupants
ventilatio
n
Thermal
m
wall.
50
W
h
sunlight. I
f
will reduc
e
raised. Fig
characteri
s
removes t
h
Figure 2.
1
The therm
a
that the a
m
located in
material.
T
to pass co
o
50 Trombe w
a
a
re dense
a
ly increase
d
the relatio
n
p
is gener
a
ty a materi
a
s
eason, a t
h
n
the living
I
n the hot s
e
at a more
n
during co
o
m
ass is gen
e
h
en a buildi
f
these wall
e
d. During
.2.19-a sho
s
tic with th
e
h
e heated ai
r
1
9. Thermal
a
l storage
fu
m
ount of m
e
the floor o
r
T
he locatio
n
o
l outside a
i
a
ll was first d
a
nd heavy.
d
and is u
s
n
ship betw
e
a
l and can
a
l has, the
m
h
ermal mas
s
space of a
e
ason, the i
n
comfortab
l
o
ler periods
,
e
rally used
ng faces th
s are on th
e
the night,
t
ws the usa
g
e
Trombe
w
r
using nat
u
mass in so
l
fu
nctio
n
is
a
e
chanical c
o
r
ceiling w
h
n
of thermal
i
r over the
c
eveloped by
a
As the q
u
s
ually able
e
en the de
n
readily be
m
ore heat c
a
s
absorbs a
n
building, t
h
n
ternal ma
s
l
e temperat
u
,
typically
a
in solar de
s
e sun, unin
e
interior, a
n
t
he heat wi
l
g
e of a ther
m
w
all. Fig.2.
1
u
ral ventila
t
a. Wint
e
l
a
r
-air-coll
e
a
n importa
n
o
oling is m
i
h
ere it is re
l
mass make
c
eiling slab
a
rchitect J. M
i
３５
u
antity of
m
to cope wi
n
sity and t
h
applied to
a
n
b
e readil
y
n
d stores h
e
h
e mass rel
e
s
s remains
a
u
re. Then
c
a
t night.
s
ign with s
o
sulated wa
l
n
d glass ins
t
l
l be emitte
m
al mass i
n
1
9-b illustr
a
t
ion with se
l
e
r
e
ctor
b
y E.
S
n
t aspect of
p
i
nimized. I
n
l
atively eas
s it possibl
e
in the eve
n
i
chel as a sim
p
m
ass incre
a
th the heat
h
ermal con
d
most buil
d
y
transferr
e
e
at during
s
e
ases the he
a
t a lower t
e
c
ooling the
o
me typica
l
l
ls of brick
,
t
alled in fr
o
d into inte
r
n
sola
r
-air-
c
a
tes in sum
m
l
ective ope
n
b.
S
S
. Morse i
n
S
p
assive des
n
practical
c
y to pass a
i
e
to supply
c
n
ing and ni
g
p
lified versio
n
a
ses, the p
o
inputs ov
e
d
uctivity o
f
d
ing mater
i
ed
through t
h
s
unny perio
d
at du
r
ing o
v
e
mperature
internal
m
l
heating s
y
,
stone, or
c
o
nt of the w
a
r
io
r
, and th
e
c
ollector fo
r
m
er how a
n
ings for ai
r
S
ummer
S
alem, Ma
s
ign, when
t
c
ooling des
i
r over sur
fa
c
ool air to t
h
g
ht. Both
m
n
of the sola
r
-
o
tential to
e
r long per
i
f
several
m
i
als. The h
i
h
e material
d
s. When t
h
v
ercast per
i
than outsi
d
m
ass can b
e
y
ste
m
s suc
h
c
oncrete di
r
a
lls, conve
c
e
air tempe
r
r
winte
r
. T
h
room with
r
flows.
s
sachusetts
[
t
he specific
a
igns, ther
m
fa
ce or wat
e
h
e floor in
t
m
ethods hav
e
ai
r
-collector i
store heat
i
ods. Fig.2.
m
aterials. T
h
i
gher ther
m
.
h
e heat is
n
i
ods or duri
n
d
e keeping t
h
e
achieved
b
h
as a Trom
b
r
ectly abso
r
c
tive heat l
o
r
ature will
b
h
is is a simi
l
thermal m
a
[
Porteous 20
0
a
tion requi
r
m
al masses
a
e
r through t
h
t
he evening
e
the effect
n the last 196
is
18
h
is
m
al
n
ot
n
g
h
e
b
y
b
e
r
bs
o
ss
b
e
l
ar
a
ss
0
1].
r
es
a
re
h
e
or
of
0s.
co
ac
c
th
e
p
a
th
e
is
b
l
o
T
h
tr
a
w
i
su
n
a
n
H
i
te
m
i
m
o
p
ar
e
oc
(
m
51
W
oling the sl
c
epted whe
n
e
thermal
m
a
vilion whic
e
rmal bloc
k
cooled. Fi
g
o
cks, about
h
e passive
h
a
nsfers hea
t
i
th a comp
l
n
light. For
e
n
d equipme
n
Fi
g
ur
e
i
gh therma
l
m
peratures.
m
portant as
p
p
timal usag
e
e
able to c
o
cupant and
m
2
K W
-1
) is
W
ard 2004.
ab and ther
e
n
2℃ to 4
℃
m
ass in a bu
i
h was built
k
s. Temper
a
g
.2.20 show
8℃ to 10
℃
h
eating and
t
between t
h
l
ex pump s
y
e
xample, c
o
n
ts for livin
g
a. Thermal
m
b.
Passive
c
e
2.20. The
r
l
mass bui
l
These bu
i
p
ect of ther
m
e
of thermal
o
pe with fl
u
equipment
the therma
l
e
by allowi
n
℃
drops in t
h
i
lding. Ver
y
by architec
t
a
ture drop is
s how ther
m
℃
drop can
cooling co
n
h
e collecto
r
y
stem. So
m
o
ncrete on t
g
during th
e
m
ass installa
t
c
ooling effects
r
mal mass
f
l
dings are
o
i
ldings ne
v
m
al mass s
u
mass is ne
e
u
ctuations i
n
gains. A r
o
l
resistance
n
g the slab
t
h
e inside p
e
y
high ther
m
t
T. Ashiha
r
achieved i
n
m
al blocks
p
be observe
d
n
cept can b
e
r
s, the ther
m
m
e building
s
he interior
o
e
day, and
r
t
ion
of the therm
a
f
or passive
c
o
ften regar
d
v
er seem h
o
u
ch as heav
y
e
de
d
to sav
e
n
room te
m
o
ugh calcul
a
of the mat
e
３６
t
o absorb h
e
e
ak room te
m
m
al mass ca
n
r
a in 1998 e
n
holes of t
h
p
rovide pa
s
d
.
e
utilized e
v
m
al mass, a
n
s
use ther
m
o
f a buildin
r
elease the
h
a
l mass
c
ooling of
T
d
ed as bui
l
o
t in sum
m
y
materials
e
the constr
u
m
perature w
h
a
tion of the
e
rial,
51
e
at during t
h
m
perature
d
n
be used f
o
x
emplifies
t
h
e bloc
k
, a
n
s
sive cooli
n
v
en in activ
e
n
d the livi
n
m
al mass to
g can hold
e
h
eat during
t
T
ono Inax
p
l
dings that
m
er or col
d
is the cost
p
u
ction cost
s
h
ich occur
d
heating ti
m
h
e occupie
d
d
uring the d
o
r passive c
o
t
he cooling
n
d the air pa
s
n
g with nat
u
e
solar arc
h
n
g space us
i
absorb int
e
e
xcess heat
t
he night.
p
avilion 19
9
have reas
o
d
in winter
p
enalty, an
d
s
. The desig
n
d
uring the
d
m
e of the co
n
d
period. T
h
ay can be a
c
o
oling. The
effect usin
g
s
sed throug
h
u
ral ventila
t
h
itecture. T
h
i
ng water o
r
e
rnal heat
r
generated
f
9
8
[WSBC 2
0
o
nably stab
. However
,
d
the estim
a
n
s using th
e
d
ay due to
n
struction
T
h
e design is
c
hieve
d
by
Tono Inax
g
very high
h
the holes
t
ion. In the
h
e building
r
air, often
r
ather than
f
rom lights
0
05].
le internal
,
the most
a
tion of the
e
rmal mass
solar gain,
T
(h) and r
c
３７
0.5( )
3600
c
mcr
T
×
×
= , c
d
r
λ
=
Eq.16
where m is the mass per square meter of material (kg m-2), c is the specific heat of the material (J kg-1
K-1), d is the thickness (m) and λ is the thermal conductivity (W m-1K-1).
３９
3. Microclimate design for
energy-saving
3.1. Microclimate and building
3.1.1. Definition of Macro- and Microclimate
Microclimate is situated in a local atmospheric zone where it is related with the energy distribution. The
definition of “macro-” and “micro-” depends on the spatial distance, and “-climate” is the environmental
variation. Climatologists have concerned with the causality of these climates, while architects have
interested in the effects of climate to the buildings.
The macroclimate can be analyzed statistically in the annual climate data that can indicate the climate
characteristic of a particular region. For example, the urban climatology concentrated on the heat island
and progressively focused to the microclimate related to the building geometry.52 The aim is a study of
energy exchanges between the urban canopy and the overlaying boundary layer or the surface, air and
mass.53
Meanwhile, architects want to know a kind of microclimate called indoor climate to improve the
building performance. They calculate energy loads of a building to maintain internal comfort. Interest
for these issues started at the oil crisis of 1973.54 The passive solar and energy efficiency by the mutual
obstructions between buildings attracted attention. The passive solar design targets in managing the
potential of the sun, and a solar envelope was proposed to maximize solar availability into the buildings
by the amount of absorption versus reflectance of radiation.55 Next, there were several studies to link the
indoor climates and to remove the mutual obstruction between buildings in the high density. The heating
and cooling gains highly relate to mutuality between outdoor and indoor environments. For example, the
air permeability gives the potential for airflow and ventilation cooling through a building. The
52 Landsberg 1981, Barry and Chorley 1987, Oke 1987, Oke et al. 1991, Escourrou 1991, Kuttler 2004.
53 Mills 1997.
54 Olgyay 1973, Markus and Morris 1980.
55 Knowles 1981.
４０
relationship between macro- and microclimate allows accurate analysis for building energy performance
and adaptations for a comfortable condition.
Extensive studies on microclimatology were done by Geiger et al. (1995) and by Landsberg (1981). The
influence of different slopes, ridges, valleys, and even glaciers on the microclimate is carefully studied.
The climatic factors are wind speed, access to solar radiation, humidity and temperature of the air, and
associated building factors are topography, orientation and building geometry. Table 3.1 shows the
climate factors of a building and related issues to analysis of microclimate effect.
Table 3.1. The factors and related issues [author].
Factors Related issues
Wind exposure Infiltration, ventilation level and energy distribution, thermo- and aerodynamic pressure
Sunlight exposure Local heating and pressure in the area
Precipitation
Moisture
Building materials, insulation performance
Wet materials degrade quickly and wet insulation conducts the heat.
Local temperature Energy balance, heating and cooling requirements
Building topography Access and the streamline of airflow to distribute the energy
Building orientation The amount of contact and access between outdoor and indoor climates
Indoor condition Heat gains and the absorption versus reflectance of radiation, air permeability for cooling
3.1.2. Microclimate design
The building microclimate can be achieved by building geometry, e.g. building surface, density, barrier,
terrain, 3D objects and huge plant etc., which introduces a pathway of airflow, a windbreak and a
non-uniform solar access etc. For example, a protected courtyard design against cold air can easily make
warmer than exposed situations. The deviation in climate plays an important role in architectural
planning. Most studies for microclimate have focused on the aspect proportion or height-to-width ratio,
the orientations and the form of buildings, and the mixture of materials, the density or the rate of
mixture.
Table 3.2 shows the planning issues by the factors of microclimate around building and the positive
effects. In site selection, favorable locations should be considered with every elevation difference,
character of land cover, which induce variations in a local climate. A less favorable site can be improved
by windbreaks and surrounding surfaces that induce an advantageous reaction to temperature and
radiation impacts. A good passive design which gives some shade in summer and allows the sun to
penetrate as much as possible in winter consider the positioning, orientation and height of buildings.
Deciduous trees aid to achieve the windbreak and seasonal irradiation impacts related to the albedo56 of
walls and other structures facing the sun. These make a substantial effect on the microclimate of
intervening spaces as well as the heating of the buildings themselves. The energy balance in form and the
56 The ratio of the amount of solar radiation is reflected by a body to the amount incident upon it.
４１
mixture of material is also related with the irradiation of floor and walls.57 Exposure versus shadow
patterns affects the surface temperatures and consequently the amount of heat transferred to air as the
sensible heat flux and consecutively the air temperature.58 The potential of airflow at low level also
depends on these factors.59 The building materials of the surfaces were also found to be decisive in the
heat storage rate60 as well as in the nocturnal cooling rate.61
Table 3.2. Planning issues and the effects [author].
Planning issues Effects
- Improved solar radiation for heating and lighting
- The use of insulation and draught proofing presents excessive
energy consumption.
Lower winter heating costs
- Wind, temperature and vapor variation for ventilation and cooling
- The provision of external shading, thermal mass and the use of
night cooling make comfortable indoor air condition.
Reduce overheating in summer and
exceedingly dry in winter
- High contact with the surrounding
- Well-balanced temperature and vapor on the site
-Pleasant outdoor air can be exchanged with indoor air.
Create more pleasant outdoor conditions
- Low impact of environment
- Pleasant outdoor condition
Improve growth of external plants and
trees
However, all of these studies have focused at only one side of the indoor or outdoor. Few researches
have performed for the microclimate of a building across outdoor and indoor to balance temperature and
humidity for human comfort. A spatial modeling of microclimate effects, which can affect the human
adaptive behavior to thermal stress,62 can be helpful to plan optimal energy loads in a house.
3.1.3. Climate design process
If a building has a control that reacts to climates, the results are presented in terms of the operative cost
for thermal comfort and the time when comfort is reached. Although the architecture design is
fundamentally correct in all aspects, thermal condition is uncertain. Hence, climate should be taken into
account at the early design stages deciding on the overall concept of a project, on the layout and
orientation of buildings, on the shape and the geometry on the spaces between buildings. Koenigsberger
et al. (1974) distinguished between three stages in climate design:
1. Forward analysis, which includes data collection and ends with a sketch design
2. Plan developments, which include the design of solar controls, overall insulation properties,
ventilation principles and activity adaptation
57 Mills 1997, Bourbia and Awbi 2004.
58 Nakamura and Oke 1988, Yoshida et al. 1990/91, Santamouris et al. 1999.
59 Hussein and Lee 1980, de Paul and Shieh 1986, Nakamura and Oke 1988, Santmouris et al. 1999.
60 Oke 1976.
61 Arnfield 1990, Mills 1997.
62 Thermal stress is defined as the physical and physiological reactions of the occupant to temperatures that fall outside of the
occupant’s normal comfort zone.
４２
3. Element design comprises closer examination and optimization of all individual design elements
within the frames of the agreed overall design concept.
This consecutive approach uses rather simple tools in the forward analysis which gives some overall
principles. Since in the last stage, it was practically impossible to go back and correct systematic errors,
only minor changes in thermal performance could be obtained by a different element design. To remedy
this, it is necessary to give the architect a set of methods and powerful tools which integrates data,
knowledge and case studies for climate adaptation in the planning process. Developing appropriate and
powerful tools and inclusion of evaluation and feedback in the system is therefore crucial to better
integrate climate issues in a design process. Since the climate fluctuation is highly unpredictable in a
short-term, a climate adaptation in a predictable way needs climate data over the long term. Information
of climate variables is collected and made available in a number of forms e.g. maximum and minimum
values, average values, probabilities and frequencies and time series.63
3.2. Arrangement
3.2.1. Microclimate effects adapting wind direction
Microclimate effects include spatially influenced phenomena, e.g. heat transfer, thermal balance,
humidification and insulation etc., which can be observed by partial differences in a local area. Since
partial differences form gradients, microclimate can be analyzed and visualized as a kind of flow with
the gradient. For example, if you are in a cold valley, your minimum winter temperatures may be lower
than what the other area indicates, because cold air is heavier than warm air and cold air is accumulated
in the valley. The main driving force causes the difference of air pressure and temperature, and the air
moves on the gradients with differences of air pressures and temperature. The difference of temperature
which derives air pressure and thereby airflow is called aerodynamic pressure and thermodynamic
pressure. The aerodynamic pressure often causes horizontal ventilation i.e. draught, and the
thermodynamic pressure causes vertical airflow from the bottom upwards.
Airflow through buildings occurs with the difference of the pressure across the building, and the
thermal balance may result in more comfort conditions for the same energy input. The airflow derives a
small movement of air and thermal buoyancy, e.g. stack effects. These effects change proportionally
according to strengths of the prevailing wind and the temperature. In principle, movement of air across
the building occurs between areas of negative (-) and positive (+) pressure. Microclimate effects are
observed between these polarities of pressure. Fig.3.1 (a) illustrates the polarities. When the building is
63 Dingman 2002.
oriented a
s
b
e much b
r
the errone
o
be well en
t
If opening
s
well distri
b
the actual
across the
b
around vo
l
(a)
Figure 3.
1
shadow, (
b
Fi
g
u
r
Other obv
i
volumes a
n
rise buildi
n
b
uildings
i
air passin
g
In order t
o
buildings
s
64 Baker and
65 Koenigsb
e
s
Fig.3.1 (a)
r
oader and
t
o
us analysi
s
t
e
r
ed
b
y wi
n
s
are widel
y
b
uted over
airflow rat
e
b
uilding. T
h
l
umes as Fi
g
1
. Wind str
e
b
) the patter
n
r
e 3.2. Wi
n
i
ous factors
n
d obstacle
s
n
gs and ob
i
n the leew
a
g
through th
o
avoid a s
h
s
houl
d
be o
v
Steemers 19
9
e
rger et al. 19
7
shows, a g
r
t
he negativ
e
s
of these e
f
n
dows and
y
distribute
d
the whole
b
e
. Natural
v
h
e shape an
g
.3.1 (
b
) sh
o
e
amlines a
r
n
for the b
u
a. Grid-
n
d streamli
n
affecting a
i
s
e.g. other
b
stacles oft
e
a
rd shadow
e inlets of
n
h
adow effe
v
e
r
at least
6
9
9.
7
4.
r
eater veloc
e
pressures
w
f
fects cause
s
distributed
d
over diffe
r
b
uilding.
64
T
v
entilation,
d orientati
o
o
ws.
r
ound a
b
ui
l
u
ilding for
m
iron layout
n
es and win
d
i
rflow arou
n
b
uildings, f
e
e
n increase
s
or the sucti
n
aturally ve
ct caused
b
6
times of t
h
４３
ity is creat
e
w
hich gene
s
inefficien
t
through th
e
r
ent façade
s
T
he resista
n
suction an
d
o
n of the bu
i
(b)
l
ding, (a) sc
m
s an
d
layo
u
d
shadow
by
n
d the buil
d
e
nces and t
r
s
the wind
p
on zone of
ntilated bu
i
b
y the seco
n
h
e height of
t
e
d on wind
w
rate suctio
n
t
window d
e
e
whole bui
l
s
of the buil
d
n
ce of airfl
o
d
infiltratio
i
lding are d
i
hematic di
s
u
ts
[Givoni 1
9
b. Checker-b
y
building
a
d
ing are the
r
ees etc. Th
e
p
ressures a
n
othe
r
struc
t
i
ldings. Fig
.
n
d row of
b
t
he first ro
w
w
ard faces,
a
n
effects wi
l
e
signs. For
l
ding.
d
ing, the su
b
o
w through
n occurs t
h
i
rectly relat
e
s
tribution o
f
9
69, Koenigs
b
oard layou
t
a
rrangemen
t
physical re
l
e
arrangem
e
n
d the air
v
t
ures has in
f
.
3.2-a sho
w
b
uildings,
t
w
of
b
uildin
g
a
nd the win
d
l
l be increa
s
cooling, th
e
b
sequent ai
r
the buildi
n
h
rough diff
e
e
d to the wi
f
wind pres
s
b
erger et al. 1
9
t
[Koenigsbe
r
l
ationship t
o
e
nt
b
etwee
n
v
elocity. T
h
f
luence on
t
w
s wind sha
d
t
he distanc
e
g
s obstructi
d
shadow
w
s
ed. Howev
e
e
wind sho
u
r
flows will
b
n
g determi
n
e
rent press
u
nd streamli
n
s
ure
and wi
n
9
74, Markus
a
Morris 198
r
ger et al. 197
o
surroundi
n
n
high and l
o
h
e position
t
he amount
d
ow effects
e
between t
h
ng the seco
n
w
ill
e
r,
u
ld
b
e
n
es
u
re
n
e
n
d
a
nd
0].
4].
n
g
o
w
of
of
.
65
h
e
n
d
４４
row of buildings. Alternatively, using a staggered in a checker-board pattern shown in Fig.3.2-b,
shadow and stagnant air zones are almost eliminated.
For the microclimate design, another important factor to choose building orientation is the wind
direction. The windward in the hot season and in the cold season in the place of construction should be
considered to decide the proper house direction which uses cool wind in summer and prevents the cold
wind from blowing into the house in winter. In Korean climate, the best orientation for the house is the
southeast because in summer the cool wind blows into the frontal windows and in winter the Siberian
cold wind blows from northwest.
3.2.2. Optimum building orientation
In the Passive House design, the building orientation is strongly related to the solar radiation. The
orientation of the building and its position on the site also have a strong influence on how and when
sunlight and air currents can enter, thus affecting daylight, air conditioning, ventilation and many other
aspects. The efficacy of passive methods included at later design stages depends largely on the initial
decision on how to situate the building within its immediate habitat. For example, east and west are bad
directions since all the year-round the solar radiation is more deeply into the room and the related air
temperature is the highest. The house facing southward is the best, because the solar radiation is little in
summer and is the highest in winter. The optimum building orientation of Seoul, Korea is simulated by
using average daily incident radiation on a vertical surface and the best orientation is South-Southeast
i.e. clockwise 157.5˚ from North. Fig.3.3 represents the simulation results using the sun path for energy
performance.
For summer cooling, the aerodynamic pressure using wind is much more important since room
Figure 3.3. House orientation considering the sun path [author].
temperatu
r
small. It is
The choic
e
and cold s
e
of the bui
l
house orie
n
gain, venti
Fig.3.4 sh
o
the directi
o
buildings
h
shapes mi
n
b
uilding o
r
because t
h
should be
m
Fi
g
ur
e
3.
2
Korea has
western se
eastern se
a
districts a
n
70% of th
e
W. Gropi
u
steep angl
e
rolling gr
o
r
es inside a
n
necessary
t
e
of the bui
l
e
asons in th
e
l
ding, the t
o
n
tation of t
h
lation and
s
o
ws the arr
a
o
n of the s
u
h
ave solar
w
n
imize wi
n
r
ientation i
n
h
e best sum
m
m
aximized
e
3.4. Schö
n
2
.3 Topog
a large a
m
a, rises pro
a
side. The
n
d the aver
a
e
whole lan
d
u
s noted th
a
e
of the su
n
o
un
d
e.g.
F
n
d outside
d
t
o organize
l
ding orien
t
e
place of c
o
o
pological
f
h
e local cli
m
s
hadow eff
e
a
ngement o
f
u
n and nat
u
w
ate
r
heatin
n
d shadow
s
n
Korean c
m
er ventil
a
for coolin
g
n
eiche (nea
r
raph
y
m
ount of to
p
gressively
i
total size
o
a
ge altitude
i
d
is slopes
o
a
t the south
e
n
during th
e
F
ig.3.5; the
d
iffer little
well horiz
o
t
ation depe
n
o
nstruction
f
eatures an
d
m
ate should
e
cts.
f
houses in
S
u
ral form
f
g panels w
h
s
when the
limate, i.e.
a
tion and s
o
g
.
r
by Berlin)
p
ography i
n
i
n the east
s
o
f the land
i
i
s 482m. T
h
o
f 20˚ and
m
e
rn exposu
r
e
hot seaso
n
orientatio
n
４５
in summer
o
ntal ventil
a
n
ds on the
fo
, the distrib
u
d
the requi
r
be chosen
b
S
chöneich
e
f
or the buil
d
h
ich are us
e
main win
d
hot-humid
o
lar shadin
g
ecological
h
n
the land.
s
ide and fo
r
i
s 99,284k
m
h
e plain are
a
m
ore.
r
e is superi
o
n
of the ye
a
n
of the bu
an
d
the th
e
a
tion by co
n
fo
llowing f
o
u
tion of sol
r
ements of
b
y statistic
a
e
, an ecolog
i
d
ing arran
g
e
d for hot w
a
d
flows fr
o
in summe
r
g
equipme
n
h
ouse com
p
The terrai
n
r
ms mount
a
m
2
. Most o
f
a
with the
g
o
r from the
ar
. Howeve
r
ildings sh
o
e
rmodyna
m
n
sidering t
h
o
ur factors:
a
r
radiatio
n
architectur
a
a
lly analyzi
n
i
cal house
c
g
ement. Th
e
a
te
r
and sp
a
o
m the no
r
r
and cold-
d
n
t to avoid
e
p
lex by Göl
l
n
of Korea
a
in ranges
w
f
the land
c
g
radient bel
o
living poi
n
r
, if the bui
o
uld
b
e adj
u
m
ic pressure
h
e direction
the wind d
i
n
on the dif
fe
a
l composi
t
n
g the facto
c
omplex w
h
e
south faç
a
a
ce heating.
r
th directio
n
d
ry in wint
e
e
xcessive s
o
l
ing and Sc
h
forms the
g
w
ith a stee
p
c
onsists of
l
o
w 5˚ is on
l
n
t of view
b
ldings hav
e
u
ste
d
from
is often v
e
of the hou
s
i
rection in
h
fe
rent surfa
c
t
ion. The b
e
rs of the so
l
h
ich consid
e
a
des of so
u
The buildi
n
n
. Otherwi
s
er
, is diffic
u
o
lar radiati
o
h
midt
[auth
o
g
ently lowi
n
p
slope on t
h
l
ow mount
a
l
y about 23
%
b
ecause of t
h
e
to be put
o
the south
e
e
ry
s
e.
h
ot
c
es
e
st
l
ar
e
rs
u
th
n
g
s
e,
u
lt
o
n
o
r].
n
g
h
e
a
in
%
.
h
e
o
n
e
rn
e
x
co
is
r
st
r
a
n
T
h
h
a
m
o
I
m
di
f
S
p
v
a
e
x
su
r
la
r
as
p
x
posure. Fu
r
nsidered as
r
eache
d
.
W
r
uctures sit
u
n
d maintain
i
h
e consider
a
a
s profound
o
dification
s
m
balanced
e
f
ference of
Figure 3.
(a)
Fi
g
ur
e
p
atial energ
y
a
riations in
x
posure cli
m
r
face as co
m
r
ger than in
p
ects at lati
t
r
thermore,
well. Whe
n
. Gropius a
n
u
ated on a
s
i
ng a bit of
p
a
tion of ter
r
effects on
s
in the mi
c
e
nergy mo
v
air pressur
e
5. Alumin
u
e
3.6. Solar
y
distributi
o
regions o
f
m
ate) is dete
r
m
pared wit
h
flat areas
a
t
ude of 45˚
N
the views
f
n
all these f
a
n
d M. Breu
s
loping hill
s
p
rivacy wit
h
r
ain in citie
the micro
c
c
roclimate
s
v
ement suc
h
e
caused by
u
m city terr
a
radiation o
n
o
ns of this
t
f
complex
t
r
mined by
t
h
a horizon
t
a
s Fig.3.6 (
a
N
at the tim
e
f
rom the h
o
a
ctors are b
a
er created s
s
ide, taking
h
walle
d
-i
n
s has an i
m
c
limate. S
m
s
ince the hi
l
h
as anaba
t
the differe
n
a
ce in Penn
s
n
slope, (a)
t
ype form
a
t
opography
t
he differen
t
t
al surface.
a
) represent
s
e
s of the eq
u
４６
o
use and t
h
a
lanced, an
imple, mo
d
advantage
n
porches in
m
portance f
o
m
all differe
n
l
ly area bri
n
t
ic and ka
t
n
ce of local
s
ylvania by
(b)
total daily
d
dist
a
a
n excellen
t
. Slope cli
t
amounts
o
The solar r
a
s
. They are
u
inoxes. Th
e
h
e wind di
r
opti
m
al pla
n
d
ern houses
,
of souther
n
the Alumi
n
o
r the hillsi
d
n
ces in slo
p
n
gs about t
h
t
abatic win
d
heat distri
b
W. Gropiu
d
irect-
b
ea
m
a
nce
b
etwe
e
t
b
ase or th
e
m
ate (som
e
f longwave
a
diation an
d
incident u
p
e
building
o
r
ection of t
n
with the l
o
,
grouped i
n
n
exposure,
n
um city te
r
d
e develop
m
p
e may cr
e
h
e differen
c
d
s forms o
b
ution
s and M. B
r
m
radiations
,
e
n
b
uilding
s
e
understan
d
e
times call
radiation r
e
d
wind vel
o
p
on slopes
o
o
rientation
r
he region
h
o
cation on
t
n
thirty-five
sharing gr
a
r
race housi
n
m
ent. The t
o
e
ate remar
k
c
e of energ
y
n the hill
d
r
eue
r
[Aroni
n
,
(b) shado
w
s
, a>b [Oke 1
9
ding of mi
c
ed terrain
e
ceive
d
b
y
a
o
city in slop
o
f differing
r
esults for t
h
North-facing
South-facing
h
ave to be
t
he contour
multi-unit
a
ssy lawns,
n
g.
o
pography
k
ably large
y
supplies.
d
ue to the
n
1953].
w
range for
9
87, author].
c
roclimatic
climate or
a
n inclined
e areas are
angles and
h
e morning
slope
slope
４７
are warmer and drain earlier in hillside areas by the sun especially toward the south. The maximum load
would be on a south 45˚ slope; whereas no direct-beam would reach north-facing slopes of greater than
45˚ angle. To avoid shading of building, the development of the slope site needs a distance considering
solar and topography angles between the buildings as
- tan
tan tan
hd
ad
α
α
β
=+ Eq.17
where a,b and d are respectively the distance between buildings and the size of a building. α and β are
respectively solar angle and topography angle. Fig.3.6 (b) represents the shadow range related to the
distance between buildings. South-facing slopes allow tighter spacing b without loss of sunshine. The
north façade has low energy flux density for large slope angle while the density is increasing for the
south façade. North-facing slopes need a wider range of a, or otherwise it causes severe overshadowing.
Developing slope area has higher building density than flat area since the building on the slope is more
suitable to get sunshine. When the slope angle is larger, smaller pitch of building considering sunshine
and higher land using rate are available. However, the careful design to maintain the scenic view is
needed.
By day, the air above the slopes can be more easily heated than the center of the lower land. Fig.3.7 (a)
illustrates the interplay of slope and valley winds during a clear summer day with light winds. As the
day progresses, the down-valley wind dies out with further heating. In the evening, the down-slope
wind sets in. The slope winds are anabatic, and the valley wind fills the valley and moves upstream with
the anti-valley wind coming downstream. Unstable upslope (i.e. the anabatic) flow arises with a closed
circulation across the land involving air sinking in the center. It is at speeds of 2m s-1 to 4m s-1 with a
maximum at about 20m to 40m from the surface.66 In hot and humid condition, it leads to the greater
precipitation along the ridges. Since the cross-valley circulation effectively transports the sensible heat
from the surrounding surfaces to warm the whole valley atmosphere, the valley air is much warmer and
a plain-to-mountain flow develops. Since the maximum pressure gradient is near the surface, the
maximum wind speed is as close to the ground. Above the ridges, an anti-valley air flowing down the
valley occurs through day.
At night, the slope winds are katabatic and reinforce the mountain wind that flows downstream, with the
anti-mountain air flowing in the opposite direction above. Since the valley surfaces are cool by the
emission of longwave radiation and cool air is heavier than warm, the outgoing radiation at night causes
a cold air layer to form near the ground surface and the air slides down. These katabatic winds usually
flow at about 2m s-1 to 3m s-1, but greater speeds are observed where the cold layer is thicker and where
the slope is steeper. Cold air behaves somewhat like water flowing towards the lowest points. The
66 Geiger et al. 1995.
４８
convergence of these slope winds at the valley center result in a weak lifting motion. All of these
katabatic flows combine into a down-valley flow known as the mountain wind that seeps out of the
mountain valleys onto the adjacent lowlands. The anti-mountain winds flow up valley aloft. The
drainage of cold air down-slope or down-valley intermittently surges rather than a continuous flow. On
winter nights, some valleys would be colder than neighboring slopes about 10˚ and more. Airflow
occurs towards the valley floor. According to Geiger et al. (1995), valley walls affect the distribution of
the nocturnal temperatures by dam action, and the concave terrain forms cold air lakes or cold air
puddles.
(a) a.Sunrise b.Morning c.Midday d.Afternoon e.Evening
(b)
Figure 3.7. Slope wind systems, (a) interplay of slope and valley winds for a day, (b) streamlines in
slopes and building arrangement [Geiger et al. 1995, Franke 1977].
Fig.3.7 (b) shows an example of the building arrangement for streamlines in slopes. A wind is blocked
by the setbacks of buildings and plantation of trees along the streets. The arrangement of buildings takes
the shape of the natural streamline, wind effectively produces the induced air movement through the
wind paths. Natural ventilation of a building is affected by the streamlines resulting from the prevailing
wind path over the natural terrain and existing obstructions of the site. The exposure to airflow will
affect the air infiltration through the building shell.
Oke (1987) introduced the flow over moderate topography. The varying elevation of the surface over
moderate topography i.e. slope up to about 17˚, usually brings about the adjusting flow. Essentially an
increase in the ground elevation which vertically constricts the flow results in acceleration. Conversely,
a drop of elevation results in a deceleration. Fig.3.8 represents some topographic forms in comparison
of the flows. The increasing elevation results in speeding up to the maximum at the hilltop. On the hill,
a wind speeds up over it like a ridge, but also around it with a maximum at the summit and on the
valley’s neck forms a jetting through the gap with a maximum at its narrowest point. The decreasing
elevation results in slowing down with a minimum speed near the base of the slope for flow downwards.
On a valley, the wind speed decreases and forms the maximum shelter near its floor. Talyor and Lee
(1984) ob
s
where
up
u
i
above the
h
hill or top
o
0.8 for c.
a. Ridge
Fi
g
ure 3
.
(
a
(
b
Figure 3.
9
The drawi
n
has been b
u
slope roof
,
middle pa
r
slope angl
located ge
n
placement
winter). T
h
from the n
o
reduces 3
0
b
ackside
w
s
erved thes
e
i
s the upstr
e
h
illtop. H i
s
o
f the upstr
e
b
.
8. Airflow
a
)
b
)
9
. Utilizatio
n
n
g of Fig.3
.
u
ilt adapta
b
,
four stagg
e
r
t. The dep
t
e. Fig.3.9
(
n
erally on
t
has an ad
v
h
e backside
o
rthwest. T
0
% to 50%
w
all is the s
e
e
wind spee
d
e
am mean
w
s
the heigh
t
e
am point
w
b
. Valley
patterns ov
e
n
of topogr
a
Ko
r
.
9 (a) show
s
b
le on a nor
t
e
red levels
t
h of the ho
u
(
b) represe
n
t
he south s
l
v
antage to
b
(i.e. north)
he hill wit
h
of the flo
w
e
condary
b
l
o
d
s and they
m
a
u
w
ind spee
d
a
t
of the top
o
w
here the h
e
c. Step u
p
e
r moderat
e
a
phy and sit
e
r
ean traditi
o
s
a house d
e
t
hwest slop
e
were desig
n
u
se is not
v
n
ts a hillsi
d
l
ope that h
a
b
lock the
S
hill and tr
e
h
trees prod
u
w
rate dep
e
o
ck to avoi
d
４９
suggested
t
a
xup
/1u
C
=
+
a
t the same
h
o
graphic fe
a
e
ight equal
s
p
d
e
topograp
h
e
condition
,
o
nal archit
e
e
sign with
a
e
, where is
o
n
ed that ar
e
v
isible fro
m
d
e house o
f
a
s a site co
n
S
iberian co
n
e
es play a r
o
u
ces a relat
i
e
nding on
t
d
the slow
w
t
he maxim
u
(/)
C
HX
h
eight abov
e
a
ture and
X
s
H/2. C is r
e
d
. Step down
h
y,
maximum
,
(a) house
b
e
ctural sche
m
a
suitable i
d
o
n 13m sli
m
e
divided b
y
m
the hill si
d
f
Korea. Th
n
dition wit
h
n
tinental ai
r
o
le as valle
y
i
vely large
w
t
he distanc
e
w
ind with a
r
u
m amplifi
c
e
its local s
u
X
is the dist
a
e
commend
e
e.
H
point (●), mi
n
b
y Körner a
n
m
e
[Gunßer
2
d
ea on an e
x
m
wide and
4
y
the two st
o
d
e. The roo
f
e Korean t
r
h
obstacles
r
flow (i.e.
t
y
walls to a
v
w
ake size a
c
e
between
t
r
elatively s
m
c
ation facto
r
u
rface and
u
a
nce from t
h
e
d 2.0 for a
,
H
ill
n
imum point
(
○
n
d Stotz in
M
2
001, K.H. L
e
x
treme slo
p
4
5
m
depth s
o
rey winter
f
is tilted 2
2
r
aditional
a
of trees a
n
t
he northw
e
v
oid the str
o
c
ting as a
w
t
he individ
u
m
all wind
w
r
as,
Eq.
max
u
is the spe
h
e c
r
est of t
h
,
1.6 for e a
n
f. Valley’s n
e
○
) [Oke 1987
]
M
urrhardt,
e
e 1986, auth
o
p
e. This ho
u
ite. Under t
h
garden in t
h
2
˚ follows t
h
a
rchitecture
n
d walls. T
h
e
st airflow
o
ng cold wi
n
w
indbrea
k
t
h
u
al trees. T
h
w
ake area. T
h
18
ed
h
e
n
d
e
c
k
]
.
(b)
o
r].
u
se
h
e
h
e
h
e
is
h
is
in
n
d
h
at
h
e
h
e
w
a
ar
c
m
e
tr
a
T
h
b
r
i
co
fe
a
th
e
pr
o
e
x
sq
u
oc
F
o
le
e
bu
bu
gr
e
o
f
K
o
Fi
g
pr
o
co
67
N
68
S
a
ll is not on
l
c
hitecture
i
e
ntioned
m
a
ditional ar
c
3.2.4
.
h
e investig
a
i
ngs about
m
urtyard is
f
a
ture drive
n
e
building
o
tection is
x
ceeding th
e
u
are court,
cu
r
throug
h
a. Square
o
r the fully
e
ward side
u
ilding face
u
ilding face
.
e
ater depth
f
height h, n
o
o
rean tradit
i
g
.3.11 sho
w
o
fitable wit
h
mposite la
y
N
akamura an
d
S
aini 1970.
l
y visual b
u
i
s an effic
i
m
icroclimat
e
c
hitecture s
c
.
Building
a
tion on re
a
m
icroclima
t
f
ormed as
F
n
by the abo
v
may be or
i
maintained
e
size of 3
A
i.e. “H” s
h
h
wind side
s
b.
R
Figur
e
exposed s
p
of the
b
uil
d
W. The a
m
.
By a co
m
with a win
d
o
effects
by
i
onal house
w
s. For the
h
the south
e
y
ers need t
o
d
Oke 1988,
S
u
t also the
w
i
ent open
s
e
effects.
F
c
heme.
attachm
e
a
l geometri
c
t
e effects a
s
F
ig.3.10 sh
o
v
e-roof wi
n
i
entated in
within the
A
, the long
h
ape, has t
h
s
lip around
R
ectangula
r
e
3.10. Sev
e
p
ace, the er
e
d
ing. The
e
m
ount of
w
m
bination o
d
protectio
n
y
airflow ar
e
constructi
o
arrangem
e
e
asterly wi
n
o
avoid lar
g
S
antamouris e
t
w
ind control
s
pace zoni
n
F
ig.3.9 (b)
e
nt and c
o
c
arrangem
e
s
much as b
u
o
ws. The w
nd
.
67
The ce
any direct
i
depth not
axis shoul
d
h
e same eff
i
building li
m
c. “H
”
e
ral types o
f
e
ction of a
e
fficiency o
w
in
d
enteri
n
f side barri
n
, since thes
e
evident u
p
o
ns also ha
v
e
nt, archite
c
n
d, this is t
h
g
e win
d
s a
n
t
al. 1999.
５０
element. T
h
n
g conside
r
represents
o
urtyard
e
nt rather
t
u
ilding geo
m
ind passin
g
ntral court
y
i
on. If the
exceeding
d
be perpen
i
ciency wit
h
m
its the de
p
”
form d.
f
court for
w
b
arrier is
e
f a barrier
i
n
g the cour
t
ers and ro
o
e elements
p
p
to a dista
n
v
e
b
uilding
c
ts conside
r
h
e main win
n
d be able
t
h
e gradatio
n
r
ing the K
the Kore
a
t
han scatter
e
m
etry. Wh
e
g
ove
r
the l
i
y
ard perfect
l
depth of t
h
3 times of
d
icular to t
h
h
the centr
a
p
th of the c
o
Perimeter re
c
w
ind protec
t
e
ssential an
d
i
s related t
o
t
yar
d
incre
a
o
f overhang
p
rotect bot
h
n
ce of 6.10
m
attachment
s
r
ed the mai
n
d in summ
e
t
o give a c
o
n
al blockin
g
orean seas
o
a
n seasonal
e
d buildin
g
e
n a buildin
g
i
nked
b
uil
d
l
y protects
t
h
e courtya
r
building si
z
h
e win
d
di
r
a
l square c
o
o
urt to 3A.
c
tangula
r
e
t
ion
[Saini 1
9
d
the prote
c
o
the heigh
t
a
ses with
u
s, the encl
o
h
overhead
a
m
from the
b
s
of walls a
n
wind dir
e
e
r, annex b
u
o
mfortable
b
g
in Korean
o
nal airflo
w
airflow p
g
is import
a
g
links to t
h
d
ings has a
c
t
he direct
w
rd
W is ch
a
z
e A. For
a
r
ection.
68
A
o
urtyard. E
d
e
. With a bar
r
9
70].
c
tion shoul
d
t
h and dis
t
u
nit distanc
e
o
sure is ext
e
and side. F
o
b
uilding fa
c
nd annex b
u
e
ction. In
o
u
ildings and
b
reeze on
t
traditional
w
and the
attern and
a
nt since it
h
e others, a
c
irculation
w
ind even if
a
nged, the
a
courtyard
A
perimeter
d
dy whirls
r
ie
r
d
be to the
t
ance from
e
from the
e
nded to a
o
r a barrier
c
e.
u
ildings as
o
rder to be
outer wall
t
he floored
room of t
h
flow of s
m
and north
w
the annex
courtyard
b
wind. The
building a
n
Dokrak-D
a
and have
e
like cells.
(a)
a.
M
Fi
g
ure
3
Fig
u
If air flow
s
the aspect
the windw
a
buildings
a
wake inter
f
wind lead
s
69 Hussein a
n
70 Hosker 19
h
e main bui
l
m
all wind ea
s
w
est wind i.
building is
b
etween th
e
Korean
bu
nd
its anne
x
a
n
g
which
i
e
xpanded u
n
M
ountain area
3
.11. Buildi
n
u
re 3.12. Ai
s
over buil
d
ratio
69
(H/
W
a
r
d
and lee
w
a
s a. When
f
erence flo
w
s
a skimmi
n
n
d Lee 1980.
85.
l
ding. Sma
l
s
y.
In mou
n
e. continen
located in
e
main buil
d
u
ilding for
m
x
es. Fig.3.1
i
s a model
o
n
til 1835.
E
b. Co
a
n
g attachm
e
rflow patte
r
d
ing arrays,
W
) and buil
d
w
ar
d
exists
,
the H/W i
n
w
as b. Wit
h
n
g flow sho
w
l
l internal
d
n
tain area, a
tal cold wi
n
front of th
e
d
ing and a
n
m
s organic
1 (b) repre
s
o
f Seouler
G
E
ach buildi
n
a
stal area
e
nt, (a) ann
e
r
ns corresp
o
the microc
l
d
ing ratio
70
,
the isolate
d
n
creases, i.
e
h
further in
c
w
n in c.
５１
d
epth make
s
form usin
g
n
ds in wint
e
e
main buil
d
n
nex buildi
n
spaces wi
t
s
ents the la
y
G
arten in B
e
n
g has an i
n
e
x building
o
nding to t
h
l
imate is m
o
(L/W) as s
h
d
roughnes
s
e
. a narrow
c
rease of H
/
s
the interp
e
g
Korean al
p
e
r as Fig.3.
1
d
ing to bre
a
n
gs shown i
n
t
h a layere
y
ered open
s
e
rlin. The b
u
n
dependent
(
against re
g
Dokr
a
h
e function
o
o
re comple
x
h
own in Fi
g
s
flow occu
r
courtyar
d
,
W, the cour
t
e
netration
o
p
habet “
ㄱ
”
1
1 (a)-a sh
o
a
k the sea
b
n
Fig.3.11
(
d structure
s
paces in a
K
u
ildings in
K
space whic
h
(
b)
g
ional wind
,
a
k-Dang
[S.
J
o
f H/W an
d
x
. Three p
a
g
.3.12. Wh
e
r
s in a cour
t
the wakes
a
t
yard
b
eco
m
o
f solar rad
i
is use
d
to a
v
o
ws. In the
b
reeze of t
h
(
a)-b does
n
by the w
a
K
orean tra
d
K
orea wer
e
h
is divide
d
,
(b) layere
d
J
. Lee 1988,
M
d
L/W
[Toud
e
a
tterns are
d
e
n no inter
a
t
yard
b
etwe
e
a
re disturb
e
m
es isolate
d
i
ation and t
v
oid the no
r
coastal are
a
h
e frontage.
n
ot have lar
a
lls, the m
a
d
itional ho
u
e
built in 14
6
d
by the wa
d
structures
M
.K. Kim 20
0
e
r
t
2005].
d
ifferent du
e
a
ction betw
e
e
n well spa
c
e
d leading
t
d
and roof l
e
he
r
th
a
s,
A
ge
a
in
u
se
6
3
lls
of
0
1].
e
to
e
en
c
ed
t
o a
e
vel
In
b
e
co
Fi
g
dr
y
d
a
I
m
ra
d
to
n
o
co
ab
T
h
If
t
tr
a
a
m
v
o
a
x
ab
in
c
71
B
72
S
73
S
74
W
75
W
the courty
a
tween i
n
-c
urtyard ca
n
g
.3.13 expl
a
y
ground h
e
a
y, and at ni
F
m
permeable
d
iation or e
n
discomfort
o
rthern faça
nfiguration
ove the roo
h
e speed of
- The a
m
- The v
e
- Adve
c
t
he wind sp
a
nsmit mor
e
m
bient air a
t
o
rtex, and t
h
x
is generate
s
ove a roo
f
c
idence im
p
B
ensalem 19
9
S
ini et al. 199
S
antamouris
e
W
edding et al
W
iren 1985/8
7
a
r
d
dwelli
n
ourtyar
d
a
n
n
be forme
d
a
ins the th
e
e
at up quic
k
ght, they w
i
F
i
g
ure 3.13
.
surfaces s
u
n
ergy resp
e
conditio
n
s
des which
a
s.
71
The vo
r
f. If the irr
a
the vortex
i
m
bient ai
r
f
l
e
rtical laye
r
c
tion from t
eed above
a
e
energy fr
o
t
the buildi
n
h
e transvers
a
s
the uplift
i
f
with som
e
p
roves the
i
9
5.
6, Kim and B
e
t al. 1999, B
a
. 1977, Dabb
e
7
, Bensalem
1
n
g, a stable
n
d above
r
d
by therm
a
e
rmal syste
m
k
ly and the
i
ll reradiat
e
a. Day
.
The ther
m
u
ch as soli
d
e
ctively. As
or increas
e
a
re slightl
y
r
tex transp
o
a
diated sur
fa
i
s related to
l
ow above t
h
r
of air in t
h
he corners
o
a
roof is lar
g
o
m the uppe
n
g corne
r
.
T
a
l compone
n
i
ng flow al
o
e
angle to
t
i
ndoor vent
i
aik 1999.
a
ik et al., 200
0
e
rdt et al. 197
3
1
991.
circulatory
r
oof-level.
a
l im
b
alanc
e
m
of court
y
reflected
h
e
the heat st
o
m
al system o
d
roofs and
a result, a
m
e
d energy
u
y
1~2℃ co
o
o
rts the heat
fa
ces are sh
i
three mec
h
h
e roofs
h
e courtyar
d
o
f building
s
g
er, the vort
e
r to the lo
w
T
he parall
e
n
t drives th
e
o
ng the w
a
t
he buildin
g
i
lation in c
o
0
.
3
, Nakamura
５２
vortex is
e
Even with
e
s due to t
h
y
ard dwelli
n
h
eat radiati
o
o
red durin
g
f a courtya
r
streets infl
u
m
bient tem
p
u
se for cool
i
o
ler due to
and excha
n
i
fted, the fl
o
h
anisms,
73
d
s
e
x enlarges
w
er vortex.
T
e
l compone
n
e
vortex in
t
a
lls due to t
g
axis, a s
p
o
mparison
t
and Oke 198
8
e
stablished
light win
d
h
e geometr
y
n
gs. Since
a
o
n influenc
e
g
the day.
rd
house
[K
o
u
ence the
m
p
eratures su
r
i
ng. Howe
v
the self-sh
a
n
ges warmi
n
o
w regime i
since the h
i
T
he wind d
i
n
t of win
d
s
t
he courtya
r
he increas
e
p
iral-type
v
t
o a perpen
d
8
, Santamouri
s
by the cor
r
d
s, the cir
c
y
of courty
a
a
djacent bu
i
e
s towards
t
b. Night
o
enigsberger
e
m
icroclimat
e
r
rounding
b
v
er, the dee
p
a
ding prop
e
n
g air in th
e
s also alter
e
i
gher ambi
e
i
rection mo
d
determine
s
r
d. A parall
e
e
d friction
n
v
ortex is in
d
d
icular inci
d
s
et al. 1999.
r
elation of
w
c
ulatory vo
r
a
rd and the
i
ldings, pav
t
he buildin
g
e
t al. 1974].
e
by impac
t
b
uildings ri
s
p
est courty
a
e
rties of th
e
e
courtyard
f
e
d to others
e
nt winds c
o
d
ifies the i
n
s
the stretc
h
e
l wind to t
h
n
ear the w
a
d
uce
d
.
74
T
h
d
ence.
75
N
o
w
ind spee
d
r
tex in th
e
irradiation
.
ements an
d
g
during th
e
t
ing on the
s
e and lead
a
r
d
has the
e
courtyard
f
or cool air
.
72
o
ntribute to
n
cidence of
h
ing of the
h
e building
a
ll. A wind
h
is oblique
o
n-uniform
d
e
.
d
e
b
uilding h
e
3.3 For
m
3.
3
3D objects
flow and l
o
speed in c
o
interruptin
comprehe
n
sense of c
o
shutting
bu
(a
)
(c
Fi
g
ur
e
Oke (198
7
b
arrier is
v
no penetra
t
from the b
wind spee
d
76 Chan et al
.
77 The Maru
e
ights and
a
m
3
.1. Wind
b
such as wa
o
calize cli
m
o
mparison
g a visual
r
n
ded as a cl
o
o
ntinuity to
u
t also micr
)
)
e
3.14. Barr
i
7
) introduc
e
v
ery dense,
w
t
ion. Howe
v
arrier incre
d
is shown
.
2001.
is a wood-flo
a
wider cou
r
b
reak
ll and huge
m
ate. The in
f
to the upw
i
r
ange and
t
o
sing devic
e
the court s
p
oclimate m
i
er usage a
n
speed
i
ed
that win
d
w
ind speed
v
er, the wi
n
ases. The r
e
in Fig.3.1
4
ored veranda
h
r
tyar
d
also
p
plants can
p
f
luence is
m
i
n
d
. Layer
e
t
he large d
o
e
from the
o
p
aces. The
l
odification
s
n
d the influ
e
i
n the vicin
i
d
speed ca
n
is conside
r
nd
speed re
l
e
lationship
4
(c). If the
h
in front of a
５３
p
romote th
e
p
rotect win
d
m
easure
d
by
e
d structure
s
o
or in the
w
o
utside but,
l
ayered wa
l
s
.
(b)
e
nce, (
a
) la
y
i
ty in the o
p
n
be modif
i
r
able imme
d
l
atively qui
c
between th
e
barrier wi
d
roo
m
shown
e
ventilatio
n
d
and radiat
e
y
the perce
n
s
of Korea
n
w
alls as Fi
g
seen the po
l
l structure
o
y
ered walls
p
en, (c) wi
n
i
ed by a ba
d
iately red
u
c
kly regain
s
e
height of
d
th is signi
in Korean tra
d
n
and the m
e
heat. So
m
n
tage of red
u
n
traditiona
l
g
.3.14 (a) r
e
int-of-vie
w
o
ffers not
o
of Korean
a
n
d streamli
n
rrier with
d
u
ced to the
“
s
its forme
r
barrier h a
n
ficantly lar
g
d
itional archi
t
ixing of ai
r
m
etimes the
y
u
ction of h
o
l
houses u
s
e
presents.
T
w
fro
m
M
ar
u
o
nly a visua
l
a
rchitectur
e
n
e zones
[au
t
d
ifferent de
“
lee eddy”
d
r
value whe
n
n
d the dista
n
ger than h,
t
ecture.
.
76
y
block ener
g
o
rizontal wi
n
s
es low wal
T
he barrier
u
,
77
provide
s
l
opening a
n
e
,
(b) the wi
n
t
ho
r
, Oke 198
nsities. If t
h
d
ue to little
n
the dista
n
n
ce relate
d
the flow c
g
y
n
d
ls,
is
s
a
n
d
n
d
7].
h
e
or
n
ce
to
an
５４
eliminate. Therefore, the pattern of wind speed in the lee conforms more to that of a high density
barrier, so no advantage is gained. The lines are parallel to the direction of flows. Airflow encounters a
solid barrier placed normal to its original direction. The horizontal and vertical dimensions in terms of
the barrier height are efficient to compare the effects of different-sized barriers. The barrier affects flow
to at least 3h above the surface. If a 10% speed reduction is assumed, the air passing by a solid barrier
provides its influence to about 10h to 15h downwind.
A barrier with low density provides a “cushion” in the cavity zone. The point with 90% recovery of the
wind speed occurs at 15h to 20h. The reduced wind speeds can be observed as far as at the 40h. A
drawing in Fig.3.14 (b) represents a distribution of wind speed and a medium density windbreak. The
finite length of the barrier generates the spatial pattern which areas near the ends of the barrier
experience increased wind speeds and probably greater turbulence. Behind a barrier, decreased
turbulence reduces the fluxes of heat and the microclimate vertical profiles are steeper than in the open.
The barrier being perpendicular to the wind is more effective. In a day, the sensible heat gives higher air
temperatures than in the open. At night, radiative heat loss on the surface is not efficiently replenished
from the atmosphere, and thus the air temperatures are lower.
Woodruff and Zingg (1952) found the windward reduction in velocity through the analysis of airflows
around four types of barriers, i.e., vertical plate, triangular and cylindrical shapes and model trees, using
11.176 m s-1 input velocity as Table 3.3 represents. There is no 75% reduction for trees since there is a
jet movement in the air through them. Trees cause a more extended area of protection than other shapes.
This is marked by the 27h distance to a 25% reduction and the relatively great distance between a 25%
and a 50% reduction in velocity. The vertical plate ranks the second best protection reducing about 44%
more than the cylindrical shape. The plate also reduces the velocity about 10% more than the triangular
shape at both near and far distances.
Table 3.3. The amount of wind reduction measured against varying heights and object shapes [Woodruff
and Zingg 1952].
The surrounding plants are a modifying factor to improve the microclimate.78 They are advantageous to
the neighboring building due to the effects on the meteorological factors, e.g. Ta, RH or v, or to the
induced energy savings in the buildings such as a result of less heating and/or cooling loads. The three
main properties to improve the microclimate for the site comfort are shading, humidification i.e.
78 Escourrou 1991, Akbari et al. 1995, Avissar 1996, Taha et al. 1997.
Object 75% reduction 50% reduction 25% reduction
Vertical plate 13.0 h 15.5 h 21.5 h
Triangular shape 10.5 h 15.0 h 20.5 h
Cylindrical shape 7.0 h 9.0 h 14.0 h
Model trees - 13.5 h 27.0 h
５５
evapotranspiration and windbreak.79 A numerical modeling or a comparison of various scenarios have
been performed in a number of related issues such as the seasonal growth of plants and changes of
density and size etc.
Fig.3.15 shows that the composition of a Korean traditional house is a large front yard and a small
backyard. Thermodynamic ventilation occurs due to the radiation difference between the front yard and
the backyard. The front yard should not have large plants that can disrupt the breeze in summer, the
dense and large plants in the backyard enables to block the reflection of solar radiation and the cold and
strong wind in winter. The residential area has 50% less wind speed by the dense and large plants.80 The
thermodynamic ventilation acts even in the absence of wind since it occurs with the difference in air
density between indoor and outdoor.
Trees in the backyard increase shadow in summer, and the kind of tree and a proper position is chosen to
increase the amount of shadow for the hottest time. The leaves absorb most of the solar radiation,
transform a part of the radiant energy to the chemical energy by photosynthesis, and thereby reduce the
heating rate of the yards. The air temperature decreases about 3℃ to 5℃ on a fine day. Dense plants
produce a relatively small wind wake area and the recirculation region with low velocity eddies behind
the obstruction. A short and high line of trees, on the other hand, can produce a relatively large wake size
acting as a windbreak.81 The density of plants generates distinct flow patterns. For a line of plants
starting at about 1.5m from the ground, 30% to 50% of the airflow rates can be according to the distance
between the individual trees. Since the wind can flow underneath and between large plants such as tree,
the distance with the building is not significant for the ventilation purpose.
Figure 3.15. Shading of backyard [K.H. Lee 1986].
Table 3.4. The effects of planting in Chicago [McPherson and Nowak 1993].
Effect Reducing energy efficiency (%)
Summer Shading 37
Evapotranspirative cooling 42
Winter Lower wind speeds 21
79 Moffat and Schiler 1981.
80 McPherson et al. 1994.
81 Honjo and Takakura 1990, McPherson et al. 1994
M
c
5
0
A
n
A
b
e
Si
n
d
o
di
r
te
n
T
h
bu
W
T
h
A
n
m
a
co
82
T
w
c
Pherson a
n
0
% to 65%
n
nual savin
g
tree locate
d
nefits are s
l
3.3.2
.
n
ce a
b
uil
d
o
wnwind e
d
r
ection and
n
dency to
d
h
e building
u
ilding faça
d
W
due to the
s
h
e optimal
g
n
energy-s
a
a
ximize th
e
nvex curv
a
T
he Chicago
U
w
ithin urban
a
n
d Simpso
n
energy-sa
v
g
s created
p
d
for shadin
g
l
ightly low
e
.
Building
d
ing perfo
r
d
dy. The sh
a
speed of
w
d
isappea
r
.
F
shape wit
h
d
e. The inc
r
s
ideslip of
a
g
eometric
fo
a
ving house
e
energy-sa
v
a
ture on the
Fi
Fi
g
ure
3
U
rban Forest
C
a
reas influenc
e
n
(1995) ass
v
ings from
g
p
er tree are
a
g
the west
w
er
b
y the ne
g
geometr
y
r
ms as a v
e
a
pe of win
d
w
ind. If th
e
F
ig.3.16 rep
r
h
the
b
uildi
n
r
ease in the
a
i
r
. Increas
fo
rm has be
shown in
F
v
ing. The
d
south side
g
ure 3.16.
T
3
.17. Energ
C
limate Proj
e
e
s local clim
a
essed vario
u
g
reen cove
r
a
s shown in
w
all is as ef
f
g
ative effe
c
y
and for
m
e
ry dense
d
depends o
n
e
main air
s
r
esents the
n
g’s height
unit buildi
n
ing the
b
ui
l
en modele
d
F
ig.3.17 ha
d
isc-like
b
u
i
consisting
T
he effects
y-saving h
o
e
ct (CUFCP)
w
a
te, energy-us
e
５６
u
s trees’ pr
o
r
in reside
n
Table 3.4.
T
f
icient as t
w
c
ts of obstr
u
m
solid
b
arri
e
n
the chan
g
s
tream bec
o
relationshi
p
h and the
l
n
g length L
l
ding size A
d
for energ
y
s an untyp
i
i
lding geo
m
of coated
h
of buildin
g
o
use at Flä
m
w
as establish
e
e
and air qual
i
o
perties on
n
tial areas
w
T
he efficie
n
w
o identical
u
ction in wi
n
e
r, the bui
l
g
es in the p
r
o
mes turbu
l
p
between
b
l
ength L m
o
i
n
creases t
h
enlarges t
h
y
-saving of
cal shape
o
m
etry, that
s
h
eat-insula
t
g
geometry
[
m
ing Str. in
[w
w
e
d to increase
i
ty.
energy-sav
w
here the
e
n
cy also de
p
trees on th
e
n
ter.
l
ding geo
m
r
oportion o
f
l
ent during
b
uilding sc
a
o
difies the
a
h
e size of d
o
h
e length o
f
a prefabric
o
f volume
a
s
tands faci
n
t
ing glass.
T
[
Saini 1970].
Berlin by
A
w
w.stadten
t
-w
i
the understa
n
ings. Chica
e
nergy nee
d
p
en
d
s on the
e
east. On t
h
m
etry also
a
f
the buildi
n
flow, the
w
a
les and wi
a
mount of
w
o
wnwind e
d
f
downwind
ated apart
m
a
nd positio
n
n
g to the s
o
T
he conve
x
A
. Salomon
i
cklung-
b
erli
n
n
ding of how
a
go
82
gaine
d
d
s are high
.
orientatio
n
h
e south, th
e
a
ffects the
n
gs and the
w
ind has a
nd shapes.
w
inds in a
d
dy current
eddy.
m
ent block.
n
setting to
o
uth, has a
x
curvature
& Scheidt
n
.de, author].
a
fforestation
d
.
n
.
e
increases t
h
allows the
b
alconies
a
narrow pr
o
with stair
c
b
athrooms
ambivalen
t
does not e
x
3.
3
The indoo
r
interconne
with still a
i
is the rea
s
partitionin
g
conjunctio
velocity e
v
Subdivisi
o
average s
p
number o
f
from inlet
t
(a)
a. 42
(b)
Figure 3.
1
h
e solar ac
c
sunlight e
a
nd balustr
o
files create
c
ases is an
forms a
h
t
and unsat
i
x
ceed over
4
3
.3. Intern
r
building
g
cted rooms
ir
since the
y
s
on why t
h
g
. If the wi
d
n
with oth
e
v
en in a lar
g
on
s with in
n
p
eed being
f
airflow pa
t
t
o outlet op
%V b. 44.
1
8. Internal
c
ess, and a
c
ntering the
ade railing
s
a lightwei
g
almost clo
s
h
eat buffer
i
sfying hig
h
4
0kWh m
-2
al partiti
o
g
eometry f
o
with the i
n
y
drop the
a
h
e multi-z
o
d
th of a
b
uil
d
e
r rooms.
H
g
e volume.
n
er walls re
d
from 44.5
%
t
terns as Fi
g
enings or f
o
5%V c.
a. Floor pla
n
airflow pa
t
c
ontinuous
room eve
n
s
and the t
r
g
ht appeara
n
s
e
d
and hi
g
for the ro
o
h
perforate
d
.
o
ning
o
rms with i
n
n
ternal part
i
a
ir velocity
a
o
ned buildi
n
d
ing is gre
a
H
owever,
p
d
uce the int
e
%
to 30.5
%
g
.3.18 (a) s
h
o
rces it to c
h
31%V d.
n
t
terns using
５７
row of bal
c
n
in winter
r
ansparent
f
n
ce for the
b
g
hly insulat
e
o
ms facing
d
wall. The
n
ternal part
i
i
tions. The
i
a
nd make t
h
n
gs usuall
y
a
ter than the
p
artitioning
e
rnal veloc
i
%
. The arr
a
h
ows. The
w
h
ange direc
t
39.9%V
several pa
r
c
onies with
. The hori
z
f
açade laye
b
uilding. T
h
e
d with ve
r
south an
d
energy co
n
i
tioning. A
n
i
nternal pa
r
h
e distribut
i
y
have ver
y
depth of it
s
with a pr
o
i
ties of the
w
a
ngement o
w
indow lo
c
t
ion a num
b
e. 36.4%V
b. S
e
r
titions, (a)
t
in comple
x
transparen
t
z
ontal stru
c
r
of horizo
n
h
e north faç
a
r
tical narro
w
d
locates b
e
n
sumption
o
n
apartmen
t
r
titions are
i
i
on of air v
e
y
low ven
t
s
rooms, a r
o
o
per openi
n
w
hole, wit
h
f the partit
c
ation allo
w
b
e
r
of times
f. 38.7%V
e
ction
t
he diagra
m
x
partitions
[
t
balustrade
s
c
turing ele
m
n
tal glass
e
a
de with t
w
w
slits. A
z
e
hind the
a
o
f the buil
d
t
consists o
f
i
nstalled to
e
locities m
o
t
ilation rat
e
o
om must b
e
n
g makes
h
h
the greate
s
ion’s open
i
w
s the air to
before lea
v
g
. 30.5
%
m
s, (b) airfl
o
[
Givoni 1969
,
s
façade la
y
m
ents such
e
lements w
i
w
o access zo
n
z
one with t
h
a
rchitectura
l
d
ing geome
t
f
a number
create a zo
n
o
re uniform
.
e
s due to t
h
e
ventilated
h
ighe
r
airfl
o
s
t reduction
i
ngs make
s
flow direc
t
v
ing the roo
m
%
V h. 36.2
%
o
w patterns
,
Lechner 199
y
er
as
i
th
n
e
h
e
l
ly
t
ry
of
n
e
.
It
h
e
in
o
w
in
s
a
t
ly
m
,
%
V
of
1].
a
n
de
p
a
b
e
ar
e
w
h
ro
o
A
m
u
V
e
ai
r
th
e
ve
th
e
T
r
th
e
co
re
c
re
l
D
u
co
th
e
is
o
m
o
o
f
83
G
n
d these ch
a
signed to
a
a
rtition is in
tter to inst
a
e
a of the a
p
h
ere air has
o
ms remai
n
high degre
e
u
lti-zone b
u
e
rtical mov
e
r
flow patte
r
e
re is no ai
r
ntilation in
e
building
f
r
ace each
w
e
airflow i
s
nnected, n
o
c
eive enou
g
l
ocation of
w
3.3.4
.
u
ring wint
e
urtyard dw
e
e
solar hea
t
o
lation of t
h
o
re pleasan
t
f
overheatin
g
Fig
u
G
ivoni 1969.
a
nges impo
s
a
voi
d
appr
e
front and n
e
a
ll partition
s
p
artment m
a
to pass fro
m
n
open whe
n
e
of porosi
t
u
ilding. Ga
n
e
ments of a
i
r
ns in a sec
t
r
flow in th
e
the second
f
orm. Airf
l
w
indward ar
r
s
forced to
f
o
t cross, en
d
g
h ventilat
i
w
indows a
n
.
Courtya
r
e
rtime, the
e
lling. The
t
gains. Alt
h
h
e courtyar
d
t
since it is
l
g
in the su
m
u
re 3.19. V
e
s
e a higher
e
ciable add
i
e
arer to the
s
near the o
u
a
y be venti
l
m
one roo
m
n
the ventil
a
t
y in the pa
r
n
deme
r
et a
l
i
rflow exist
t
ion of the
b
e
second fl
o
floor is po
s
l
ow throug
h
r
ow throug
h
f
low vertic
a
d
or make
i
on. Even
nd
addition
a
r
d roofin
g
fully glaze
d
roof atriu
m
h
ough less
d
yields w
a
l
ess windy.
m
me
r
.
e
ntilation p
a
resistance
i
tional resi
s
inlet wind
o
u
tlet and t
h
l
ated by th
e
m
to anothe
r
a
tion is requ
i
r
tition shou
l
l
. (1992) su
in the buil
d
b
uilding. If
t
o
or. Howe
v
s
sible sinc
e
h
the buildi
h
or aroun
d
a
lly to ano
t
sharp turns
in comple
x
a
l fins chan
g
g
d
atrium b
u
m
building h
a
insulation
i
a
rme
r
the e
n
However,
t
a
rametric
m
５８
on airflow.
s
tance to a
i
o
w and the
a
h
e air veloci
e
main stre
a
as Fig.3.18
(
i
red. It is p
r
l
d be consi
d
ggested a
m
d
ing partiti
o
t
here is onl
v
er, with a
e
the positi
v
ng should
g
d
the buildi
n
t
her floor p
l
, since spa
c
x
partitions
g
e the airfl
o
u
ilding has
a
s 1℃ to 2
℃
i
s gained f
r
n
vironmen
t
t
hese featur
e
m
odels for t
h
The size
o
i
rflow. Th
e
a
ir has 30.5
%
ty is 36.2
%
a
m, satisfa
c
(
b)-a, as lo
n
r
eferable fo
r
d
ered to en
a
m
inimum p
o
o
ns. The arr
o
y
one wind
s
mall outle
t
v
e (+) and
n
g
o from po
s
n
g to meet
i
l
an, the air
f
c
es that are
, all airflo
w
o
w pattern.
a benefit
higher
℃
t
e
r
om the ro
o
t
. Another
b
e
s have a d
i
h
e courtyar
d
o
f the inter
n
e
velocities
%
to 31% o
f
%
to 39.9%.
8
c
tory ventil
a
n
g as the co
n
r
the upwin
d
a
ble the na
t
o
rosity of 5
0
o
ws Fig.3.1
ow at the f
i
t
in the sec
n
egative (-)
s
itive to ne
i
ts downwi
n
f
low patter
n
not crosse
w
s are nat
u
which is
w
e
mperature
d
o
f transpare
n
b
enefit is t
h
i
sadvantage
d
roofing
[B
n
al opening
are lowes
t
f
inlet air ve
8
3
Since a g
r
ation can b
n
nections b
e
d
room to b
e
t
ural ventil
a
0
%.
8 (b)-b sho
w
i
rst floor in
c
ond floor,
t
pressure ar
e
gative pres
s
n
d counter
p
n
should b
e
d by airflo
w
u
rally con
n
w
armer tha
n
d
uring day
t
n
t surfaces
,
h
at the atri
u
of cooling
ensalem 199
1
should be
t
when the
locity. It is
r
eater total
e obtained
e
tween the
e
the larger.
a
tion in the
w
s vertical
the house,
t
he natural
e
as around
s
ure areas.
p
art. When
e
smoothly
w
may not
n
ected and
n
the open
ime due to
,
the better
u
m may be
in the case
1
].
Bensalem
ventilatio
n
experimen
t
cross vent
i
closed wi
n
a single g
l
different v
When onl
y
windows
a
in average
cross-vent
i
temperatu
r
whereas i
n
thermal co
s
-1
. It mea
n
The use o
f
By shadin
g
time is the
n
the wind, i
n
improving
Fig.3.20 s
h
The struct
u
diagonal
w
Figure 3.
2
84 Markus a
n
1 clo: A m
e
clot
h
1 met: Esti
(1991) st
u
n
strategies
t
al ventilat
i
i
lated room
n
dows are u
n
l
ass roof o
f
entilation r
a
y
the roof w
i
a
re opened,
w
than that
o
i
lation thr
o
r
es are dec
r
n
the two
p
mfort zone
8
n
s that the
c
f
a partly o
p
g
the court
,
n
increase
d
n
which, c
o
the insulat
i
h
ows a pub
l
u
re is a con
v
w
alls. The f
o
2
0. Public h
o
n
d Morris 198
0
e
asure of the
r
h
ing and insul
mation of M
e
u
died the i
n
and obser
v
i
on models
and the co
m
n
bearable, s
f
a courtya
r
a
tes impro
v
i
ndows are
o
w
hile the r
o
o
f the cour
t
o
ugh the r
o
r
ease
d
. Th
e
p
revious ca
s
8
4
of 26℃ t
o
c
omfort tim
e
p
aque moni
t
,
the cooles
d
up to 5 ho
u
o
mfort is re
a
i
on of the b
u
l
ic housing
w
v
ersion of t
h
o
u
r
-storey r
o
o
using at K
ö
0
.
r
mal resistanc
e
ation value o
f
e
tabolic rate, t
y
n
door ther
m
v
ed the se
v
for the wi
n
m
bination
o
ince the op
e
r
d is used,
c
v
es the indo
o
o
pene
d
, the
o
of vents ar
e
t
yard dwel
l
o
om wind
o
e
wind tun
s
es it is 0.
2
o
28℃ or 3
0
e
can be in
c
t
or roof pro
v
t condition
s
u
rs to 6 ho
u
a
ched in the
u
ilding als
o
w
ith a glas
s
h
e existing t
o
w is set of
f
ö
p
eniker St
r
e
and include
s
f
clothing itse
l
y
pical metab
o
５９
m
al condit
i
v
eral venti
l
n
d tunnel t
e
o
f both. The
e
rative tem
p
c
ross-venti
l
o
r climate.
airflow pa
t
e
closed, th
e
l
ing. A co
m
o
ws induce
s
nel test w
i
2
5m s
-1
. T
h
0
℃ for PM
V
c
reased to
u
v
ides
b
ette
r
s
for the s
u
u
rs in most
o
whole occ
u
o
leads to g
r
s
house cov
e
ransverse
w
f
from the fi
r
r
. in Berlin
b
s
the insulatio
l
f. 21℃, 50%
o
lic rate for a
s
i
on using
t
l
ation rate
s
e
st with an
indoor co
n
p
eratures o
n
l
atio
n
thro
u
t
tern is simi
l
e
indoo
r
co
n
m
bination o
f
s
greater
a
i
th the atri
u
h
e improve
m
V
0 with 1.
0
u
p to 3 hour
s
r
shading i
n
u
rrounding
r
o
f the roo
m
u
pancy peri
o
r
eate
r
impr
o
e
ring a larg
e
w
ing of two
-
r
ewall rou
g
b
y O. Steid
l
n provided b
y
RH, 5m/s air
s
edentary per
s
t
he parame
t
s
and patte
r
open court
y
n
ditions of
a
n
daytime a
r
u
gh the roo
m
l
a
r
to the o
p
n
ditions are
f
the roof
w
a
ir movem
e
u
m config
u
m
ent of air
0
clo and 1
m
s
of the da
y
n
summer t
h
r
oom can
b
m
s except in
o
d. Shadin
g
o
vement.
e
inner cou
r
-
housing m
o
g
hly by the
d
l
e
[modified
fr
y
any layer of
movemen
t
.
s
on, 58.2 W
m
t
ric model
r
ns. Fig.3.
1
y
ard and g
l
a
glaze
d
atri
u
r
e above 33
m
window
s
p
en courtya
r
slightly wa
r
w
indow op
e
e
nts and t
h
u
rations sh
o
movemen
t
m
et, air vel
o
y
time.
h
an the full
y
b
e obtained.
the northe
r
g
the façade
r
t designed
b
o
dules that
a
d
epth of the
fr
om Heckma
n
trapped air b
e
m
-2h-1.
with seve
r
1
9 shows t
h
l
azed roofi
n
u
m with fu
l
℃. Whene
v
s
which all
o
rd
. If the ro
o
r
mer by 0.5
e
ning and t
h
h
e indoor
a
o
ws 0.5m
s
t
enlarges t
h
o
city of 0.1
y
glazed on
e
The comf
o
r
n ones faci
n
windows a
n
b
y O. Steid
l
a
re divided
b
building. T
h
n
n 1994, auth
o
e
tween skin a
n
r
al
h
e
n
g,
l
ly
v
er
o
w
o
m
℃
h
e
a
ir
s
-1
,
h
e
m
e
s.
o
rt
n
g
n
d
l
e.
b
y
h
e
or
].
n
d
６０
intermediate space was transformed into a glassed-in access hall with ramps the length of the building.
The housings are accessed through a short entry hallway. In the housings along the access hall, the
kitchens and baths are lit and ventilated via the hall: the outside-oriented housings have inside baths, but
kitchens with large windows to the park. The glass surfaces in front of the sleeping and living areas
developed around the façade recesses and the kitchen and the small bedroom can be entered from the
living room. The hall is covered by roofs of glass and a passive energy concept enables for efficient
planting under the glass roof.
3.3.5. Roof opening and stack effect
Ventilation is concerned with the supply of fresh air and especially in hot climates the promotion of
convective cooling with the air movement at a relatively slow rate. The two main ways in which natural
ventilation occurs are through the stack effect in calm conditions, through combined stack effect and
wind and through wind only at air speed in excess of 3m sec-1. Since the velocities above the roof level
are much greater than at wall level, roof openings with clerestory windows, ridge projections or
wind-catchers85 can derive more airflow. They are particularly advantageous in densely built areas
which have significantly smaller projections than the building volumes. Gandemer et al. (1992) tested
the effectiveness of clerestory openings in roofs by wind tunnels and showed that the clerestory area
Table 3.5. Effects of clerestory on average internal airflow rates [Busato 2003].
Not good Good
Figure 3.21. Exposed roof-ventilation holes of the gable roof of Mr. Eu’s house [M.K. Kim 2001].
85 They potentially act either as air inlets or as extractors depending on the wind direction.
needs to
b
direction.
A properl
y
as much
a
clerestory
part of the
particularl
y
provided
b
In Korean
an expose
d
Korean al
p
Since the
l
warm air i
rooms, co
o
Thermal t
y
difference
many shaf
t
a large mo
t
as
where P
s
i
Since a sta
climate co
central sp
a
F
i
86 Bittencou
r
b
e at least
y
designed c
a
s 40% by
o
openings r
e
roof and i
n
y
useful str
a
b
y a single
w
traditional
h
d
roof-vent
i
p
habet “
ㄱ
”
l
ayered sp
a
n the kitch
e
o
l air is dra
w
y
pe ventila
t
and air de
n
t
s are instal
l
t
ive force,
a
s the stack
ck pressure
nditions w
h
a
ce moves f
r
ig
ure 3.22.
r
t 1993.
20% of th
e
lerestory o
p
o
penings a
n
e
lative to t
h
n
the down
w
a
tegy for a
w
indow op
e
h
ouse desi
g
i
lation hol
e
an
d
is com
p
a
ces need
v
e
n. Since
w
w
n at the b
o
t
ion utilize
n
sity. Vent
i
l
ed in a gre
a
a
nd therefo
r
pressure (
P
promotes t
h
h
ere the te
m
r
om the bo
t
Stack effe
c
e
cross-sec
t
p
ening incr
e
n
d 15% by
h
e building’
s
w
in
d
part f
o
deep-plane
d
e
ning.
g
ns, expose
d
e
of the ga
b
p
ose
d
of 3 l
a
v
entilation,
t
w
armer airfl
o
o
ttom of th
e
s the stac
k
i
lating shaf
t
a
t cross-sec
t
r
e the more
P
a) in the h
e
h
e vertical
a
m
perature
d
t
tom corner
c
t of an IH
K
６１
t
ional area
e
ases the av
e
inlets.
86
T
a
s
central a
x
o
r exhausts
.
d
space or
k
d
roof-vent
i
b
le roof of
M
a
yere
d
spac
t
he roof o
p
o
w vent o
u
e
rooms.
k
effect wh
i
t
s are insta
l
t
ional area,
air will be
m
0.042
s
P
=×
e
ight of sta
c
a
ir moveme
d
ifference i
n
of the wall
K
’s office i
n
of the bui
l
e
rage indo
o
a
ble 3.5 ill
u
x
is. The bes
t
.
The intro
d
k
itchen wh
e
i
lation hole
s
M
r. Eu’s h
o
es with sev
e
p
ening is e
f
u
t of the to
p
i
ch is a th
e
l
le
d
to expl
there may
b
m
oved. The
hT
×
×
c
k h (m) fo
nt, shafts a
r
n
winter is
of each ro
o
n
Karlsruhe
l
ding perp
e
o
r ai
r
speed
i
u
strates the
t
position f
o
d
uction of r
e
re flow ra
t
s
are often
i
o
use. The
h
e
ral annex
b
f
fectively d
e
p
part of th
e
e
rmal forc
e
oit the stac
k
b
e a large te
m
motive for
c
r the temp
e
r
e effective
large. The
o
m facing t
h
b
y C. Stef
f
e
ndicular t
o
i
n cross-ve
n
incorrect
p
or
inlets is
i
oof ventila
t
t
es cannot s
i
nstalled. F
i
h
ouse has
a
b
uildings o
n
e
signed to
e
opening t
h
e
caused b
y
k effect in
m
perature
d
c
e is the “s
t
e
rature diff
e
for internal
air passin
g
h
e wall to t
h
f
an
[Lefèvre
2
o
the wind
o
n
tilated roo
m
p
ositioning
i
n the upwi
n
t
ion may
be
ufficiently
b
i
g.3.21 sho
w
a
shape of t
h
n
a sloped h
i
discharge t
h
rough loft
y
temperat
u
a building.
d
ifference a
n
t
ac
k
” press
u
Eq.
e
rence T (
℃
ventilation
g
through t
h
h
e openings
2
002].
o
w
m
s
of
n
d
e
a
b
e
w
s
h
e
i
ll.
he
of
u
re
If
n
d
u
re
19
℃
).
in
h
e
at
６２
the top of the same wall. It works well with buildings of three or more stories as Fig.3.22 represents.
Warm and light air rise in an internal multi-storey solar chimney with venting at roof level. While the
the sun heats a solar chimney at the top of the building, the air moves in a duct. The temperature
differences significantly increases airflow. The ventilation can provide a comfortable temperature
without air conditioning. Since the shaft is large enough and located high, the inlets and outlets
maximize the effect of prevailing winds.
3.4. Façade elements
3.4.1. Microclimate in opening control
If the difference between the indoor and outdoor temperatures is not large, the vertical pressure
gradients do not differ between inside and outside since the difference between the air densities is not
large. In this situation, an aerodynamic pressure with ventilation is higher than a thermodynamic
pressure. If the air pressure on either side is equal by a single opening at a certain level in the building,
there is no thermodynamic airflow and stack effect through this opening. Therefore, effective horizontal
aerodynamic ventilation with wind is more important to modify the microclimate than stack effect
ventilation. If the indoor air is warmer and thereby less dense than the outdoor air, a vertical pressure
gradient in the building is smaller than one of the outside, and the indoor air does not flow well. If the air
pressure between inside and outside, and above and below is different, the ventilation rate is
proportional to the density of the air. For two openings at different heights, if the indoor temperature is
higher than outside, a pressure difference forms. While a depression inducing an inward flow occurs at
the lower level, high indoor pressure occurs near the upper opening and the air flows outwards. Thus,
the indoor air can circulate. For the lower indoor temperature, the positions are interchanged and the
flow direction reversed.
Olgyay (1973), first proposed to systemize the incorporation of climate into architectural design.
However, the method just considers the outdoor climate data only and it is not suitable to the largely
varied indoor environment by outdoor climate. It is thus suitable for application only in humid regions
where ventilation is essential during a day and there is little difference between the indoor and outdoor
conditions. The application particularly in the subtropics, leads to erroneous results in Korean climate
since the indoor climate does not always needs ventilation.
６３
3.4.2. Opening locations and shapes
For the design of an individual space, air distributions or concentrated jets should be determined to plan
the most preferred ventilation. The main factors affecting airflow patterns are the sizes and shapes of
inlet apertures. The location, type and configuration of the inlets and the configuration of other adjacent
elements such as internal partitions and projections etc. affect the ventilation performance.
The opening sizes and shapes are important factors that determine airflow inside a building. If air flows
straight through the room, ventilations occur only in a limited part that has high air velocity. The cost of
windows is expensive, i.e. a square meter of window is normally 2.5 times more expansive than a
square meter of wall. A large window is more difficult to shield a direct solar penetration or a cold wind.
In a district in high latitude, the main function of windows is to obtain natural lights, and the window
shape is often vertically rectangular. In a tropical region, the window mainly performs ventilation, thus
the window shape is frequently horizontally rectangular.
Dăng (1985) analyzed the efficiency of different window heights for a hot and humid climate. If the
height of a window is greater, the air can move quicker above the upper half of the room. On the
contrary, the air velocity decreases for the lower half. When the height of a window is small, the air
velocity is large, and the shape of the streamline is narrow. A large window performs better for the
indoor ventilation. However, the width of the window should not be smaller than 0.5 times of the width
of the room to generate air streams covering at least 70% of the floor area. The window form with a
medium height and a large width stretches the air streams, and thereby has the best efficiency for natural
ventilation. Moreover, it is the easiest to shield direct solar penetrations or a cold wind.
The shape and configuration of opening modifies the internal airflow. For a fixed opening size, a
horizontally square and vertically shaped inlet yields different air motions in the room. Horizontal inlets
provide larger internal airflows than squared or vertical inlets. A wind incidence angle of 90˚ i.e.
perpendicular to the window surface offers the optimal performance for horizontal inlets. Fig.3.23-a
shows the percentage of indoor air speeds for different locations of openings. Hence, the introduction of
vertical louvers increases the performance of ventilation in horizontally shaped inlets since they can
catch more winds. Fig.3.23-b represents the percentage of indoor air speeds for different angles of
louvers. Although a rectangular opening also provides well-distributed internal airflows, the
performance is not enough to cover the room.
T
w
o
p
in
d
w
i
hi
g
w
i
us
i
fe
a
1
2
3
T
h
th
e
re
l
ve
re
l
ve
w
i
e
x
T
h
ai
r
In
87
G
88
H
89
G
Figure 3.2
3
w
o openin
g
p
enings is
r
d
ependent
o
i
nd. With t
w
g
her, rangi
n
i
nd directio
n
i
ng two wi
n
a
tures as fo
l
1
. The relat
i
linear pr
o
2
. A room
n
distributi
o
3
. If the mo
h
e perform
a
e
ventilatio
n
l
ated to the
ntilation is
l
atively hi
g
ntilation p
e
i
ndward wa
l
x
ists even t
h
h
e outlet si
z
r
flow rate o
c
this case, p
G
ivoni 1969.
H
.T. Kim et a
l
G
ivoni 1969.
a.
3
. Perform
a
g
s in oppo
s
r
eferre
d
to
o
f the wind
w
o opening
n
g from 30
%
n
and the a
x
n
dows with
l
lows;
i
onship
b
et
w
o
portion.
n
ormally ha
s
o
n of air sp
del’s lengt
h
a
nce of vent
n
performa
n
wind dire
c
possible i
n
g
her than t
h
e
rformance
l
l than at th
e
h
ough there
z
e affects t
h
c
curs. A s
m
art of the k
i
l
. 1988.
With differen
t
a
nce of diff
e
s
ite walls i
m
as “cross-
v
direction a
n
s for both
t
%
to 50% o
f
x
is betwee
n
1/4 size of
w
een the o
u
s
wind shad
eed and dir
h
is long, th
ilation usin
g
n
ce of wind
o
c
tion. Tabl
e
n
an asym
m
h
e pressure
of window
s
e
edges an
d
is no press
u
h
e indoor
a
m
aller outlet
i
netic energ
y
t
openings
e
rent wind
d
m
proves v
e
v
entilation
”
n
d the indo
o
t
he windw
a
f
the extern
a
n
inlet and
o
the wall pe
u
ter wind s
p
ow with vo
r
ection.
e distributi
o
g
adjacent
w
o
ws on adj
a
e
3.6-a clas
s
m
etric plac
e
s at the si
d
s
at a side
o
d
some pres
s
u
re differe
n
a
irflow rate
s
than the inl
e
y
converts
t
６４
b.
d
irection w
i
e
ntilation r
a
”
. If there
i
o
r velocity
i
a
rd and the
l
a
l wind spe
o
utlet.
87
In
rformed at
t
p
eed and th
e
r
tex after i
n
o
n of indoo
r
w
indows e
x
a
cent walls
d
s
ifies the
w
e
ment of
w
d
es of the
o
f a buildin
g
s
ure differe
n
n
ce in the s
y
s
. If the ou
t
e
t, the air v
e
t
o static pre
s
With differen
t
i
th shape a
n
a
tes, and t
h
i
s one ope
n
i
s approxi
m
l
eeward si
d
ed for the
d
a study of
t
he center
o
e
average i
n
n
flows. The
r
r
air veloci
t
x
tremely de
p
d
epends on
w
ind directi
o
w
indows si
n
windward
g
. The pres
s
n
ce in the a
s
y
mmetric sc
h
t
let is larg
e
e
locity can
n
s
sure near t
h
t
louver angl
e
n
d angles o
f
h
e natural
v
n
ing, the
a
m
ately 10%
t
d
es, the ave
r
d
ifferent inl
e
indoor air
m
o
f the oppo
s
n
door ai
r
sp
e
r
efore, a pa
r
t
y is slowly
p
ends on th
e
the pressur
o
n into goo
n
ce the pre
wall. Tabl
e
s
ure is grea
t
s
ymmetric
p
h
eme.
e
r than the
i
n
ot be distri
b
h
e leeward
o
e
s
f
opening
[
B
v
entilation
a
ir velocity
t
o 15% of t
h
r
age veloci
t
e
t and outl
e
m
otion,
88
a
s
ite wall sh
o
e
ed genera
l
r
t of inflow
s
decreased.
e
wind dire
c
e distributi
o
d or bad c
a
ssure at th
e
e
3.6-b ill
u
t
er at the c
e
p
lacement
o
inlet openi
n
b
uted over
t
o
pening. F
o
B
usato 2003].
using two
is almost
h
e external
t
y is much
e
t sizes, the
simulatio
n
o
wed some
l
ly is in the
s
has worse
c
tion since
o
ns closely
a
ses. Some
e
center is
u
strates the
e
nter of the
o
f windows
n
g, a large
t
he room.
89
o
r the same
６５
Table 3.6. Airflow related to the opening location or wind direction [modified from Lechner 1991].
a. Not
good
b. Good
or
Fair
size of inlet and outlets, the internal air speed is related to the building envelope irrespective of the angle
of incidence of the wind.
Although the cross-ventilation using windows of two opposite walls are optimum in rooms with
openings, such configuration is not common.90 If the angle of wind is perpendicular to the inlet for most
configurations, opposed to inclined wind incidences, the high average air speeds can be achieved by
openings in two adjacent walls. The total size of the openings in the walls with the smallest area of
openings almost determines the internal air distributions with intermediate openings. It is also an
important point in planning a multi-zone space.
The different opening sizes between inlet and outlet modifies the airflow shape and solar penetration. In
Korea, the Janggyeong Panjeon91 in Haeinsa Temple uses different sizes of the upper and lower parts
for the front windows arrangement. The front windows form an iso-scales triangle with base size 1,
height 2 as Figure 3.24 (a) shows, and the rear windows are reversely arranged. In the front elevation,
the lower part opening size is 4 times larger than the upper part one. In the rear elevation, the upper part
opening size is 1.5 times greater than the lower part one. The opening size comes up to around 18% to
29% of the front-backside wall area and this result gives the constant air circulation. The design
intended to be effective cross-ventilation for preservation of woodblocks of scriptures against
deterioration.
The building is quite famous in Korea due to the efficient ventilation, effective moisture prevention,
proper balance of temperatures and well-designed arrangements. The building features different size
and shape, of the windows at each wall of the building, different height of each side wall, arrangement
of shelves in the hall, and the location of the building. Recently, computer simulations found out the
airflow characteristic in Janggyeong Panjeon shows very well distributed airflows in the room even
though the building is 60.5 m wide and 35 m deep. Fig.3.24 (b) shows that the indoor air velocity is very
stable and low with about 0.15m/s while the outdoor air velocity is varying. On a winter day a breeze
90 Bittencourt 1993.
91 It was added in the UNESCO world heritage lists in 1995.
F
w
i
th
a
h
o
A
l
bu
b
l
o
a
g
T
h
ai
r
a
w
T
h
as
pe
in
t
92
G
(a)
(b)
F
i
g
ure 3.2
4
i
th a veloci
t
a
n outside,
o
rizontal an
d
l
though it d
o
u
ilding ena
b
o
cks in the
h
g
ood exam
p
3.4.3
.
h
e vertical
p
r
flow shape
w
all with a
v
h
e position
a
a vertical
rpendicula
r
t
ernal flow
b
G
ivoni 1969.
4
. Opening
s
t
y of 0.5m/s
and the r
d
vertical g
r
o
esn’t hav
e
b
les sunligh
t
h
ot and hu
m
p
le of contr
o
.
Projecte
d
p
rojections
and rates s
i
v
ertical pro
j
a
nd size of
e
win
d
-catc
h
r
winds. T
h
b
y altering
a. F
r
a. O
n
s
izes contr
o
, the indoo
r
oom has
u
r
adients ha
v
e
any heatin
t
control or
m
id summer
o
l temperat
u
d
buildin
g
such as e
x
i
nce they d
e
j
ection can
i
e
xternal pr
o
h
e
r
. The in
t
h
e vertical
the pressur
e
r
ont façade
n
a summer d
a
o
l of Jangg
y
r
air velocit
y
u
niform te
m
v
e uniformi
t
g and cooli
n
ventilatio
n
and the dr
y
u
re and hu
m
g
structur
e
x
ternal wi
n
e
rive the pr
e
i
nduce cros
o
jections ar
e
t
ernal vent
i
projection
s
e
around th
e
６６
a
y
y
eong Panj
e
y
is 50% lo
w
m
perature
d
t
y of less t
h
n
g equipm
e
n
performa
n
y
and cold
w
m
idity by o
n
e
n
g-walls or
e
ssure diffe
r
s-ventilati
o
e
related to
t
i
lation rate
s
are effici
e
e
inlet. For
e
on, (a) the
s
[modifie
d
w
er. In su
m
d
istribution
h
an 2℃.
e
nt, the deh
u
n
ce for the
p
w
inter over
6
n
ly microcl
i
internal p
a
r
ence. If th
e
o
n in rooms
w
t
he prevaili
s are enha
n
e
nt to mo
d
example, fi
n
b. Sun co
n
b. On a wi
n
s
tructure, (
b
d
from Y.W.
L
m
mer, the
bu
through t
h
u
midificati
o
p
reservatio
n
6
00 years.
Ja
i
mate.
a
rtitions ca
n
e
wind
b
lo
w
w
ith only a
ng wind. E
x
n
ced espec
i
d
ify the pat
t
n
walls can
n
trol
n
te
r
day
b
) mean air
f
L
ee 1986, S.
M
u
ilding insi
d
h
e four se
a
o
n perform
a
n
of the wo
o
Ja
nggyeong
n
modify t
h
w
s obliquel
y
single exte
r
x
ternal proj
i
ally for s
k
t
ern and d
i
significant
l
f
low speed
M
. Lee 1999].
d
e is cooler
a
sons. The
a
nce of the
o
d printing
P
anjeon is
h
e internal
y
up to 60˚,
r
ior wall.
92
ections act
k
ewed and
i
rection of
l
y increase
Table 3.7
Not go
o
Good
or
fair
a
.
F
ventilatio
n
distributio
n
b
locking a
ventilatio
n
For the s
h
frequently
or Fig.3.2
5
horizontal
of horizon
t
eliminates
circulatio
n
living spa
c
levels is d
e
shows, wi
l
gap betwe
e
modifying
the elevat
i
opposite d
i
large soli
d
two-store
y
downward
floor.
. Effects o
f
o
d
.
F
i
g
ure 3.2
5
n
through
w
n
. Howeve
r
streamline
,
n
. Table 3.7
h
ading pro
p
used in a
h
5
-c, due to
projection,
t
al projecti
o
the down
w
n
passing a
b
c
e. Howev
e
e
sirable. T
h
l
l tend to re
e
n projecti
o
the down
w
i
on builds
t
i
rection. T
h
d
surface w
i
y
b
uilding
s
flow, but t
h
f
wing-wall
s
b.
5
. Horizont
a
w
indows o
n
r
, an incorr
e
,
makes the
shows the
s
p
erties, ho
r
h
ouse desig
n
increasing
and Fig.3.
2
o
ns. As Fig
.
w
ard airflo
w
b
ove the oc
c
e
r, this may
h
e introduc
t
instate the
u
o
n and buil
d
w
ard pressu
r
t
he rel
a
tive
l
h
e airflow p
i
th the ele
v
s
hown in
F
h
e airflow
o
s
on cross-
v
a
l projectio
n
n
the same
e
ct usage, e
.
opposite e
ff
s
everal flo
w
r
izontal pr
o
n
. They can
the amou
n
2
5-b and Fi
g
.
3.25-b rep
r
w
at the inl
e
c
upant’s he
be efficie
n
t
ion of a d
i
u
pward flo
w
d
ing, show
n
r
e at the top
l
y large m
a
attern is ve
r
v
ation and
a
F
ig.3.25-f,
o
n the uppe
r
６７
v
entilation
a
c.
n
s and airfl
o
wall and
.
g. several
f
ff
ect such a
s
w
patterns b
y
o
jections s
u
modify int
n
t of the en
t
g
.3.25-c re
s
r
esents, the
e
t and pus
h
a
d
, i.e. up
w
n
t for space
s
i
stance
b
et
w
w
s into the
n
in Fig.3.
2
of the inlet
a
gnitude o
f
r
y similar t
o
a
nothe
r
pos
s
airflows o
n
r
floo
r
shap
a
nd the win
d
d.
o
w pattern
s
side of a
b
f
ins placed
o
s
blocking o
y
vertical p
r
u
ch as ove
r
ernal air p
a
t
ering airfl
o
s
pectively s
h
horizontal
p
h
es the air-
s
w
ard flow, i
s
such as k
i
w
een the pr
o
original co
u
2
5-d, simil
a
opening.
M
f
pressures,
o
the case
o
s
ible reme
d
n
the grou
n
es upward
f
d
direction
[
s
[modified fr
o
b
uilding b
y
o
n the sam
e
f the natura
r
ojections.
r
hangs, ca
n
a
tterns from
o
w. Fig.3.2
h
ows roo
m
s
p
rojection
p
s
tream tow
s of little u
s
i
tchens wh
e
o
jection an
u
rse of flo
w
a
rly recover
M
eanwhile,
a
and incre
a
o
f Fig.3.25-
c
d
y is a larg
e
nd
floor
m
f
low due to
[
Busato 2003
,
e.
o
m Busato 20
y
changing
e
side of ea
c
a
l flows, an
d
n
opies and
Fig.3.25-a
5-a is the
r
s
with diffe
r
p
laced abo
v
ards the ce
s
e for dire
c
e
re ai
r
extr
a
d window,
w
shown in
s the down
w
a
large soli
d
a
ses the air
-
c
. Fig.3.25
-
e
roof para
p
m
ay be sati
s
the ceiling
,
Lechner 199
f.
0
3].
the press
u
c
h window
d
thereby p
o
verandas
a
to Fig.3.2
5
r
oom with
o
r
ent locati
o
e the openi
n
iling. The
a
t cooling i
n
a
ction at hi
g
as Fig.3.2
5
Fig.3.25-a.
w
ard flow
b
d
surface w
i
-
stream in
-
e illustrate
s
p
et wall. I
n
s
factory w
i
of the grou
n
1]
.
u
re
or
o
or
a
re
5
-b
o
ut
o
ns
n
g
a
ir
n
a
g
h
5
-c
A
b
y
i
th
an
s
a
n
a
i
th
n
d
In
m
a
e
nj
m
o
e
x
fl
o
a
n
o
v
ro
o
as
si
z
th
e
sp
a
de
a
n
al
l
1
m
re
p
al
l
F
o
sli
S
o
ar
c
Korean tra
d
a
in buildin
g
nj
oy the su
m
o
isture fro
m
x
posed to th
o
or can be
o
n
d addition
a
v
erhang an
d
o
f in summ
e
a.
M
Fi
g
ure 3
.
Fig.3.26-b
z
e of colum
n
e
floor ind
u
a
ce on the
f
nsity. In w
i
n
d thereby t
h
l
ows a high
m
to 1.2m
f
p
resents th
e
l
owing for
s
3.4.4
.
o
r adjusting
ts such as l
o
me openin
c
hitecture
d
d
itional ho
u
g
. Fig.3.26-
a
m
mer life as
m
the groun
e south an
d
o
pene
d
and
a
a
lly much
c
d
the deep f
l
er
, Korean
t
M
aru structure
.
26. Out-st
a
shows. Th
e
n
, is favora
b
u
ces a micr
o
f
loor, the c
o
i
nter, a doo
r
h
e microcl
i
radiation
h
f
itted to the
e
cross sec
t
s
ummer sh
a
.
Opening
direct pen
e
ouve
r
s, jal
o
g slits suc
h
d
esign, latti
c
u
ses, a pec
u
a
shows th
e
shown in
F
d in summ
e
d
the usage
a
cross-ven
t
c
ooler than
l
oor structu
r
t
raditional
a
a
nding stru
c
e
deep eave
b
le to avoi
d
o
climate ef
f
o
ol air of t
h
r
closes the
i
mate effec
t
h
eating wit
h
altitude o
f
t
ion of the
r
a
ding and
w
slits
e
tration of
s
o
usies and
h
h
as fins al
c
e window
a
u
lia
r
floor s
t
e
structure o
F
ig.3.26-a.
T
e
r. The mo
s
of a void
bo
t
ilation occ
u
the living
s
r
e. Since t
h
a
rchitecture
s
b. Roo
f
c
tures, in th
e
s keep dire
c
d
the overh
e
f
ect with a
h
e bottom c
a
north wall
t
is stoppe
d
h
a deep sol
a
f
the sun pr
o
r
oof struct
u
w
inter heati
n
s
everal out
d
h
orizontall
y
so change
t
a
nd rattan
b
６８
t
ructure for
f the Maru.
T
he Maru a
l
s
t importan
t
o
ttom. In s
u
u
rs. The ai
r
s
pace due
t
h
is process
n
s
generally
h
f
with eave su
p
e
Korean tr
a
c
t sunlight
o
e
ating and t
h
small char
c
a
n be exud
e
on the floo
d
. The well
-
a
r penetrati
o
motes the
u
re with ea
v
n
g.
d
oo
r
factor
s
y
pivoted sa
t
he directi
o
b
linds are a
l
summer ca
l
The Maru
l
lows lighti
n
t
features o
f
u
mmer, the
r
underneat
h
t
o the dou
b
n
eeds a goo
h
ave out-st
a
p
porters
a
ditional re
s
o
ut of the r
o
h
e heavy ra
i
c
oal brazier
e
d onto the
r
, cross-ve
n
-
designed r
o
on into the
radiation i
n
v
e support
e
s
such as s
o
shes are of
t
o
n of the p
e
ways used
t
l
led Maru i
s
is used as
a
n
g and ven
t
f
the struct
u
two walls
o
h
the floor i
s
b
le shading
d shading
o
a
nding roo
f
s
c. Sola
r
s
idence
[au
t
o
oms in su
m
i
n. The dif
f
. If air flo
w
floor due t
o
n
tilation do
e
o
of conside
Maru. The
n
winter. F
e
rs and the
o
la
r
radiati
o
t
en attache
d
e
netration.
t
o provide
s
s
often atta
c
a
main floor
e
t
ilation and
u
re are the
o
o
f living s
p
s
also cross
use of the
o
f over 35
%
f
s
with eave
r
angles
t
hor, K.H. Le
e
m
mer, whi
c
f
erence of r
a
w
s through
t
o
the differ
e
e
s not occu
r
ring the so
l
length of t
h
ig.3.26-c r
e
seasonal s
o
o
n and win
d
d
in front o
f
In
K
orean
s
oft sunligh
c
hed to the
e
d room to
avoids the
o
rientatio
n
p
ace on the
-
ventilated
large roof
%
under the
supporters
e
1986].
c
h has 60%
a
diation on
t
he opened
e
nce of air
r
anymore,
l
ar altitude
h
e eaves is
e
spectively
o
lar angles
d
, opening
f
openings.
traditional
t.
Vertical m
u
the deepn
e
solar radia
t
and
b
efore
mm, and F
window si
z
range of s
o
Fi
g
Fi
gu
Louvered
o
shading p
r
technologi
considera
b
combines
t
sensor co
n
the interio
r
design. Fi
g
double ski
n
glass blad
e
operable
g
differently
Sensors, t
h
day, contr
o
suppleme
n
u
llions sho
w
e
ss and siz
e
t
ion. Thise
s
sunset. In
t
igure 3.27
c
z
e with 20
o
lar radiati
o
a. Front
g
ure 3.27.
O
u
re 3.28. D
e
o
penings c
a
r
ojections a
n
cally sophi
s
b
le advanta
g
t
raditional
m
n
trol). Sout
h
r
atrium ar
e
g
.3.28 sho
w
n
façade d
e
e
s and trus
s
g
lass windo
w
dependin
g
h
at are pro
g
o
l them. T
h
n
tary and n
o
w
n in Fig.3
.
e
of mullio
n
s
slits perfo
r
t
he case of
o
c
shows the
h
bars since
t
o
n area.
O
pening slit
e
bis tower
i
a
n increase
t
n
d perforat
e
s
ticate
d
an
d
g
es in term
s
m
aterials a
n
h
, East and
W
e
highly d
e
w
s a buildin
g
e
signed by
R
s
rods that
a
w
s. The ou
t
g
on the an
g
g
rammed to
h
e louvers
a
o
t mandato
r
.
27 generat
e
n
s. The adv
a
r
m as a fixe
d
o
pening sli
t
h
orizontal
c
t
he size of
i
b. Rear
s of Jangg
y
i
n Berlin d
e
t
he amount
e
d blocks
s
d
highly eff
e
s
of the co
n
n
d natural v
e
W
est façad
e
tailed and
s
g
with glas
s
R
. Piano.
O
a
ctivate the
i
t
er glass p
a
g
le that the
y
open duri
n
a
llow cooli
n
r
y. The me
c
６９
e
horizonta
l
a
ntage of v
e
d
vertical l
o
t
s of Jangg
y
c
ut for the
d
i
nterval is
n
y
eong Panj
e
e
signed by
R
of airflow
b
s
ince they
a
e
ctive curta
i
n
servation
o
e
ntilation
w
es, that ha
v
s
how envir
o
s
panels wit
h
O
pe
r
able gl
a
i
r openings
a
nels open
u
y
are pivot
e
n
g the nigh
t
n
g breezes
c
hanical sy
s
l
shadows a
n
e
rtical mul
l
o
uver that c
a
y
eong Panj
e
d
etails. The
n
ot regular.
c
e
on on the
e
R
. Piano
[au
t
b
y coupling
a
ct as a wi
n
i
n wall oper
a
o
f energy, l
i
w
ith innovat
i
v
e high sola
o
nmentally
h
louvers a
t
a
ss louver
s
, are place
d
u
p to a 70˚
e
d at and
a
t
and ventil
a
to enter th
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s
tem operat
e
n
d the shap
l
ions is tha
t
a
n block so
l
e
on, the siz
e
drawing us
e
The slante
d
c
. Slit
e
levation o
f
t
ho
r
, www.
bu
with other
nd
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R
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ting syste
m
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ghting, us
e
i
ve technol
o
r exposure
advanced
t
east, sout
h
s
upported b
d
27 inches
angle of r
o
a
llow for w
a
a
te the hea
t
e
building,
e
s only wh
e
e of shado
w
t
they temp
o
l
ar radiatio
n
e
of the int
e
e
s the aver
a
d
lines mar
k
f
a module
[
a
u
ilding envelo
p
elements
w
R
. Piano is
m
. The curt
a
e
r control a
n
o
gy (pivoti
n
as well as
t
solutions i
n
h
and west
e
y two axes
outside an
o
tation, the
y
a
rm weath
e
t
accumula
t
making ai
r
e
n the tem
p
w
s depends
o
o
rary provi
n
after sunr
i
e
rval is 65~
7
a
ge interval
k
the possi
b
a
utho
r
].
p
es.org].
w
ith high-le
v
developin
g
a
in wall off
e
n
d comfort.
n
g panels w
i
t
he faç
a
des
n
curtain w
a
e
levations a
n
that hold t
h
inner wall
y
reflect li
g
e
r ventilati
o
t
ed during t
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r
-conditioni
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p
erature dr
o
o
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de
i
se
7
0
of
b
le
v
el
g
a
e
rs
It
i
th
of
a
ll
n
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h
e
of
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ht
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h
e
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g
o
ps
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m
a
d
o
a
n
fl
o
pr
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A
d
o
f
th
e
sa
s
pr
e
W
F
3.
Cl
ar
c
e
n
m
u
C
O
si
n
a
n
de
T
h
h
a
93
B
low 5 or ℃
a
intenance
o
uble skin
w
n
d produces
o
ors maxi
m
o
perties du
r
d
justable h
o
f
airflow. T
h
e
room. Sas
s
h makes d
o
e
ssure buil
d
W
hen the ca
n
a. 300mm
F
i
g
ure 3.29
.
5. Anal
y
3.5.1
.
imate desi
g
c
hitects at
a
n
ergy-savin
g
u
ltiple desi
O
NTAM, a
n
n
ce they ca
n
n
alysis is n
o
signs.
h
e Europea
n
a
rmonize re
B
ensalem 19
9
exceeds 20
platforms
b
w
all and lou
v
a greenhou
m
izes the h
e
r
ing the da
y
o
rizontal lo
u
h
e up to 20˚
hes can div
e
o
wnwards
a
d
-up above
t
n
opy makes
adjustable lo
.
Airflow p
a
y
sis of b
u
.
Problem
g
n tools suc
h
a
n early des
g
. These to
o
gn elemen
t
n
d SPAR
K
n
quickly a
n
o
t sufficie
n
n
Parliamen
quirements
9
5.
. The bu
i
℃
b
etween th
e
v
ers is extr
e
se effect d
u
e
at gain in
y
and radiat
e
u
ve
r
s are es
upwards p
o
e
rt the upw
a
a
irflow in t
h
t
he windo
w
a downwa
r
uvers
a
tterns of v
e
u
ilding
m
s for ene
r
h
as the co
m
ign stage t
o
o
ls are not
t
s.
93
Howe
v
K
etc., are
m
n
alyze com
p
n
t to analy
z
t has draw
n
within th
e
i
lding achie
e
two skin
s
e
mely effec
u
ring the wi
n
the winte
r
,
e
s it back a
t
pecially be
n
o
sition of b
l
a
rd airflow
h
e roo
m
. C
a
w
. The press
u
r
d pressure,
e
ntilation f
o
m
icrocli
m
r
gy asses
s
m
fort diagr
a
o
establish t
h
efficient t
o
v
er, compu
t
m
ore precis
e
p
lex influe
n
z
e the buil
d
n
up the dir
e
e
European
７０
ves natural
s
act as ho
r
tive in red
u
n
ter. The e
x
an
d
it abs
o
t
night.
n
eficial sin
c
l
ades show
n
as Fig.3.29
-
a
nopies sh
o
u
re below t
h
a flow dir
e
b. Sashes
o
r several s
l
m
ate
s
ment
a
m, solar c
h
h
e guidelin
e
o
investiga
t
t
er simulat
i
e
and quan
t
n
tial effects
d
ing micro
c
e
ctive on “E
Communi
t
ventilation
r
izontal su
n
u
cing the he
a
x
posed con
c
o
rbs the e
x
c
e they allo
w
n
in Fig.3.2
9
-
b represen
t
o
wn in Fig.
3
h
e window
s
e
cts into the
l
it types
[Bu
h
arts, and h
e
e
s, recom
m
t
e the qua
n
i
on tools,
e
t
itative to
e
of several
d
c
limate sin
c
nergy Perf
o
t
y and to
f
for around
n
shades. T
h
a
t penetrati
o
c
rete wall at
x
cess heat
w
w
greater c
o
9
-a can stil
l
t
s. A casem
3
.29-c can
e
s
enforces
u
living zon
e
sato 2003, K
o
e
at gain an
d
m
endations
o
n
titative ass
e
e
.g. Energy
P
e
stimate th
e
d
esigns. Ho
c
e they ju
s
o
rmance of
B
f
rame the
m
60% of the
h
e combina
t
o
n during t
h
the outer e
d
w
ith its the
o
ntrol of th
l
channel th
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ent or reve
r
e
liminate t
h
u
pwar
d
flo
w
e
.
c. Canopies
o
enigsberger
e
d
loss estim
a
o
r design s
o
e
ssment fo
r
P
lus (EP),
e
energy co
wever, the
p
s
t establish
B
uildings (
E
m
in a man
d
year. The
t
ion of the
h
e summer
d
ges of the
rmal mass
e direction
e
flow into
r
sible pivot
h
e effect of
w
direction.
e
t al. 1974].
a
tions help
o
lutions for
r
single or
TRNSYS,
nsumption
p
arametric
the rough
E
PBD)” to
d
atory and
７１
holistic way. The German Energy Conservation Regulation “Energieeinsparverordnung” (EnEV,2001),
implemented in February 2002, refers to a calculation methodology for the energy performance of
buildings which already covers most of the aspects mentioned in the general framework for a
calculation procedure in the EPBD. The German DIN (German Standardization Institute) V 18599 is an
Excel-based calculation tool. The DIN V 18599 series of preliminary standards provide a method of
calculating the overall energy balance of buildings. DIN 18599 is dealing with the energetic assessment
of buildings in a much more detailed way.
However, there are a few tools to deal with several climate modifications of building design in the
energy assessment. Climate models are classified by several scales: from kilometers to few centimeters.
The main problem with the parametric analysis always uses a large scale that is probably suitable for
urban planning issues. However, the microclimate modification of the building design is substantially
variable in the large scale. Thus, the computer simulation tools for parametric analysis cannot be used
for building microclimate analysis. For example, natural ventilation is very difficult to analyze with the
parametric model accurately although the tools can predict the performance of mechanical ventilation
systems. There are four main complex factors for the analysis of natural ventilation.
- Geometric dimensions of building site
- Exterior and interior configurations of buildings
- Aerodynamic variation by airflow movement
- Thermodynamic pressure by the temperature variation
3.5.2. Previous methods
Despite the difficulty to analyze the microclimate modification, a lot of research has been carried out to
understand microclimate phenomena e.g. heat diffusion, natural ventilation, solar radiation heating and
evaporative cooling etc. Most research has utilized three methods as follows94
(1) Model/field experimental method
Field experiments can provide the temporal average airflow rate passing through a naturally ventilated
building. Katayama and Tsutsumi et al. (1996) performed a full-scale measurement of 4 indoor thermal
factors, i.e. airflow speed, air temperature, wet bulb temperature and globe temperature, using a field
experimental method. However, the problem is the complexity to obtain a good measurement. Model
experiments are much suitable to be more controllable and reliable than the field experimental method.
94 Tan 2005.
７２
A model with several design parameters for wind tunnel test provides the wind pressure coefficients
around buildings. For example, model experiments with several types of windows can provide several
detailed information on the velocity coefficients, jet contraction coefficients and discharge
coefficients.95 A wind tunnel investigation virtually analyzes the aerodynamic effects on the pressure
distribution on building adjacent.96
(2) Analytical methods
When we investigate the complex physical phenomena, some assumptions are efficient to simplify the
problem and derive simplified equations. For example, the design of natural ventilation systems for
passive cooling is very difficult to predict the natural forces, buoyancy offsets, the prediction of
ventilation rates, position and size of the openings. However, analytical methods can investigate the
complex problem by a simplified geometry model, e.g. simple analytical formulas for a volume or a
zone. A theoretical expression for the stratification interface compares to an ousting model, and a good
agreement with the experiment measurements can be obtained.
For the multi-volume or –zone, the expression of each zone is combined to another to accomplish
relatively networked-zone models. A multi-zone model assumes that a building zone has only one
homogeneous condition with a uniform temperature and pressure. Several zones can be connected with
other zones with different condition by openings between rooms and/or openings to the outside. The
multi-zone analysis is the decomposition of the entire model into a so-called “connection model” or
“graph model” as Fig.3.30 represents. A graph of the zones shows the physical structure with
connections between zones.
a. structural components b. Room faces c. Relational objects d. Room graph
Figure 3.30. The geometric representation of building zones and the structural component graph [van
Treeck and Rank 2004].
Several sub-level units (r1,2, f1,2,3, b1,2,3), that define room, wall, roof and floor etc. shown in Fig.3.30 ,
visualize the analysis structures for computer simulation. The topological relations between all faces can
be derived by the graph of room faces. For example, wall is a unit being outside, inter-zone or inside
95 Flourentzou et al. 1998.
96 Jozwiak et al. 1995.
７３
walls. The room graph represents the geometric property between the indoor and outdoor or in the indoor
air volumes. The graph model provides simplicity, straightforward solutions that allow the prediction of
bulk flow through the whole building driven by wind buoyancy or mechanical systems. Most building
analysis software is based on the multi-zone model.
TRNSYS97 and EP98 are the most famous programs to analyze a complex building energy by breaking
the problem into a series of smaller components. Each small component is independently analyzed at
first, gradually couples with other components and forms a large component system. Although the
software tools solve a parametric equation of mass and energy balance for multi-zone buildings, they
cannot represent detailed temperature and airflow distributions related to the thermal and aerodynamic
effects in the complex geometric configuration.
(3) CFD methods
Computational Fluid Dynamics (CFD) method numerically solves a set of partial differential equations
for the conservation of mass, momentum (i.e. Navier-Stokes) equations, thermal energy, and
concentrations. Navier and Stokes found the generic form of differential equations in the 19th century
as a simple variation function derived by a small, or finite, volume of fluid. The variable represents
predicted quantities such as pressure, velocities in three directions, temperature, concentration and
turbulence quantities at any point in the 2- and 3 dimensional models. Small modifications, e.g. the
amount advection into the volume or diffused out from it, can be represented by a variable in the space.
The method can provide a detail of distributed air temperature, velocity and contaminant concentration
within individual spaces and turbulence models throughout an entire building.
The main process includes the geometry definition, the grid generation and the numerical simulation.
The geometric definition sets up the boundary conditions where the problems are located, and the grid
generation entails the specification of the physical configuration by dividing the boundary conditions
up into a grid containing of small volume units. The partial differentials between nodes on the grid are
iteratively solved. Fig.3.31-a shows the grid generation with physical configuration and Fig.3.31-b
represents a partial differential, i.e. flow, in the grid. For example, the mass flow rate m between two
nodes i and j sets up in the grid, and a flow Aij between i and j is derived by different pressures p at the
nodes. Kij is pressure loss coefficient of the flow between node i and j. The accuracy of result depends
on the size of the grid. When the sums of total errors for all the variables reach a predetermined and
acceptable level, the final solution can be obtained. The acceptable level is called “convergence into the
solution”.
97 http://www.trnsys.com.
98 The US department of energy 2007.
In
ai
r
a
n
de
T
h
sh
o
a
n
co
th
e
sh
o
tr
a
re
q
so
u
recent yea
r
r
quality.
M
n
d ventilatio
signs and t
h
h
e CFD me
t
o
ws that C
F
nd
radiation
nvection a
n
e
wall. In
o
ws great
d
a
nsfer that
c
q
ui
r
ement.
M
u
th wall du
Fi
g
ure 3
.
Fi
gu
r
s, CFD has
M
odern ener
g
n problem
i
h
e process
r
t
ho
d
also p
r
F
D can ana
l
. The sout
h
n
d radiation
Fig.3.32-b,
d
ifferences
i
c
an be anal
y
M
oreover,
e to the eff
e
a. Para
m
.
31. The an
a
a. CF
D
u
re 3.32.
V
attracted d
u
g
y simulati
o
i
n a
b
uildin
g
r
equires a l
a
r
ovides det
l
yze a high
e
h
wall sho
w
, respectiv
e
a compari
i
n the day-a
y
zed in the
the increas
e
e
cts of con
v
m
eters relate
d
a
lyze
d
vari
a
D
pattern wit
h
V
alidity for
w
u
e to the rel
i
o
n tools usi
n
g
. However
a
rge syste
m
aile
d
ther
m
e
r resolutio
n
w
n in Fig.3
e
ly, and the
n
son betwe
e
verage ther
m
coupled C
e
of heatin
g
v
ection tha
n
d
to network
n
a
ble param
e
h
a south win
d
w
ith and wi
７４
i
ability for
t
n
g CFD ar
e
, it is still c
o
m
powe
r
.
m
al environ
m
n
of the th
e
.32-a gain
s
n
transfers t
h
e
n the CFD
m
al analys
i
FD calcula
t
g
load can
b
n
another a
n
n
odes
e
ters as the
d
o
w
thout CFD
t
he evaluati
e
specificall
y
o
mplex to a
p
m
ent and c
o
e
rmal condi
t
s
heat from
h
e heat to t
h
method a
n
i
s of a roo
m
t
ion enlarg
e
b
e greater
fo
n
alysis met
h
b. Flow
flow in the
b. Day-avera
g
in a buildi
n
on of indo
o
y
designed
p
ply CFD t
o
o
ntaminant
t
ions e.g. c
o
room ai
r
a
h
e outside
b
n
d another
m
m
. The incre
a
e
s 9.4% of
fo
r the case
h
od without
analysis elem
grid netwo
r
g
ed values
f
o
r
n
g model
[K
o
r thermal c
o
to address
t
o
the real a
r
informatio
n
o
nduction,
c
a
nd other s
u
b
y conducti
o
m
ethod wi
t
a
se of conv
e
the total h
e
with wind
o
CFD.
ents
rk
[Tuomaal
a
r
south wall
K
endric
k
1993
]
o
mfort and
t
he heating
r
chitectural
n
. Fig.3.32
c
onvection
u
rfaces by
o
n through
t
hout CFD
e
ctive heat
e
ating load
o
ws on the
a
2002].
]
.
3.
5
A naturall
y
to the ev
o
fluctuatin
g
radiations
and therm
o
Topologic
a
surroundi
n
particularl
y
temperatu
r
speed in i
n
and geom
e
Typical m
u
example,
P
temperatu
r
temperatu
r
details as
F
geometry
a
the space.
show diffe
In a micr
o
hybrid m
o
parameter
i
5
.3. Hybri
d
y
ventilate
d
o
lution of
o
g
direction
fluxes. The
o
dynamics
a
l and ge
o
n
g buildin
g
y
on the wi
n
r
e and spe
c
n
ternal sour
c
e
tric factors
u
lti-zone
m
P
edestrian
w
r
e, relative
r
e. 3D CF
D
F
ig.3.33 sh
o
a
nd topogra
p
Simulation
rent indoor
o
scale, a 3
D
o
dels are s
t
i
zation. For
d
model f
d
and therm
a
o
utside air
f
and magn
i
microclim
a
of fluids, i.
o
metric
b
ui
l
g
s definitel
nd
-driven
v
c
ific humid
i
c
e/sink ter
m
.
m
odels can
n
w
ind comf
o
humidity,
D
methods
c
o
ws. The v
a
p
hy etc., ea
results un
d
conditions
.
D
flow mo
d
t
udie
d
to
s
example, t
h
or micro
c
a
lly inhom
o
f
low and i
n
i
tude, turb
u
a
te modific
a
e. equation
s
l
ding desi
g
y have st
r
v
entilation.
i
ty. An ad
v
m
s can defin
e
n
ot accurat
e
o
rt depends
solar radi
a
c
an estimat
e
a
riations in
t
sily show t
h
d
er differen
t
.
Figure
d
el is ther
m
s
implify th
e
h
e air flow
７５
c
limate an
o
geneous
bu
n
side buoy
a
u
lence, te
m
a
tion can b
e
s
of conser
v
g
ns also a
f
r
ong impa
c
The intern
a
v
ection-diff
u
e
the micro
c
e
ly predict
on the typ
e
a
tion and
m
e
accuratel
y
t
he airflow
,
h
e intercon
n
t
periods, e
.
3.33. 3D C
F
m
al and ene
r
e
process
b
analysis o
f
alysis
u
ilding mo
d
a
ncy, stack
m
perature,
h
e
defined b
y
v
ation of
m
f
fect the
m
c
ts on th
e
a
l sources a
n
u
sion equa
t
c
limate mo
d
the effects
e
s of activi
t
m
ostly dete
r
y
local airfl
o
,
being affe
c
n
ections of
t
.
g. round a
F
D
[author].
r
gy analysi
b
y some
a
f
CFD impr
o
d
ifies the b
u
effects a
n
h
umidity, s
h
y
the funda
m
m
ass, mome
n
m
icroclimat
e
e
natural
v
n
d sinks m
o
t
ion that d
e
d
ification i
n
of microc
l
t
y, dressing
r
mined by
o
ws and th
e
c
ted by sit
e
t
emperatur
e
year, seaso
s needs hi
g
a
ssumption
s
o
ves some
c
u
ilding mic
r
n
d thermal
h
ortwave
a
m
ental law
s
n
tum, heat
a
e
changes.
v
entilation
o
dify the d
i
e
scribes the
n
duced by t
h
l
imate mod
, specific
w
the wind
e
condition
e
-specific d
e
e
, humidity
a
n, week an
d
g
h complex
i
s
and cons
t
c
onstraint
f
r
oclimate d
u
flows wit
h
a
nd longwa
v
s
of dynam
i
a
nd moistu
r
Terrains a
n
performan
c
i
stributions
loss of fl
o
h
e topologi
c
ifications.
F
w
eather e.g.
speed and
distributio
n
e
sign, build
a
nd velocit
y
d
day etc.,
c
i
ty. Recent
l
t
raints in t
h
f
or multi-zo
n
u
e
h
a
v
e
i
cs
r
e.
n
d
c
e,
of
o
w
c
al
F
or
air
air
n
in
ing
y
in
c
an
l
y,
h
e
n
e
７６
ventilation simulation. A multi-zone simulation can offer the initial condition to the CFD simulation. A
recent interest of the building simulation research is the integration between a CFD method and another
simple energy simulation method. Zhai (2003) introduced several coupling strategies to integrate a
CFD method with the EnergyPlus (EP) simulation. Negrao (1995) also studied a CFD simulation
integrating the building thermal simulation in the EP in order to improve the building energy
consumption and the indoor air equality. His work especially focused to solve the ambiguity problem of
the boundary condition in the CFD method using EP. EP interactively gives a feedback of building
thermal changes to the CFD solver. There are several reasons that EP is suitable for the integration:
1. The performance of EP has proven through the long history. The initial prototype was developed by
Clarke (1977). After that, it has been under constant development until today.99
2. It was well validated through large scale exercises.100
3. It has it’s own coupling capability between the energy simulation and CFD for combined building
and plant systems. External coupling admits the use of user-defined functions to set up a broad
range of parameters. A comparison between internal and external coupling is available.101
Gao and Chen (2003) developed three strategies for the coupling of the CFD and multi-zone model as in
Table 3.8. The virtual coupling does not mix a CFD simulation with a multi-zone simulation in the
coupling procedure. This coupling calculates air pressures using the CFD method and then input the
pressures into a multi-zone simulation tool. In the Quasi-dynamics coupling, CFD applies to the
simulation of each single zone in a multi-zone network. A CFD analysis makes reliable information
about the airflow field in a single zone. The accurate analysis of a zone can improve the calculation of
another single zone. This means that transferring results of a CFD simulation once back to the
multi-zone model, the multi-zone model simulation re-runs to update the results. This procedure is
called “ping-pong”. The fully dynamic coupling is an extension of the quasi-dynamic coupling for the
complete multi-zone. The CFD’s grid is laid on the multi-zone model’s network and substitutes a
particular zone. The dynamic coupling method requires a mutual feedback called “onion” between the
multi-zone and CFD simulations.
A combination of a CFD method and multi-zone energy simulation method can provide complementary
information for energy movements in the building. For a turbulence scheme, a model combining 3D
flow and 2D energy simulations significantly reduces the complexity and saves the processing time.102
These works mainly are utilized to improve the result in mechanical ventilation simulation. A
multi-zone model predicts the average temperature in all zones and overall airflow, while a CFD
99 Djunaedy 2005.
100 Lomas et al. 1994, Vandaele and Wouters 1994.
101 Negrao 1995, Beausoleil-Morrison 2000.
102 Arnfield et al. 1998.
method ca
n
Table 3.8.
Virt
Qu
a
3.
5
Since the
simplifica
t
coefficien
t
that the pr
e
percentag
e
modify th
e
multi-zon
e
The cooli
n
103 Hensen 1
9
104
N
ovosela
c
n
get the d
e
Strategies
f
ual coupling
a
si-dynamics
coupling
Fully
dynamic
coupling
5
.4. Exper
i
prediction
t
ions an
d
a
s
t
s obtained
b
e
ssure coef
f
e
of porosit
i
e
external
e
building i
n
n
g effect of
9
99.
c
2005.
e
tails of te
m
f
or the cou
p
- This method
s
- Flow pressur
e
-The flow pres
s
-CFD improve
s
- Multi-zone ne
-More reliable
r
-The result tra
n
-An extension
o
-Substitution a
-Mutual feedb
a
i
mental e
x
of airflo
w
s
sumptions
b
y wind tu
n
f
icients are
i
es, airflo
w
pressures.
n
warm and
ventilation
m
peratures a
n
p
ling of the
s
eparately sim
u
e
s are calculate
s
ures are used
f
s
the result of e
a
twork combine
s
r
esults for a sin
g
n
sfe
r
s once bac
of
the quasi-dy
n
particular zone
a
ck called “onio
n
x
pression
w
rates wi
t
. Bittencou
n
nel tests wi
reliable on
l
w
rates tend
Higher po
r
humid cli
m
can be def
i
７７
n
d airflows
CFD and
m
u
lates a CFD m
e
d by CFD meth
f
or a multi-zon
e
a
ch single zone
s
the state of e
a
g
le zone can b
e
k to the multi-z
o
n
amic coupling
m
of the multi-zo
n
n
”
104
between t
h
of model
t
hin buildi
n
rt (1993) i
n
th solid mo
d
l
y for build
i
to be over
-
r
osities ov
e
m
ate.
i
ned by a f
u
in some p
a
m
ulti-zone
m
e
thod and a mu
od
e
simulation
in multi-zone s
a
ch single zone
e
obtained by ai
o
ne model and
r
m
ethod to the
w
n
e model’s net
w
h
e multi-zone m
o
s
n
gs is dif
f
n
troduced
a
d
els. A pro
b
i
ngs with p
o
-
estimated
er
50% ar
e
u
nction of a
i
a
rticular zo
n
m
odel
.
lti-zone metho
d
imulation
rflow analysis
r
e-run like “pin
g
w
hole multi-zon
e
w
ork
o
del and CFD
s
f
icult, the
a
simplifie
d
b
lem of this
o
rosities o
f
since airfl
o
e
considera
b
i
r temperat
u
n
es.
d
.
g
-pong”
103
e
coupling
s
imulations
energy si
m
d
method
u
simplifica
t
f
up to 25%
.
o
ws throug
h
b
le for ve
n
u
re, airflow
m
ulation u
s
u
sing press
u
t
ion metho
d
.
With a lar
h
the buildi
n
n
tilatio
n
o
f
rate and h
e
s
es
u
re
d
is
ge
n
g
f
a
e
at
ca
p
w
h
(
K
A
i
sp
a
w
h
T
h
bu
co
di
s
re
f
in
c
T
a
Fi
g
105
106
107
108
p
acity.
105
W
h
ere N is th
K
). Q is heat
i
r Change r
a
a
ce and the
h
ere R and
V
h
e analytic
a
u
ilding. Cro
s
nnection o
f
s
charge coe
f
erence wi
n
c
idence an
d
a
ble 3.9. A
n
(a)
g
ure 3.34.
E
Koenigsberg
e
Liddament 1
9
The discharg
e
If the angle o
f
in an open fi
e
W
e can esti
m
e ventilatio
n
loss or gai
n
a
te per Hou
r
volume of
V
are respe
c
a
l metho
d
s
s
s-ventilati
o
f
volumes,
fficient
107
o
n
d spee
d
,
a
d
distance f
r
n
alytic met
h
Conditions
Wind only
a. With win
g
E
xperimen
t
e
r et al. 1974.
9
86.
e
coefficient
i
f
incidence
p
e
e
ld and 0.1+
0
m
ate heat lo
n
rate (m
3
s
n
rate (w), a
n
r
(ACH) is
d
space.
c
tively infil
t
implifies a
i
o
n in a sing
l
walls and
o
f openings
a
n
d
∆C
p
is
r
om obstru
c
h
od for cro
s
g
walls
t
al expressi
o
i
s often assu
m
rpendicular t
o
0
.0183 (90˚–
U
ss due to v
e
Q
=
s
-1
), and T
i
a
n
d 1300 is
v
d
efined by
o
A
t
ration rate
i
rflow mov
l
e building
i
openings
a
and A
w
(m
2
)
wind pres
s
c
tions.
s
s-ventilati
o
Schematic
b. Witho
u
o
n, (a) pred
i
m
ed 0.65.
o
opening is 0
˚
U
r angle) for
3
７８
e
ntilation r
a
1300 (
i
NT
T
=
−
a
nd T
o
are
r
v
olumetric
s
o
bserving t
h
3600CH
R
=
(m
3
s
-1
) an
d
ement as a
i
s simplifie
d
a
s Table 3.
9
)
is the area
s
ure-drop
c
on
of single
1
u
t wing walls
i
cted and o
b
˚
≤Ur angle≤ 3
3
0˚≤ Ur angle
a
tes empiri
c
)
o
T
r
espectivel
y
s
pecific he
a
h
e volume
o
/
R
V
d
volume o
f
function o
d
by theore
t
9
shows.
Q
of equival
e
c
oefficient
1
0
buildings
[
V
F
wd
QC
A
=
2
1
/1/(
W
A
A
=+
b
served pre
s
0
˚, the coeffi
c
≤ 90˚.
c
ally as
y
indoor an
d
a
t of air (J
m
o
f ai
r
enteri
f
room (m
3
)
f pressure
d
t
ical expres
Q
w
(m
3
·s
-1
)
e
nt opening
s
0
8
as a fun
c
V
ickery and
K
F
ormula
1/
2
()
wr p
A
UCΔ
2
23
)1/(AA
+
+
s
sure coeffi
c
c
ient is 1.2 for
d
outdoor t
e
m
-3
K
-1
). The
ng (or leav
e
)
.
106
d
ifference
i
sion for the
is airflow
r
s
. U
r
(m s
-1
)
c
tion of th
e
K
arakatsanis
1
2
2
4
)A+
(b)
c
ients (C
Q
),
typical value
s
Eq.20
e
mperature
number of
e
s) into the
Eq.21
i
n a sealed
geometric
r
ate, C
d
is
is outdoor
e
angle of
1
978].
(b) energy
s
for building
７９
balance between wall and room air [Vickery and Karakatsanis 1978, Zhai and Chen 2001].
For higher porosities, further corrections are possible by the error of the flow coefficients. Fig.3.34 (a)
compares the predicted and observed coefficients for buildings with 46% porosity with and without
wing walls.109 The predicted coefficients may include particular errors when the incident angle of the
wind is skewed to the façade between 0˚, i.e. parallel to opening, and 45˚.
A multi-zone energy simulation utilizes the energy balance equations110 derived from the analytic
method of inter zone air and surface heat transfer. The energy balance equation for a room air is
,_
1
/
N
i c i other heat extraction room P
i
qA Q Q V C T t
ρ
=
+− = ΔΔ
∑ Eq.22
where Σqi,cAi is convective heat transfer from enclosed N surfaces to the room air by the convective flux
qi,c from a surface i, and Ai is the area of total surface. Qheat_extraction and Qother respectively denote the heat
extraction rate of a room and heat gains from lights, people, appliances and infiltration etc.
ρVroomCpΔT/Δt is the energy change of room volume Vroom where ρ is the air density, and Cp is air specific
heat. The temperature change of room air ΔT can be observed by the sampling time interval Δt, i.e.
normally one hour. Fig.3.34 (b) illustrates the energy balance on the interior surfaces of wall, ceiling,
floors, roofs and slabs.
Assuming the uniform and known room air temperature, the interior surface temperature can be
determined by simultaneously solving the surface heat-balance equation. Inversely, the convective heat
transfer of the enclosure surfaces determines the cooling and heating loads. A multi-zone simulation
uses these methods to solve the heat-balance equation or to calculate heating and cooling loads.
However, the method cannot estimate partial variations caused by a microclimate modification.
Computational dynamic principles can define partial variations e.g. airflows driven by the temperature
gradients and/or by the external wind pressures. CFD is a numerical method to solve the equations of
partial variations.
CFD consists of three main steps: building modeling, definition using 3D grids and numerical solution.
The modeling of a building includes the arrangement of the various assemblies, geometries, enclosures,
assignment of materials, the respective thermal properties, sources of radiant and convective heat, solar
gains, occupancy and air resistances etc. The grid definition splits the building into a number of units for
analysis. Thus, the size of grid is directly related to the complexity of solution and the size of errors. A
more complex model requires a larger number of grid arrays and larger computer power.
A combination of the multi-zone energy simulation and the CFD method is used for the energy
109 Vickery and Karakatsanis 1978.
110 Zhai and Chen 2001.
８０
simulation in this study. The multi-zone method predicts the average temperature using Finite Volume
Method (FVM) that analyzes one node point per a zone. The CFD method refines the single node result
of FVM at using multi-grids. EP and Fluent111 respectively performs the multi-zone simulation and
dynamic simulation. A new proposal in this study is the allocation of multi-scale grids for the CFD, a
coarse scale grid is used for the analysis of large outdoor winds, and fine scale grids with a large number
of nodes is used to update the result of the coarse scale results. The results of FVM can be easily
updated by the CFD method with a fine grid since the FVM uses a coarse scale grid for multi-zone
analysis.
111 http://fluent.com/
Fluent Inc. is a company based in Lebanon, New Hampshire that develops software for CFD.
８１
4. Microclimate energy simulation
4.1. Multi-zone energy simulation
4.1.1. Multi-zone simulation method using EP
Multi-zone energy analysis and Computational Fluid Dynamics (CFD) methods respectively provide
the complementary information of mean and variance of energy in the building zones. The multi-zone
analysis method such as EnergyPlus (EP) addresses to calculate the energy performance of building
zones and building envelops installed for HVAC.112 The results are averaged indoor condition with
cooling/heating loads, coil loads and energy consumption in a time interval, e.g. from a sub-hour or
hour, day to a year. However, the EP cannot analyze the microclimate effects in the building. On the
other hand, CFD tools, such as Fluent software, can analyze the partial differences in air velocity,
temperature, a relative humidity and contaminant concentration, that may offer some detailed
prediction of the thermal comfort in building zones. For example, some partial differences are observed
as dynamics of thermal and energy flows. Hence, a combination of EP and CFD can evaluate the
average energy consumption and energy gains with a microclimate modification.
EP has many innovative simulation capabilities such as time steps of less than one hour, heat
valance-based zone simulation multi-zone airflow, thermal comfort and photovoltaic systems. Version
2.0 has extensive examples of HVAC input files, weather processor, heat/cool option on furnace, air
loop, high temperature radiant heating/cooling, more operative controls for all radiant modeling,
desiccant dehumidifier, system sizing, plenum (return and supply), example active Trombe wall input
template, air cooled condenser, energy meters, low temp radiant heating/cooling, interior surface
convection, evaporative cooler models, airflow sizing, improved sky model for daylight calculations,
ability to read multiple interval per hour weather data files, return air heat gain (from lights)
enhancement calculation, flat plate exhaust air heat recovery.
112 Crawley et al. 2001.
T
h
i
m
te
m
sh
a
co
H
V
m
a
w
i
H
e
x
fo
r
113
114
115
116
117
h
e input is
a
m
proved to
h
m
plate, m
o
a
ding of s
k
ordinates, i
n
V
AC equip
m
a
cro capab
i
i
ndow mult
i
H
VAC loop
m
x
haust fan,
fa
r
materials
a
IFC: Industr
y
CAD interop
e
Fanger 1970.
IDF “librarie
s
Mendler and
Fi
g
ur
e
a
text form
h
ave IFC
113
o
isture calc
u
k
y IR by
o
n
te
r
zone a
i
m
ents e.g.
i
lity for in
p
i
plier, spec
t
m
odeling, i
n
fa
n control,
f
a
nd constr
u
y
Foundation
C
e
rability.
s
” for materi
a
Odell 2006.
e
4.1. Input
with a nu
m
to IDF gen
e
u
lations, t
h
o
bstruction
s
i
rflow and
n
fan coil,
u
p
ut files (a
u
t
ral input f
o
n
cluding b
r
f
an motor
p
u
ctions etc.
F
C
lasses, ISO/
P
a
ls, constructi
o
interface o
f
m
ber of enti
t
e
ration cap
a
h
ermal co
m
s
, controls
n
atural vent
i
u
nit heater,
u
u
xiliary pr
o
o
r glass, an
d
r
anch-
b
ase
d
p
lacement,
s
F
ig.4.2 rep
r
P
RF PAS 16
7
o
ns etc.
８２
f
EP
[The U
S
t
ies as Fig.
4
a
bility,
114
H
m
fort mode
l
for natural
i
lation (CO
M
u
nit ventil
a
o
gram), fe
n
d
window
U
d
input and
f
s
imple inpu
t
r
esents the
m
7
39
.
S
department
o
4
.1 shows.
T
VAC input
l
ing and re
ventilatio
n
M
IS), refer
e
a
tor, windo
w
n
estration
c
U
-value and
f
low resolv
e
t
and outpu
t
m
odules of
o
f energy 20
0
T
he recent
v
templates,
e
porting.
115
n
through
w
e
nce data s
e
w
AC sim
u
c
alculations
,
solar heat
g
e
r, simple l
a
t
preproces
s
EP.
117
0
7a].
v
ersion of
i
e
xample pa
It is possi
b
w
indows,
3
e
ts.
116
Ther
e
u
lations, E
PM
,
frame an
d
g
ain coeffic
i
a
unch progr
s
or, referen
c
i
nterface is
ssive input
b
le to use
3
D surface
e
are lots of
PM
acro i.e.
d
dividers,
i
ent report
am for EP,
c
e data sets
Figure 4.
3
4.
1
EP uses a
n
temperatu
r
including
p
Eq.23. A
n
energy b
a
temperatu
r
space vol
u
Fi
g
ur
e
3
. Multi-zo
n
1
.2. Calcul
n
extension
r
es i.e. volu
m
p
hysical pa
r
n
ode netwo
r
a
lance equ
a
r
es T
1
, T
2
,
…
u
mes. For a
e
4.2. EP s
c
n
e analytica
l
ation of i
n
of time ser
i
m
e-to-volu
m
r
ameters.
T
r
k of space
v
a
tion of a
…
,T
n-1
, T
n
f
o
simple on
e
c
hematic an
d
l
energy si
m
n
ternal t
e
i
es solutio
n
m
e connect
i
T
he parame
t
v
olumes in
c
multi-zon
e
o
r n numbe
r
e
layer slab
８３
d
modules
[
m
ulation of
E
e
mperatu
r
n
in Finite
V
i
o
n
s from h
t
ers can be
o
c
luding hea
t
e
in Eq.2
2
r
nodes ex
p
with two i
n
[
The US depa
r
E
P
[The US d
r
es in mul
t
V
olume Me
t
eat sources
.
o
ptimized
b
t
sources o
r
2
, the equ
a
p
lains the v
a
n
terior nod
e
r
tment of ene
r
epartment of
e
t
i-zones
t
hod (FVM
)
.
Fig.4.3 ill
u
b
y the time
r
sinks is sh
o
a
tion with
a
riations of
e
s and con
v
r
gy 2007a].
e
nergy 2007,
a
from Tani
m
)
to calcula
t
u
strates the
series solu
t
o
wn in Fig
finite dif
fe
air temper
a
v
ection at
b
a
uthor, modif
i
m
oto et al. 200
t
e the inter
n
FVM meth
o
t
ion shown
4.3. From t
h
fe
rence no
d
a
ture
b
etwe
b
oth sides, t
h
i
ed
4].
n
al
o
d
in
h
e
d
al
en
h
e
re
s
w
h
e
x
T
h
w
i
so
u
fa
i
a
d
e
x
w
h
D
F
F
o
T
o
s
ulting fini
t
h
ere
"
i
q
den
o
x
posed to th
e
h
e analytic
f
i
th Laplace
u
rce which
i
rly compli
c
d
dition of a
x
tension of
t
h
ere the pa
r
are coeffic
i
F
i
g
ure 4.4.
o
r the first l
a
o
link the t
w
t
e differenc
e
010
()qATT
C
′′ =−
o
tes the he
a
e
environm
f
unctions a
r
transform
varies as a
f
c
ated terms
source or
t
wo layers,
e
r
ameters ar
e
i
ent matric
e
Two layer
a
yer, it was
w
o layers a
n
e
equations
1
0
(
dT
C
hA T
dt =
−
a
t flux for t
h
ental temp
e
r
e formulat
e
were intro
d
f
unction of
with spatia
sink betw
e
e
.g. a wall
w
e
also given
e
s. The arro
w
examples
fo
determine
d
n
d include t
h
1
1
()
()
Ts
qs
⎡
⎤
=
⎢
⎥
⎣
⎦
are given
b
21
1
)TT
TR
−
−
+
,
h
e i-th nod
e
e
ratures.
e
d by Lapl
a
d
uced by
D
time and lo
l deriv
a
tiv
e
e
en two la
y
w
ith two di
f
2
2
()
()
Ts
A
qs
C
⎡⎤⎡
=
⎢⎥⎢
⎣⎦⎣
in Fig.4.4.
x
w
means th
fo
r deriving
d
that in the
11
11
()
()
Ts A
qs C
⎡⎤⎡
=
⎢⎥⎢
⎣⎦⎣
h
e heat sou
r
2
2
()
()
Ts
T
qs q
⎡⎤⎡
=
⎢⎥⎢
⎣⎦⎣
11
11
() (
() (
As B
Cs D
⎡
=
⎢
⎣
８４
b
y
2
(
i
dT
ChA
T
dt
=
e
. C is air s
p
a
ce transfo
r
D
egiovanni
cation can
b
e
s. The seco
y
e
r
element
s
f
ferent mat
e
22
22
() ()
() ()
A
sBs
C
sDs
⎡
⎤
⎢
⎥
⎦
⎣
x
is a vecto
r
e direction
the Laplac
e
Laplace d
o
12
12
() ()
(
() ()
(
sBsT
sDsq
⎤⎡
⎥⎢
⎦⎣
r
ce betwee
n
2
2
()
()
s
ou
r
T
s
q
s
+
+
⎡
⎤+
⎢
⎥
⎦
⎣
2
2
)()
)()
sTs
sqs
+
+
⎧
⎤⎡ ⎤
⎪
⎨
⎥⎢ ⎥
⎪
⎦⎣ ⎦
⎩
12
2
)TT
T
TR
−
−+
,
p
ecific hea
t
r
m includin
g
(1988). Th
b
e incorpor
a
nd method
s
as Fig.4.
4
e
rials, is,
3
3
()
()
Ts
qs
⎡
⎤
⎥
⎣
⎦
r
of state v
a
of the heat
e
transform
sin
k
o
main
(
)
(
)
s
s
⎤
⎥
⎦
n
them, the
f
0
()
r
ce
s
⎤
⎥
⎦
0
()
source
qs
⎫
⎡
⎤⎪
+
⎬
⎢
⎥⎪
⎣
⎦⎭
,
"
(
ii
qAT
=
−
t
, and A is
t
g
sources o
r
e first met
h
a
ted. The e
q
shows mor
e
4
shows. T
h
a
riables, t is
sink.
extension
t
k
s
[The US de
f
ollowing s
u
⎬
2
)T
t
he area of
t
r
sinks. T
w
h
od repres
e
q
uation inv
o
e
details in
v
h
e Laplace
time, and
A
t
o include s
o
partment of e
n
u
bstitution
s
Eq.23
t
he surface
w
o methods
e
nts how a
o
lves some
v
olving the
t
r
ansform
Eq.24
A
, B, C and
o
urces and
n
ergy 2007].
Eq.25
s
are made:
８５
311122
3
11122
() 0
() () () () ()
() ()() () () () () source
Ts
Ts As Bs As Bs
qs q sqs Cs Ds Cs Ds
⎧
⎫
⎡
⎤⎡ ⎤
⎡⎤⎡ ⎤⎡ ⎤
⎪
⎪
=+
⎨
⎬
⎢
⎥⎢ ⎥⎢⎥⎢ ⎥⎢ ⎥
⎪
⎪
⎣⎦⎣ ⎦⎣ ⎦
⎣
⎦⎣ ⎦
⎩⎭
3
11122 11
3
11122 11
() 0
() () () () () () ()
() ()
() () () () () () () source
Ts
Ts As Bs As Bs As Bs
qs q s
qs Cs Ds Cs Ds Cs Ds
⎡
⎤⎡⎤⎡⎤⎡⎤⎡ ⎤⎡⎤
=+
⎢
⎥⎢⎥⎢⎥⎢⎥⎢ ⎥⎢⎥
⎣⎦⎣⎦⎣ ⎦⎣⎦
⎣
⎦⎣⎦
Eq.26
If a layer is added to the left side of the first layer, the entire right side of the Eq.26 can be multiplied by
the transmission matrix of the new layer. Conversely, if a layer is added to the right of the second layer,
the vector containing the Laplace transform of the temperature variations can be replaced by the product
of the transmission matrix of the new layer and the vector at the next state. The term dealing with the
heat source is not affected. While Eq.27 is correct for any single or multi-layered elements, the first
term in the heat source transmission matrix does not appear to match the compactness of the other terms
in the matrix equation. Hence, for the n-th nodes, the extended series can be bundled by a generalized
equation which is correct for any single or multi-layered elements as
()
11
11
() 1 ()()
()
() ()
() () () ()
() ()
1() ()
() () ()
source
nN
Ds Dsbs
ds
qs Ts
Bs Bs Bs qs
qs Ts
As bs
Bs Bs Bs
++
−
⎡⎤⎡ ⎤
−
⎢⎥⎢ ⎥
⎡⎤ ⎡⎤
⎢⎥⎢ ⎥
=+
⎢⎥ ⎢⎥
−
⎢⎥⎢ ⎥
⎣⎦ ⎣⎦
⎢⎥⎢ ⎥
⎣⎦⎣ ⎦
Eq.27
The terms in the heat source transmission matrix may appear to be reversed. It is expected that only the
layers to the left of the source will affect q1(s), but the presence of b(s) in the element multiplied by
qsource(s) to obtain q1(s) seems to be contradictory. In fact, the entire term, b(s)/B(s), must be analyzed to
determine the effect of qsource(s) on q1(s). In essence, the appearance of b(s) removes the effects of the
layers to the right of the source from B(s) leaving only the influence of the layers to the left of the
source.118
For a transient solution, the airflow rate between i-th and j-th node can be approximated by the
conservation assumption of air mass as119
,
i
j
ii
j
dm FF
dt
=
+
∑ Eq.28
where mi is the mass of air in the i-th node, and Fj,i and Fi respectively denote the airflow rate between
i-th and j-th node and the non-flow process at the i-th node that is generally assumed as a quasi-steady
initial condition dmi/dt=0.
When multi-zones are set up with the FVM with a number of nodes, a control of the volume-to-volume
heat transfer from a heat source to a sink is the next issue, since a control is a problematic issue for
HVAC studies. A setpoint scheme is used to maintain the comfort temperature and the sum of energy
consumption is calculated. Fig.4.5 illustrates the setpoint temperature scheme for heating and cooling.
118 The US department of energy 2007.
119 Tan 2005.
T
h
co
4.
T
h
m
i
d
o
v
a
co
a
n
m
o
bu
a
m
a
n
de
ne
m
i
ar
c
h
e total
b
ui
l
oling.
Figure 4.5
.
2. Micr
o
h
e multi-zo
i
croclimate
o
es not hav
e
a
lues, i.e. p
a
ntinuous f
o
n
d forms th
e
o
difies the
g
u
ilding and
t
m
ount of op
e
n
alysis acc
o
termines t
h
eds a high
r
i
croclimate
c
hitectural
d
l
ding energ
y
.
Controlli
n
o
climate
ne energy
modificati
o
e
any detail
i
a
rameters,
o
o
rm e.g. ai
r
-
e
rmo- and
g
eometry o
f
t
hereby ve
n
e
ning, affe
c
o
mpanies t
h
h
e path of
a
r
esolution
a
modificati
o
d
esigns can
F
i
y
consump
t
n
g temperat
u
energy
v
simulation
o
n since th
e
i
nformatio
n
o
f a source
-
flow, pres
s
aerodyna
m
f
space. Th
i
n
tilation per
f
c
ts the venti
l
h
e topogr
a
a
irflows an
d
a
nalysis wit
h
o
n, the buil
d
result over
ig
ure 4.6.
S
t
ion can be
u
re scheme
v
ariatio
n
described
e
model us
e
n
between a
and a sink.
s
ure differe
m
ic flows.
T
i
s means th
f
ormance,
h
l
ation perf
o
a
phical or
g
d
the buildi
h
a large a
m
d
ing energy
25% energ
y
S
imulation
m
８６
estimated
b
for heating
n
model
in chapter
e
s a combi
n
source and
Microcli
m
nce, evapo
t
T
he flows
a
at a design
h
eat balanc
e
o
rmance an
d
g
eometrica
ng geomet
r
m
ount of gr
i
performan
c
y
-saving co
m
m
odel and
t
b
y the sum
and coolin
g
4.1 is not
n
ation of li
n
a sink, alt
h
m
ate modifi
e
t
ranspiratio
n
a
re affecte
d
element ca
n
e
and energ
y
d
the natura
l
l consider
a
r
y modifies
i
d. If the ar
c
c
e will be i
m
m
pared to
c
t
hree modu
l
of energy
i
g
[The US de
efficient t
o
n
ear equati
o
h
ough it can
e
s the state
n
, and tem
p
d
by an arc
n
modify t
h
y
efficienc
y
l
cooling p
o
a
tions. Th
e
the path.
M
c
hitect can
g
m
proved.
A
c
onvention
a
l
es
[author].
i
nputs for
h
e
partment of e
n
o
simulate
o
ns. For e
x
estimate t
h
of buildin
g
p
erature va
r
hitectural
d
h
e microcli
m
y
etc. For e
x
o
ssibility. T
h
e
sloping t
o
M
icroclima
t
g
et inform
a
A
dequate mi
a
l house des
i
h
eating and
n
ergy 2007].
effects of
x
ample, EP
h
e state and
g
air with a
r
iation etc.
d
esign that
m
ate in the
x
ample, the
h
e air flow
o
pography
t
e analysis
a
tion of the
croclimate
i
gn for one
８７
year.120
Here, three models for a microclimate architectural design are proposed: outdoor model, indoor model
and microclimate model. These models make it possible to analyze separately the climate condition of
outdoor and indoor energy performance, and the mutual relationship between the indoor and outdoor
conditions is estimated by microclimate model. Fig.4.6 illustrates the relationship between the three
modules. For the simulation of models, each module has a capability that can be sophisticatedly
modulated and functionally optimized by the CFD method. Additionally, the modules can be mutually
cooperated between the functions with an energy-saving effect. The energy balance among the models
is the mediator between thermal condition and microclimate modification. When an architect inputs a
design, the influences for outdoor and indoor thermal condition are calculated and evaluated for the
energy-saving. If the design is not adequate to save building energy, the simulation tool shows
quantitative results such as energy gain or loss.
4.2.1. Outdoor model
Outdoor model shows the direct relationship between the atmospheric process and indoor climate
condition. Although some models of outdoor thermal comfort have studied to approximate the thermal
condition of the street, field and urban etc. from several climate data, recent methods can simulate
different scales of atmospheric processes. Outdoor climate models can be classified according to their
scales that range from kilometers to a few centimeters. Although the general climate can be defined by
macro scale, this is not suitable to use for architecture design since smaller scale modifications than
building size occur. Microclimate should be considered to discriminate the microclimate effect in the
partial architectural design.
Table 4.1. The physical properties that can be analyzed using CFD [Novoselac 2005].
120 Hawkes and Forster 2002.
８８
In a micro scale, 3D air flows should be analyzed and visualized to obtain information of thermal and
energy processes. Typically, these processes employ a simplified turbulence scheme. A computer
simulation with CFD tool numerically solves the thermo- and aerodynamic equations that can be
represented by a set of partial differences of temperatures, pressures, density and velocity etc. It can
provide the distribution, balance and concentration of thermal condition in an individual space or
throughout the entire building. In a building space, air velocity generates an indoor airflow’s Reynolds
number that is in the transient of turbulent range. '
φ
φφ
=
+ is the flow property where
φ
is the sum of a
time average and '
φ
is a fluctuation in the governing N-S equations. The form of the RANS
(Reynolds-averaged Navier-Stokes) equations can be obtained by conservation of continuity,
momentum, energy, concentration shown in Table 4.1. The continuity is the property of being
continuous between topological spaces form. The mathematical property is obeyed by mathematical
objects in which all elements are within a neighborhood of nearby points. The momentum equation
defines the product of the mass and velocity of an object. Since energy is strictly conserved and is also
locally conserved, the energy equation in the Table defines the energy transferring from the potential
energy to kinetic energy and then back to potential energy constantly. The concentration is the measure
of how much of a given substance there is mixed with another substance. The equation is very similar to
the energy equation.
These concerned equations consist of values of pressure p, component velocity ui, where i =1, 2, 3,
temperature T, and concentration c with air density ρ, air viscosity μ, Prandtl number Pr, Schmidt
number Sc and specific capacity c. The term ρβ(T0−T)gi is the Boussinesq model for the thermal
buoyancy effect on momentum where β is the thermal expansion coefficient of air, g is the gravitational
acceleration, and T0 is the reference temperature. The source terms for energy and concentration are
respectively denoted by St and S.121
The thermal comfort sensation in outdoor spaces is a factor that significantly influences the house shape
and the pattern of heating and cooling. In a hot and humid area, an opened house is preferred to increase
natural ventilation. Actually the heating and cooling designs depend on prevailing climatic conditions
of the outdoor spaces. The outdoor model is the starting point for architecture designs based on climate
data and site condition. The model is based on the fundamental laws of thermodynamics and prognoses
the evolution of airflow, turbulence, temperature, humidity and short- and longwave radiation fluxes. A
CFD method is suitable to analyze the model since it provides a well-founded numerical basis for the
fundamental laws of fluid dynamics and thermodynamics. The advantages of CFD are shown in Table
4.2. CFD can obtain information of in-stationary, non-hydrostatic, prognoses all exchange processes
including wind flow turbulence, radiation fluxes and temperature and humidity. It allows a process of
several time periods from a day, week to year cycle. The high resolution of partial differences allows a
121 Novoselac 2005.
detailed r
e
heights, d
e
structure a
n
Table 4.2.
a
Fig.4.7 sh
o
topograph
y
possible s
o
velocity a
n
to the out
l
vicinity o
f
introduce
d
velocity
U
p
On a slopi
n
e
presentatio
e
sign detai
l
n
d properti
e
The advan
t
A
pplication ra
n
Possible repr
e
Various input
Resolutions
A
dditionally p
o
a
.
I
mbalance
d
o
ws an exa
m
y
. Such an
o
lar radiati
n
d pressure.
l
et surface
f
the surfac
e
d
a zero eq
u
U
p
of flow is
n
g topogra
p
n of comp
l
l
s and irre
g
e
s compos
e
t
ages of C
F
n
ges
e
sentations
models
o
ssible ranges
d
condition
Figure 4.
7
m
ple of a he
a
inhomoge
n
on and wi
n
The outlet
b
for all oth
e
e
can be d
e
u
ation turb
u
increased
b
p
hy, e.g. a h
i
l
ex structu
r
g
ular geo
m
e
d of severa
l
F
D
[author].
- Microclima
t
-
A
nalysis in
- In-stationa
r
- Airflow tur
b
- Detailed re
p
- Represent
a
- Various sh
a
- Various ty
p
- Porous ob
s
- Physiologi
c
- Complexe
s
-
A
vailability
- Providing
a
- Allowing hi
g
- Allowing th
e
- Fine readi
n
- Fine readi
n
- Outdoor co
- Calculation
b.
7
. Sloping t
o
a
ting and c
o
n
eous site c
n
d exposu
r
b
oundary c
o
e
r variables
e
fined by
c
u
lence mod
e
b
y a point
P
i
lly area, th
e
８９
r
es, e.g. re
p
m
etrical for
m
l
layers is
p
t
e dynamics m
o
a day, week a
n
r
y, non-hydrost
a
b
ulence, radiati
o
p
resentation of
a
tion of building
a
pes, heights,
d
p
es of specific p
s
tacle to wind a
n
c
al processes o
f
s
volume with s
e
of various grou
a
large number
o
g
h spatial resol
u
e
high tempora
l
n
g of the microc
l
n
g related to ur
b
mfort
availability of
M
Outdoor air
f
o
pographic
a
o
oling plan
ondition
m
r
e. Topogr
a
o
ndition is
d
. The outl
e
c
omponents
e
l for the
b
P
where is f
a
e
estimatio
n
p
resentatio
n
m
s etc. An
p
ossible.
o
del
n
d year cycles
a
tic, prognoses
o
n fluxes, temp
e
complex struct
u
s
d
esign details, i
r
roperties and s
t
n
d solar radiati
o
f
evapotranspir
a
e
veral layers
nd
o
f outputs with
a
u
tion
l
resolution
l
imate changes
b
an geometry
M
ean radiant te
m
f
low analysis
a
l design p
r
derived by
s
m
odifies mi
c
a
phy, barri
e
d
efined by
o
e
t boundar
y
parallel to
oundary c
o
a
r from the
n
of relative
n
of buildi
n
alysis of
v
all exchange p
r
e
rature and hu
m
u
res
r
regular geome
t
t
ructure
o
n
a
tion
a
limited numb
e
m
perature
c.
H
eatin
g
r
ocess
[auth
o
s
ite and air
f
c
roclimate
d
er
and pro
j
o
utlet press
u
y
condition
the surfac
e
o
ndition as
F
surface of
w
temperatur
e
n
gs with v
a
v
arious typ
e
r
ocesses
m
idity
t
ric forms
e
r of inputs
g
and cooling
p
o
r].
f
low analys
i
d
ue to the
d
j
ection des
i
u
re and by
z
with the v
e
e
s. Chen a
n
F
ig.4.8-a il
l
w
all by a di
s
e
is useful t
o
a
rious shap
e
e
s of speci
f
p
lan
i
s of a slopi
n
d
ifferences
i
gn affect
a
z
ero gradie
n
e
locity in t
h
nd
Xu (19
9
l
ustrates. T
h
s
tance Δy
p
.
o
plan a pro
p
e
s,
f
ic
n
g
of
a
ir
n
ts
h
e
9
8)
h
e
p
er
fa
ç
co
de
w
a
re
s
pr
o
T
h
i
m
w
i
th
e
o
u
as
s
ge
o
f
T
a
ç
ade and w
ndition on
signed to u
t
a
ter by a co
n
s
ults. Whe
n
o
pe
r
buildi
n
h
e outdoor
m
m
prove the
i
ndows des
i
e
harsh ex
t
u
tside the h
o
s
ociate
d
to
ometry, mi
c
f
previous c
h
a
ble 4.3. O
u
indow desi
g
topograph
y
t
ilize the i
m
n
trol syste
m
n
the site c
o
n
g type, po
s
m
odel pro
v
energy eff
i
i
gn. For ex
a
t
remes of s
u
o
me, and r
e
wide energ
c
roclimate
v
h
apters cor
r
a. Zero
e
u
tdoor mod
e
g
ns for pas
y
should b
e
m
balance th
e
m
. The micr
o
o
ndition is
s
itioning, f
o
v
ides an op
t
i
ciency. It
a
mple, a sp
e
u
mmer su
n
e
duces the
n
y simulatio
v
entilation
r
esponding
t
e
quation turb
u
Figure 4.
8
e
l and indo
o
sive solar
h
e
concerne
d
e
rmal cond
i
o
climate m
o
analyzed
b
o
rm, barrier
s
t
imization
p
includes l
a
e
cial type o
f
n
and chilli
n
n
eed for su
p
n ranges s
u
described i
n
t
o the outd
o
u
lence
8
. Outdoor
m
o
r model co
９０
h
eating or
v
d
for energ
y
i
tion for he
a
o
dification
o
b
y the outd
o
s
, opening
a
p
ossibility
fo
a
ndscaping,
f
ecological
n
g winter
w
p
plementar
y
u
ch as build
n
the previ
o
o
or models.
b. Fl
o
m
odel
[Chen
ncerned to
c
v
entilation
c
y
-saving.
S
a
ting an
d
c
o
o
n the slop
i
o
or simula
t
a
nd courty
a
for
the mod
i
thermal c
o
object is pl
a
w
inds. It i
m
y
heating a
n
ing orienta
t
o
us chapter
s
o
w model on t
o
and Xu 1998
c
hapte
r
, (a)
c
ooling. Th
e
S
ome
m
ode
r
o
oling by c
i
i
ng topogra
p
t
ion model,
a
rd etc. for
e
i
fication o
f
o
ntrol of
o
a
nned to pr
o
m
proves co
m
n
d cooling.
t
ion, topog
r
s
. Table 4.
3
o
pography
, author].
outdoor m
o
e
non-unif
o
rn buildin
g
i
rculating
h
p
hy yields t
h
architects
e
nergy-savi
n
f
the topolo
g
o
uter wall,
o
tect the b
u
m
fort both
The outdo
o
r
aphy, barri
e
3
(a) shows
o
del, (b) in
d
o
r
m
therma
l
g
s are ofte
n
h
eated air o
r
h
e differen
t
can choos
e
n
g.
g
ical site t
o
façade an
d
u
ilding fro
m
inside an
d
o
r model i
s
e
r, buildin
g
the numbe
r
d
oor model
[author].
l
n
r
t
e
o
d
m
d
s
g
r
９１
4.2.2. Indoor model
The indoor model combines multi-zone energy simulation using EP shown in chapter 4.1 and
microclimate energy simulation using CFD. The integrated analysis of the different zones can obtain
the total energy influences of relative temperature and humidity in a building. However, the influence of
the saturation pressure and the latent heat affect the multi-zone energy simulation. The saturation
pressure induces the particular flow that affects the ventilations and evaporation in a zone or between
zones as Fig.4.9 (a) shows. The indoor air flows should be controlled by several architectural design
elements shown in Table 4.3 (b): courtyard dwelling designs, effects of afforestation, building
geometry, internal partitioning, opening control and slits, roof opening and stack effect, overhangs and
projections.
When the sun enters through the windows, the warm air is circulated in the building’s interior space.
The multi-zone energy simulation technique presents some energy-saving using thermal mass which
absorbs excess heat during the day and releases the heat at night. Natural ventilation is employed for
cooling of overheated air. However, a parametric ventilation model in the multi-zone model does not
calculate the air movement. It solves some equations with parameters and approximates the uniform
thermal conditions. For instance, FVM calculates the mean temperature of each volume. The problem is
that a room with a large window allowing direct solar penetration has a partial uncomfortable condition
in the room. Moreover, partially overheated air occurs by thermodynamic air circulations. A parametric
model cannot analyze such a non-uniform air condition derived by thermo- and aerodynamic processes.
Hence, the CFD method should be added to the multi-zone energy simulation.
(a) a. Diagram of Non-uniform areas b. An example
(b) a. Inlet b. Airflow in a zone c. Outlet
Figure 4.9. Thermo- and aerodynamic processes, (a) thermodynamic, (b) airflow by aerodynamic
microclimate [author].
９２
Table 4.4. The utilization of microclimate modification [author].
Effects Applications
Cooling
- Maintaining the indoor temperature below that of the outdoor air
- Decreasing cooling load and improve indoor thermal comfort condition
- Provision radiative cooling from shade, ventilation control and evaporative cooling
Heating - Maintaining the indoor temperature above that of the outdoor air
- Avoidance overheating problem
Dehumidification - Elimination the water content of the ambient air to acceptable levels
Humidification - Provision the water content to the dry air
Table 4.5. Sub-tools of Fluent software [author].
Sub-tools Purpose
Computational grid
generation - Division of the domain into discrete control volumes
Discrete dependent
variables allocation
- Integration of the governing equations on the individual control volumes
- Construction of algebraic equations
- Several discrete dependent variables: Velocities, pressure, temperature and
conserved scalars
Linear solutions - Linearization of the discretion equations and solution
- Updated values of the dependent variables
The thermo- and aerodynamic processes explain the exchange rates of momentum, heat sources,
building zones and the atmosphere. The heat flux rates can be determined by a thermodynamic model.
The heat flux can be modulated or suppressed by the aerodynamic resistance on a hard surface as Fig. 4.9
(b) illustrates. The air resistance on a surface regulates the transpiration rate, global radiation,
temperature, wind speed and pressure. A wall is primarily used for house design to mark boundaries that
directly modify the air-circulation patterns. This changes the energy consumption because different air
patterns cause different heat gains and losses. Thus, the analysis of air movement is important to make
an energy efficient design. The microclimate modification can be used to distribute the overheated air or
balance the indoor thermal condition. Cooling, heating, dehumidification and humidification effects of
microclimate modification can be applied to several applications shown in Table 4.4.
A simulation for complex 3D air flow with different air temperatures needs a reliable CFD tool. In this
study, the Fluent software solving the governing integral equations for mass and momentum, energy,
species transport, and other scalars such as turbulence is used. Fluent software package offers several
sub-tools for the different purposes shown in Table 4.5. Any domain can be easily divided into discrete
control volumes using a computational grid generator. The governing equations on the individual
control volumes can be integrated to construct algebraic equations for discrete dependent variables such
as velocities, pressure, temperature and conserved scalars. Linearization of the discretion equations and
solution of the resultant linear equation system yields updated values of the dependent variables.
The governing equations should be solved sequentially (i.e., segregated from one another) because the
Figure 4.
1
software
[
F
governing
performed
in Fig.4.1
0
criteria ar
e
4.3. Mu
A multi-s
c
accurate s
o
a series o
f
greatly re
d
large num
b
using the
m
which co
m
Macrocli
m
program e
s
in Korea.
microclim
a
in small u
n
1
0. Numeri
c
F
luent Inc. 20
0
equations
before a c
o
0
and Tabl
e
e
met.
lti-scale
c
ale metho
d
o
lution. Th
e
f
coarse gri
d
d
uce the nu
m
b
er of cont
r
m
ulti-scale
s
m
bines the
m
m
ate data is
u
s
timates th
e
However,
t
a
te modific
a
n
it scales.
c
al solution
0
2].
are non-li
n
o
nverged s
o
e
4.6 sum
m
EP-CFD
d
is attract
i
e
multi-scal
e
d
levels. T
h
m
ber of iter
a
r
ol volume
s
between
m
m
acro- and
m
u
sed to cal
c
e
local aver
a
t
he results
a
tions with
in the Flue
n
n
ear (and
c
o
lution is o
b
m
arizes the
p
analysis
i
ve to mat
h
e
scheme c
a
h
e use of s
e
a
tions and t
h
s. This stu
d
m
acro- and
m
m
icroclima
t
c
ulate the a
v
a
ge value i
n
derived fr
o
thermo-, a
e
９３
n
t
c
oupled). S
e
b
tained. Th
e
p
rocess. T
h
ematician
s
a
n accelerat
e
veral scal
e
h
e processi
n
d
y employ
s
m
icroclima
t
t
e analysis.
v
erage val
u
n
a volume
b
o
m climate
e
rodynamic
s
Step
Step 1 - Up
d
initial
Step 2 - Sol
v
for p
r
- Up
d
Step 3
- Sol
v
corre
equa
t
- Ne
c
field
s
Step 4 - Sol
v
- Tur
b
- Up
d
Step 5 - Ch
e
Table 4.6.
e
veral iter
a
e
iterative
p
hese steps
s
due to t
h
e the soluti
o
e
s for anal
y
n
g time, pa
r
s
a multi-sc
t
es. Fig.4.1
u
e which ca
n
b
y using cl
i
data are n
s
. A CFD
m
d
ate based on t
h
ized solution
v
e the moment
u
r
essure and fac
e
d
ate the velocit
y
v
e Poisson-typ
e
ction, continuit
y
t
ions
c
essary correcti
o
s
and the face
m
v
e scalars equ
a
b
ulence, energ
y
d
ated values of
t
e
ck for equation
Procedure
a
tions of t
h
p
rocedure i
n
are contin
u
h
e converg
e
o
n
b
y com
p
y
sis units, i.
r
ticularly
w
ale metho
d
1 represent
n
combine
v
i
mate data
o
ot exact in
m
ethod iter
a
Procedure
h
e current solut
u
m equation usi
e
mass fluxes
y
field
e
equation for t
h
y
equation and l
o
ns to the pres
s
m
ass fluxes
a
tions
y
, species and
r
t
he other varia
b
convergence
of Fluent s
o
h
e solution
n
cludes so
m
u
ed until th
e
e
nce perfor
m
p
uting only
c
.
e. grids wi
t
w
hen the mo
d
d
that analy
z
s the multi
-
v
alues of s
m
o
bserved at
some zon
e
a
tively upda
t
ion and the
ng current valu
e
h
e pressure
inear momentu
s
ure and veloci
t
r
adiation are sol
b
les
o
lver
[autho
r
loop must
m
e steps sh
o
e
converge
n
m
ance to t
c
orrections
t
h nodes, c
d
el contain
s
z
es the flo
w
-
scale sche
m
m
all units.
E
some stati
o
e
s due to t
h
t
es the resu
e
s
m
t
y
ved
r
].
be
o
wn
n
ce
he
of
an
s
a
w
s
m
e
E
P
o
ns
h
e
lts
９４
Figure 4.11. Multi-scale scheme using macroclimate and microclimate scales [author].
Since the FVM solver in EP program results in a single result per volume, the smoothness assumption
for several nodes of the volume is applied. In the volume, a grid with many nodes should be set up for
the CFD solution. The initial condition of CFD is that the nodes of the CFD solver for the volume have
the same value to the FVM result. Only corrections of EP are calculated by the CFD method.
Let a set of linear equation as
0
real
Ab
φ
+
= Eq.29
be a EP parametric linear equation. real
φ
is the exact solution i.e. real value. If we assume that the linear
approximation is not accurate due to microclimate modifications, there may be a defect d associated with
thermo-, aerodynamic components.
A
bd
φ
+
= Eq.30
A correction
ψ
for d should be estimated by a CFD method.
N
P
CFD solution
EP solution
real
φφψ
+ Eq.31
Hence, the real combination of EP and CFD can seek the optimal real value as
() 0Ab
φ
ψ
+
+= Eq.32
Instead of the real combination in Eq.32, a multi-scale analysis in this study uses EP solution
A
bd
φ
+
=
and CFD update Ad
ψ
=− as
() 0AbA dd
φ
ψ
+
+=− Eq.33
The combination will be simulated for energy-saving house design. The simulation strategy of EP-CFD
coupling is shown in Table 4.7.
９５
Table 4.7. Process of EP-CFD coupling [author].
Step Simulation strategy Detail
Step 1 Site selection and
climate data
acquisition
-Choose a local area of S. Korea.
-The climate data of the area is obtained from Korean Meteorological
Administration.122
Step 2 Generalized climate -Approximation of the outdoor climate by the climate data given in Step 1
Step 3 Indoor EP model -Indoor energy efficiency is estimated by multi-zone analysis using EP in
the generalized climate.
Step 4 Outdoor microclimate
model
-The thermal and humidity condition are varied by the outdoor microclimate
effects and topographical gradient.
-The energy consumption is modified by the evapotranspiration and
balance process in thermo- and aerodynamic flow.
-The thermo- and aerodynamic flow is estimated by CFD.
Step 5 Indoor microclimate
model
-Several microclimate factors given in chapter 4.2.2 to support insulating,
heating and cooling are added and evaluated.
-The energy efficiency from EP is improved by several design factors using
flows which are analyzed by CFD.
-The factors support the indoor multi-zone simulation to improve the indoor
thermal balance which takes a role as a Passive House design.
Step 6 Evaluation of
energy-saving effects
-The economical cost and total energy are evaluated by comparison
between the microclimate model and EP model.
4.4. Graph modeling for real house analysis
This chapter represents the graphs modeling of EP-CFD method for energy simulation shown in the
previous chapters. An energy simulation with CFD is normally too complex to use for planning of a real
house because a building has a lot of design elements, e.g. windows, walls, floors, doors and air
leakages etc., related to airflows, and CFD uses all connections of complex design elements. A real
house with several design elements shown in Fig.4.12 (a)-a needs a lot of information extracted from a
building description to calculate airflows. Airflows can be modified by size, orientation and location of
building surfaces which contain slits and openings. 3 zones are set up to simplify from real and complex
airflows to a simple networked model such as airflow network shown in Fig.4.12 (a)-b. The airflow
network model solves equations with building’s physical parameters which are modified by building
design elements and predicts air pressures and temperature.
The airflow network model is defined in a set of functions in EP called AirflowNetwork and the
functions use wind pressure coefficients to simulate multi-zone airflows driven by natural wind and air
distribution system. Heat and moisture gains or losses and distribution also can be calculated by the
functions. Fig.4.12 (b) represents a set of the AirflowNetwork functions to simulate the model shown in
122 http://www.kma.go.kr.
(a
)
(b
)
F
i
Fi
g
o
f
ve
ve
123
)
)
ig
ure 4.12.
a
Fi
g
ur
e
g
.4.12 (a)-
b
f
the opena
b
ntilation c
o
ntilation c
o
E.g.
A
irflow
N
a. Real hou
s
Graph mo
d
A
a
. EP analysis
e
4.13. All
o
b
. The Airfl
o
b
le exterior,
o
ntrols
123
in
d
o
ntrol or no
t
N
etwork:
M
ul
t
s
e model
d
eling, (a) g
r
A
irflowNet
w
b. E
x
pa
n
o
cating EP’
s
o
wNetwork
:
interior wi
n
d
icate whe
t
t
. There ar
e
t
izone: Surfac
r
aph model
w
ork and r
e
n
sion from EP
s
volume a
v
:
Multizone
:
n
dows and
t
her a heat
t
e
3 thermal
z
eCrackData
a
９６
of EP met
h
e
gular EP o
b
to CFD
v
erage valu
e
:
Zone spe
c
doors in th
e
t
ransfer su
r
z
ones, Zon
e
a
nd
A
irflowN
e
b.
A
irflowN
e
h
od for the
3
b
jects
[auth
o
c. CFD a
n
e
to CFD n
o
c
ifies the ve
n
e
correspo
n
r
face of a
w
e
-1, Zone-
2
e
twork:
M
ulti
z
e
twork model
o
3
zones, (b
)
o
r,
t
he US dep
n
alysis
o
des of the
v
n
tilation co
n
n
ding therm
w
all has an
o
2
and Zone-
z
one: Surface
O
o
f CFD
)
relationsh
i
artment of en
v
olume
[aut
h
n
trols that
a
al zone. Su
r
opening or
3. There ar
e
Object.
i
p between
ergy 2007b].
h
or]
.
a
pply to all
r
face-level
individual
e
openable
Table 4.8.
a.
G
b.
G
exterior
w
Door-3. E
x
Node-2 is
a
airflow pa
t
124 Note that
Graph mo
d
G
raph model
of
G
raph model
of
w
indows,
W
x
ternal Nod
e
a
ssociated
w
t
tern,
124
an
d
airflows of E
P
d
els of EP
a
of
EP
of
CFD
W
indow-1,
W
e
-1 is assoc
w
ith the faç
a
d
the arrow
s
P
model sho
w
a
nd CFD
[a
u
W
indow-2
a
iated with t
h
a
de contain
i
s
show the
p
w
only the pat
t
９７
u
thor].
a
nd Windo
w
h
e façade t
h
i
ng Windo
w
p
rocess am
o
t
ern without
d
w
-3, and o
p
h
at contains
w
-3. Airflo
w
o
ng Airflo
w
d
etails.
p
enable int
Window-1
w
network
m
w
Network f
u
erior doors
and Windo
m
odels can
s
u
nctions an
d
, Door-2 a
n
w-2. Exter
n
s
how possi
b
d
between t
h
n
d
n
al
b
le
h
e
fu
n
T
h
o
bj
R
e
ca
n
m
u
a
n
C
F
p
o
w
h
V
o
i.
e
th
e
v
a
zo
ca
l
a
n
In
T
a
pr
e
w
i
a
dj
G
r
re
a
n
ctions an
d
h
e dashed a
r
bj
ect indica
t
e
al airflow
p
n
be analy
z
u
lti-zone fl
o
n
d CFD is t
h
F
D. EP use
s
o
ints with t
h
h
ich fills th
e
o
lume aver
a
e
. single no
d
e
values in
t
a
lues in eac
h
nes as Fig
l
culation f
o
n
d .
the numer
i
a
ble 4.8 cla
s
e
dict a sin
g
i
ndows and
dj
acent zon
e
r
aph model
a
l house.
d
regular E
P
r
rows indic
a
t
e the comp
o
p
attern is
m
z
ed by CF
D
o
w networ
k
h
e main pr
o
s
an analysi
s
h
e partial d
i
e
copies of
t
a
ge values
o
d
e, for CFD
t
o the expe
n
h
zone into
r
.4.13-c re
p
or
each zon
e
i
cal solutio
n
s
sifies EP
a
g
le value o
f
doors in a
e
s. A graph
is simple a
n
P
functions.
a
te the com
p
o
nents that
m
odified by
w
D
. A coupli
n
k
and airflo
w
o
blem for c
o
s
unit calle
d
i
fferentials.
t
he EP’s a
v
o
f 3 zones
a
’s multiple
n
n
de
d
node
p
r
eal and ph
y
p
resents. T
h
e
. Calculati
n
n
s, EP and
a
nd CFD m
e
f
DF, solar
single zon
e
contains al
n
d efficien
t
The solid
a
p
onents in
a
interact wi
t
w
in
d
press
u
n
g of EP a
n
w
dynamic
o
upling. Fi
g
d
node point
To combi
n
v
erage valu
e
a
re expande
n
odes. The
p
oints of C
F
y
sical airfl
o
h
e values
o
n
g nodes a
n
CFD resp
e
e
thods
b
y
n
gain, sha
d
e
. CFD pre
d
l paramete
r
t
in visualiz
i
９８
a
rrows repr
e
a
linkage o
bj
t
h the zone
u
re and air
t
n
d CFD me
t
s. Howev
e
g
.4.12 resp
e
which has
t
n
e EP and
C
e
s into the
n
d to CFD
b
number of
n
F
D as Fig.
4
o
w using th
e
o
f neighbo
r
n
d boundar
y
e
ctively us
e
n
ode points
d
ing, natura
d
icts airflo
w
r
s that are r
e
i
ng physic
a
e
sent a ref
e
bj
ect. The d
a
air.
t
emperatur
e
t
hods offer
s
er
, the diffe
e
ctively ill
u
t
he average
C
FD, this
s
n
ode points
b
y allocatin
g
n
ode point
s
4
.13-a and
b
e
differenti
a
r
ing zones
y
condition
s
e
FVM an
d
which can
l
ventilatio
n
w
s, speeds
a
e
quired for
a
l paramete
r
e
rence from
a
she
d
arro
w
e
distributio
s
a combin
a
rence of re
s
u
strates the
value, and
C
s
tudy propo
of CFD.
g
the EP’s
v
s
from EP is
b
show. CF
a
ls with the
are bound
a
s
are respec
t
d
Finite Ele
m
express ai
r
n
and U-v
a
a
nd directi
o
energy cal
c
r
s in compl
e
object A t
o
w
s pointing
t
ns between
a
tion of ad
v
s
olutions
be
resolutions
C
FD needs
ses a grap
h
v
olume ave
r
increased
b
D refines t
h
values of n
e
a
ry conditi
o
t
ive repres
e
m
ent Meth
o
r
flow patter
n
a
lue etc. b
y
o
ns
b
etwee
n
c
ulation in
e
x geometr
y
o
object B.
t
o the Zone
zones and
v
antages of
e
tween EP
of EP and
more node
h
modeling
r
age value,
b
y copying
h
e average
e
ighboring
o
n for the
e
nted by
o
d (FEM).
n
s. EP can
y
all of the
n
values of
each zone.
y
such as a
９９
5. Microclimate design methods in S.
Korea: Simulation results using unit
EP-CFD
Energy simulation using EnergyPlus (EP) and Computational Fluid Dynamics (CFD) is applied to the
cases shown in Table 5.1. The graph modeling described in the previous chapter is used for unit design.
While EP calculates the air temperature of each zone, thermo- and aerodynamics among adjacent zones
can be calculated by EP-CFD. In this study, Fluent software125 is employed for the CFD simulation. A
combination of some design elements of Korean traditional, passive and climate architecture which are
expected to be efficient for heating and cooling are tested by EP-CFD simulation and classified into 4
cases. The 1st case is a combination of elements which are efficient for passive cooling, and the 2nd
case includes all passive heating elements. Case 1 and 2 respectively includes design elements which
are generally considered to improve the heating and cooling efficiency. Although a lot of different
studies were surveyed and described in previous chapters, few studies considered the best combination
since it is very difficult to counterbalance cooling and heating efficiencies. Some design elements can
increase heating gain but decrease the efficiency for cooling gain and some other elements vice versa. In
this study, cases of heating and cooling gains are separated firstly and the full combination of all cases is
tested for the counterbalance. Case 3 is the full combination of all tested elements in case 1 and 2.
Considering heating and cooling gains for heating and cooling efficient cases and full combinations, the
best combination of the energy efficient design elements is chosen. The 4th case is the best combination
which counterbalances heating and cooling efficiency.
For the 1st and 2nd cases, some good building elements for thermo- and aerodynamics are chosen by
the Passive House standard. Thermo- and aerodynamics can be utilized to make effective ventilation
ratio in passive cooling and to avoid overheating in passive heating etc.
125 The Fluent simulation has been carried out in cooperationwith Prof. Dr.-Ing. P.U. Thamsen of the Fluidsystemdynamik
Institut (SDI), TU-Berlin. License information: Fluent, Inc. license file for TU Berlin__9482_ren2006, License
268961540 created 11-jun-2007 by al, Windows NEW or Renewed Floating/Network License, SERVER
130.149.13.193 000102142b52 7241.
１００
Table 5.1. List of Elements in classified microclimate design methods for energy-saving houses [author].
(1) Maximum cooling efficiency can be obtained when air flows through the zone are continuous
through the geometry without a discontinuity on the streamline. Only continuous streamlines of airflow
through a house can bring about a strong microclimate effect because air movement through a house,
which occurs through partial pressure differences, distributes indoor air temperature and humidity.
Hence, it is most important to set up building geometry which has a smooth and continuous streamlines
through the house. Near the windows, doors, and openings, aerodynamics occur due to differences in
wind pressures and cause ventilation effects. Airflow can be mixed with thermodynamic effects such as
thermal buoyancy, stack effects due to the thermal distribution in the house.
(2) Maximum heating efficiency can be obtained by a high performance Passive House design.
However, overheating and imbalanced problems in the house should be avoided. The thermodynamics
１０１
of heat transfer is sufficient to solve these problems. Heat transfer always occurs from a warmer area to
a cold one and can never stop.126 If thermal energy is transferred from an overheated area to a cold area,
the areas reach thermal equilibrium. Thermal buoyancy, stack effects and solar chimney spreads the
heat from overheated zones to cold zones and results in thermal balance. The thermal condition in
thermally balanced rooms is easy to maintain and saves heating energy during cold nights. The
simulation results with several design elements will be described in the following chapters.
126 Note that it can be slowed down.
１０２
5.1. Arrangement
5.1.1. Microclimate of building orientation: the highest heating gain and small
indoor airflow
Above all, building orientation can play a significant role in determining the solar gains received. If a
house is oriented to 45˚, facing east or west will be more susceptible to receiving adverse low altitude of
sunlight in the morning and evening. The building zones are heated from early on the day and the
overheated air of these zones within the building is maintained during the day. Fig.5.1 (a) represents the
overheated temperature in the zone using CFD simulation. The maximum temperature of the air is
estimated at 34.7822℃ and the value is much higher than for human comfort.
Hence, the strong passive cooling through airflow is needed to discharge the overheated air. The
overheated air in the zone cannot be ventilated due to the small microclimate. As mentioned in Chapter
3.4.2, the opening control should be designed to drive the movement of the air more quickly and the
perpendicular of the wind direction has the best efficiency to develop a large amount of air pressure.
However, the amount of air through the window of a 45˚ oriented house is too small since the wall of the
building set to a south easterly wind direction and flow over the exterior. Fig.5.1 (b) represents the form
and the magnitude of airflow and the horizontal-vertical plots of the 3D CFD result.
(a) a. Temperature map b. Aerodynamic flow plot
(b) a. Vertical plot b. Horizontal plot
Figure 5.1. Result of orientation of the CFD, (a) 2D plot, (b) 3D plot [author].
N
S
18 24 32 (Temperature, ℃)
１０３
The minimum temperature 24.5918℃ is found in part of the wall but the average temperature is
29.942℃. It is lower than 30℃ of the single EP simulation result but a very small cooling gain from
microclimate can be expected. In general practice, air temperatures in the region of 23 to 25℃ are
regarded as being acceptable as a comfort zone in summer and 20 to 22℃ in winter. This form does not
have a good microclimate cooling effect in the design but it may be utilized when the zone needs no
flow and still air. One solution for the oriented building is minimizing glazing on the east-west façades
or providing solar shading of the south to avoid solar penetration. Fig.5.3-a shows the comparison of
temperature between the zone to the southeast and to the south.
5.1.2. Microclimate on topography: large microclimate cooling effect with high
air pressure
Building on topography has a strong microclimate effect since by day the air above the slopes can be
more easily heated than the lower area. Hence, strong anabatic airflow which was described in Chapter
3.2.3 is accompanied by strong air pressure due to the difference of air temperature. The building
located higher on the hill side obtains a large amount of strong wind and the aerodynamic effect of
microclimate enhances the performance of passive ventilation cooling. Fig.5.2-a illustrates the
difference in thermal conditions between the higher and lower slopes. The building ventilation near the
window in the thermal color map can be represented in comparison with the air temperature above the
overheated ground.
a. Thermal map b. 3D flow plot of aerodynamic
Figure 5.2. Result of building in topography [author].
The maximum temperature of the air is calculated by the CFD method and the quantity value in the
maximum temperature is 37.525℃ above the hill side. On the other side, the lowest temperature value
is 20.4619℃ and the difference between maximum and minimum is 17.0631℃ which is much larger
than the difference for flat land. The flow plot from the strong aerodynamic in Fig.5.2-b shows the
small eddy current in the zone, which adapts the indoor air temperature to the outdoor quickly. The
average temperature in the zone on topography is 26.6817℃ and the microclimate cooling effect can be
18 24 32 (Temperature, ℃)
e
x
te
m
In
to
p
sl
o
co
S.
T
h
fo
r
q
u
ge
T
h
w
h
x
pected to
r
m
peratures
the Kore
a
p
ography h
a
o
pe of a hil
oling wind
K
orea.
Fi
gu
5.1.3
.
t
h
e courtyar
d
r
increased
u
ality of lif
e
ometry of t
h
h
e main ad
v
h
ile outside
r
each 3℃
a
b
etween th
e
a
n traditio
n
a
ve been u
s
l side. Sea
s
as Fig.5.4
s
a. Or
i
Fi
g
ure 5
.
a. Hou
s
u
re 5.4. A
c
.
Microcli
m
he house
d
is one of
t
densities.
T
e
. This ch
a
h
e
b
uildin
g
v
antage of t
h
the
b
uildi
n
a
nd more t
h
e
zone on t
o
n
al architec
t
s
e
d
for the s
s
onally the
w
s
hows. The
s
i
entation (
s
ou
.
3. Compar
i
s
e design on t
o
c
ooling sch
e
m
ate of c
o
t
he most fa
v
T
he garden
o
a
pte
r
invest
i
g
is more i
m
h
e courtya
r
n
g it is very
h
an the zo
n
o
pography
a
t
ure sche
m
ummer sea
s
w
indow is
s
e design el
e
theast and
s
o
u
i
son of the
r
o
pography
e
me of a K
o
o
urtyard
c
v
orite hous
e
o
f the cour
t
i
gates the
m
m
portant tha
n
rd
house is
t
hot and su
n
１０４
n
e on flat l
a
a
nd on flat
l
m
e, a lot o
f
s
on. The m
a
fully open
e
e
ments can
u
th) b.
T
r
mal condit
i
o
rean tradit
c
ooling: t
h
e
designs t
o
t
yard can al
m
icroclima
t
n
the insul
a
t
hat the co
u
n
ny. It is pr
o
a
n
d
. Fig.5.
3
l
and.
f
microcli
m
a
in buildin
g
e
d towards
t
be utilized
T
opography a
n
i
on with co
o
b. Open
i
ional hous
e
h
ermodyn
o
provide e
a
so provide
a
t
e dimensio
a
tion for the
u
rtyard easi
l
o
tected fro
m
3
-b represe
n
m
ate desig
n
g
is normall
y
t
he south a
n
to plan a
m
n
d on flat lan
d
o
ling gain
[
a
i
ng control
e
on topogr
a
amic air
c
a
sy and nat
u
a
n indoor
g
n of the c
o
architects.
l
y has a pa
r
m
the direc
t
n
ts the co
m
n
elements
y
located o
n
nd
is used
t
m
odern hous
e
d
a
uthor].
a
phy
[author
]
c
irculatio
n
u
ral privac
y
g
reen space
o
urtyard sin
c
r
tial shade
a
t
hot and st
r
m
parison of
related to
n
the south
t
o take the
e
design in
]
.
n
through
y
, allowing
raising the
c
e the real
a
nd is cool
r
ong win
d
s
１０５
even when the building is orientated in any direction. Fig.5.5 (a)-a illustrates the air velocity of outdoors
and courtyard. When the outdoor air velocity is over 4m s-1, the aerodynamic velocity is 0m s-1 or very
small. Hence, the microclimate gain in the courtyard is more related to the thermodynamic effect. The
temperature difference between hot outdoors and cool courtyard forms a circulation vortex in the
courtyard. Fig.5.5 (a)-b shows the microclimate air circulation due to the thermal difference between
house and courtyard.
By day, the courtyard is cooler than the house which heats up as a result of solar radiation, and the down
flow air raises the air density. The dense cool air moves through the building through the courtyard
(a) a.Horizontal airflow plots b. Vertical airflow plots
(b) a. 3D airflow plot b. 2D airflow plot
Figure 5.5. Result of courtyard cooling between house and courtyard, (a) air velocity and the
microclimate air circulation, (b) thermodynamic air circulation [author].
openings. The wall of the house gets cool by night and the courtyard is then warmer than the house.
Hence, the warm air in the courtyard rises and the pressure in the courtyard decreases. The air from
outside at night comes through the house by cross-ventilation and the warmer air is evaporated in the
courtyard. The night ventilation caused as a result of the courtyard is represented by the 2-D airflow plot
shown in Fig.5.5 (b)-b. Fig.5.6 (a) shows the air temperatures of courtyard, indoor and outdoor by day
and night.
However, in the hot and humid Korean climate, the courtyard cooling is only partially effective in the
building and the total cooling efficiency is not high as Fig.5.6 (a) represents. The average indoor
temperature is 26.324℃ by day and 26.147 ℃ by night. However, the microclimate airflow produced
by the thermal imbalance can always make indoor airflows and this feature can be utilized for designs
N
S
N
S
0 3.5 7
(Velocity, m s-1)
18 24 32
(Temperature, ℃)
w
h
i
m
1-
y
p
a
Fi
g
T
h
w
a
co
te
m
ai
r
T
o
he
di
r
ai
r
in
d
bu
a
te
m
T
h
te
m
Fi
g
w
i
a
r
h
ich need
g
m
portant iss
u
y
ear shado
w
a
rameters f
o
(a)
g
ure 5.6.
A
5.1.4
.
h
e courtyar
d
a
rm since t
h
urtyard is
m
perature i
n
r
.
o
improve t
ating meth
o
r
ect heat lo
s
r
circulatio
n
d
oor tempe
r
u
ilding but i
m
glass roof
m
peratures
h
e average
m
perature
o
g
.5.7 (a) sh
o
i
thout roof
w
r
oof is muc
h
g
ood ventil
u
e so as to
u
w
range o
f
o
r cooling.
F
A
ir temperat
u
.
Microcli
m
d
can prote
c
h
e air tem
p
very simil
a
n
the court
y
he heat ga
i
o
d. The atr
i
s
s by the gl
a
n
, the neigh
b
r
ature is 1
9
m
proved s
o
is very
w
in the cour
t
air temper
o
f the build
i
o
ws the co
m
w
ith therm
o
h
better. Th
e
ation. For
u
tilize the
t
f
the court
y
F
ig.5.5 (b)-
a
u
re of cour
t
m
ate of c
o
c
t against
d
p
erature is
n
a
r to the
o
y
ard, whic
h
i
n of the z
o
i
um of the
c
a
ss. The ave
b
oring zon
e
9
.488℃. T
h
o
lar heat ga
i
w
arm and
p
t
yard, indo
o
ature of t
h
i
ng surroun
d
m
parison o
f
o
dynamic ai
e
atrium of
t
the design
,
t
hermal im
b
y
ard is ne
e
a
shows the
t
yard, (a) i
n
o
urtyard
r
d
irect and s
t
n
ot the sa
m
o
utdoor te
m
h
is related
t
o
ne, the roo
c
ourtyard c
a
rage air te
m
e
can get ab
h
e main he
a
i
n sufficien
t
p
leasant wi
t
o
r and outd
o
h
e courtyar
d
d
ing the co
u
f
the therm
a
r circulatio
n
t
he courtya
r
１０６
,
the contr
o
b
alance for
t
e
ded to de
t
3D airflo
w
(b)
n
door and o
u
r
oof: atri
u
t
rong win
d
m
e as the w
i
m
perature
b
t
o the hum
a
f glazing o
a
n obtain r
a
m
perature i
n
out 4℃ hi
g
a
t loss may
t
ly recover
s
t
h less wi
n
o
or betwee
n
d
without
a
u
rtyard wit
h
a
l condition
s
n
. The patt
e
r
d can bloc
k
o
lling of t
h
t
he microc
l
t
ermine th
e
w
of outdoo
r
u
tdoor by d
a
u
m passi
v
but the air
i
nd temper
a
u
t the airf
l
a
n comfort,
f the court
y
a
diative he
a
n
the courty
a
g
her temper
a
occur thro
u
s
the amoun
t
n
d. Fig.5.6
n
courtyar
d
a
roof is -
5
h
out a roof
i
s
between
c
e
rn of therm
k
the direct
c
h
e local te
m
l
imate. A c
o
e
window
c
r
, indoor an
d
a
y and nig
h
v
e heatin
g
temperatu
r
a
ture. The
a
l
ow is sta
b
is lower th
a
y
ard can b
e
a
t through t
h
a
rd atrium i
s
a
ture by da
y
u
gh the roo
f
t
of loss. H
e
(b) repre
s
d
s with a ro
o
5
.328℃ an
d
i
s 14.992℃
c
ourtyards
w
al conditio
n
c
old airflo
w
m
perature i
s
o
mputer si
m
c
ontrol seq
u
d
the court
y
h
t
, (b)
with a
n
r
o
g
using c
o
r
e in winter
a
ir tempera
t
b
le thus th
e
an that of t
h
e
utilized a
s
h
e glass an
d
s
26.814℃.
y
time and t
h
f
glass surf
a
e
nce, a cou
r
s
ents the a
v
o
f an
d
a wi
t
d
the aver
a
.
w
ith a glass
n
in the cou
r
w
, and the c
o
s
the most
m
ulation of
u
ence and
y
ar
d
.
n
d without
o
of
[author].
o
urtyard
cannot be
t
ure in the
e
effective
h
e outdoor
s
a passive
d
avoid the
By indoor
h
e average
a
ces of the
r
tyard with
v
erage air
t
hout roof.
a
ge indoor
roof and a
r
tyard with
o
ld airflow
slides on t
h
as Fig.5.7
(
and the w
a
Fig.5.7 (b)
(a)
(b
)
Fi
g
ure
5
The advan
t
condition
o
courtyard
i
previous c
h
without a
r
thermody
n
opened, th
e
Fig.5.7 (a)
Another
m
the surfac
e
airflow is
discharge
d
effects by
suitable to
suitable fo
r
h
e surface
o
(
b)-a repre
s
a
ll of the c
o
-b shows.
a. Co
u
)
a. Court
y
5
.7. Result
o
t
age of a c
o
o
f the cour
t
i
s overheat
e
h
apter. Th
e
r
oof, due to
n
amic micr
o
e
airflow th
r
-a exempli
f
m
ethod is a
r
e
near the f
l
opposite t
d
by roof o
p
roof openi
n
design a l
a
r
small bui
l
o
f the roof
a
s
ents. On th
o
urtyard an
d
u
rtyard with
a
y
ard with a g
l
o
f courtyar
d
o
urtyard is
t
t
yard. Hen
c
e
d by day, t
h
e
ventilatio
n
stack effe
c
o
climate ca
n
r
ough the z
o
f
ies this cas
r
oof openin
g
l
oor and te
n
o the cros
s
p
enings an
d
n
gs are big
g
a
rge buildi
n
l
dings whic
h
a
nd glass ro
o
e contrary,
d
the air ca
n
a
glass roof
l
ass roof
d
roof, (a) t
h
airf
l
t
he isolatio
n
c
e, the cour
t
h
e cross-ve
n
n
performa
n
c
ts. The ind
o
n
occur. If
o
ne remov
e
e.
g
which us
e
n
ds to rise
u
s
-ventilatio
n
d
the cold
a
g
er than th
e
n
g with a
c
h
want to s
t
１０７
o
f and natu
r
if a roof do
n
not be he
a
h
ermal con
d
l
ows betwe
e
n
of the out
e
t
yard roof
i
n
tilation is
a
n
ce of the
c
o
or temper
a
the windo
w
e
s the heat o
e
s the stack
u
p to the ro
o
n
through
a
ir comes f
r
e
effects
by
c
ourtyard.
T
t
ore the hea
t
r
ally sinks
d
es not exis
t
a
ted well d
u
b. Co
u
b. Cou
r
d
ition of c
o
e
n courtyar
d
e
r wall and
i
s necessar
y
a
lso a good
c
ourtyard a
t
a
ture is low
w
s of the e
x
f the court
y
effects sin
c
o
f. In this c
a
the exteri
o
r
om the wi
n
y
exterio
r
o
p
T
he exterio
r
t
by day an
d
10
25
d
own the s
u
t
, cold air c
a
u
e to the sh
a
u
rtyard witho
u
r
tyard withou
t
o
urtyar
d
in
w
d
with roof
the glass r
o
y
in the col
d
solution as
h
t
rium is bet
er than tha
t
x
terior wal
l
y
ard but im
p
c
e the over
h
a
se, the dir
e
o
r openings
n
dows of t
h
p
enings. H
e
r
openings
d
to use the
20 3
0
0 2
5
u
rface of th
e
a
scades do
w
a
ding of th
e
u
t roof
t
roof
w
inte
r
,
(b)
c
and witho
u
o
of maintai
n
d
winter in
h
as been d
e
t
ter tha
n
in
t
in the cou
r
l
and court
y
p
roves the i
n
h
eated air is
e
ction of th
e
. The ove
r
h
e zone. Th
e
e
nce, the r
o
are an eas
y
heat for th
e
0
(Temperature,
5
(Total pressur
e
e
exterior w
a
w
n the surf
a
e
courtyard
c
omparison
u
t roof
[auth
o
n
s the ther
m
Korea. If t
h
e
scribed in t
h
the courty
a
r
tyard and t
h
y
ard wall
a
n
door clima
t
generated
o
e
rmodyna
m
r
heated air
e
rmodyna
m
o
of opening
y
method a
n
e
cold nigh
t
℃)
e
, Pa)
a
ll
a
ce
as
of
o
r].
m
al
h
e
h
e
a
r
d
h
e
a
re
t
e.
o
n
m
ic
is
m
ic
is
n
d
t
.
１０８
5.2. Form
5.2.1. Microclimate in roof shapes: strong shading and control of wind stream
direction
The architect or designer typically designs the general shape of the roof in the preliminary design stage.
As described in chapter 3.4.3, design of roof shapes is related to the both shading and wind streamline.
The flat roof is a very common style in areas with little rain or snow to provide a platform for heating
and other mechanical equipment. The flat roof can eliminate the ceiling joists. However, it is difficult to
design a passive cooling system through the roof since when air is heated it becomes less dense and
rises. The air movement through the zone generates local areas with high and low pressures. If a space
has high air outlets in conjunction with low inlets, ventilation occurs as the air within the space is heated
and the greater the vertical distance between the outlet and inlet, the greater the ventilation rate that can
be obtained.
The gable roof shown in Fig.5.8 is one of the most common type of roof in residential construction and
uses two slanted roofs that meet to form a ridge between the support walls. The gable roof can offer the
largest ceiling space and roof outlets near the ridge are sufficient to derive a stack effect in which the
wind from outdoors is heated and naturally moved into the roof outlets. The positive air pressure in the
a. Horizontal plot b. Vertical plot
c. Thermal map d. 3D streamline plot of pressure
Figure 5.8. Result of gable roof with shading overhang and roof ventilation [author].
N
S
-5 2.5 10 (Pressure, Pa)
18 24 32 (Temperature, ℃)
18 24 32 (Temperature, ℃)
N
S
N
S
front side
o
visualizes
t
air pressu
r
ventilatio
n
rainbow c
o
maximum
about 28
℃
represente
d
The edge
o
raise the i
n
Figure 5.
9
(a)
Figure 5.
1
o
f the hous
e
t
he positiv
e
r
e different
i
n
allowing r
e
o
lors and
v
temperatur
e
℃
and 24
℃
d
in Fig.5.8
o
f the roof
n
ternal ve
n
(a)
(b)
9
. Result of
c
1
0. Compar
i
-10
0
e
is change
d
e
and negati
v
i
als the roo
f
e
gular air c
h
v
ery clearl
y
e
of the air
i
℃
in the li
v
-b.
can be use
d
n
tilation rat
e
a. Airflow ov
a. Airflow p
l
c
urved roo
f
i
son of ther
a
0
10 (T
o
d
into negat
i
v
e pressure
f
form allo
w
h
anges. Fig
.
y
represent
s
i
s 35.423℃
v
ing space
d
as extern
a
e
s or the s
u
er gable roo
f
l
ot with total
p
f
, (a) air-str
e
mal condit
i
nd exterior
o
tal pressure, P
a
１０９
i
ve pressur
e
and the m
a
w
s for the
b
.
5.8-c visu
a
s
the temp
e
near the ro
o
near the
fl
a
l projectio
n
u
nshade. It
f
p
ressure
e
amline co
m
pressu
r
(b)
i
on (a) cool
i
wall temp
e
a
)
e
when the
a
a
gnitude usi
n
b
etter inter
n
a
lizes the th
e
e
rature gra
d
o
f but the i
n
fl
oor. The
3
n
s; they ac
t
can effici
e
m
parison be
t
r
e and ther
m
i
ng gain be
t
e
ratures bet
w
-10
10
a
ir is acros
s
n
g 3D stre
a
n
al cross-v
e
e
rmal rang
e
d
ient betw
e
n
door air te
m
3
D airflow
t
as horizo
n
e
ntly reduc
e
b. Airflow ov
b. Thermal
t
ween gabl
e
m
al conditi
o
t
ween flat
a
w
een gable
0
20
s
the roof ri
d
a
mline plot.
e
ntilatio
n
a
n
e
by pseudo
e
en floor
a
m
perature
n
plot of ae
n
tal wind-c
a
e
heat gain
er curved ro
of
plo
t
e
roof and c
u
o
n of curve
d
a
nd gable r
o
and curve
d
10 (Total pre
30 (Tempe
r
d
ge. Fig.5.
8
As a result
n
d roof sp
a
coloring w
i
a
nd roof. T
h
ear the roo
f
rodynamic
a
tchers whi
and impro
v
f
u
rved roof,
d
roof
[auth
o
o
of, (b) ind
o
d
roofs
[auth
o
ssure, Pa)
r
ature, ℃)
8
-d
of
a
ce
i
th
h
e
f
is
is
ch
v
e
(b)
o
r].
o
or
o
r].
１１０
human comfort in summer. While the roof is overheated by solar radiation, the living zone can maintain
the cool air temperature in the walls, using the shading effect and the microclimate aerodynamic
cooling, resulting in strong ventilation effects. The minimum temperature 15.592℃ is formed in the
floor and the average air temperature is 25.168℃. The 3D plot of the airflow is represented in Fig.5.8-a
and b. The differences in cooling efficiency achieved by the design forms can be compared with the flat
form shown in Fig.5.2. A temperature comparison between flat and gable roof is shown in Fig.5.10 (a).
5.2.2. Microclimate of curved roof: minimum wind resistance and small eddy
current
The roof design in cold winter is an important factor to control energy flow. The Korean winter airflow
blowing from Siberia is very strong and cold. In this condition, the wind resistance of the roof affects
the pattern of air currents around the zone. In the colder regions, most residential roofs have a steep
slope due to the large amount of snow. However, the Korean winter is not humid but dry and the amount
of snow is not great. Hence, the consideration of airflow for roof design is more important.
The most common design of roofs in Korea is the gable roof as Fig.5.9 (a)-a shows. By computer
simulation, the gable roof form generates a large eddy current due to unstable pressure around the house.
When a high wind blows, the positive pressure from the side and below and the negative pressure from
above generate the uplift air pressure. The airflow accompanying the high wind resistance created by
the roof eddies around the exterior of the house. The shape and slope of the roof deck and the edge
configuration also involves similar high pressure effects. Strong local wind effects with the eddy
current due to the pressure are difficult to control.
A design form is investigated in this chapter to minimize the eddy current by controlling the energy
flow. A curved roof using the streamline shape shown in Fig.5.9 (a)-b does not disturb the flow over the
model and eliminates or reduces wall effects on the house. The streamline shape allows the wind to
decelerate gradually along the back part of the building. This helps prevent the boundary layer from
separating, and thus produces much less pressure drag. Hence, the streamline plot of the curved roof
represents the very smooth airflow lines passing the house with such a roof shape. By comparing
between 5.9 (a)-a and b, the magnitude of total pressure around a house using the curved roof is much
smaller than one using a gable roof. A large amount of cold wind quickly passes over the roof surface
and the flow path continues naturally without producing an eddy as Fig.5.9 (b) shows. The stable
airflow over the house helps to avoid a loss of heat from interior sources through the wall. In the results,
the energy losses decrease and about 9% additional energy gain can be obtained. Fig.5.9 (b)-b shows the
thermal plot of the zone and the average temperature of the zone is 16.574℃. The comparison of the
average temperature of indoor and exterior between gable roof and curved roof is shown in Fig.5.10 (b).
１１１
5.2.3. Microclimate in fence design: deriving small wind and airflow on the site
Air movement within an environment is required to get rid of discomfort through heat and humidity and
to provide fresh air to the space. In the site condition, occupants do not need strong wind for human
comfort. A strong wind reduces the sensible heat and humidity due to higher evaporative cooling on the
skin. However, the extremely strong airflow cannot be endured due to the wind discomfort. The general
design specifications for air movement are that the air speed should not be above 1.5 m s-1 around the
body.
For that reason, a long history of utilizing windbreaks including natural trees and artificial fences are
used for preventing wind damage, increasing productivity, and improving the quality of the living
environment. Fence design using walls and huge plants can be used to protect against wind and direct
hot air. Layered spaces in the Korean traditional house usually use the design of low walls as a form of
organic space with a cell structure divided by the walls.
(a) a. Velocity magnitude b. Vertical plane cut of airflow field
(b) a. A part of the house b. Aerial view of real site
Figure 5.11. Result of fence design in Korean house, (a) 3D streamline plot of airflow, (b) the present
state of Mr. Jung’s house [author].
Fig.5.11 (a)-a represents the streamline of wind control using the fence design. This simulation uses
low fences which are generally constructed in Korean traditional architecture designs. The distribution
N
S
0 1.5 3 (Velocity, m s-1)
18 24 32 (Temperature, ℃)
１１２
of the velocity magnitude is decreased by the walls and the small windbreaks in the fence. An effective
barrier design for windbreak is perpendicular to the wind but the streamline through the site should not
be blocked by the design. Hence, the continuous path of the airflow should be considered in the design
stage. For the simulation purpose, the fence form is employed from “Mr. Jung’s house” which is located
in Hamyang, Kyungsangnamdo, S. Korea. Fig.5.11 (b) shows a picture of the site and the aerial view of
the real site condition. The simulation model is simplified to the single house using the real fence form.
In the simulation result, the average wind speed through the site is 2.823m s-1 but the speed on the site
surrounded by the wall is decreased to the 0.920m s-1. The percentage of the total decrease in speed is
67.4%.
In Fig.5.12 (a)-b, the temperature and flow shape are visualized by a horizontal plane cut of the flow
field. The windbreaks are placed at various distances from the buildings and walls, and different effects
exerted by the building and windbreak can be shown in the flow shape. If the distance was less than 4
times of the fence’s height, the standing vortex in front of the building is dominated by the lower part of
the flow field and there is no difference between porous windbreaks with afforestation and solid wall.
5.2.4. Microclimate of windbreaks: cold wind protection in winter
The direct wind blocking called wind shelter is the most efficient concept using microclimate in winter.
Wind shelter can be provided by several design methods using other buildings, wall, natural
afforestation or artificial windbreaks. However, the purpose of wind shelter is not only against wind
velocity producing extra wind-chill but also driving rain and snow.
(a) a. Temperature plot b. Flow plot with total pressure
(b) a. Flow plot with total pressure b. 3D streamline plot
Figure 5.12. Cold wind protection, (a) using wall and projection, (b) using trees [author].
-10 0 10 (Total pressure, Pa)
10 20 30
(Temperature, ℃)
-10 0 10 (Total pressure, Pa)
The main
exterior s
u
The erecti
o
Hence, th
e
pressure i
s
b
y wind s
i
height. As
roof proje
c
overhangs
,
this desig
n
protecting
streamline
due to the
climate wi
t
Similar wi
wind. Lin
e
speeds. T
h
b
locking
u
remain. If
t
narrower
a
the requir
e
and shelte
r
using tree
s
Figure 5
feature of
u
rface direc
t
o
n of a bar
r
e
geometri
c
s
very impo
r
i
deslip aro
u
in the desc
r
c
tion is incl
u
,
the wind-
s
n
, the 16%
the cold
w
very clear
l
pressure c
h
t
h stable ai
r
nd shelter
e
e
s of trees
p
h
e average
t
u
sing trees
t
here is a g
a
a
reas may c
a
e
d effect. Fi
g
r
ing using
a
s
can obtain
.13. Avera
g
winds aro
u
t
ly meets th
r
ier can get
c
set-up be
t
r
tant. The
e
u
nd a
b
uild
r
iption of c
h
u
ded to blo
c
s
heltering e
heat loss
i
w
ind. The t
h
l
y illustrate
s
h
ange. Som
e
r
flow.
e
ffects can
b
p
lay a role
t
emperatur
e
and the str
e
a
p between
a
use strong
g
.5.13 sho
w
a
wall and
p
31% and 1
g
e indoor t
e
u
n
d
b
uildin
g
e direct col
d
rid of the
d
t
ween the
b
e
ffective de
s
ing is the
d
h
apter 3.3.
1
c
k the airflo
ffect is exe
m
i
s avoided
a
h
ermal co
n
s
the air bl
o
e
times the
s
b
e generat
e
as a medi
u
e
of the zo
n
e
amline. T
h
trees, thei
r
local wind
w
s the comp
a
p
rojection,
a
5% gains,
r
e
mperature
s
１１３
g
s is a cir
c
d
wind and
d
irect wind
b
uilding a
n
s
ign featur
e
d
istance be
t
1
, the dista
n
w from the
m
plifie
d
as
a
nd the av
e
n
dition of t
h
o
cking effe
c
s
pace betw
e
e
d by very l
u
m density
w
n
e is 17.53
6
h
e trees ca
n
r
performan
c
effects. He
n
a
rison of a
v
a
n
d
using t
r
r
espectivel
y
s
of no win
d
c
ulation dri
v
the eddy o
c
but is not
p
n
d wall tha
t
e
of the set-
u
t
ween the
b
ce is decid
e
roof. By a
c
the plot w
i
e
rage temp
e
h
e zone is
c
t which th
e
e
en windbr
e
arge plants
w
indbrea
k
6
℃. Fig.5.
1
n
weaken
v
c
e as a bar
r
n
ce, severa
l
v
erage temp
r
ees. Shelte
r
y
.
d
shelter, s
h
v
en by the
c
curred by
t
p
erfect for
t
may cont
r
u
p to remo
v
b
arrier and
e
d as 1/3 of
c
ombinatio
n
i
nd streaml
i
e
rature of
t
represente
d
e
wind gets
e
aks and a
h
plant whic
h
and spread
1
2 (b) resp
e
v
ery strong
r
ier is decre
l
rows of tr
e
eratures be
t
r
ing, using
h
elters usin
g
b
uilding g
e
t
he geomet
r
removing
e
r
ol the mi
c
v
e eddy wh
building a
n
the buildin
g
n
of side ba
r
i
nes in Fig.
t
he zone is
d
in Fig.5.
1
out of the
h
h
ouse surfa
c
h
can prot
e
the distrib
u
e
ctively sh
o
winds but
ased since
t
e
es are nee
d
t
ween no w
i
a wall and
p
g
wall and
p
usi
n
e
ometry. T
h
r
ic resistan
c
e
ddy curre
n
c
roclimate
a
irls generat
nd
the
b
arr
i
g
size and t
h
r
riers and r
o
5.12 (a)-b.
21.411℃
b
1
2 (a)-a. T
h
h
ouse surf
a
c
e has a lo
c
e
ct against t
h
u
tion of wi
n
o
ws the wi
n
low airflo
w
t
he flows i
n
d
ed to achie
v
i
n
d
-shelteri
n
p
rojection,
p
rojection a
n
n
g tree
[auth
o
h
e
c
e.
n
ts.
a
ir
e
d
i
e
r
h
e
o
of
In
b
y
h
e
a
ce
c
al
h
e
n
d
n
d
w
s
n
to
v
e
n
g
or
n
d
o
r].
P
e
h
u
th
a
m
o
A
cl
i
m
o
fl
o
a
n
is
he
T
h
o
f
In
v
e
(a
)
(b
)
5.2.5
.
t
e
ople gene
r
u
midity usu
a
a
t range.
H
o
vement is
floating bu
i
i
mate, laten
t
o
st commo
n
o
ating archi
t
n
d cross-ve
n
efficient f
o
lps to catc
h
h
e 3D plot
o
f
the floor a
n
Korean tr
a
e
ry popula
r
)
a.
3
)
a.
Figure 5.
1
S
18
2
-5
2
.
Microcli
m
he floor
r
ally can to
l
a
lly ranges
H
owever, if
low or ther
e
i
lding usi
n
g
t
energy tr
a
n
method
i
t
ectural de
s
n
tilation thr
o
o
r cooling.
R
h
the strong
o
f airflow i
n
n
d by locati
a
ditional ar
c
r
as a seas
o
3
D airflow pl
o
Z
one over pi
1
4. Buildin
g
2
4 32 (T
e
2
.5 10 (
T
m
ate in b
u
l
erate wide
r
from abou
t
the humid
i
e
is no mo
v
g
pilotis ca
n
a
nsfer with
a
i
s designin
g
s
ign offers
t
o
ugh the sp
a
R
aising th
e
est winds
a
n
Fig.5.14 (
a
ng the win
d
c
hitectural
d
o
nal dwell
i
ot
lotis
g
over pilot
i
N
e
mperature, ℃
)
T
otal pressure,
u
ilding o
v
r
ranges of
h
t
the mid 3
0
i
ty is in th
e
v
ement, peo
p
n
be often o
b
a
ir motion i
g
the large
s
t
he unit the
a
ce under t
h
e
building
s
a
nd to keep
a
)-a shows t
h
d
ow high u
p
d
esign, the
i
ng for su
m
b. Horizo
n
b. Low
-
i
s, (a) resul
t
wind
p
)
Pa)
１１４
v
er pilotis
:
h
umidity th
0
s to the u
p
e
upper 60
s
p
le feel un
c
b
served in
t
s more imp
o
s
t surface
f
opportunit
y
h
e floo
r
, to
s
tructure cr
e
cool air fr
o
h
at raising
a
p
in the wal
pavilion w
i
m
mer. In t
h
n
tal cut near t
h
-
set building
t
of flow fi
e
p
ressure di
s
:
cooling
e
an of air te
m
p
per 60s an
d
s
, along wi
t
c
omfortabl
e
t
he subtropi
o
rtant to ge
f
or the zo
n
y
for maxi
m
allow bree
z
e
ates fully
o
m the sha
d
a
b
uilding
o
l is better f
o
i
th pilotis
s
h
e simulat
i
h
e floor
e
ld and a K
o
s
tribution f
o
e
fficiency
m
perature.
I
d
people ca
n
t
h high air
e
.
cal climate
.
t rid of hu
m
n
e for effic
i
m
izing the
v
z
es to flow
t
shaded spa
d
y ground s
p
o
n stilts is e
f
o
r ventilati
o
s
hown in F
i
i
on result,
c.
K
ore
a
c. Compar
i
o
rean pavil
i
o
r different
p
of airflo
w
I
n internal
s
n
tolerate
h
temperatur
e
.
In the hot
m
idity in th
e
i
ent evapo
r
v
olume of
a
t
hrough the
ce underne
p
ace under
f
ficient fo
r
t
o
n.
i
g.5.14 (a)-
c
when the
a
n pavilion on
i
son between
a
i
on, (b) co
m
p
orosities (
%
w
under
s
paces, the
h
umidity in
e
s, and air
and humid
e
zone. The
r
ation. The
a
ir currents
house and
a
th, which
the house.
t
he cooling
c
has been
maximum
stilts
a
and b
m
parison of
%
)
[author].
１１５
temperature outdoors is 29.211℃, the minimum temperature 12.426℃ is reached in part of the floor as
Fig.5.14 (a)-b shows and the average air temperature in the zone is 22.17℃. It shows that the design is
suitable for cooling in the hot and humid Korean summer. For cross-ventilation performance, Fig.5.14
(b) compares the difference of wind pressure distribution between building over pilotis and low- set
building with varying degrees of porosities. At higher porosities, the flow through the building modifies
the external pressures and airflow rates obtained from the pressure coefficients. A building on pilotis
has a larger pressure coefficients and results in a better microclimate cooling effect since higher
porosities are desirable for ventilation purposes in a warm and humid climate.
One of the most important issues for passive architectural design is the internal environmental comfort
and a target for the room temperature of the building is to range between 20℃ and 23℃ in summer. To
adopt a design for comfort would be difficult since excessive mechanical ventilation should be avoided
or at least minimized in the design. Designs considering natural ventilation performance have generally
been employed without airflow simulation or microclimate consideration. Wrong design achieves only
small effects since the natural ventilation problem is strongly related to the microclimate pressure as
Chapter 3.4.1 and 3.4.2 introduced. If the pressure difference between outdoor and indoor is zero or too
small, air movement cannot occur. Hence, a single opening is not efficient for natural ventilation since
air pressure differences through the window is very small even when the temperature difference exists.
To obtain a better ventilation rate with cross-ventilation, window openings in opposite walls are
efficient. However, only few results from researches for cross-ventilation performance of window
shape and position exist. Fig.5.15 compares the thermal condition between ventilation using pilotis and
cross-ventilation of low-set building. The building with pilotis can easily get a more cooling effect than
cross-ventilation. However, the difference in maximum and average temperatures is not so big, i.e. 1℃
to 2℃. The building with piloties is not usual in normal house design on a flat site due to the high cost.
The cross ventilation is a cost effective method although it needs more efforts for placing two opposite
windows. The building with pilotis can be applied to sloping topography efficiently.
Figure 5.15. Comparison of thermal condition with cooling gain between ventilation using pilotis and
cross-ventilation of low-set building [author].
１１６
5.2.6. Microclimate of heat diffusion: Indoor airflow for heat recovery
Heat diffusion is one of the microclimate effects to balance the thermal condition. If part of a mass is
heated, the heat transfers to another cool part. Diffusion equilibrium is reached when the concentrations
of the diffusing substance in the two compartments become equal. Heat recovery is an efficient concept
to utilize heating imbalance which often occurs in passive heating and cooling design.
For example, if a room has a window which is getting the sun, the area in the sunshine is heated by solar
radiation but the other area is relatively cooler than the heated area. In the afternoon, the region can be
overheated. A lot of passive solar design, shading is a very important solution for the case but the heat
diffusion from the overheated region which moves a part of the heat to the cold region can be a better
solution.
Figure 5.16. Thermodynamic heat diffusion process using isothermal particle tracking [author].
The heat recovery method is a process to transfer the heat energy in the air of an overheated zone to the
supply air for the other zone. A combination of indoor ventilation designs can be applied to transfer heat.
However, the natural ventilation concept is more complex to approximate the thermal condition of the
zones. Microclimate simulations like the EP-CFD method enable the design of heat balance between
the zones. Fig.5.16 shows a tracking of air particles of isothermal condition which diffuse from the air
of heated source to the air of non-heated space. There are some problems in visualizing the simulation
result. The thermodynamic flow in the zone cannot visualize the aerodynamic simultaneously since the
magnitude of the thermodynamic is much smaller than the outdoor aerodynamic airflow. Fig.5.17 (a)-a
shows the situation. Large needle flows are shown outside of the zone and no needle flows in the zone.
In this case, the distribution of the temperature shown in Fig.5.17 (a)-b can be utilized in visualizing the
thermodynamic.
10 20 30 (Temperature, ℃)
１１７
A good application is attached to sun-space design where the outdoor air is preheated and overheated in
the space and the warmer air enters into the occupied zones in a building. Another application is the
aniso-thermal condition of the zones. Neighboring two zones shown in Fig.5.17 (b)-a have different
passive heating zones. The left zone does not have a window and cannot directly heat, and the right zone
is getting large radiative heats by a large window. Fig.5.17 (b)-b shows the 3D model of the zone set-up.
To observe the thermodynamic microclimate effect, the environmental condition should not derive
aerodynamic flows. By setting of no airflow, and the zones should be fully insulated by the material.
The simulation result shows the heat transfer from the overheated right zone to the non-heated left zone.
Although the direct heating gain of the left zone is zero, the thermodynamic heat gain can sufficiently
recover the indoor temperature over 25℃.
This feature can be utilized for heat recovery. If one zone cannot have any passive heating design, the
consideration of microclimate air circulation, i.e. note that similar to zone-to-zone ventilation, is useful
(a) a. Needle map of airflow b. Distribution map of temperature
(b) a. Heat balancing b. 3D model of zone set-up
Figure 5.17. Difficulty in visualizing thermo- and aerodynamic simultaneously, (a) simple zone, (b)
two different heating zones [author].
for passive heating design. During a cold winter night, when the temperature of the zone decreases, the
circulation of the air enables the maintenance of the thermal condition by transferring heat from the
neighboring zone.
Therefore, it shows that adequate indoor e.g. zone-to-zone natural ventilation designs can supply and
maintain thermal comfort. Fig.5.18 represents the temperature with 5 hours passive heating by day and
heat distribution by night. The temperature of the right zone quickly rises from the initial temperature
10℃ to 40℃. The left zone similarly obtains the heat from the right zone and the temperature rises to
30℃. By night, the right zone loses heat by the heat balancing to the left zone. The left zone can
N S
10 20 30 (Temperature, ℃)
m
a
w
h
5.
T
h
ae
r
si
n
Fi
g
ai
r
ve
th
e
th
r
di
s
w
i
w
i
b
e
cr
o
di
s
Fi
g
m
i
o
u
a
intain the
t
h
en the hea
t
3. Faça
d
5.3.1
.
h
e uniform
a
r
odynamic
p
n
ce there i
s
g
.5.19 (a) r
e
r
velocity i
s
locity is 1
e
rmodyna
m
r
ough an o
u
s
tribution i
s
i
de range o
f
i
dely from
0
tween ind
o
o
ss-ventilat
s
co
m
fort c
o
g
.5.19 (
b
)
s
i
croclimate
u
tlet than th
Figure 5.
1
t
hermal co
m
t
of the zon
e
d
e eleme
.
Microcli
m
a
nd no
n
-u
n
p
ressure is
t
s
no differe
n
e
sults in a h
i
s
1.73 m s
-1
.37 m s
-1
.
m
ic microcl
i
u
tlet, the i
n
s
unstable a
f
4.82 Pa to
1
0
.04 m s
-1
t
o
o
or and
o
ion by aer
o
o
ndition.
s
hows that
effects in c
r
e uniform
w
a. Day
1
8. Tempe
r
m
fort durin
g
e
losses. T
h
nts
m
ate of
w
n
iform win
d
t
he driving
n
ce in vert
i
i
gher indoo
, the indoo
r
It demon
s
i
mate for c
r
n
door pres
s
s Fig.5.19
(
1
1.26 Pa.
A
o
1.61 m s
-
1
o
utdoor an
d
o
dynamic
i
examples
o
r
oss-ventil
a
w
indow ca
s
r
ature of th
e
g
the 5 ho
u
h
e design u
s
w
indow sh
a
d
ow shape i
force of th
e
i
cal pressu
r
r pressure
b
r
air velocit
s
trates tha
t
r
oss-ventila
t
s
ure is hig
h
(
a)-a shows
A
s a result, t
h
1
. The war
m
d
the pre
s
i
s deteriora
t
o
f non-uni
f
a
tion. The t
o
s
e. Althoug
h
１１８
e
zone-to-z
o
u
rs since th
e
s
es a door o
p
a
pe: Fast
a
s compare
d
e
natural ve
n
r
e gradient
s
b
ut small fl
o
y is 0.04
m
t
aerodyna
m
t
ion. If the
h
er but ind
o
and the va
r
h
e indoor ai
r
m
er indoor
a
s
sure will
t
ed. Stagn
a
f
orm shape
s
o
tal pressur
e
h
the non-
u
b.
N
o
ne natural
v
e
heat can
b
p
ening bet
w
a
nd well-
d
d
in this ch
a
n
tilation. O
n
s
. In this c
a
o
w lines ne
a
m
s
-1
to 1.61
m
ic micro
c
wind inpu
t
o
or air is
d
r
iation of t
h
r
velocity i
n
a
ir causes t
h
have a r
i
a
nt humidit
y
s
and distri
b
e
plot has
m
u
niform inl
e
N
ight
v
entilation
[
b
e recovere
w
een left a
n
d
istribute
d
a
pter. Fig.5.
n
ly horizon
t
a
se unifor
m
a
r inlet and
o
m s
-1
and
t
c
limate is
m
t
from the i
n
d
ense and
w
h
e total pre
s
n
the zone i
s
h
e microcli
m
i
sing tren
d
y
in the d
e
b
utions ha
v
m
ore stream
l
e
ts using t
w
[
author].
d from the
n
d right zon
e
d
cross-v
e
19 represe
n
t
al airflows
m
window s
o
utlet. The
m
t
he mean o
f
m
ore imp
o
n
let is not
d
w
armer. T
h
s
sure indoo
r
s
unstable a
n
m
ate therm
a
d
. The eff
i
e
nse air m
a
v
e more ae
r
l
ines near t
h
w
o large wi
n
right zone
e
s.
e
ntilation
n
ts that the
are shown
hape as in
m
ean input
f
output air
o
rtant than
d
ischarged
h
e pressure
r
s covers a
n
d changes
a
l pressure
i
ciency of
a
y cause a
r
odynamic
h
e inlet and
n
dow sizes
１１９
(a) a. Total pressure b. Velocity magnitude
(b) a. Total pressure b. Velocity magnitude
(c) a. Uniform window shape b. Non-uniform window shape
Figure 5.19. Airflow pattern in cross-ventilation, (a) uniform window shape, (b) non-uniform window
shape, (C) 3D streamline plot of airflow [author].
induce the large amount of wind with large pressure, indoor air has regularly distributed pressure and
the magnitude is smaller than the uniform window case because the outlet quickly emits the indoor air.
Near the window, very fast airflow occurs but the density of the indoor air is low since the density of the
air is proportional to the ventilation rate. The comparison of pressure and velocity between uniform
window and non-uniform window is represented in Fig.5.20 (a).
Two window openings at different heights using different window sizes form the vertical difference of
pressure and the pressure difference result in indoor airflow distributed evenly. Air density is larger by
inward flow through the larger window at the low level, rising air occurs. Hence, the streamline of
cross-ventilation is low at the inlet and high at the outlet as Fig.5.19 (b)-b shows. The advantage is that
the path of the streamlines is shorter than one for Fig.5.19 (a)-b and the indoor air can be exchanged
quicker by the cross-ventilation with non-uniform window shape. As chapter 3.4.2 described, when the
rooms with a wind shadow with vortex after inflow, the part of inflow is worse on distribution of air
N
S
-10 0 10 (Total pressure, Pa)
0 2.5 5 (Velocity magnitude, m s-1)
-10 0 10 (Total pressure, Pa)
0 2.5 5 (Velocity magnitude, m s-1)
18 24 32 (Temperature, ℃)
sp
e
n
a
th
e
re
p
T
h
is
d
p
a
w
i
a
n
it
Fi
g
cr
o
W
sh
a
re
s
4.
2
in
d
(a
)
A
n
th
e
so
l
e
ed or air d
i
a
tural path
w
e
lower sid
e
p
resents.
h
e larger ou
t
d
istributed
a
a
rtial kineti
c
i
ndow with
n
gle of inci
d
is utilized
t
g
.5.19 (c)
r
o
ss-ventilat
W
hen the av
e
a
pes, the
s
pectively
2
2
4℃ coole
r
d
oor tempe
r
)
a.
P
Fi
g
ure 5.
5.3.2
.
p
n
other imp
o
e
size but a
l
l
ar heat an
d
i
rection tha
n
w
ith air tem
p
e
drives out
t
let windo
w
a
round the
w
c
energy is
c
inlet and o
d
ence of the
t
o a house
r
epresents
t
ion.
e
rage outdo
o
indoor te
m
2
3.524 and
r
than the cr
r
atures bet
w
P
ressure
20. Compa
r
.
Microcli
m
p
assive so
o
rtant facto
r
l
so configu
r
d
lose heat t
o
n
that near
o
p
erature si
n
the warme
r
w
in compar
i
w
hole spac
e
c
hanged to
utlet of the
wind. This
design of
h
t
he airflo
w
o
r tempera
t
m
perature
o
21.284℃.
T
oss-ventila
t
w
een unifor
m
r
ison betw
e
m
ate of
w
lar desig
n
r
of natural
r
ation of inl
e
o
the outsid
e
o
utlet. An
o
n
ce the hot
a
r
air away f
r
i
son to the i
n
e
and this si
static press
u
same size
design wit
h
h
ot and hu
m
w
patterns
w
t
ure is 29.4
3
o
f uniform
T
he cross-
v
t
ion with u
n
m
window
a
b. Compa
r
e
en unifor
m
veloci
t
w
indow sh
n
ventilation
e
t window
e
e
. The large
１２０
o
ther advan
t
a
ir tends to
r
r
om the out
l
n
let windo
w
tuation is a
c
u
re around
depends o
n
h
non-unifo
r
m
id climat
e
w
ith tempe
r
3
7℃ for th
e
window
s
v
entilation
w
n
iform win
d
a
nd non-un
r
ison of air ve
m
window a
n
t
y
,
(b) aver
a
ape: opt
i
is the patte
r
e
.g. shape a
n
r the windo
t
age of the
n
r
ise up. Th
e
l
et located
i
w
produces
g
c
hieved by
s
the leewar
d
n
the porosi
t
r
m window
e
to get th
e
r
ature distr
i
e
uniform
w
s
hape and
w
ith non-u
n
d
ow. The c
o
iform wind
locity
n
d non-uni
fo
a
ge outdoo
r
i
mal inlet
r
n of indoo
r
n
d position
w, the mor
e
n
on-unifor
m
e
cool air fr
o
i
n the uppe
r
g
reater airf
l
s
maller out
l
d
opening.
H
t
y of the z
o
can obtain
t
e
better ve
n
i
bution of
n
w
indow and
non-unifor
m
n
iform win
d
o
mparison
o
ow is give
n
fo
rm windo
w
r
and indoo
r
design f
o
r
airflow. I
t
of inlet. W
i
e
daylight a
n
m
shape is t
o
o
m the inle
t
r
side as Fig
l
ow rates
bu
l
ets than inl
e
H
owever, t
h
o
ne irrespe
c
t
he cooling
n
tilation pe
r
n
on-unifor
m
non-unifor
m
m windo
w
d
ow shape
o
f average o
u
n
in Fig.5.2
0
(b)
w
, (a) press
u
r
temperatu
r
o
r ventila
t
t
is related
n
i
ndows let i
n
d solar gai
n
o
result in a
t
located in
.5.19 (b)-b
u
t air speed
e
ts, since a
h
e uniform
c
tive of the
gain when
r
formance.
m
window
m
window
w
shape is
can obtain
u
tdoor and
0
(b).
u
re and air
r
es
[author].
ion and
n
ot only to
n light and
n
can enter
but the la
r
however,
i
window c
a
performan
c
high effici
e
The aerod
y
vertical u
p
difference
small, cor
r
should be
a
The great
e
concentrat
e
height is
n
winter. Th
The large
w
Hence, a
w
room has t
h
a.
Sq
18 2
4
r
ger the lo
s
i
s worse in
a
n avoid t
h
c
e in winte
r
e
ncy of sol
a
y
namic pre
s
p
war
d
airfl
o
air temper
a
r
esponding
a
djuste
d
to
e
r height of
e
d above t
h
n
ot efficient
e optimum
w
idth of a
w
indow op
e
h
e best effi
c
a. Horizon
t
Fi
g
u
r
Sq
uare, horizo
Figure 5.
2
4
32 (T
e
s
ses are. T
h
winter du
e
h
e heat los
r
will be w
o
a
r radiation
s
sure often
o
ws. Howe
v
a
ture betw
e
to only 1
%
the aerody
n
a window
r
h
e upper h
a
since air v
window s
h
window is
e
ning with
a
c
iency of n
a
t
al plo
t
r
e 5.21. Air
f
ntal and verti
2
2. Coolin
g
e
mperature, ℃
)
h
us, larger
e
to the he
a
s in winte
r
o
rse. Henc
e
for winter
a
causes hor
i
v
er, hot an
d
e
en indoor
a
%
to 2% o
f
n
amic micr
o
r
esults in q
u
a
lf of the ro
elocity dec
r
h
ape can pr
o
efficient t
o
a
medium
h
a
tural venti
l
f
low plots
o
cal shape wi
n
g
performa
n
)
１２１
windows
c
a
t loss thro
u
r
however,
e
, this chap
t
a
nd ventila
t
i
zontal ven
t
d
humid co
n
a
nd outdoo
r
f
the aerod
y
o
climate.
u
icker air
m
om height.
r
eases in t
h
o
vide a
b
al
a
o
obtain sol
a
h
eight and
a
l
ation and
e
b.Vertical
o
f horizont
a
n
dows
n
ce for win
d
c
an give b
e
u
gh the wi
n
the ventil
a
t
er investi
g
t
ion for su
m
t
ilation and
n
dition in
K
r
so the th
e
y
namic pre
m
ovement
h
Window h
e
h
e lower ha
l
a
nce betwe
e
a
r radiatio
n
a
large wid
t
e
asiest to s
h
plo
t
l inlet with
b. Co
m
d
ow shape
a
e
tter indoo
r
n
dow. On
t
a
tion in su
m
g
ates a goo
d
m
mer.
the thermo
d
K
orean sum
m
e
rmodynam
ssure. Hen
c
h
owever, th
e
ight whic
h
l
f and it ca
n
e
n these su
m
n
and good
v
t
h coverin
g
h
ield it at th
e
c. T
h
temperatur
e
m
parison of t
h
a
nd air velo
c
r
ventilatio
n
t
he contrar
y
m
mer or s
o
d
window s
h
d
ynamic p
r
m
er is diffi
c
ic pressure
c
e, the wi
n
e streamlin
h
is larger
t
n
not be eas
i
m
mer and
w
v
entilation
g
almost th
e
e
same tim
e
h
ermal strea
m
e
[author].
h
e air velociti
e
c
ities
[autho
r
n
in summ
e
y
, the smal
l
o
lar
r
adiati
o
h
ape to all
o
r
essure cau
s
c
ult to hav
e
is often v
e
n
dow openi
n
e of the air
han the ro
o
i
ly blocked
w
inter facto
r
performan
c
e
width of t
h
e
.
m
line
e
s
r
].
er
,
l
er
o
n
o
w
s
es
e
a
e
ry
n
g
is
o
m
in
r
s.
c
e.
h
e
１２２
Fig.5.21 represents the wind stream of the window opening with a medium height and large width. The
aerodynamic in vertical plot shown in Fig.5.21-a exemplifies the smaller effect than the aerodynamic in
horizontal plot. The horizontal plot shows the increased air velocity but a narrowed air-streamline since
the air pressure is bigger when the height of the window is smaller. The amount of air density is
sufficient to obtain the indoor ventilation effect. The configuration of the window opening modifies the
internal airflow speeds since the horizontally and vertically shaped inlet openings yield different shapes
of air motions. Horizontally shaped inlets provide much higher internal air speeds than square or
vertical inlets as Fig.5.22-b shows. By comparing the average air velocities, the horizontal shape has
70% to 130% larger velocity than the squared and vertical shapes and the highest air velocities are
similar in the percentage gain of velocity for the horizontal shape.
The cooling gain of horizontal shape is about -3 and -1.85℃ more than the vertical and squared shapes
respectively. For the indoor condition with a horizontally shape window, the maximum temperature
36.172℃ is formed in the wall near inlet due to the radiative gain and the minimum and the average
indoor temperature are 20.3281 and 26.4127℃. Fig.5.22 respectively shows the comparison of
temperatures and pressures between square, horizontal and vertical shaped windows. Fig.5.21-c
represents the thermal streamline of a horizontal shape window that exemplifies that the horizontal
shape front window and door at the back can be efficiently utilized for a cross-ventilation. The optimal
glazing ratio of a horizontal shape window which is the same as the width of the wall is about 35% and
the window has the best cooling gain in summer and passive heating gain in winter. .
5.3.3. Microclimate of building projection: enhancing microclimate pressure and
protecting direct solar gain
In the previous chapter, for a building without projection, opening sizes and the shapes were important
factors that determine the airflow. However, the opening design is often dependent upon the wind and
solar direction and the microclimate effect is largely related to them. Hence, air density control to get
more pressure difference is needed. Air pressure is produced when the difference of local density is
distributed due to the amount of air input to the space. Hence, the horizontal and vertical projections e.g.
external wing-walls, partitions and fins etc. affect the amount of air pressure and internal airflow rates
by prevailing wind. Fig.5.23 (a) represents that external projections act as a wind-catcher which raises
the internal ventilation rate for skewed and perpendicular winds due to the pressure difference near the
projection.
The airflow through the window raises the velocity of indoor flow since the projection increases the
amount of the wind streams entering the inside. Another advantage of the horizontal projection is
efficiency to protect from direct solar radiation and hot wind from the room. The shade of inlet opening
generates
a
flow at th
e
Fig.5.23.
Otherwise
,
and in res
u
increases
o
significant
of the vert
i
(a)
(b)
(c
Fi
g
ure
The comp
vertical pr
o
29.45℃ a
horizonta
l
-
a
cooler su
r
e
inlet and
p
,
the vertic
a
u
lt, the flo
w
o
n the surfa
c
ly enhance
d
i
cal project
i
a.
H
ori
z
a. airfl
o
)
a. te
m
5.23. Micr
o
arison of t
h
o
jections a
n
nd the in
d
l
and verti
S
-
10 0
S
18 24
r
face than
t
p
ushes the
a
l projectio
n
w
direction
c
e but a lot
d
d
ventilatio
n
i
on and the
z
ontal project
i
o
w
m
perature of
v
o
climate of
verti
c
h
e thermal
n
d without
d
oor tempe
r
cal projec
t
10 (Total
32 (Temp
e
t
he surface
cool air to
w
n
s shown i
n
. When th
e
d
ecreases a
t
n
performa
n
airflow sh
a
i
on
v
ertical proje
c
b
uilding pr
o
c
al projecti
o
condition
o
projection
r
atures are
t
ions and
2
N
pressure, Pa)
N
e
rature, ℃)
１２３
of the roo
f.
w
ards the c
e
n
Fig.5.23 (
a
e
wind is b
l
t
the back o
n
ce. Fig.5.2
3
a
pe.
c
tion
o
jection, (a
o
n, (b) hori
z
o
f a zone
w
is shown i
n
20.428℃
2
3.524℃
b
f.
The proj
e
e
iling. The
a
)-b are eff
i
l
ocked by t
f the surfac
3
(c)-a resp
e
)
pressure
d
z
ontal proj
e
w
ith cross-
v
n
Fig.5.24.
and 19.88
2
b
y the cro
s
S
e
ction elim
i
thermal c
o
i
cient to m
o
he fin of a
e. Hence, t
h
e
ctively sh
o
b. Vertical p
r
b. 3D plot
b. 3D plot
d
ifference
b
e
ction, (c) v
e
v
entilation
If the outd
o
2
℃
b
y th
e
s
s-ventilat
i
i
nates the
d
o
nditio
n
is
r
o
dify the pr
e
projection
,
h
e inlet flo
w
o
ws the hig
h
r
ojection
etween of
h
e
rtical proj
e
between h
o
or temper
a
e
cross-ve
n
i
on witho
u
N
d
ownwar
d
h
r
epresented
e
ssure patt
e
,
the press
u
w
is raised a
n
h
cooling g
a
h
orizontal a
n
e
ction
[auth
o
orizontal a
n
a
ture is ab
o
n
tilation w
i
u
t projecti
o
h
ot
in
e
rn
u
re
n
d
a
in
n
d
o
r].
n
d
o
ut
i
th
o
n,
re
s
ca
t
th
e
pe
pr
o
in
d
Fi
g
u
r
s
pectively.
t
ching perf
o
e
wind catc
h
rformance
i
o
jection so
m
d
oor overh
e
r
e 5.24. Co
m
The coolin
g
o
rmances.
A
h
ing is still
i
s more im
p
m
etimes ca
n
e
ating.
m
parison o
f
g
gain of h
A
lthough th
e
effective i
n
p
ortant tha
n
n
not block t
h
f
thermal c
o
orizontal p
r
e
gain of ve
r
n
the vertic
a
n
gain of sh
a
h
e direct su
１２４
o
ndition of
c
r
ojection is
r
tical proje
c
a
l projectio
n
a
ding for t
h
n, the high
v
c
ross-ventil
a
projectio
n
jointly ob
t
c
tion is sma
n
. The resu
l
h
e indoor t
e
v
entilation
p
a
tion with
h
n
s and with
t
ained
b
y e
f
ller than th
e
l
t exemplif
i
e
mperature.
p
erformanc
h
orizontal a
n
out project
i
f
ficient sha
d
e
horizontal
i
es that the
v
Although
t
e seems to
r
n
d vertical
i
on
[author].
d
ing, wind
projection,
v
entilation
he vertical
r
emove the
１２５
6. Application of microclimate
simulation to a real-house design
6.1. A real-house in a suburb of Seoul, S. Korea
Although a lot of studies for energy simulation have been done by researchers of physics, climatology
and architecture, they did not try to apply their method to a real house design. Single EP simulation
cannot obtain the detail of energy flow in the design and single CFD simulation is too complex to make
the problem to converge into the real solution in the whole house design. In this study, the problem can
be overcome by the EP-CFD method and the microclimate analysis drew several efficient design factors
for energy-saving in chapter 5. The factors are applied to estimate energy gain in real designs. The
application of these factors in real house models is important to prove energy performance in real house
design. Note that the purpose of this chapter is not to analyze house designs, but to test the energy
efficiency of the microclimate factors in these designs.
Pine Tree House which is the 6th design of Min-Maru series127 by GAWA Design Group128 is located in
the highest area in the Min-Maru house complex. The main feature of the house is two masses with
different kinds of space and the topography preservation by pilotis. Pile foundations with treated
timbers are used to float the living room and the kitchen on the slope of the mountain and the room
space forms a skip floor over the topography. The skip-up-floors form separated spaces for different
uses as guest room, living room and bedroom by the building levels. The house has the size of
12600×14700×7600 and two stories. Fig.6.1 shows the layouts and pictures of the house.
The motive of the choice of Pine Tree House is
- This house has several topographical features to be able to observe microclimate effects.
- This house has high capacity to control several microclimate effects.
- This house employs several Korean traditional designs e.g. Maru (Korean wooden floor),
Jungja (Korean pavilion) and Ondol (a Korean floor heater) etc. which is attractive to the
Korean people.
127 A&C Publishing 2004.
128 GAWA Design Group, http://www.kawadesign.co.kr.
１２６
(a) a. 1st floor plan b. 2nd floor plan c. Section
(b) a. On a slope b. Panorama c. Court to the north d. Living room
Figure 6.1. Pine Tree House by S.Y. Choi, (a) drawings, (b) views [author].
Some limitation of this test in the real house model is that the actual measurement of microclimate was
not available and the microclimate factors are estimated by computer simulation based on macro
climate and the house design data. Thus, the test result may be not exactly equal to the real energy
consumption however it is not exceed the allowable margin of error.
By interview with the architect and residents, this house maintains the temperature of 18℃ to 20℃. The
main heating of this house is floor heating using boiler and water coil and an assistance of heating of a
fireplace is used. The energy consumption including hot water is approximated as a total of 1,000,000
Won for oil, and 300,000 Won for electric charges including lighting. This house is sufficiently cool in
summer due to the careful design and this house does not use electrical air conditioning and cooling.
The architects and occupants suppose that employing some traditional house designs in the modern
house designs may be helpful to obtain such results.
The main construction using concrete with reinforcing rod and lightweight woods are represented in
Table 6.1. The zones in the house are set up with microclimate design elements, geometrical features
and materials. Fig.6.2-a and b represent the CAD model of the zones which are classified with layers
and a plane cut of the CAD model. The sun-path diagram shown in Fig.6.2-c is used to estimate the
solar and shadow range for EP energy simulation. The CAD model is converted to a 3D solid model
since the CAD model with 2-D meshes cannot be directly used for CFD simulation. Fig.6.2-d shows the
Table 6.1.
a.
M
3D solid
m
6.2. Co
n
A data mo
d
these entit
i
must hav
e
programs
i
etc. Thus,
w
domain-sp
b
een seve
r
b
eing able
constructi
o
To overc
o
industry h
a
the case o
f
Constructi
o
M
esh drawing
m
odel that i
s
n
verting
d
el in any
g
i
es are relat
e
some kin
d
i
nternally r
e
w
hile these
ecific infor
m
r
ely constra
i
to extract t
h
o
n manage
m
o
me the li
m
a
s been de
v
f
the
b
uildi
n
o
n material
s
b. P
l
Figure
s
input mod
Model
f
g
iven doma
i
ed to each
o
d
of under
e
present da
t
applicatio
n
m
ation abo
u
i
ned by the
h
e relevant
i
m
ent, opera
t
m
itations
o
v
eloping an
d
n
g industry,
s
and outli
n
l
ane-cut
6.2. CAD
m
el for Flue
n
f
rom CA
D
i
n describe
s
o
ther. Sinc
e
lying data
t
a using ge
o
n
s can accur
a
u
t entities.
I
limited int
e
i
nformatio
n
t
ion, and so
o
f general-
p
d
using obj
e
this transla
t
１２７
n
e of Pine
T
c
.
m
odel of Pi
n
n
t software.
D
to IFC
s
the attribu
t
e
all compu
t
model. Tr
a
o
metric ent
i
a
tely descri
b
I
n the case
o
e
lligence of
n
from the r
e
on.
p
urpose ge
o
e
ct-
b
ased d
t
es to a dat
a
T
ree House
[
.
Sun-path di
a
n
e Tree Ho
u
t
es of the e
n
t
er progra
m
a
ditional 2
D
i
ties such a
s
b
e geometr
y
o
f the AEC
such appli
c
e
presentati
o
o
metric re
p
ata models
a
model tha
t
[
author].
a
gram
u
se
[author].
n
tities in th
a
m
s deal with
D
CAD a
n
s
points, lin
e
y
in any do
m
industry, t
e
c
ations in r
e
o
n that is ne
e
p
resentatio
n
that are sp
e
t
is built ar
o
d. 3D solid
r
a
t domain a
some kind
s
n
d generic
3
es, rectang
l
m
ain, they
c
e
chnologica
l
e
presenting
e
ded for de
s
n
s, every
d
e
cific to th
e
o
und buildi
n
r
endering
s well as h
o
s
of data, th
3
D modeli
n
l
es and pla
n
c
annot capt
u
l
progress
h
b
uildings a
n
s
ign, analys
d
esig
n
-relat
e
ir domain.
n
g entities a
n
o
w
ey
n
g
n
es
u
re
h
as
n
d
is,
ed
In
n
d
th
e
th
e
m
o
e
x
A
m
o
sp
a
p
a
o
n
e
ir relation
s
e
se buildin
g
o
del is still
x
tracted and
simple but
o
del is in t
h
a
ce becaus
e
a
rt of a buil
d
n
(for exa
m
a. Bounda
ry
Fi
gu
s
hips to one
g
entities; t
h
mainly gr
a
used for v
a
critical ex
a
h
e represe
n
e
it does no
t
d
ing model,
m
ple, see th
Fi
gu
ry
mesh
u
re 6.4. Ad
another (se
h
us, its pri
m
a
phic. Such
a
rious purp
o
a
mple of t
h
n
tation of a
t
exist as a
d
and will in
e simple
w
u
re 6.3. Di
f
aptable me
s
e Fig.6.3).
G
m
acy is gr
e
a data mo
d
o
ses, e.g. d
o
h
e differenc
e
space. Tra
d
d
istinct ph
y
clude the a
p
w
all-to-spac
f
ference be
t
b. House mes
s
h for bette
r
１２８
G
eometry i
s
e
atly reduc
e
d
el is rich i
n
o
cumentati
o
e
between
a
d
itional 2D
y
sical entit
y
p
propriate
r
e relations
h
t
ween CA
D
h
r
analysis r
e
s
only one
o
e
d, even th
o
n
informati
o
o
n, visualiz
a
a
geometri
c
and 3D C
A
y
. However,
r
elationship
s
h
ip shown
D
and IFC
[I
S
c
e
solution n
e
o
f the prope
r
o
ugh the in
t
o
n about th
e
a
tion, or an
a
c
data mod
e
A
D progra
m
a space en
t
s
to walls;
c
in Fig.6.3.
S
O/PRF PAS
]
c
. Mesh detai
l
e
ar model e
d
r
ties, amon
g
t
erface to c
r
e
building
t
a
lysis.
e
l and a bu
i
m
s do not
r
t
ity will be
c
eilings, flo
o
Industry
F
]
.
l
of a par
t
d
ges
[author
]
g
others, of
r
eating the
t
hat can be
i
lding data
r
epresent a
an integral
o
rs, an
d
so
F
oundation
]
.
Classes (I
F
representa
t
as 3D real
b
etween r
i
from an a
p
to derive t
h
performed
analysis g
r
the house.
6.3. Cli
m
For the si
m
and micro
c
effects are
Table 6.2.
Figure
6
F
C) is build
i
t
ion standa
r
-world obj
e
i
val produc
t
p
plication u
s
h
e same in
f
by Autode
s
r
id can be c
l
m
ate da
t
m
ulation,
m
c
limate ana
selected in
Constructi
o
6
.5. Heatin
g
i
ng a data
m
r
d and file
f
e
cts, mainl
y
t
s with no
c
s
ing a build
i
f
ormation
f
s
k Architec
t
l
assified to
e
t
a and f
e
m
acro clima
t
lysis. The
c
9 sub-data
o
n material
s
T
Diffuse sol
a
External dr
y
Direct norm
Prevailing
w
Wind direct
i
Relative hu
m
Time of rai
n
Sum of rain
Cloud cove
r
a. Seoul
g
and cooli
n
m
odel that i
s
f
ormat for
d
y
so that ar
c
c
ompromis
e
i
ng data m
o
f
rom an ap
p
t
ural Deskt
o
e
ach zone.
F
e
atures
t
e data are
p
c
limate feat
u
as Table 6.
2
s
and outli
n
T
ype of data
a
r on the horizo
n
y
bulb temperat
u
al solar intensit
w
ind speed
i
on
m
idity
n
fall
fall
r
s
n
g loads by
１２９
s
the result
o
d
efining arc
h
c
hitectural
C
e
s.
Thus, i
n
o
del, where
a
p
lication us
i
o
p (ADT) s
o
F
ig.6.4 sho
w
p
repared to
u
res which
2
shows.
n
e of Pine
T
n
tal
u
re
y
the differe
n
o
f standard
i
h
itectural a
n
C
AD users
n
formation
a
a
s several c
o
i
ng a geo
m
o
ftware. W
h
w
s the exa
m
use the cli
m
are related
T
ree House
[
Un
W
m
℃
W
m
m
s
Clockwise de
g
0-
1
0.1
0.1
m
8 steps fr
o
n
ce of sola
r
i
zation, an
d
n
d const
r
u
c
can transf
e
a
bout spac
e
o
mplex cal
c
m
etric data
m
h
en a mod
e
m
ples of ro
u
m
ate featu
r
to buildin
g
[
author].
it
m
-2
℃
m
-2
s
-1
g
. from North
1
h
m
m
o
m 0 to 8
b. B
e
r
radiation
b
d
it gives ar
c
c
tional CA
D
e
r design d
a
e
s can be e
a
c
ulations w
i
m
odel. The
e
l finishes c
o
u
gh classifi
c
r
es for ener
g
g
energy or
e
rlin
b
etween Se
o
c
hitects a d
a
D
graphic d
a
a
ta to and
f
a
sily obtain
i
ll be requir
converting
o
nverting, t
h
c
ation mesh
g
y simulati
o
microclim
a
o
ul and Ber
l
[auth
o
a
ta
a
ta
f
ro
ed
ed
is
h
e
in
o
n
a
te
l
in
o
r].
１３０
Fig.6.5 shows the difference of heating and cooling loads between Korea and Germany. Although
Korea has similar solar radiation gain, cooling load in summer is higher due to the higher air
temperature and humidity and heating load in winter is due to the lower air temperature and humidity.
This means that a house in Korea needs more cooling and heating energy than one in Germany.
In East Asia, interactions between the rapidly mixing atmosphere and the slowly changing oceans are
largely responsible for the monsoon season, particularly as they affect Korea, China and Japan.
Geographically, Korea is a transitional zone between the continental landmass of northeast Asia and the
island arc rimming the western Pacific Ocean. The western coast, which is open to continental Asia, is
vulnerable to the influence of the winter continental climate. The eastern coast, on the other hand, is
sheltered from the winter monsoon by the Taebaek-range, the backbone mountain of the eastern Korean
Peninsula. Although Korea has the general characteristics of a temperate monsoon climate, there is
geographic diversity, particularly during the cold winter season.
The climate of Korea is characterized by four distinct seasons i.e. spring, summer, autumn and winter.
The contrast between winter and summer is striking. Winter is bitterly cold and influenced primarily by
the Siberian air mass while summer is hot and humid due to the maritime pacific high. The transitional
seasons of spring and autumn are sunny and generally dry.
Spring begins during the middle of April in the central part of the country, and toward the end of April
in the northern region. As the Siberian high pressure weakens, the temperature rises gradually. Yellow
sand dust which originates in the Mongolian desert occasionally invades Korea during early spring. The
sandy dust phenomena often causes low visibility and eye irritation.
The summer can be divided into two periods; a rainy period which occurs during the early summer
months, a hot and humid period which occurs during late summer. The weather during the rainy period
is characterized by a marked concentration of rainfalls. More than 60% of the annual precipitation is
concentrated between June and July. In particular, July sees many rainy days which are followed by
short dry spells and clear skies. Much of the rainfall is due to summer monsoons which originate in the
Pacific Ocean. Rainfall during the summer time is characterized by heavy showers. Daily precipitation
often exceeds 200mm, with extremes topping 300mm. Occasional torrential storms caused by typhoons
that pass through the peninsula from China may sometimes cause a great deal of damage, although the
loss of life is rare in these instances. Annually, about 28 typhoons occur in the western Pacific. Regional
temperature contrasts are not striking during the summer season although the northern interior and the
littoral are cooler than temperature in the south. In August, the temperature rises abruptly as the rainy
season. During this period, the weather is extremely hot and humid, particularly in the western plains
and the southern basin area. The daily high temperature often rises to over 38℃. Nights are also hot and
humid.
１３１
Autumn is the season with crisp weather, much sunlight and changing autumn leaves. This is the
transitional season between the hot and humid summer and the cold and dry winter months. Beginning
in October, the continental air mass brings dry, clear weather. Traditionally, Koreans enjoy the season
of harvest, which is one of the most important national holidays in Korea. It is celebrated as a harvest
festival, and occasionally referred to as the Korean version of the American Thanksgiving. Autumn
weather is nicely, expressed in the simple words of the old Korean saying “The sky is high and the
horses get fat”.
In winter, the monsoonal arctic air from the interior of the Asian continent brings bitter cold and dry
weather and occasionally snowfall, adding warmth to the cold and dry winter weather periodically.
Significant regional climate variations are caused by differences in elevation and proximity to the seas
as well as by differences in latitudinal location. Regional difference in the monthly mean temperature
during the month of January between the northern and the southern peninsula is about 26℃. Snow
remains longer on the ground in the north. The frost-free period varies from about 130 days in the
northern interior to about 180 days in the central region. In the southern coast, the frost-free period is
roughly 225 days of the year.
Temperatures in Seoul are similar to those in New York City which is located 500km farther north than
the latitude of Seoul. Fig.6.6-a shows the outdoor dry-bulb temperature over 1 year of S. Korea. The
variation of annual mean temperature ranges 10℃ to 16℃ except for the mountainous areas. August is
the hottest month with the mean temperature ranging 23℃ to 33℃. January is the coldest month with
the mean temperature ranging -5℃ to 5℃. Annual precipitation is about 1,500mm in the central region.
More than a half of the total rainfall amount is concentrated in summer, while precipitation of winter is
less than 10% of the total precipitation. The prevailing winds are southeasterly in summer, and
northwesterly in winter. The winds are stronger in winter, from December to February, than those of
any other season as the wind speeds graph in Fig.6.6-c shows. The land-sea breeze becomes dominant
with weakened monsoon wind in the transitional months of September and October.
The relative humidity shown in Fig.6.6-d is highest in July at 80% to 90% nationwide, and is lowest in
January and April at 30% to 50%. It has a moderate value of about 70% in September and October. The
monsoon front approaches the Korean Peninsula from the south in late June, migrating gradually to the
north. Significant rainfall occurs when a stationary front lies over the Korean Peninsula. The rainy
season over Korea continues for a month from late June until late July. A short period of rainfall comes
in early September when the monsoon front retreats back from the north. This rain occurs over a period
of 30 days to 40 days in June through July at all points of S. Korea, with only some lag in time at
different stations, and accounts for more than 50% of the annual precipitation at most stations. The
rainy season can be estimated by the direct and diffusion solar gain over 1 year shown in Fig.6.6-b. The
southern coastal and its adjacent mountain regions have the largest amount of annual precipitation
１３２
a. Outdoor dry-bulb temperature b. Direct and diffuse solar gain
c. Wind Speeds d. Outdoor Relative Humidity
Figure 6.6. Korean climate analysis using EP over 1 year [author].
which is over 1,500mm. Since most of the precipitation is concentrated in the crop growing areas in the
south, the water supply for agriculture is normally well met. Even though the annual mean precipitation
is more than 1,200mm, however, Korea often experiences drought due to the large fluctuation and
variation of precipitation, making the management of water resources difficult.
6.4. Microclimate design elements
Korean traditional design elements in Pine Tree House129 are employed to modify microclimate effects.
However, there were no scientific evidences for the designs since few studies of them have been done.
Chapter 5 investigated several microclimate design elements and analyzed the efficiency of the
elements using EP-CFD simulation. These studies will be applied here to the real-house design
129 See Chapter 6.1.
１３３
a. Orientation b. Three air zones c. Topography
d. Sectional view e. Building over pilotis f. Windbreakers
Figure 6.7. Microclimate design elements of Pine Tree House [author].
elements of Pine Tree House.
First, the building orientation of Pine Tree House has a small shift to southwest as Fig.6.7-a shows.
However, a modification is used for the simulation since most Korean traditional architecture designs
prefer to choose the south or southeast direction. Although the south direction is adequate to passive
solar design, the main direction of summer winds in S. Korea is southeast direction. For the best
microclimate effect, the simulation modem uses the modification of southeast direction for passive
cooling performance with strong aerodynamic to discharge the overheated air.
The most progress of microclimate design in Pine Tree House is the usage of openings, possibly opened
or closed by seasonal features. The door of the space can be opened widely to diffuse air and heat in
summer. This prevents some zones with solar radiation from overheating. If a zone is overheated,
indoor ventilation with openings can spread the heat to the neighboring cool zone. For the local heating,
the door should be closed as well. Thus, the zones are separated into isolated zones and the geometric
relationships between the zones are defined as Fig.6.7-b shows.
Pine Tree House is located on a low hill using architectural methods on topography. As the description
in chapter 5.1.2, the topography plays roles to get strong microclimate effects with anabatic airflow.
Some window designs enable large openings for the wind and partial building utilizes pilotis to avoid
１３４
heated ground and to obtain passive cooling effects. Fig.6.7-c represents the set-up of a building on the
topography.
Pine Tree House uses some non-uniform window shapes to raise a ventilation performance of vertical
direction of the room since two window openings at different heights using different windows sizes
form the vertical difference of pressure. Fig.6.7-d shows a non-uniform window of Pine Tree House.
This design generates very effective cooling gain of ventilation in summer. Some windows, especially
located in the front side, use small horizontal projections shown in Fig.6.7-d which play a role as a
wind-catcher that raises the internal ventilation rate. The size of the projection is not sufficiently big to
protect from solar radiation however, the large gable roof sufficiently shades a direct solar penetration.
The projection modifies the pressure pattern near the window and thereby derives different
microclimate effects. The house does not use many vertical projections since the “H” form, i.e.
perimeter rectangular court, of the house is enough to perform vertical wind-catchers since two
encircled courtyards draw a high density of wind.
Instead of a roof overhang, a large gable roof is designed to block the direct solar radiation and performs
a wind-catcher. A gable roof is efficient to derive a stack effect that the wind from outdoors is heated
and naturally moved into the roof outlets. Some holes shown in Fig.6.7-e are accompanied with the
slopes of large roof. The large roof edges act as horizontal wind-catchers like external projections that
raise the internal ventilation rates or the sunshade.
Living space in summer is very important since the hot days are much longer than cold days in Korea.
Especially, the high humidity in summer is the biggest problem to design human comfort space using
passive architecture designs. In traditional Korean architecture concepts, Maru (i.e. floor) using pilotis
or pavilion using pilotis is very famous and favorite of people due to the effective cooling without
artificial air conditioning. A floating architectural design using pilotis is used for a part of the living
space as Fig.6.7-e shows.
The real site condition of Pine Tree House does not use the wall since the house is connected to the
neighboring house. The walls of the neighboring house act as windbreaks. The geometrical influences
of the neighboring house are not considered due to the complexity of simulation. However, the
microclimate efficiency of solid walls and windbreaks are driven by a simple set-up shown in Fig.6.7-f.
For the backside of the house, an artificial fence as a dense windbreaker is laid to prevent the Siberian
cold wind from the North and the trees of medium density block only strong wind. Small wind passed
through the natural trees gives a cooling effect to reduce the sensible heat of occupants and visual
beauty as well.
Table 6.3 represents pictures of the design elements of Pine Tree House. The left column of the Table
１３５
Table 6.3. Drawing of details and snapshots for design elements of Pine Tree House [author].
shows the partial details of section and the right column represents design concepts of Korean
traditional houses. Parquetry is a small size of floor to generate a local cooling area and the kitchen
court uses a concept of courtyard to preserve and utilize the cooking heats. The yellow soil is efficient
material for floor heating since the soil includes large amount of minerals which radiates longwave ray.
The Maru and pavilion using pilotis are an efficient structure for summer and Ondol is a traditional
１３６
Korean under floor heating system for indoor climate control similar in principle to a Roman hypocaust.
The main components are a fireplace or stove (also used for cooking) located below floor level in
outside (traditionally in separated kitchen), a heated floor underlay by horizontal smoke passages, and a
vertical chimney to provide a draft. The heated floor is supported by stone piers, covered by clay and an
impervious layer such as oiled paper. The Ondol was typically used as a sitting and sleeping area, with
warmer spots reserved for honored guests. For these reasons, most modern residences in Korea utilize
circulating hot water, or electrical cable.
6.5. Energy efficiency
Thermo- and aerodynamic microclimate design method including passive design is quantitatively
evaluated by EP-CFD simulation. First, EP simulation results the average values of zones which are
estimated from site and zones. The resolution of the values is one node per volume of zone, thus the EP
simulation cannot estimate the streamline of real airflow. However, the method is not complex and easy
to evaluate the energy performance of building zones with passive and active set-ups.
The calculation of the heating and cooling loads on a building or zone is the most important step in
determining the size and type of cooling and heating equipment required to maintain comfortable
indoor air conditions. Building heat and moisture transfer mechanisms are complex and as
unpredictable as the weather and human behavior, both of which strongly influence load calculation
results.
Table 6.4. Some of the factors that influence results [author].
If the factors as shown in Table 6.4 are once used for calculation of a complex equation, the heating and
cooling loads can be obtained as the result of the equation. They are always used by active design
researchers, developers of building envelop and architects etc., however, they can be useful factors to
evaluate the thermal and comfort of the passive designs and the set-ups. Then, a comparison between
１３７
the passive design and active method e.g. electronic air conditioning concludes the needs of additional
energy consumption of the passive designs, if the passive designs do not have sufficient condition of
zero energy. The evaluation of microclimate design methods will perform such a comparison and
concludes the needs of the amount of additional energy input. Although zero energy building with
passive design methods is the best case, such a zero energy performance using only passive methods is
too ideal and difficult to achieve.
In winter, heat loss increases the total heating load. Transmissions through the confining walls, floor,
ceiling, glass and other surfaces cause heat loss. If a zone loses the heat below a comfortable
temperature, occupants feel discomfort. To recover the comfort condition, energy inputs should
compensate the heat loss. The infiltration through trickles and openings causes large amounts of heat
loss. The wind speed also has great effect on outside surface resistance in conduction heat transfer and
on high infiltration loss. Normally, the heating load is estimated for evaluation of winter design.
Otherwise, cooling load is related to the heating gain. If the heat is obtained in high temperature, the
heat should be removed by a cooling method to make a comfort. Heat gain is the rate at which heat
enters a space, or heat generated within a space during a time interval. Hence, cooling load is the rate
that heat gains can be compensated to make a comfort air temperature. The difference between the
space heat gain and the space cooling load is due to the storage of a portion of radiant heat in the
structure. The convective component is converted to space cooling load instantaneously.
By EP simulation, changes of topographic, window ratio and insulation are evaluated. Fig.6.8
represents the heating and cooling loads which occur through the changes of different conditions. EP
does not have CFD calculation, the method uses a simple parametric estimation based on analytical data
related to the pressure coefficients. The differences of slope angle increases the heating load and
decrease the cooling load as Fig.6.8 (a) and (b) show. The additional heating gain is caused by the solar
radiation since building can be warmer and drain earlier in hillside. The cooling gain i.e. decrease of
cooling load is due to the large amount of microclimate which is produced by the different thermal
condition by solar radiation. Heating by day causes anabatic airflows since the heated air moves up and
pressure decreases. The large amount of airflows makes a cooling gain of about 3kW m-2 per 10 degree.
The changes of window ratio make smaller heating and cooling loads due to the large effects of the air
movements. The average heating and cooling loads are respectively about 114kW m-2 and 72kW m-2
and the values are much smaller than the results of topography. Fig.6.8 (b) represents the graphs heating
and cooling loads. EP simulation shows that the larger window is not helpful for cooling since the
increase of radiation through the window causes overheating and the cooling load is increased in
summer. Although the windows are a cause of the heat loss in winter, the increase of heating gain
through the window increases the heating gain.
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１３９
with the values. The geometrical features which derive the thermo- and aerodynamic states can be
analyzed by CFD method.
Table 6.5. Heating and cooling models based on the simulation results of microclimate design elements
130 [author].
a. Heating load b. Cooling load
Figure 6.9. Comparison of heating and cooling loads EP-CFD method using microclimate design
models [author].
130 HTC: Heat Transmission Coefficient.
１４０
4 energy-saving test models, i.e. 2 for heating and 2 for cooling are derived from the simulation results
of microclimate design elements shown in Chapter 5, and compared to the energy performance of the
original model. Table 6.5 shows the 4 test models. The original model has a virtual house condition
based on the Pine-tree house. The house is located on a slope to the southwest with a gable roof and
double glazed window. For the heating model, wind-sheltering and insulation are added. For the
cooling model, geometry and window shape are changed. The heating and cooling gains using
modifications of Pine Tree House using the 4 models are compared to the results of the full application
in the original model, i.e. blue dashed lines. The heating and cooling models can be jointly used for
thermal condition for both winter and summer. Fig.6.9-a shows the comparison of heating loads
between original model and 2 heating models and Fig.6.9-b represents the cooling load comparison
between original model and 2 cooling models.
The original model of Pine Tree House has a lot of Korean traditional design elements that enables to
derive microclimate effects. However, the model does not consider passive solar design with strong
insulation. Hence, the heating model 1 slightly modifies the original house for a better passive heating
performance. Energy performance using design elements of Pine Tree House is analyzed by streamline
of thermo- and aerodynamics showing physical distribution of temperature, pressure and kinetic energy
etc. Fig.6.9 shows the heating and cooling load from CFD method. Only 12 times of the simulations are
performed due to the complexity of calculation.131 The dashed lines indicate the results of the full
application by using all design elements. Some design elements are efficient only for one between
heating and cooling. For example, design elements for a high ventilation performance are good for
summer but not efficient for winter. Hence, the main aim of EP-CFD simulation is to find some good
combinations which accomplish positive microclimate effects.
The orientation is shifted to the south and the wind-sheltering using medium density trees. The
insulation is added and inter zone thermodynamic is utilized for air balancing between zones. The main
changes in the “heating model 1” are the consideration of passive solar designs. The simulation results
in Fig.6.9-a shows the improvement of peak heating load of more than 30kW·m-2 in winter due to the
passive heating gain. For the heating model, wind-sheltering and insulation are added. For cooling
model, geometry and window shape are changed.
Designs using pilotis, non-uniform shape window which enhances the aerodynamic is not employed
since aerodynamic microclimate makes better effects for cooling but worse effects for heating. The 2nd
heating model is a trial to improve the 1st model. The enforcement of density in wind-sheltering shows
a better performance to block the direct and small cold wind. The insulation of the roof and the window
is used. The modification reduces 8.3kW m-2 in maximum heating load in cold winter as Fig.6.9-a
131 Note that CFD simulation generally needs about 1000~1000000 times more computation costs than EP method.
１４１
shows.
A lot of progress of heating gain has been due to the studies of Passive House. However, passive
cooling in hot and humid climate, such as S. Korea’s increases is getting attention from a lot of
researchers since few studies have been done. So far, microclimate design methods are methods that
efficiently obtain the cooling gain by considering streamline by thermo- and aerodynamic pressures in
the designs. The 2 modifications of the original model for cooling are proposed to obtain the better
cooling gain and to decrease the cooling load in the hot and humid summer. The first model changes the
orientation to south.
The glass insulation is employed since the intrusion of hot winds was often observed in the
microclimate simulations of Chapter 5. The thick wall insulation is not considered due to the result of
Fig.6.8 (c), however roof insulation is very important to block the overheated air in the roof.
To improve the blocking performance of the heated downwind from roof, cooling model 1 and 2 use a
horizontal projection and a large gable roof respectively. The 1st cooling model uses uniform shape
window for cross-ventilation. In addition, the cooling performance of the 1st cooling model is improved
by employing the building using pilotis and strong ventilation using non-uniform shape windows. The
1st cooling model reduces the 14kW m-2 of peak cooling loads and the 2nd model obtains additional
cooling gain of 10kW m-2. The 2nd model totally reduces more than 20kW m-2 in peak cooling loads in
summer and shows the lowest cooling load in summer as Fig.6.9-b shows.
a. Thermal plot b. Vertical plot of airflows
c. Horizontal plot of airflows at the 1st floor d. Horizontal plot of airflows at the 2nd floor
Figure 6.10. EP-CFD simulation results of Pine Tree House [author].
10 20 30
(Temperature, ℃)
１４２
The large gable roof and the non-uniform windows are a very efficient method to enable to improve the
streamline of microclimate flow and the performance of solar control. Fig.6.10 shows the EP-CFD
simulation results using needle flow plots and Table 6.6 shows the part of a building and the percentage
of heat loss. The results show the decisive point for heating and cooling design since the heat loss has
great effects related to the human comfort.
The efficiency of passive designs can be compared to active methods since active methods can show us
the amount of envelopes and operation time. A simple HVAC model in EP is used to calculate zone
temperature. Fig.6.11 represents the temperature comparison between passive and active methods.
In a cold winter day, the zone temperature using coil heating with a target temperature of 24℃ can offer
20℃ to 23℃. The passive method using improved insulation raises the indoor temperature without
energy input but causes an overheating problem at 12:00pm to 2:00pm. To solve the problem, the active
Table 6.6. Part of a building and percentage of heat loss (i.e. based on the Fine Tree house models)
[author].
a. Winter day (based on the coldest day) b. Summer day (based on the hottest day)
Figure 6.11. Zone temperature comparison between passive method and HVAC model [author].
１４３
method uses inter-zone ventilation by using thermal sensors and controller. EP has the computer
simulation module for inter-zone ventilation and the result shows the good passive heating performance
with comfort thermal condition of 18℃ to 26℃. The inter-zone flow net method in EP enables to
estimate the inter-zone ventilation by the virtual air-circulation network. It is not a real air circulation
method132 and parametric approximation method. The method shows a similar thermal performance of
19℃ to 27℃. The microclimate thermodynamic using inter-zone opening and small inlet opening with
passive solar design can offer a thermal condition of 19℃ to 29℃ which overcomes the overheating
problem. The peak temperature is uncomfortable 29℃ but the duration of the temperature is only 1 hour.
The passive methods can save about 20% heating and electronic cost of the active methods.
In a hot summer day with an average maximum temperature, the zone without ventilation is overheated
by passive solar design and the thermal range is 32℃ to 41℃. The large cooling load is needed to
reduce the heat of the zone. The objective is to compare the passive cooling methods with a
performance of an active cooling and to find the best. A scheduled active cooler which starts operation
at 7:00am and ends at 6:00pm can reduce 20% of the daytime temperatures. If the active cooler is turned
off, the zone temperature is raised. Whole day ventilation in an insulated zone can offer a better thermal
condition which has a smoothly varying curve in the range of 23℃ to 33℃. A mixed-ventilation shows
similar a performance with the whole day ventilation but the input energy of whole day ventilation
needs 48% additional energy. A summer cooling method using passive cooling and microclimate
aerodynamic simultaneously improves the cooling performance and the thermal condition is laid on the
Figure 6.12. 1 year temperature comparison between a passive method and a combination of passive
method and flow net of microclimate design [author].
132 Note only CFD is a real airflow calculation based on partial differential method.
１４４
range of 23℃ to 29℃. The HVAC is very efficient in winter to make isothermal conditions but does not
have a big advantage in summer. A large amount of air passing through the zone can quickly reduce the
heat from a hot and humid zone, and the best method is to utilize cross-ventilation.
The 1-year performance between simple passive modeling and a passive modeling combined with
microclimate design method shows that microclimate method reduces the thermal variance. Fig.6.12
represents the 1 year temperature by EP simulation. CFD cannot be utilized for 1 year calculation due to
the complexity hence; the calculation utilizes the flow net method in EP after setting of the
microclimate design elements. In the result, thermal variances in simple passive method are larger than
10℃ but the combination with microclimate has smaller variances of 5℃ to 10℃. The main advantage
of microclimate design elements improve the airflow between outdoor and indoor in summer and
enable to utilize inter-zone air current in winter. Consequently, higher indoor temperatures in winter
and lower temperatures in summer are obtained. The features make it possible to save building energy
costs by reducing heating and cooling loads.
１４５
7. Conclusions
Energy-saving is recently getting more attraction due to the increases of energy security in many
countries. Increase of living standards has caused huge energy consumption for heating, cooling and air
conditioning in many parts of the world. Nowadays, energy simulation, which analyzes climate, the
physical features of architectural material and designs simultaneously, has become more popular.
Energy loads of architecture are virtually predicted by energy simulation and then a controller adopts
the HVAC system based on the prediction. Several methods provide quantities of predictions, of the
performance of HVAC: experiment measurement, analytical model and multi-zone model.133 However,
these methods are not suitable to be applied to passive heating and cooling without a controlling system.
Passive heating and cooling can significantly reduce energy costs required for mechanically aided
HVAC methods. However, the shortcoming is that it is difficult to control. Geometric analysis with heat
and airflows is additionally needed to make passive heating and cooling designs controllable.
Microclimate can modify heating and cooling loads, thereby overall energy consumption. The
observation of microclimate for energy simulation is essential since the energy consumption is largely
related to the local climate. Decisions taken by architects can have a significant impact on energy
consumption, indoor climate performance, thermal comfort and productivity. Architects need to be able
to predict air movement, temperature distribution and concentrations. Using well proven computational
techniques such as dynamic thermal energy modeling and CFD, effects of microclimate modifications
in architectural designs can be simulated without physical modeling tests. Dynamic thermal energy
modeling measures thermodynamic effects e.g. inter-zone thermal balance and buoyancy force and
CFD simulation is undertaken to examine the aerodynamic operation of the natural ventilation
concepts.
At the design stage, architects can predict annual energy and microclimate performance using these
methods. The contributions of this study include four main parts:
- Study of energy simulation, dynamic thermal energy modeling and CFD simulation tools.
- Development of a dynamic energy simulation method suitable for microclimate analysis
- Study of microclimate modification for energy-saving by architecture design elements.
- Design recommendation for passive, microclimate and energy-saving house design.
133 See chapter 3.3.2.
１４６
(1) Study of energy simulation, dynamic thermal energy modeling and CFD simulation tools
Energy simulation in a complex building geometry calculates very complex equations with several
physical parameters. However, multi-volume, or multi-zone method reduces the complexity of the
calculation by single node per zone. This method needs an algebraic equation representing partial
differential equations of a zone and the solution is an average value. Most commercial software uses a
multi-zone model and EnergyPlus (EP) is the most famous program to estimate the heating and cooling
gain and energy consumption. However, single node per zone is too rough to consider airflow e.g.
buoyancy and ventilation effects etc.
CFD method numerically solves a set of partial differential equations with a grid array of many nodes
per zone. The method can calculate the dynamics of distributed air temperatures, velocity throughout an
entire building and hence it is more suitable for microclimate analysis than the multi-zone method. An
advantage is that CFD can use realistic 3D geometry definition which is corresponding to CAD design.
However, the method requires large computational power since it is complex to apply the method to
building geometry. The most famous software for CFD is Fluent. The study presents comparisons
between the multi-zone and CFD method shown in Table 7.1.
(2) Development of a dynamic energy simulation method suitable for microclimate analysis
Microclimate can be measured by a very complex combination of several factors e.g. heating location,
solar radiation, inter-zone ventilation, size of opening, wind force and buoyancy force etc. For the
simplicity, this study proposes a novel method to analyze microclimate of energy imbalance which is
estimated by the multi-zones energy simulation. In this study, the term microclimate refers to energy
distribution and its variations e.g. thermo- and aerodynamics in space and time.
Table 7.1. Comparisons between multi-zone and CFD method [author].
Multi-zone (EP) CFD (Fluent)
Number of nodes 1 per a zone More than 1000 per a zone
Heating analysis Average temperature Interzone balance, buoyancy force
Cooling analysis Average temperature Natural ventilation, wind force
Advantage Simplicity Accuracy
Table 7.2. Accuracy of thermal prediction [author].
Cooling (℃) Heating (℃)
EP 28 22
EP-CFD 22.8~32.4 17.2~24.7
Differences -5.2~4.4 -4.8~2.7
１４７
At the early design stage, architects cannot detail fix the planning. Therefore, the multi-zone model
rather than CFD can fit the prediction task and provide a whole building analysis to improve the design.
CFD method always needs a careful preparation for the early stage of simulation. Instead of requiring
the initial condition for CFD, EP-CFD method, i.e. the coupling method of multi-zone and CFD,
calculates the average temperature of each zone by multi-zone method and puts in differences of the
calculated temperatures to CFD for microclimate analysis. This method was validated for the buoyancy
and inter-zone balance by comparing it with the single EP simulation. Table 7.2 shows that the EP-CFD
can obtain more accurate results for microclimate effects with variances about ±18.57%~21.82% for a
heating and cooling calculation than single EP. Although results from EP are the homogeneous average
temperature in a zone, results from EP-CFD show thermal distribution. Simulation results in Chapter 5
and 6 also show similar variances within the range between maximum and minimum temperatures.
(3) Study of microclimate modification for energy-saving by architectural design elements
This study investigated microclimate modification using design elements of Korean traditional and
passive house for energy-saving. Microclimate modification involves the best use of architectural
design elements to maximize or limit sunlight, shade and air movement. The modifications involve the
design of the house and associated construction e.g. wall, fences and courtyard etc. Landscape
modifications involve the use of plants to further increase or decrease the impact of the sun and wind
upon the local environment. Several design elements strongly influence the degree to which interior
comfort requires energy inputs for heating or air conditioning.
Table 7.3. Strength of thermo- and aerodynamic microclimate for architectural design elements [author].
１４８
The elements are orientation, topography, roof shape, fence design, piloties, window shape and
courtyard etc., 134 which are potentially efficient for energy-saving on various site conditions in S.
Korea, and they can be classified into cooling or heating elements. These elements are applied to
EP-CFD energy simulation to estimate heating and cooling loads and flow directions. Microclimate
analysis, which is combined within the energy simulation, enables to predict and choose the elements
for energy-saving. Microclimate effects can be observed by distribution of air temperature in building
sectors and the distribution can be represented by thermo- and aerodynamic flows. The strength of
thermo- and aerodynamic microclimate effects for design elements are compared in Table 7.3. The
elements, i.e. courtyard, curved roof, fence design, windbreak, huge plant, uniform window shape, with
few or no effects are marked using “–”.
Building orientation has the strongest effects for both thermo- and aerodynamic microclimate since a
concentration of solar access makes rising trend of the air and the difference of air pressure.
Topography has also strong thermodynamic effects since by day the air above the slopes can be more
easily heated than the lower area. The orientation is important to determine the directions of solar and
wind access for heating and cooling respectively. Although microclimate of a courtyard is slight due to
less daylight and natural ventilation, roof glazing of a courtyard provides better heating gain and more
thermodynamic effect such as stack effect. Gable roof form is one of the most efficient designs which
can utilize the stack effect for roof ventilation. However, thermodynamic of gable ventilation is
stronger than the courtyard’s stack effect because fresh air coming from eaves of gable roof causes an
effective aerodynamic effect pushing warm air in the room out. Curved roof is the method which
minimizes aerodynamic effect in winter since it has very small air resistance. Wind-sheltering using
fence design, windbreak and huge plants are efficient aerodynamic method to reduce strong winds in
winter and save heating energy. The performances of wind-sheltering depend on the density of the
elements and the order of aerodynamic strength is fence design, huge plants and windbreak. Windows
act as solar and air inlets, which are very important for both heating and cooling. The shapes of
windows modify the amount of inflows and streamline of the flows. Different size windows i.e.
non-uniform windows shape induces a higher ventilation performance due to the pressure difference
than the uniform window shape. Although aerodynamic effects of the horizontal window shape is
smaller than one of the non-uniform window, the horizontal window is more efficient for heating
because it can get more solar energy. Vertical and horizontal projections, e.g. external wing-walls,
partitions and fins etc., can be combined with window designs and play a role as a wind blocker or a
wind-catcher and they can be utilized as shading devices. The aerodynamic microclimates for vertical
and horizontal projections have similar strengths although they generate different airflow shapes.
Fig.7.1 classifies the thermo- and aerodynamic microclimate into heating and cooling elements and
represents energy performances. If the elements in Table 7.3 are corresponded to heating and cooling
134 see Chapter 5.
Fi
gu
effects in
F
gain, and
microclim
a
(4) Ener
gy
There are
method a
n
geometry,
since it ca
n
equations.
modificati
o
A naturall
y
to the ev
o
fluctuatin
g
modeling
t
direction,
t
node point
is the mai
n
node poin
t
u
re 7. 1 Cl
a
F
ig.7.1, we
aero-dyna
m
a
te modific
a
y
simulatio
two comp
u
n
d Computa
t
e.g. graph
o
n
divide a
However,
o
ns with b
u
y
ventilated
o
lution of
o
g
direction,
t
echnique t
h
t
emperatur
e
s in a zone
i
n
problem s
t
s.
a
ssification
can know
t
m
ic effect
a
tion are w
o
n method
f
u
ter simul
a
t
ional Flui
d
o
r connecti
o
complex e
n
the resol
u
u
ilding desi
g
and therm
a
o
utside air
f
magnitude
,
h
at analyze
s
e
, humidity,
i
ncluding t
h
ince CFD
m
by heating
t
hat all the
r
does not
o
rthy of a c
f
or microc
l
a
tion meth
o
d
Dynamic
s
o
n model,
f
n
ergy bala
n
u
tion of s
o
g
ns.
a
lly inhomo
f
low and i
n
,
turbulenc
e
s
the airflo
w
turbulence
h
e microcli
m
m
ethods al
w
１４９
and coolin
g
r
mo-dynam
i
mean dire
c
lose attenti
o
l
imate mo
d
o
ds to anal
y
s
(CFD) me
f
or multi-z
o
n
ce proble
m
o
lution is
geneous b
u
n
side buoy
a
e
, temperat
u
w
using flu
i
levels and
m
ate modif
i
w
ays need
a
g
effects of
i
c effects a
r
c
tly better
o
n.
d
ification:
E
y
ze
b
uildi
n
thod. The
p
o
ne. The ad
v
m
into seve
r
not suffic
i
u
ilding incl
u
a
ncy, stack
u
re, humid
i
id
dynamic
concentrati
i
catio
n
s. H
o
a
detailed i
n
elements i
n
r
e not direc
cooling.
H
E
P-CFD co
u
n
g energy
p
p
arametric
m
v
antage of
t
r
al sub-co
m
i
ent to ob
u
des microc
effects a
n
i
ty and rad
i
. CFD can
p
ons of cont
o
wever, a la
c
n
itial condit
i
n
Table 7.3
[
tly related
t
H
owever, t
h
u
pling
p
erformanc
e
m
ethod use
s
t
his metho
d
m
ponents wi
serve the
limate mo
d
n
d thermal
i
ations flu
x
p
redict the
aminants a
t
c
k of the in
i
i
on as muc
h
[
author].
t
o the heati
n
h
e effects
e
: paramet
r
s
a simplifi
d
is simplic
i
th paramet
r
microclim
a
d
ifications d
u
flows wit
h
x
es. CFD i
s
air speed a
n
t
thousands
i
tial conditi
o
h
as increas
n
g
of
r
ic
ed
i
ty
r
ic
a
te
u
e
h
a
s
a
n
d
of
o
n
ed
１５０
Figure 7.2. Energy simulation method using EP-CFD coupling [author].
In this dissertation, a hybrid method of parametric equation and CFD is proposed. While the initial
energy condition is calculated by a parametric equation in the EnergyPlus (EP) software, a CFD method
considers the result of EP method as the initial condition of CFD solver and estimates the difference
between the parametric estimates and the real building condition with microclimate modifications. This
method can automatically initialize without any complex manual definitions and obtain much detailed,
accurate and dynamic energy condition as Fig.7.2 depicts.
(5) Design recommendation for arrangement
Microclimate modification for heating gain is closely related to the common knowledge of Passive
House, green building and sustainable architecture. A low-energy house reduces the energy resource
and minimizes environmental impacts, i.e.
- Maximizing the opportunities to use solar energy
- Compact plan forms reduce infiltration losses
- Optimized glazing ratios for heat gains and lighting
- Using thermal mass to reduce fluctuations in room temperatures
- Sheltering the building from strong cold wind.135
However, the demand for cooling can be reduced by careful consideration of the site, building geometry,
design elements for
- Maximizing the potential use of natural wind for natural ventilation
- Using thermo- and aerodynamic flow to avoid overheating
- Controlling the streamline of airflow using design elements
- Reducing the internal loads by distributing and balancing
- Shield windows from unwanted solar gain in the hot season.
135 This reduces the unwanted cold air infiltration.
１５１
Table 7.4. The thermal effects of glazing directions in S.Korea [author].
Clockwise orientation from North Thermal effect
150°~190° Best
83°~150° and 190°~260° Fair
0°~83° and 260°~360° worst
Design recommendation based on EP-CFD energy simulations may be helpful for architects to assess
energy conservation early and throughout the design process. A house is carefully sited and arranged to
reduce energy-use for heating and cooling. Standard design elements e.g. site, form, windows, walls,
and roofs etc., are selected to control/collect/store solar heat or to ventilate/ discharge/ exchange the
heat. Typically, reductions of heating and cooling loads allow smaller HVAC equipment, resulting in
little or no increase in construction cost.
South-facing building orientation: Installing south-facing glazing enables the collection of solar energy,
which is partially stored in walls, floors, and/or ceiling of the space, and later released. Glazing must
face within 15˚ of true south, and the affected areas must be compatible with daily temperature swings.
The savings of heating energy are augmented by productivity-enhancing benefits of lighting. The
functioning of the space should not be compromised by direct glare from glazed openings or by local
overheating. The optimum building orientation can be simulated by using average daily incident
radiation on a vertical surface. The thermal effects for some building orientations are compared in Table
7.4, The best building orientation in Seoul, Korea is South to South-Southeast i.e. clockwise 157.5˚ to
180˚ from North as Fig.3.3 depicts.
Topography: Differences in slopes make remarkably large modifications of microclimate, since the
solar radiation and wind velocity are much large. A house on the slope is more suitable to use summer
breezes. Air movements such as anabatic and katabatic winds occur generally due to the difference of
radiation supply in a hilly area. If the opening control utilizes the upward and downward winds, the
winds exchange the indoor air temperature to the outdoor quickly. An open floor plan and openings are
located to catch prevailing breezes are efficient for summer cooling. Topography moderates the room
temperature, saves energy and preserves open space.
Local wind environment: For hot and humid summer, ventilation is beneficial for convective or
evaporative cooling. The movement of air through a building geometry is generated by differences in
air pressure as well as temperature. The layout of the surrounding buildings acts as barriers, diverting
the flows into narrower. The resulting patterns of airflow are affected more by building geometry and
orientation than by air speed.
Building arrangement: It is important to make the largest passive heating effect with good solar access.
１５２
Solar access is possible by keeping the south elevation free from obstructions. Arrangement of
buildings creates a wind shadow which is a low-pressure area at the back of each house. The best
arrangement is to stagger the houses according to the prevailing wind direction.
(6) Design recommendation for form
Sun space: Avoid configurations that produce heat losses or gains with no compensatory benefits. The
sun space should bring daylight to the interior while providing a solar chimney for natural ventilation
during mild weather. In some cases, atriums can collect useful solar heat in cold climates—serving as a
kind of transition zone, with larger temperature swings than would otherwise be appropriate in the rest
of the building. The atrium’s configuration should be defined at the earliest possible stages of the design
process, before an undesirable or arbitrary configuration is locked in.
Courtyard dwelling: A courtyard does not perform well due to less daylight and natural ventilation.
Sunspace performs in a similar way to a courtyard, although the ventilation is better than a courtyard
due to stack effects. There may be a need to consider ventilation to the upper floors due to the low stack
pressures at higher levels. Roof glazing can be applied to a courtyard to provide lighting and to improve
the heating gain with the passive heating method. Atrium of courtyard easily obtains solar heat through
the glass and avoids the direct heat loss. Solar heat gain can be controlled through use of fritted glass or
louvers.
Roof opening and stack-effect ventilation: Heated air rises within a mid- or high rise building to the top,
where it exits through roof openings. This process induces ventilation of the adjoining spaces below.
Spaces that are not adversely affected by increased air motion are appropriate targets for natural
ventilation, which effectively conditions the space during fair weather without using air conditioning.
In the very hot seasons, night cooling with cross-ventilation is more effective than stack-effect
ventilation. An atrium often serves as an ideal solar chimney to exhaust hot air.
Building shape: The shape of a building determines how much area is exposed to the outdoors through
exterior walls and ceilings. Exposed area should be minimized to save energy. When a house has a
complex shape, exposed surface area increases both construction and energy costs. Narrow form uses
less energy in total, and this leads to a reduction in electrical load. This outweighs any slight increase in
infiltration losses due to a large façade area.
Differentiated Façades: Differentiated façade is really an approach to determinate designs and styles
and is known as one of the most effective low-energy house strategies. The appearance of various
façades makes differ in the environmental loads. The architects create variations in the façade design,
１５３
the use of space behind the façade, and the low-energy house strategies being employed.
Windbreak: For winter, a house should be buffered against chilling winds to reduce infiltration into
interior spaces and lower heat loss. A windbreak may be in the form of a narrow path, a garden wall, or
a dense stand of trees. Windbreaks reduce wind velocity and produce an area of relative calm on their
leeward side. The extent of this wind shadow depends on the height, depth, and density of the
windbreak, its orientation to the wind, and the wind velocity. Windbreaks work either by deflecting the
wind up and over a building thereby forming a protective wind shadow, or by catching it in the twigs
and branches of a double or triple row of trees which breaks up its speed. A well designed windbreak
can reduce wind velocity by 85%, and reduce winter heating costs by 10% to 25%.
(7) Design recommendation for façade elements
Window: The architect applies functional criteria to the size, proportion, and location of windows.
When a windows size becomes larger, much more solar could enter the indoor, and the indoor
temperature would rise. It is a disadvantage to reduce temperature in the hot and humid summer of
Korea. Suitable window sizes should be optimized by glazing ratio. A window with a large width is
better to obtain both solar radiation and good ventilation than one with a large height. For summer
cooling, location of windows should be carefully chosen to serve as air inlets to face prevailing winds.
Windows can be controlled by projection. The projection located ahead (or afterward) of a window
respectively blocks (or catches) the wind. When cross-ventilation is planned for window shape,
different sizes between inlets and outlets induce higher ventilation rate wind with large pressures. For
the cold season, trickles around windows should be blocked since they usually are the major source of
air leakage which affects significantly the building energy. With double glazing windows, the indoor
temperature rises about 2℃ in winter while 0.1℃ in summer. Double glazing windows are a benefit for
thermal comfort.
Glazing ratio: Buildings with a very small glazing ratio consume more energy than ones with larger
glazing ratios. However, increasing glazing ratios much above about 50% produces little extra benefit.
The optimum glazing ratio is in the region of 35% for building surfaces. The optimum glazing ratio for
roof-light is no more than 20%. Before finalizing, glazing ratios should be checked for overheating
possibilities in summer.
Thermal mass: For an optimum effect of passive house, floor and wall finish materials with high heat
storage capacity must be exposed to direct illumination by the low winter sun. Thermal mass is ideally
placed within the building and situated where it still can be exposed to winter sunlight but insulated
from heat loss. However, for hot humid summer season, it needs to be strategically located to prevent
１５４
overheating. It should be placed in an area that is not directly exposed to solar gain and allowed
adequate ventilation at night to carry away stored energy without increasing internal temperatures any
further. The best solution is a proper shading design considering sun’s altitude because the sun’s
altitude is higher than summer.
Shading: Shading should be used to provide cost-effective, aesthetically acceptable, functionally
effective solar control. Particularly in summer, shading is very important to decrease indoor
temperature and to avoid an overheating problem. It works well on south façades where overhangs
provide effective shading for the space and the angle of shading device should be optimized for
moderate solar penetration. Shading west façades is critical in reducing peak cooling loads. A wide
range of shading devices are available, including overhangs on south façades, fins on east and west
façades, interior blinds and shades, louvers, and special glazing such as fritted glass. Reflective shading
devices can further control solar heat gain and glare. Devices without moving parts are generally
preferable. Movable devices on the exterior are typically difficult to maintain in corrosive environments
or in climates with freezing temperatures. Other design elements, such as overhanging roofs, can also
serve as shading devices.
(8) Future work
In this study, microclimate modification and energy simulation for a lot of design elements are studied
for achieving comfortable indoor environment and minimizing energy consumption in low storey and
high density. However, almost in all major cities in Asian countries, development of residential
buildings is characterized by high rise apartments. Environmental influence in most apartments is much
greater than single family houses. While increasing insulation levels and sealing air leaks in the
building and ductwork are applied to newly developed houses, energy efficiency for similar thermal
conditions is difficult in the low storey and high density housing. The studies of microclimate
modification for low-energy house should be adapted and developed for energy-saving in low storey
and high density houses. This means the spatial expansion from a small house to a low housing and high
rise building.
Architects and building planers want to maintain or increase the accuracy and quality of estimates. The
microclimate is an extremely complex system consisting of a lot of feedback loops and nonlinear
relationships between the different natural and artificial elements. Building microclimate is also
influenced by neighboring buildings and urban geometry. Studies in this thesis do not consider the
effects of neighboring buildings. For high accuracy result, combing method with other climate analysis
tools which can handle larger scale, e.g. urban, than a building is needed. The topics arises a lot of ideas
for future works: flow around and between buildings, thermal exchange processes at the ground surface,
１５５
at walls and vegetations etc. turbulence around building canyon, etc.
Other interesting issue is to measure the accuracy of the computer simulation by using the physical
simulation e.g. wind tunnel test, sensor measurement, etc. Although the computer simulation methods
are quick, economic and efficient solution using virtual design analysis, they may result in some
inaccuracy and non-practical solutions when unconsidered elements sometimes causes remarkable
effects. Real measurements using physical sensors monitoring the temperature, humidity, air velocity
etc. or wind tunnel test analyzes these inaccurate situations and helps to establish the more accurate and
practical measures for the microclimate effects. The future works will include material tests, physical
unit analysis, microclimate sensor measurements, wind tunnel tests for building geometries, etc.
１５７
Appendix
A-1. Data flow in EP-CFD simulation
A-2. EnergyPlus (EP) building parameters
BUILDING,
\unique-object
\required-object
\min-fields 7
A1 , \field Building Name
\required-field
\default NONE
N1 , \field North Axis
\note degrees from true North
\units deg
\type real
\default 0.0
A2 , \field Terrain
\note Country=FlatOpenCountry | Suburbs=CountryTownsSuburbs | City=CityCenter |
Ocean=body of
water (5km) | Urban=Urban-Industrial-Forest
\type choice
１５８
\key Country
\key Suburbs
\key City
\key Ocean
\key Urban
\default Suburbs
N2 , \field Loads Convergence Tolerance Value
\units W
\type real
\minimum> 0.0
\default .04
N3 , \field Temperature Convergence Tolerance Value
\units deltaC
\type real
\minimum> 0.0
\default .4
A3 , \field Solar Distribution
\note MinimalShadowing | FullExterior | FullInteriorAndExterior
\type choice
\key MinimalShadowing
\key FullExterior
\key FullInteriorAndExterior
\key FullExteriorWithReflections
\key FullInteriorAndExteriorWithReflections
\default FullExterior
N4 , \field Maximum Number of Warmup Days
\type integer
\minimum> 0
\default 25
A4 ; \field Calculate Solar Reflection From Exterior Surfaces
\note deprecated field. Use SolarDistribution Value
\type choice
\key No
\key Yes
\note The choice Yes requires that Solar Distribution = FullExterior or FullInteriorAndExterior
\default No
The IDF form is
BUILDING,
PSI HOUSE DORM AND OFFICES, ! Building Name
36.87000, ! Building Azimuth
Suburbs, ! Building Terrain
4.0E-02, ! Loads Convergence Tolerance
0.4, ! Temperature Convergence Tolerance
FullInteriorAndExterior, ! Solar Distribution
25; ! Maximum Number of Warmup Days
１５９
A-2. Energyplus climate weather data file access
DesignDay,
\min-fields 15
A1 , \field DesignDayName
\type alpha
\required-field
\reference DesignDays
N1 , \field Maximum Dry-Bulb Temperature
\required-field
\units C
\minimum> -70
\maximum< 70
\note
\type real
N2 , \field Daily Temperature Range
\note Must still produce appropriate maximum dry bulb (within range)
\note This field is not needed if Dry-Bulb Temperature Range Modifier Type
\note is "delta".
\units deltaC
\minimum 0
\default 0
\type real
N3 , \field Humidity Indicating Temperature at Max Temp
\note this will be a wet-bulb or dew-point temperature coincident with the
\note maximum temperature depending on the value of the field
\note Humidity Indicating Temperature Type
\note required-field if Relative Humidity schedule is not used
\units C
\minimum> -70
\maximum< 70
\type real
N4 , \field Barometric Pressure
\required-field
\units Pa
\minimum> 70000
\maximum< 120000
\type real
\ip-units inHg
N5 , \field Wind Speed
\required-field
\units m/s
\minimum 0
\maximum 40
\ip-units miles/hr
\type real
N6 , \field Wind Direction
\required-field
\units deg
１６０
\minimum 0
\maximum 359.9
\note North=0.0 East=90.0
\type real
N7 , \field Sky Clearness
\required-field
\minimum 0.0
\maximum 1.2
\default 0.0
\note 0.0 is totally unclear, 1.0 is totally clear
\type real
N8 , \field Rain Indicator
\minimum 0
\maximum 1
\default 0
\note 1 is raining, 0 is not
\type integer
N9 , \field Snow Indicator
\minimum 0
\maximum 1
\default 0
\note 1 is Snow on Ground, 0 is no Snow on Ground
\type integer
N10, \field Day Of Month
\required-field
\minimum 1
\maximum 31
\type integer
\note must be valid for Month field
N11, \field Month
\required-field
\minimum 1
\maximum 12
\type integer
A2 , \field Day Type
\required-field
\note Day Type selects the schedules appropriate for this design day
\type choice
\key Sunday
\key Monday
\key Tuesday
\key Wednesday
\key Thursday
\key Friday
\key Saturday
\key Holiday
\key SummerDesignDay
\key WinterDesignDay
\key CustomDay1
１６１
\key CustomDay2
N12, \field Daylight Saving Time Indicator
\minimum 0
\maximum 1
\default 0
\note 1=Yes, 0=No
\type integer
A3 , \field Humidity Indicating Temperature Type
\note Type of humidity indicating temperature (Wet-Bulb or Dew-Point)
\type choice
\key Wet-Bulb
\key Dew-Point
\key Schedule
\default Wet-Bulb
A4 , \field Relative Humidity Day Schedule
\object-list DayScheduleNames
\note only used when previous field is "schedule"
\note the hour/time interval values should specify relative humidity (percent) from 0.0 to 100.0
A5 , \field Dry-Bulb Temperature Range Modifier Type
\note Type of modifier to the dry-bulb temperature calculated for the time step
\type choice
\key Multiplier
\key Delta
\default Default Multipliers
A6 ; \field Dry-Bulb Temperature Range Modifier Schedule
\object-list DayScheduleNames
\note the hour/time interval values should specify range from 0.0 to 1.0 of the
\note maximum temperature
A-3. EnergyPlus input data file for solar penetration calculation
ZONE,
Zone2, !- Zone Name
...;
LIGHTS,
Zone2, !- Zone Name
BLDG Sch 3, !- SCHEDULE Name
1464.375, !- Design Level {W}
...;
SURFACE:HeatTransfer,
Zone2-WallExt-South, !- User Supplied Surface Name
WALL, !- Surface Type
Vabs0.50, !- Construction Name of the Surface
Zone2, !- InsideFaceEnvironment
...;
SURFACE:HeatTransfer:Sub,
Zone2-WallExt-South-Wndo0, !- User Supplied Surface Name
WINDOW, !- Surface Type
１６２
DOUBLE PANE WINDOW, !- Construction Name of the Surface
Zone2-WallExt-South,!- Base Surface Name
...;
DAYLIGHTING:DELIGHT,
DElight Zone2, !- User Supplied DElight Zone Name
Zone2, !- Host Zone Name
1, !- Lighting control type
0.0, !- Min input power fraction for continuous dimming
0.0, !- Min light output fraction for continuous dimming
0, !- Number of steps for stepped control
1.0, !- Probability lighting will be reset when needed
0.5; !- Gridding Resolution {m2}
DAYLIGHTING:DELIGHT:Reference Point,
RefPt 4, !- User Supplied Reference Point Name
DElight Zone2, !- DElight Zone Name
2.25, !- X-coordinate of reference point {m}
4.0, !- Y-coordinate of reference point {m}
0.9, !- Z-coordinate of reference point {m}
1.0, !- Fraction of zone controlled by reference point
1000.; !- Illuminance setpoint at reference point {lux}
DAYLIGHTING:DELIGHT:Complex Fenestration,
CFS-REDIRECT, !- User Supplied Complex Fenestration Name
BTDF^GEN^LIGHTSHELF^0.25^20.0^1.00^0.5, !- Complex Fenestration Type
Zone2-WallExt-South, !- Base Surface Name
Zone2-WallExt-South-Wndo0, !- Doppelganger Surface Name
0.0; !- Fenestration Rotation {deg}
A-4. Boundary condition setup in Fluent
1. Zones and zone types are initially defined in pre-processor.
2. To change zone type for a particular zone:
3. Define Boundary Conditions...
4. Choose the zone in Zone list.
5. Can also select boundary zone using right mouse button in
Display Grid window.
7. Select new zone type in Type list.
8. Explicitly assign data in BC panels.
- To set boundary conditions for particular zone:
- Boundary condition data can be copied from one zone to another.
- Boundary condition data can be stored and retrieved from file.
１６３
- Boundary conditions can also be defined by UDFs and Profiles.
9. Setup of velocity Inlet by specify Velocity by Magnitude, Normal to Boundary, Components and
Magnitude and Direction
10. Setup of pressure inlet by specifying total Gauge pressure, total temperature and inlet flow direction
11. Setup of pressure outlet by specifying static gauge pressure
１６４
12. Setup of Wall Boundaries by specifying solid regions, thermal boundary conditions, wall roughness
and translational or rotational velocity
13. Setup of Internal Face Boundaries by specifying Fans, Radiators, Porous jump, preferable over
porous media and interior walls.
１６５
Bibliography
A&C Publishing, “Details: Architecture + Interior”, Min-Maru 6 houses by S.Y. Choi, Nr.9, 2004.
Ahn, H.K., “Analysis of indoor climate of Jang-Kyung-Gak in Hae-In Temple”, Kyeong Hee University, 1993.
Akbari, H., Rosenfeld, A.H., Taha, H., “Cool construction materials offer energy saving and help reduce smog”, ASTM
standardization news 23, 1995.
Alvarez, S., Sanchez, F., “Guidelines on Microclimate around Buildings”, Final Report, POLIS project, 1998.
Albrecht, R., Paker, L., Rehberg, S., Reiner, Y., “Umweltlastung durch ökologische Bau- und Siedlungsweisen”, Band 1,
Band2, Bauverlag GMBH, Wiesbaden und Berlin, 1084.
Alonso, D.V., Dominguez, S.A., “Use of Vegetation and Water to Promote Passive Cooling”, The 1st International
Conference on Ecology and the City 2001, Universidad de Barcelona, 2001.
Anderson, J., Shiers, D., “The green guide to specification”, an environmental profiling system for building materials and
components, 3rd edition, Blackwell Science, 2002.
Antolini, H.L., “Solar heating & cooling”, Active & passive systems, hot water heaters, pools, spas & tubs, 4th edition, Lan
publishing Co., 1980.
Arnfield, J., “Canyon geometry, the urban fabric and nocturnal cooling: a simulation Approach”, Phys. Geogr., 1990.
Arnfield, J., Herbert, J.M., Johnson, G.T., “A numerical simulation investigation of urban canyon energy budget variations”,
Proc. 13th Int. Conf. on Biometeorol. And Aerobiol., Albuquerque, New Mexico, 1998.
Aronin, J.E., “Climate & Architecture”, Progressive Architecture Book, Reinhold Publishing Corporation, 1953.
Avissar, R., “Potential effects of vegetation on urban thermal environment”, Atmos. Envir., 1996.
Aynsley, R.M., Melbourne, W., Vickery, B.J., “Architectural Aerodynamics”, Applied Sciences Publishers Ltd., London,
1977.
Baik, J.J., Park, R.S., Chun, H.J., Kim, J.J., “A laboratory model of urban street canyon flows”, J. Appl. Meteorol., 2000.
Baker, N., Steemers, K., “Energy and Environment in Architecture”, E & FN Spoon, 1999.
Barry, G.R., Chorley, R.J, “Atmosphere, weather and climate”, 5th edition, Methuen & Co Ltd. London, 1987.
Beausoleil-Morrison, I., “The Adaptive Coupling of Heat and Airflow Modeling Within Dynamic Whole-Building
Simulation”, Ph.D. Thesis, Energy Systems Research Unit, Department of Mechanical Engineering, University of
Strathclyde, Glasgow, UK, 2000.
１６６
Bensalem, R., “Wind-driven Natural Ventilation in Courtyard and Atrium-type Buildings”, Ph.D. Thesis, University of
Sheffield, Great Britain, 1991.
Bensalem, R., “Climate-responsive”, Lund Institute of Technology, Lund University, 1995.
Bittencourt, L.S., “Ventilation as a Cooling Resource for Warm-humid Climates: An Investigation on Perforated Block Wall
Geometry to Improve Ventilation inside Low-rise Buildings”, Ph.D. Thesis, Universidade Federal de Alagoas, 1993.
Bohe, W.M., “Energiesparhäuser: eine neue Generation con Gebäuden”, Deutsche Verlags Anhalt Stuttgart, 1996.
Bourbia, F., Awbi, H.B., “Building cluster and shading in urban canyon for hot-dry Climate”, Renewable Energy, 2004.
Boutet, T.S., “Controlling Air Movement: A Manual for Architects and Builders”, Mac Graw- Hill, NY, 1987.
Britannica Encyclopaedia / 브리태니커 백과사전, 2004.
Brown, D.E., Fox, M., Pelletier, M.R., Hoffman, L., “Sustainable Architecture White Papers”, Earth Pledge Foundation
Series on Sustainable Development, Earth Pledge Foundation, 2001.
Busato, L., “Passive cooling and energy efficient strategies for the design of a hotel on the Southern coast of Pernambuco,
Brazil”, LEARN, London Metropolitan University, 2003.
Calder, K.E., “Koreas Energy Insecurities Comparative and Regional Perspectives”, the Korea Economic Institute of
America (KEI), 2005.
Casey, F.J.M., “Comfort in heat without AC”, AEE, 2002.
Chan, A.T., So, E.S.P., Samad, S.C., “Strategic guidelines for street canyon geometry to achieve sustainable street air
quality”, Atmos. Envir, 2001.
Chen, Q., Xu, W., “A zero-equation turbulence model for indoor airflow simulation”, Energy and Buildings, 1998.
Chiras, D.D., “The Solar House: Passive Heating and Cooling”, Mother Earth News, 2002.
Clark, M., “Designing for climate - Buildings and Urban Design in the Tropics”, James Cook University, 2003.
Clarke, J.A. “Environmental systems performance”, Ph.D. Thesis, Department of Architecture and Building Science,
University of Strathclyde, Glasgow, UK, 1977.
Clarke, J.A., “Energy Simulation in Building Design”, 2nd edition, Butterworth-Heinemann, 2001.
Cofaigh, E.O., Fitzgerald, E., “A Green Vitruvius”, Principles and Practice of Sustainable Architectural Design, James &
James Press, 1999.
Cofaigh, E.O., Olley, J.A., Lewis, J.O., “The climatic dwelling”, an introduction to climate-responsive residential
architecture, James & James Ltd., 1996.
Comfortable low energy architecture (CLEAR), “Climatic design”, London Metropolitan University, 2004.
Crawley, D.B., Lawrie, L.K., Winkelmann, F.C., Buhl, W. F., Pedersen, C.O., Strand, R.K., Liesen, R.J., Fisher, D.E., Witte,
M.J., Henninger, R.H., Glazer, J., Shirey, D., “EnergyPlus: New, Capable, and Linked”, In Proceedings of the Performance
of Exterior Envelopes of Whole Buildings VIII, December 2001.
Crosbie, M.J., “The Passive Solar Design and Construction Handbook”, 2nd edition, Wiley Press, 1997.
Dabberdt, W.F., Ludwig, F.L., Johnsson, W.B., “Validation and applications of an urban diffusion model for vehicle
１６７
emissions”, Atmos. Envir., 1973.
Daoudi, N.S., “Comfort and discomfort in a study space”, AEE, 2002.
Dăng, P.N., “Architektonisch-technische Lösungen zur Verbesserungen des Mikroklimas in Gebäuden unter Bedingungen
des heißen feuchten Klimas/ Architectural engineering devices for improve indoor microclimate under the hot and humid
conditions ”, Hanoi college of Civil Construction,1985.
Degiovanni, A., “Conduction dans un “mur” multicouche avec sources: extension de la notion de quadripole”, International
Journal of Heat and Mass Transfer, Volume 31, 1988.
De Paul, F.T., Shieh, C.M., “Measurements of wind velocity in a street canyon”, Atmos.
Envir., 1986.
Dingman, S.L., “Physical Hydrology,” 2nd edition, Englewood Cliffs, Prentice Hall, NJ, 2002.
Djunaedy, E., “External coupling between building energy simulation and computational fluid dynamics”, Technische
Universiteit Eindhoven, 2005.
Drexel, T., “Die neuen Öko-Häuser”, DVA, München, 2004.
Dzioubinski, O., Chipman, R., “Trends in Consumption and reduction: Household Energy Consumption”, economic &
social Affairs, 1999.
Economic Commission for Europe, “Guideline on Sustainable Human Settlement Planning & Management”, United
Nations, 1996.
Edward, B., Turrent, D., “Sustainable housing”, Principles & Practice, Taylor & Fransis, 2005.
Escourrou, G., “Le climat et la ville”, Géographie d'aujourd'hui. Nathan. Paris, 1991.
Fairey, P.W., “Passive Cooling and Human Comfort”, Florida solar energy center, 1994.
Fanger, P.O., “Thermal Comfort-analysis and Applications in Environmental Engineering”, New York: McGraw-Hill, 1970.
Feist, W., Peper, S., Görg, M., “CEPHEUS-Project information No. 36”, Final Technical Report Efficient Passive Houses as
European Standards (CEPHEUS), July 2001.
Fleury, B., “Ventilative Cooling, Paper presented at Workshop on Passive Cooling”, Application of CFD to naturally
ventilated Buildings, A guide for practitioners, www.flovent.com, Ispra. CEC, Joint Research Centre Flomerics Ltd. 1990.
Flourentzou, F., Van der Maas, J., Roulet, C.A., “Natural ventilation for passive cooling: measurement of discharge
coefficients”, Energy and Buildings, 1998.
Fluent Inc., “Airpak 2.1 Tutorial Guide”, April 2002.
Foster, N., “Solar Architektur für Europa”, Birkhäuser, 1996.
Foster, N., Scheer, H., “Solar Energy in Architecture and Urban Planning: Third European Conference on Architecture”,
James & James Science Publishers Ltd, 1993.
Franke, E., “Stadtklima, Ergebnisse und Aspekte für die Stadtplanung”, Beiträge zur Umweltplanung, Karl KrämerVerlag,
Stuttgart, 1977.
Gandemer, J., Barnaud, G., Sacré, C., Millet, J.R., “Guide sur la Climatisation Naturelle de l’Habitat en Climat Tropical
Humide. Tome 1: Methodologie de Prise en Compte des Parametres Climatiques dans l’Habitat et Conseils Pratiques”,
CSTB, Nantes, 1992.
１６８
Gao, Y., Chen, Q., “Coupling of A multi-zone airflow analysis program with a computational fluid dynamics program for
indoor air quality studies”, Proceedings of the 4th International Symposium on Heating Ventilating and Air Conditioning,
Beijing, China, 2003.
Geiger, R., Aron, R.H., Todhunter, P., “The climate near the ground”, 5th edition, Vieweg, 1995.
Gissen, D., “Big and Green: Toward Sustainable Architecture in the 21st Century”, Princeton Architectural Press, 2002.
Givoni, B., “Man, Climate and Architecture”, Elsevier publishing company limited, 1969.
Givoni, B., “Passive and Low energy cooling of buildings”, Van Nostrand Reinhold, New York, 1994.
Gonzalo, R., “Bewusst Bauen”, Wege zum solaren und energiesparenden Planen, Bauen und Wohnen, Edition Erasmus,
1994.
Goulding, J.R., Lewis, J.O., Steemers, T.C., “Energy conscious design”, a primer for architects, Batsford for the commission
of the European Communities, 1992.
Gunßer, C., “Wohnen am Hang”, Deutsche Verlags-Anstalt, Stuttgart, Muenchen, 2001.
Güttler, P., “Berlin und seine Bauten”, Ernst & Sohn Verlag für Architektur und technische Wissenschaften Berlin, 2002.
Guyot, G., “Physics of the environment and climate”, John Wiley & Sons, 1998.
Haglund, B., Rathmann, K., “Vital signs”, Thermal mass in passive solar and energy conserving buildings, University of
Idaho, 1996.
Han, P.W., “The environmental ecological interpretation of a traditional Korean settlement”, Architectural institute of Korea,
1996.
Hawkes, D., Forster, W., “Energy Efficient Buildings: Architecture, Engineering, and Environment”, W. W. Norton &
Company, 2002.
Heckmann, O., “Grundrißatlas, Wohnungsbau”, Birkhäuser, 1994.
Hens, H., “Building Physics-Heat, Air and Moisture”, Fundamentals and Engineering Methods with Examples and
Experiences, Ernst & Sohn, 2007.
Hensen, J., “A comparison of coupled and de-coupled solutions for temperature and air flow in a building”, ASHRAE
Transactions, 1999.
Herzog, T., Kaiser, N., Volz, M., “Solar Energy in Architecture and Urban Planning”, European conference on Solar Energy
in Architecture and Urban planning, Prestel Publishing, April, 1996.
Höppe, P.R., “Heat balance modeling”, Experientia 49, 1993.
Hollmuller, P., Lachal, B., “TRNSYS compatible moist air hypocaust model”, Final report, Centre universitaire d’études
des problèmes de l’énergie, CH - 1205 Genève, 1998.
Honjo, T., Takakura, T., “Simulation of thermal effects of urban green areas on their surrounding areas”, Energy and
Buildings, 1990.
Hosker, R.P.J., “Flow around isolated structures and building clusters: a review”, ASHRAE Transactions, 1985.
Hottel, H.C., Sarofim, A.F., “Radiative Transfer”, Chapter 3, McGraw-Hill, 1967.
１６９
Hussein, M., Lee, B.E., “An investigation of wind forces on the 3D roughness elements in a simulated atmospheric boundary
layer flow”, University of Sheffield, UK, 1980.
ISO/PRF PAS 16739 IFC 2. x Platform specification.
Jendritzky, G., Menz, G., Schirmer, H., Schmidt, K.W., “Methodik zur räumlichen Bewertung der thermischen Komponente
im Bioklima des Menschen”, Beiträge der Akademie für Raumforschung und Landesplannung, Hannover Universität, 1990.
Jittawikul, A., “Climatic maps for passive cooling methods utilization in Thailand”, Journal of Asian architecture and
building engineering, 2004.
Jones, A.R., “Sustainable Architecture: The Green Buildings of Nikken Sekkei”, Academy Press, 2000.
Joo, C.S., “A study on the architectural planning of the hill housing”, Hanyang University, 1989.
Jozwiak, R., Kacprzyk, J., Zuranski, J.A., “Wind tunnel investigations of interference effects on pressure distribution on a
building”, Journal of wind engineering and industrial aerodynamics, 1995.
Kang, B.S., “도시집합주택의 계획/Plan of city residence”, 공동주택연구회/Korea research council for multi-family housing,
도서출판 발언
/Bal Eon, 1996.
Katayama, T., Tsutsumi, J., Ishii, A., “Full-scale measurements and wind tunnel tests on cross-ventilation”, Journal of Wind
Engineering and Industrial Aerodynamics, 1992.
Katayama T., Tsutsumi, J., “Investigation and numerical simulation of the wind effects on thermal comfort in a house”,
Journal of wind engineering and industrial aerodynamics, 1996.
Kendrick, J.F., “An overview of combined modeling of heat transport and air movement”, Technical Note 40, Air Infiltration
and Ventilation Centre, Coventry, UK, 1993.
Kim, B.S., Kim, K.H., “A Study on Thermal Environment and the Design Methods to Save Energy in Small Glass-Skin
Commercial Buildings”, Journal of Asian architecture and building engineering, 2004.
Kim, J.J., Baik, J.J., “A Numerical Study of Flow and Pollutant Dispersion Characteristics in Urban Street Canyons”,
Journal of Applied Meteorology, 1999.
Kim, H.J., “A study on the design characteristics of hillside apartment housing based on a gradient”, Architectural institute
of Korea, 2001.
Kim, H.T., Kim, S.I., Park, B.J., “A study on the State of air motion and it’s velocity distribution in the room by the models
testing”, Architectural institute of Korea, 1988.
Kim, M.K., “A Study on the Ecological Expressive Characteristics of Traditional Residence in Korea”, Architectural
institute of Korea, 2000.
Kim, M.K., “A Study on the Characteristics of the Ecological Expression in Traditional Korean Residence”, Gyeongsang
National University, 2001.
Kiraly, J., “Architektur mit der Sonne,” 7nd edition, C.F. Müller Verlag Heidelberg, 1996.
Klingele, M., “Architektur und Energie,” Planungsgrundlagen für Büro- und Verwaltungsbauten, Verlag C.F. Müller, 1994.
Knowles, R.L., “Sun, Rhythm and Form”, MIT press, London, 1981.
Koenigsberger, O.H., Ingersoll, T.G., Mayhew, A., Szokolay, S.V., “Manual of Tropical Housing and Building”, Longman,
London, 1974.
１７０
Köhler, M., “Ökologische Untersuchungen an Extensiven Dachbegrünung/ Ecological Analysis of Extensive Green Roofs”,
Poster zu Verhandlung der Gesellschaft für Ökologie, 1989.
Korea Electric Power Corporation /한국전력통계, http://www.kepco.co.kr, 2007.
Korea National Statistical Office, Republic of Korea, http://www.nso.go.kr/, 2003.
Köster, H., “Tageslichtdynamische Architektur”, Grundlagen, Systeme, Projekte, Birkhäuser, 2004.
Krusche, P.M., Althaus, D., Gabriel, I., “Ökologisches Bauen”, Herausgegeben vom Umweltbundesamt, Bauverlag GMBH
Wiesbaden und Berlin, 1982.
Kuttler, W., “Stadtklima”, Umweltchem Ökotox, 2004.
Landsberg, H.E., “The urban climate”, International geophysics series, Academy press, New York, 1981.
Lechner, N., “Heating, Cooling, Lighting: Design Methods for Architects”, John Wiley &sons, 1991
Lee, E.J., Kim, G., Kim, J.T., “Optimization of slope and orientation of building integrated photovoltaic systems based on
local climatic aspect in Korea”, Kyung Hee university, Republic of Korea, 2004.
Lee, K.H., “The environmental characteristic of Korean traditional house from the view in passive environmental control”,
The Architectural Institute of Korea, 1986.
Lee, K.I., “World collective theme houses”,
도서출판 발언
/Bal Eon, 1993.
Lee, S.H, Heo, I.H., Lee, K.M., Kwon, W.T., “Classification of Local Climatic Regions in Korea”, Korean Meteorological
Society, 2005.
Lee, S.J., “Investigation for planning adaptable house to regional characteristic in the south seaside province of Korea”,
Korea University, 1988.
Lee, S.M., “Architectural environment of Jangkyunggak at Haein Temple”, Dongguk University, 1999.
Lee, Y.W., “A study on the location of Hae-in temple”, Han yang University, 1986.
Lefèvre, P., “Architectures durables”, 50 réalisations environnementales en France et. en Europe : Allemagne, Angleterre,
Italie, Hollande, Edisud, Paris, Systèmes solaires, 2002.
Liddament, M., “Air Infiltration Calculation Techniques: An Applications Guide”, Air Infiltration and Ventilation Centre,
Bracknell, 1986.
Liu, Y., “Climatic Design in Beijing, China, a Study of a Residential Multi-storey Building”, AEE, 2002.
Lomas, K.J., Eppel, H., Martin, C.J., “Bloomfield, D. P. Empirical validation of thermal building simulation programs using
test room data”, International Energy Agency ECBCS Annex 21 Report, Building Research Establishment, Watford, UK,
1994.
Loxsom, F.M., Clarke, G., “A National Assessment of Passive Nocturnal Cooling from Horizontal Surface”, San Antonio:
Solar Data Center, Trinity University, 1980.
Ludwig, J.W., “Solar 4.Architektur und Energie”, America Haus, 1981.
Markus, T.A., Morris, E.N., “Buildings, Climate and Energy”, Pitman Publishing, London, 1980.
Matsumoto, T., “Lifestyles and Energy Consumption in Households”, The University of Kitakyushu, 2003.
１７１
Mayer, H., Höppe, P., “Thermal comfort of man in different urban environments”, Theor. Appl. Climatol., 1987.
Mayer, H., “Human-biometeorological assessment of urban microclimates according to the German VDI-guideline 3787
part II”, Prepr. 2nd Urban Envir. Symp. Albuquerque, New Mexico, 1998.
Mayer, H., Matzarakis, A., “Methoden zur human-biometeorologischen Bewertung von Klima- und Lufthygiene für die
Stadt- und Regionalplanung”, Die Richtlinie VDI 3787 Blatt 2, Teil I: Klima, .Kommission Reinhaltung der Luft im VDI und
DIN Normenausschuss, Schriftenreihe Band 31, 1999.
Mayer, M., “Urban bioclimatology”, Experientia, 1993.
Mazria, E., “The passive solar energy book, a complete guide to passive solar home, greenhouse and building design”,
Rodale Press, 1979.
McPherson, E.G., Nowak, D.J., Rowntree, R.A., “Chicago’s urban forest ecosystem: Results of the Chicago urban forest
climate project”, General Technical report, USDA forest service, 1994.
McPherson, E.G., Nowak, D.J., “Quantifying the impact of trees: The Chicago Urban Forest Climate Project”, Unasylva
No.173, 1993.
McPherson, E.G., Simpson, J.R., “Shade trees as a demand-side resource”, Home energy 2, 1995.
Meir, L.A., Pearlmutter, D., Etzion, Y., “On the microclimatic behavior of two semi enclosed attached courtyards in hot and
dry region”, Building and Environment, 1995.
Mendler, S.F., Odell, W., Lazarus, M.A., “The HOK Guidebook to Sustainable Design”, Wiley Press, 2000.
Mills, G., “An Urban Canopy-Layer Climate Model”, Theor. Appl. Climatol., 1997.
Moffat, A.S., Schiler, M., “Landscape design that saves energy”, William Morrow and Co., New York, 1981.
Möllring, F., Schempp, D., Krampen, M., “Solares Bauen”, 2nd edition, Rudolf Müller Verlag, Köln,1994.
Monteith, J.L., “Principles of environmental physics”, Edward Arnold, London, 1973.
Moore, S., Trulsson, N.B., McGregor, S.M., “Living Homes: Sustainable Architecture and Design”, Chronicle Books, 2001.
Mostaedi, A., “Sustainable Architecture: Hi-Tech Housing”, Gingko Press, 2003.
Nakamura, Y., Oke, T., “Wind, temperature and stability conditions in an eastwest oriented urban canyon”, Atmos. Envir,
1988.
Negrao, C. O. R., “Conflation of Computational Fluid Dynamics and Building Thermal Simulation”, Ph.D. Thesis, Energy
Systems Research Unit, Department of Mechanical Engineering, University of Strathclyde, Glasgow, UK, 1995.
Novoselac, A., “Combined airflow and energy simulation program for building mechanical system design”, The
Pennsylvania State University, 2005.
Oke, T.R, “The distinction between canopy and boundary - layer urban heat island”, Atmosphere, 1976.
Oke, T.R., “Boundary Layer Climates”, 2nd edition, Methuen. London, New York, 1987.
Oke, T., Johnson, G.T., Steyn, D.G., Watson, I.D., “Simulation of surface urban heat islands under “ideal” conditions at
night”, Boundary−Layer Meteorol., 1991.
Olgyay, V., “Design with climate”, Bioclimatic approach to architectural regionalism, 4th edition, Princeton University,
1973.
１７２
Owens, S., “Energy, environmental sustainability and land-use planning”, Sustainable Development and Urban Form, Pion,
London, 1982.
Porteous, C., “The New Eco-Architecture: Alternatives from the Modern Movement”, E & FN Spon, 2001.
Pople, N., “ Gebäude Visionen: Architektur der Zukunft”, Kohlhammer, 2001.
Ridky, R., “Siedlungsökologische Eckwerte zum Bebauungsplan, Mit Gestaltungshilfen zur Topographieanpassung für
umweltschonende Wohnbaumaßnahmen”, Dortmunter Vertrieb für Bau- und Planungsliteratur, 1991.
Roaf, S., “Ecohouse 2”, a design guide, Architectural press, 2003.
Rosenlund, H., “Climatic Design of Buildings using Passive Techniques”, Luvit Education Centre, Sweden, 2000.
Saini, B.S., “Architecture in Tropical Australia”, Lund Humphries for the Architectural Association London, No.6, 1970.
Santamouris, M., Daskalaki, E., “Case Studies: In Natural Ventilation”, James and James Science Publishers, 1998.
Santamouris, M., Papanikolaou, N., Koronakis, I., Livada, I., Asimakopoulos, D., “Thermal and airflow characteristics in a
deep pedestrian canyon under hot weather conditions”, Atmos. Envir., 1999.
Santamouris, M. Asimakopoulos, D., “Passive cooling of buildings”, Europian Commission directorate general XVII for
Energy, James and James Science Publishers, London, 1996.
Scherer, D., “Infrared image database of Kreisel in Berlin”, Fachgebiet Klimatologie, Institut für Ökologie, Technische
Universität Berlin, 2006.
Schittich, C., “In Detail Solar Architecture”, strategies, visions, concepts, Birkhäuser, 2004.
Seoul Statistical Yearbook, Seoul Metropolitan Government, 2007.
Sharma, A., Dhote, K.K., Tiwari, R., “Climatic Responsive Energy Efficient Passive Techniques in Buildings”,
IE(I)Journal-AR, 2003.
Shashua-Bar, L., Hoffman, M.E., “Vegetation as a climatic component in the design of an urban street”, Energy and
Buildings, 2000.
Shin, S.C., “에너지기술개발 동향 및 우리나라 전략/ Energy technical development trend and the strategy”, Science &
Technology policy institute, 2005.
Simpson, B.J., Purdy, M.T., “Housing on sloping sites”, Construction Press, London and New York, 1984.
Smagorinsky, J., “Global atmospheric modeling and the numerical simulation of climate weather and climate modification”,
Wiley, New York, 1974.
Smith, P., Pitts, A.C., “Concepts in practice Energy”, B.T. Batsford, 1998.
Smith, P.F., “Sustainability of the cutting edge”, Emerging technologies for low energy buildings, Architectural Press,
2003.
Smith, P.F., “Architecture in a Climate of Change”, 2nd edition, Architectural Press, 2005.
Stimmann, H., Kieren, M., “Die Architektur des neuen Berlin”, nicolai, 2005.
Taha, H., “Urban climates and heat islands: albedo, evapotranspiration and anthropogenic heat”, Energy and Buildings,
1997.
１７３
Talyor, P.A., Lee, R.J., “Simple guidelines for estimating wind speed variations due to small scale topographic features”,
Climatol. Bull., 1984.
Tan, G., “Study of natural ventilation design by integrating the multi zone model with CFD simulation”, Massachusetts
Institute of Technology, 2005.
Tanimoto, J., Hagishima, A., Chimklai, P., “An approach for coupled simulation of building thermal effects and urban
climatology”, Energy and Buildings, 2004.
The Chartered Institute of Building Service Engineers (CIBSE), “The Chartered Institute of Building Services Engineers
Handbook”, 1997.
The Intergovernmental Panel on Climate Change (IPCC), “IPCC Fourth Assessment Report (AR4): Climate Change 2007”,
2007.
The Kentucky Division of Energy (KDOE), “Energy Efficient Home Plans for Kentucky”, A Plan Booklet of Energy
Efficient Homes with Performance Analysis, Commonwealth of Kentucky, 2003.
The Korea Institute of Construction Technology (KICT), “친환경건축물 비용편익분석연구용역결과/ The cost-benefit analysis
research result of environmental construction”, 2005.
The US department of energy, “Getting Started with EnergyPlus”, University of Illinois, 2007a.
The US department of energy, “Input Output Reference: The Encyclopedic Reference to EnergyPlus Input and Output”,
University of Illinois, 2007b.
The US department of energy, “EnergyPlus Engineering Reference: The Reference to EnergyPlus Calculations”, University
of Illinois, 2007.
The 2005 World Sustainable Building Conference (WSBC), “Sustainable design book”, SB 05, Building a sustainable future,
Tokyo, 2005.
Toudert, F.A., “Dependence of Outdoor Thermal Comfort on Street Design in Hot and Dry Climate”,
Freiburg,Albert-Ludwigs-Universität Freiburg, November 2005.
Treberspurg, M., “Neues Bauen mit der Sonne”, Ansaetze zu einer klimagerechten Architektur, Springer-Verlag, Wien, New
York, 1994.
Tuomaala, P., “The Implementation and evaluation of airflow and heat transfer routines for building simulation tools”, VTT
publication 471, Ph.D. Thesis, Helsinki University of Technology, 2002.
Ulseth, R., Stang, J., Hoel, T.I., Noeres, P., Klose, P., Hölder, D., Althaus, W., Ahonen, M., Koo, K.D., “District Heating and
Cooling in Future Buildings”, IEA-District heating and cooling project, 1999.
Vandaele, L., Wouters, P., “The PASSYS services summary report”, Commission of the European Communities, Research
and Development, Brussels, Belgium, 1994.
Van Treeck, C., Rank, E., “Geometrical and topological issues for coupling dimensionally reduced multizone models with
high-resolution CFD techniques”, Lehrstuhl für Bauinformatik, Technische Universität München, 2004.
Vickery, B.J., Karakatsanis C., “External wind pressure distributions and induced internal ventilation flow in low-rise
industrial and domestic structures”, ASHRAE Transactions, BRE, 1978.
Walker, R.R., Shao, L., Woolliscroft, M., “Natural ventilation via courtyards: the application of CFD”, In Proceedings 14th
AIVC Conference, Copenhagen, 1993.
１７４
Walton, G.N., “The Thermal Analysis Research Program Reference Manual Program (TARP)”, National Bureau of
Standards (now National Institute of Standards and Technology), 1983.
Ward, I.C., “Energy and environmental issues”, for the practicing architect, Thomas Telford, 2004.
Wedding, J.B., Lombardi, D.J., Cermak, J.E., “A wind tunnel study of gaseous pollutants in city street canyons”, J. Air
Pollut. Contr., 1977.
Wiren, B.G., “Effect of surrounding buildings on wind pressure distribution and ventilation heat losses for single family
houses”, Int. Swedish inst. for building Research., 1985.
Wiren, B.G., “Effect of surrounding buildings on wind pressure distribution and ventilation heat losses for single family
houses”, the international Swedish institute for building Research, Gavle. Sweden, 1987.
Woodruff, N.P., Zingg, A.W., “Wind tunnel studies of fundamental problems related to windbreaks, U.S. Department of
Agriculture, Washington, D.C., 1952.
Yannas, S., “Adaptive Skins and Microclimates”, the 21st Conference on Passive and Low Energy Architecture, Eindhoven,
the Netherlands, PLEA, 2004.
Yeang, K., “Tropical Urban Regionalism”, building in a Southeast Asian city, Singapore Concept Media, 1987.
Yoshida, A., Tominaga, K., Watani, S., “Field measurements on energy balance of an urban canyon in the summer season”,
Energy and Buildings, 1990/91.
Zhai, Z., Chen, Q., “Strategies for coupling energy simulation and computational fluid dynamics programs”, Seventh
International IBPSA Conference Rio de Janeiro, Brazil, 2001.
Zhai, Z., “Developing an integrated design tool by coupling building energy simulation and computational fluid dynamics”,
Ph.D. Thesis, Department of Architecture, Massachusetts Institute of Technology, 2003.
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