ene gies
Re iew
E alua ion o School Building Ene gy Pe o mance
and Class oom Indoo En i onmen
Ji ka Mohelníko á1, Milosla No o ný1and Pa la Moco á2,*
1Facul y o Ci il Enginee ing, B no Uni e si y o Technology, 602 00 B no, Czech Republic;
[email p o ec ed].cz (J.M.); no o ny[email p o ec ed].cz (M.N.)
2Facul y o Fo es y and Wood Technology, Mendel Uni e si y, 613 00 B no, Czech Republic
*Co espondence: [email p o ec ed]
Recei ed: 21 Ap il 2020; Accep ed: 12 May 2020; Published: 15 May 2020

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Abs ac :
Exis ing building s ock ep esen s po en ial o ene gy sa ing eno a ions. Ene gy sa ings
and indoo clima e com o a e key demands o sus ainable building e u bishmen . Especially in
schools, indoo com o is an ex emely impo an issue. A case s udy o ene gy consump ion in
selec ed school buildings in empe a e clima ic condi ions o Cen al Eu ope egion was pe o med.
The s udied buildings a e ep esen a i es o a ious school p emises cons uc ed h oughou he
las cen u y. The e alua ion was based on da a analysis o ene gy audi s. The goal was aimed a
assessmen o he school building en elopes and hei in luence on ene gy consump ion. One o he
s udied schools was selec ed o de ailed e alua ion. The school class oom was moni o ed o indoo
he mal and isual en i onmen s. The moni o ing was pe o med o compa e he cu en s a e and
eno a ion scena ios. Resul s o he e alua ion show ha he school buildings a e highly ine icien
e en i eno a ed. Indoo clima e in class ooms is la gely in luenced by windows. Sola gains a ec
in e io he mal s abili y and dayligh ing. The mal insula ion quali y o building en elopes and
e icien sola shading sys ems appea o be undamen al asks o school eno a ion s a egies.
Keywo ds: ene gy pe o mance; ene gy audi s; school buildings; indoo clima e
1. In oduc ion
Cu en ends a e aimed a he imp o emen in building ene gy pe o mance and
sus ainabili y
[1,2]
. Mode n cons uc ion me hods acili a e mo e ene gy conscious buildings
compa ed o old building s ocks [
2
–
4
]. Newly designed buildings comply wi h op-le el ene gy
e iciency[
5
,
6
].Ne e heless,building e u bishmen ep esen sa a ionalapp oach owa dssus ainable
de elopmen [
7
,
8
]. Ene gy conscious eno a ion became one o he p omising ways o educe ca bon
dioxide emissions om buildings [
9
,
10
]. Exis ing buildings in he EU egion ep esen massi e
po en ials o ene gy sa ings [
1
,
2
]. Ene gy eno a ion has u mos impo ance o he esiden ial and
public buildings sec o s. These buildings exe high ene gy consump ion o hea ing and en ila ion o
cooling sys ems as well as a i icial ligh ing.
Especially school buildings ha e been objec s o ene gy sa ing in e es s. Conside able numbe s
o p og ams a e ocused on school buildings pe o mance [
11
–
13
]. Ze o emissions and high quali y o
indoo en i onmen we e opical asks o he p ojec “School o he Fu u e”, wi hin he ame o he
EU p og amme [
14
]. The aim o he p ojec was o communica e examples o e icien buildings unde
di e en Eu opean clima es.
S a egies o ene gy consump ion [
15
–
21
] and he mal com o assessmen s [
22
–
26
] we e
de eloped o educa ional buildings.
Ene gy e iciency, oge he wi h indoo clima e com o , a e key ea u es o good p ac ice school
pe o mances in acco dance wi h sus ainable a chi ec u e p inciples [
27
,
28
]. Building en elopes play a
Ene gies 2020,13, 2489; doi:10.3390/en13102489 www.mdpi.com/jou nal/ene gies
Ene gies 2020,13, 2489 2 o 17
subs an ial ole in he buil en i onmen [
29
,
30
]. Pa icula ly windows in luence indoo he mal and
isual com o [31–33].
The abo emen ioned o e iew shows he impo ance o ene gy e iciency and indoo clima e
conscious a i udes [
34
] owa ds educa ional buildings. A s udy ocused on he assessmen o selec ed
ep esen a i es o school buildings in empe a e clima ic condi ions was pe o med o e alua e hei
ene gy sa ing po en ials in acco dance wi h ecen ends o highly ene gy e icien schools in Cen al
Eu ope [35].
2. Ma e ials and Me hods
A case s udy aimed a an analysis o ene gy consump ion in selec ed school buildings in he
Cen al Eu ope egion was pe o med. The s udied buildings a e ep esen a i es o a ious school
p emises. The e alua ion was based on he analysis o da a om ene gy audi s o speci ica ion o
cu en s a e o building en elopes and hei in luence on ene gy consump ion. One o he s udied
schools was selec ed o de ailed e alua ion. The school class oom was moni o ed o indoo he mal
and isual clima e.
2.1. Analysis o Ene gy Audi s
The selec ed schools [
36
] we e s udied o hei ene gy consump ion. They a e ep esen a i es
o an exis ing school building s ock o cons uc ion s yles h oughou he las cen u y. Many schools
a e e y old and some o hem a e lis ed as his o ically p o ec ed p emises. Mos o hem a e ene gy
ine icien . The mal insula ion imp o emen s and windows e o i a e equi ed o upg aded e iciency.
The case s udy is ocused on analysis o he buildings’ ene gy pe o mance and eno a ion po en ials.
The school buildings we e selec ed in acco dance wi h he building si e locali y and clima ic
condi ions, (Figu e 1and Table 1). The buildings’ cons uc ion is commonly ep esen ed by solid
b ick (70%) and ce amic block (18%) mason y sys ems o ein o ced conc e e p e ab ica ed echnology
(12%). Cen al gas hea ing is widely used in he schools, while elec ic hea ing has mino applica ion.
The school buildings’ ene gy consump ion is spen on hea ing and ho wa e se ices (80%), a i icial
ligh ing and elec ic appliances (12%) and auxilia y ene gy demands (8%).
Ene gies 2020, 13, x FOR PEER REVIEW 2 o 18
Ene gy e iciency, oge he wi h indoo clima e com o , a e key ea u es o good p ac ice school
pe o mances in acco dance wi h sus ainable a chi ec u e p inciples [27,28]. Building en elopes play
a subs an ial ole in he buil en i onmen [29,30]. Pa icula ly windows in luence indoo he mal
and isual com o [31–33].
The abo emen ioned o e iew shows he impo ance o ene gy e iciency and indoo clima e
conscious a i udes [34] owa ds educa ional buildings. A s udy ocused on he assessmen o selec ed
ep esen a i es o school buildings in empe a e clima ic condi ions was pe o med o e alua e hei
ene gy sa ing po en ials in acco dance wi h ecen ends o highly ene gy e icien schools in Cen al
Eu ope [35].
2. Ma e ials and Me hods
A case s udy aimed a an analysis o ene gy consump ion in selec ed school buildings in he
Cen al Eu ope egion was pe o med. The s udied buildings a e ep esen a i es o a ious school
p emises. The e alua ion was based on he analysis o da a om ene gy audi s o speci ica ion o
cu en s a e o building en elopes and hei in luence on ene gy consump ion. One o he s udied
schools was selec ed o de ailed e alua ion. The school class oom was moni o ed o indoo he mal
and isual clima e.
2.1. Analysis o Ene gy Audi s
The selec ed schools [36] we e s udied o hei ene gy consump ion. They a e ep esen a i es
o an exis ing school building s ock o cons uc ion s yles h oughou he las cen u y. Many schools
a e e y old and some o hem a e lis ed as his o ically p o ec ed p emises. Mos o hem a e ene gy
ine icien . The mal insula ion imp o emen s and windows e o i a e equi ed o upg aded
e iciency. The case s udy is ocused on analysis o he buildings’ ene gy pe o mance and eno a ion
po en ials.
The school buildings we e selec ed in acco dance wi h he building si e locali y and clima ic
condi ions, (Figu e 1 and Table 1). The buildings’ cons uc ion is commonly ep esen ed by solid
b ick (70%) and ce amic block (18%) mason y sys ems o ein o ced conc e e p e ab ica ed
echnology (12%). Cen al gas hea ing is widely used in he schools, while elec ic hea ing has mino
applica ion. The school buildings’ ene gy consump ion is spen on hea ing and ho wa e se ices
(80%), a i icial ligh ing and elec ic appliances (12%) and auxilia y ene gy demands (8%).
Figu e 1. Map wi h locali ies o he s udied school buildings 1 o 18, (map:
h ps://geology.com/wo ld/czech- epublic-sa elli e-image.sh ml).
Figu e 1.
Map wi h locali ies o he s udied school buildings 1 o 18, (map: h ps://geology.com/wo ld/
czech- epublic-sa elli e-image.sh ml).
Ene gies 2020,13, 2489 3 o 17
Table 1. Buildings loca ion, geome y and hea losses.
Building
Yea o
Cons uc ion
(Reno a ion)
Locali y Building Geome y Building En elope
Al i ude
[m]
La i ude
Longi ude
[◦]
A e . Win e
Tempe a u e
[◦C]
Building
Volume
[m3]
G oss Floo
A ea/Hea ed
Volume [m−1]
Hea
Loss
[kW]
A e age U
Value
[W m−2K−1]
11900
(2000) 248 49.763969 N
17.180405 E 4.1 3264 0.63 90 0.907
21950 210 49.456479 N
17.450230 E 3.9 23,278 0.40 373.1 1.27
31994 272 49.038646 N
17.814872 E 3.9 19,255 0.4 303.6 1.136
41931 272 49.038646 N
17.814872 E 3.9 3448 0.47 61.1 0.954
51890 334 49.458565 N
18.056868 E 3.8 1938 0.574 50.1 0.97
61984 304
49.6819311 N
18.3673219 E 3.7 23,955 0.45 434 1.087
71949 336 49.712716 N
13.204605 E 3.6 3491 0.43 88.7 1.23
81978 387 49.443259 N
13.248114 E 3.7 1471 0.85 61.1 0.95
91937 520
49.7161561 N
13.9473069 E 3.5 7163 0.47 102 0.90
10 1930 440
49.4248869 N
13.8817589 E 3.7 11,427 0.503 276.5 1.05
11 1988 225 50.289161 N
14.824512 E 3.8 5288 0.40 99.4 0.82
12 1960 188 48.9.07468 N
16.775371 E 4.5 4140 0.48 82.6 1.18
13 1929 450 50.129276 N
16.499965 E 3.6 6670 0.40 160.6 1.21
14 1967 179 49.059797 N
17.495850 E 3.6 3326 0.46 78 1.33
15 1980 675 49.908449 N
17.211115 E 3.1 4131 0.68 130 1.02
16 1887
(1962) 378 49.303454 N
14.158029 E 3.7 21,777 0.37 380.6 1.1
17 1980 334 49.820923 N
18.262524 E 3.6 22,423 0.25 424.5 0.76
18 1894
(2014) 280 50.655668 N,
14.724856 E 2.9 17,244 0.24 396 0.72
2.2. School Class oom The mal and Dayligh E alua ion
One o he s udied buildings was selec ed o de ail e alua ions—building 18 (Table 1). The main
goal was he mal and dayligh assessmen o he school class ooms. The school building cons uc ed
in 1894 is lis ed as a his o ically p o ec ed p emise (Figu e 2) [
37
]. The h ee-s o ey building has a
solid b ick mason y and oo uss load-bea ing s uc u es. The g ound loo is dedica ed o he main
en ance and school acili ies as well as managemen and adminis a i e depa men s. Educa ional
ooms a e on he i s and second loo .
Ene gies 2020, 13, x FOR PEER REVIEW 4 o 18
Figu e 2. His o ical building o p ima y school, locali y Mimoň, CZ [37].
The school has spacious side li class ooms. One o hem, loca ed on he second loo , was
selec ed o he e alua ion. Fi s ly, he class oom he mal assessmen was pe o med o he cu en
s a e and compa ed wi h eno a ion scena ios. Secondly, he class oom dayligh e alua ion was
ca ied ou . Dayligh illuminance and luminance measu emen s we e aken and comple ed wi h a
dayligh simula ion s udy.
2.2.1. The mal E alua ion
The he mal s udy was ocused on he building acade and i s in luence on indoo clima e. The
ex e nal wall he mal ansmi ance and condensa ion isks we e s udied. The e alua ion was ca ied
ou o h ee a ia ions:
• cu en s a e: wall wi h 8 cm o he mal insula ion on he in e io side;
• eno a ion scena io I: wall wi h 15 cm o he mal insula ion on he in e io side;
• eno a ion scena io II: wall wi h 15 cm o he mal insula ion on he ex e io su ace.
The so wa e Teplo [38] was used o he e alua ion. The so wa e is in ended o undamen al
analyses o building cons uc ions like he mal esis ance R (m
2
KW
−1
) and U- alue (W m
−2
K
−1
)
calcula ions, empe a u e p o iles, in e s i ial condensa ion analysis and speci ica ion o annual
balance o condensed and e apo a ed amoun wi hin building cons uc ions in acco dance wi h
s anda d me hodology o ISO 6946 and ISO 13788 [39,40] and o he s anda d equi emen s [41].
Bounda y condi ions o he he mal e alua ion acco ding o [
41]
a e ollowing:
• design ou doo empe a u e -13.0 °C, locali y—GPS: 50.655668 N, 14.724856 E;
• design indoo ai empe a u e 21.0 °C (class oom);
• design ela i e humidi y o ou doo ai 84.0%;
• design ela i e humidi y o indoo ai 55%.
Two-dimensional empe a u e dis ibu ion o he wall de ails a window jambs in he cu en
s a e and design a ia ions wi h in e nal and ex e nal he mal insula ion we e simula ed using he
so wa e A ea [38]. The so wa e is dedica ed o complex he mal analyses o building cons uc ion
de ails o speci ica ion o po en ial he mal b idges in wo dimensional s a iona y hea ans e and
wa e apou di usion simula ions in acco dance wi h s anda d me hodology o ISO 10211 [42].
A s udy o he in luence o he eno a ed acade on indoo he mal s abili y was pe o med
[41,43]. The he mal s abili y was selec ed as an indica o o indoo he mal clima e. The mal s abili y
o he class oom was simula ed o win e and summe season condi ions using he so wa e S abili a
[38]. The in e nal empe a u e d op du ing a hea ing lapse in win e and summe indoo empe a u e
ise we e calcula ed. The goal o he e alua ion is o compa e in luence o windows on he indoo
he mal en i onmen .
2.2.2. Dayligh E alua ion
Figu e 2. His o ical building o p ima y school, locali y Mimoˇn, CZ [37].
Ene gies 2020,13, 2489 4 o 17
The school building main enance has been limi ed by design obs uc ions like many o he
his o ical p emises. The building was eno a ed in 2014 unde an a chi ec u al p ese a ion e iew.
The eno a ion was mainly aimed a he building en elope. Window and acade e o i was comple ed.
I was no allowed o change he his o ical s yle o he acade and o his eason, ex e nal walls we e
he mally insula ed om he in e io side.
The school has spacious side li class ooms. One o hem, loca ed on he second loo , was selec ed
o he e alua ion. Fi s ly, he class oom he mal assessmen was pe o med o he cu en s a e
and compa ed wi h eno a ion scena ios. Secondly, he class oom dayligh e alua ion was ca ied
ou . Dayligh illuminance and luminance measu emen s we e aken and comple ed wi h a dayligh
simula ion s udy.
2.2.1. The mal E alua ion
The he mal s udy was ocused on he building acade and i s in luence on indoo clima e.
The ex e nal wall he mal ansmi ance and condensa ion isks we e s udied. The e alua ion was
ca ied ou o h ee a ia ions:
•cu en s a e: wall wi h 8 cm o he mal insula ion on he in e io side;
• eno a ion scena io I: wall wi h 15 cm o he mal insula ion on he in e io side;
• eno a ion scena io II: wall wi h 15 cm o he mal insula ion on he ex e io su ace.
The so wa e Teplo [
38
] was used o he e alua ion. The so wa e is in ended o undamen al
analyses o building cons uc ions like he mal esis ance R (m
2
KW
−1
) and U- alue (W m
−2
K
−1
)
calcula ions, empe a u e p o iles, in e s i ial condensa ion analysis and speci ica ion o annual balance
o condensed and e apo a ed amoun wi hin building cons uc ions in acco dance wi h s anda d
me hodology o ISO 6946 and ISO 13788 [39,40] and o he s anda d equi emen s [41].
Bounda y condi ions o he he mal e alua ion acco ding o [41] a e ollowing:
•design ou doo empe a u e −13.0 ◦C, locali y—GPS: 50.655668 N, 14.724856 E;
•design indoo ai empe a u e 21.0 ◦C (class oom);
•design ela i e humidi y o ou doo ai 84.0%;
•design ela i e humidi y o indoo ai 55%.
Two-dimensional empe a u e dis ibu ion o he wall de ails a window jambs in he cu en
s a e and design a ia ions wi h in e nal and ex e nal he mal insula ion we e simula ed using he
so wa e A ea [
38
]. The so wa e is dedica ed o complex he mal analyses o building cons uc ion
de ails o speci ica ion o po en ial he mal b idges in wo dimensional s a iona y hea ans e and
wa e apou di usion simula ions in acco dance wi h s anda d me hodology o ISO 10211 [42].
A s udy o he in luence o he eno a ed acade on indoo he mal s abili y was pe o med [
41
,
43
].
The he mal s abili y was selec ed as an indica o o indoo he mal clima e. The mal s abili y o he
class oom was simula ed o win e and summe season condi ions using he so wa e S abili a [
38
].
The in e nal empe a u e d op du ing a hea ing lapse in win e and summe indoo empe a u e
ise we e calcula ed. The goal o he e alua ion is o compa e in luence o windows on he indoo
he mal en i onmen .
2.2.2. Dayligh E alua ion
Na u al ligh in luences indoo clima e and wellbeing. Especially in educa ional buildings, isual
com o is c ucial. Dayligh posi i ely a ec s s uden s’ ale ness and heal h [
44
]. Re iews o he
impo ance o dayligh ing in schools [
45
,
46
] show ela ionships be ween he occupan s’ esponses and
na u al ligh ing. The posi i e impac o dayligh in class ooms was p o en [
47
,
48
]. Dayligh ing in
educa ional buildings has been a opical ask o p o essional p ojec s [
49
–
51
]. Ex ensi e su eys o US
schools in di e en clima e condi ions we e pe o med [
52
]. The EU p og amme [
53
] p omo es dayligh
in eg a ion o high pe o mance indoo en i onmen in schools. These ac i i ies a e in ag eemen
Ene gies 2020,13, 2489 5 o 17
wi h he main p inciples o sus ainable de elopmen [
54
,
55
] and a chi ec u al design s a egies [
56
–
59
]
as well as s anda d ecommenda ions [60–62].
Dayligh Measu emen s
Dayligh illuminance was moni o ed in he class oom. The in en ion was o s udy he
class oom isual en i onmen unde he mos cha ac e is ic dayligh condi ions h oughou he
yea . The measu emen ime was limi ed due o he accessibili y schedule in o he class oom.
Measu emen s we e pe o med wi hou pupils’ occupancy o e weekends in Ma ch 2017.
The class oom is a spacious place o loo a ea 11.9
×
7.63 m and clea ance heigh 4 m. I has h ee
big windows, o wid h abou 2 m and heigh 2.5 m (Figu es 3and 4). The dayligh measu emen s we e
aken o a se o six y poin s on a wo king plane. The plane is loca ed 0.85 m o e he class oom
loo le el (Figu e 4). The se o poin s is posi ioned in dis ance o 1 m a ound he oom pe ime e .
Spacing o he poin s is 1.10 m by 1.126 m. Simul aneously wi h he in e io measu emen s, he ex e nal
illuminance was moni o ed on unshaded ho izon al plane ou doo s. Sky luminance was also s udied.
Ene gies 2020, 13, x FOR PEER REVIEW 5 o 18
Na u al ligh in luences indoo clima e and wellbeing. Especially in educa ional buildings,
isual com o is c ucial. Dayligh posi i ely a ec s s uden s’ ale ness and heal h [44]. Re iews o
he impo ance o dayligh ing in schools [45,46] show ela ionships be ween he occupan s’ esponses
and na u al ligh ing. The posi i e impac o dayligh in class ooms was p o en [47,48]. Dayligh ing
in educa ional buildings has been a opical ask o p o essional p ojec s [49-51]. Ex ensi e su eys o
US schools in di e en clima e condi ions we e pe o med [52]. The EU p og amme [53] p omo es
dayligh in eg a ion o high pe o mance indoo en i onmen in schools. These ac i i ies a e in
ag eemen wi h he main p inciples o sus ainable de elopmen [54,55] and a chi ec u al design
s a egies [56–59] as well as s anda d ecommenda ions [60-62].
Dayligh Measu emen s
Dayligh illuminance was moni o ed in he class oom. The in en ion was o s udy he class oom
isual en i onmen unde he mos cha ac e is ic dayligh condi ions h oughou he yea . The
measu emen ime was limi ed due o he accessibili y schedule in o he class oom. Measu emen s
we e pe o med wi hou pupils’ occupancy o e weekends in Ma ch 2017.
The class oom is a spacious place o loo a ea 11.9 × 7.63 m and clea ance heigh 4 m. I has h ee
big windows, o wid h abou 2 m and heigh 2.5 m (Figu es 3 and 4). The dayligh measu emen s
we e aken o a se o six y poin s on a wo king plane. The plane is loca ed 0.85 m o e he class oom
loo le el (Figu e 4). The se o poin s is posi ioned in dis ance o 1 m a ound he oom pe ime e .
Spacing o he poin s is 1.10 m by 1.126 m. Simul aneously wi h he in e io measu emen s, he
ex e nal illuminance was moni o ed on unshaded ho izon al plane ou doo s. Sky luminance was also
s udied.
The dayligh illuminance was measu ed using wo calib a ed illuminance me e s Tes o 545
(calib a ion 2017). One illuminance me e was aken o in e io measu emen s and he second de ice
measu ed ex e nal ho izon al illuminance. Lase ange inde Bosch GLM 50 C P o essional was used
o se poin s on he wo king plane. T ipods we e also used o s abilize he illuminance me e a he
equi ed heigh . The ex e nal illuminance senso was posi ioned on he oo . The measu ing
ins umen s we e synch onized. Ou doo and indoo illuminance alues we e measu ed a he same
ime. The illuminance da a p ocessing was ca ied ou in MS Excel and S a is ica so wa e [63].
Figu e 3. View in o he class oom [37].
Figu e 3. View in o he class oom [37].
Ene gies 2020, 13, x FOR PEER REVIEW 6 o 18
Figu e 4. Plan o he class oom wi h poin s 1 o 60 on he wo king plane (0.85 m o e he loo ).
Fu he mo e, moni o ing o he su ace luminance was aken in he class oom isual ield.
Luminance Me e LS-100 Konica Minol a is used o measu emen s.
Dayligh Simula ions
The class oom isual en i onmen was also s udied on he basis o dayligh simula ions. The
cu en s a e dayligh ing is compa ed wi h designed a ia ions. The design s a e is ep esen ed by
eno a ion scena io II wi h wo a ia ions o window glazing (double o iple glass uni s). Dayligh
simula ions we e un in so wa e Dayligh Visualize [64] o he ollowing pa ame e s:
• ligh e lec ance ρ [-] o he class oom su aces in cu en s a e ( esp. designed s a e): loo
inishing 0.35 ( esp. 0.5), wall su aces 0.7 ( esp. 0.9), ceiling 0.84 ( esp. 0.9).
• window glass ligh ansmi ance τ [-]: double glazed uni s 0.81, iple glazed uni s 0.73.
• he sou h-eas o ien a ion o he class oom windows (Figu e 5).
Dayligh simula ions we e un o an annual balance o in e nal ho izon al illuminance unde
wo sky models [65]:
• CIE clea sky model o simula e sunligh condi ions.
• CIE o e cas sky model o conside a ion o he mos un a ou able dayligh si ua ion.
The balance was simula ed o he 21s day o e e y mon h and day ime 12:00.
Finally, he class oom dayligh ing was also simula ed o designed a ia ions and compa ed
wi h s anda d equi emen s acco ding o EN 17037 [61] as ollows:
• Dayligh illuminance simula ed o he clea sky model on 21s June, a 12:00 was compa ed wi h
a ge illuminance 300 lux.
• Dayligh ac o simula ion o he o e cas sky model was compa ed wi h a ge dayligh ac o
DT = 2%.
Figu e 4. Plan o he class oom wi h poin s 1 o 60 on he wo king plane (0.85 m o e he loo ).

Ene gies 2020,13, 2489 6 o 17
The dayligh illuminance was measu ed using wo calib a ed illuminance me e s Tes o 545
(calib a ion 2017). One illuminance me e was aken o in e io measu emen s and he second de ice
measu ed ex e nal ho izon al illuminance. Lase ange inde Bosch GLM 50 C P o essional was used
o se poin s on he wo king plane. T ipods we e also used o s abilize he illuminance me e a
he equi ed heigh . The ex e nal illuminance senso was posi ioned on he oo . The measu ing
ins umen s we e synch onized. Ou doo and indoo illuminance alues we e measu ed a he same
ime. The illuminance da a p ocessing was ca ied ou in MS Excel and S a is ica so wa e [63].
Fu he mo e, moni o ing o he su ace luminance was aken in he class oom isual ield.
Luminance Me e LS-100 Konica Minol a is used o measu emen s.
Dayligh Simula ions
The class oom isual en i onmen was also s udied on he basis o dayligh simula ions.
The cu en s a e dayligh ing is compa ed wi h designed a ia ions. The design s a e is ep esen ed by
eno a ion scena io II wi h wo a ia ions o window glazing (double o iple glass uni s). Dayligh
simula ions we e un in so wa e Dayligh Visualize [64] o he ollowing pa ame e s:
•
ligh e lec ance
ρ
[-] o he class oom su aces in cu en s a e ( esp. designed s a e): loo inishing
0.35 ( esp. 0.5), wall su aces 0.7 ( esp. 0.9), ceiling 0.84 ( esp. 0.9).
•window glass ligh ansmi ance τ[-]: double glazed uni s 0.81, iple glazed uni s 0.73.
• he sou h-eas o ien a ion o he class oom windows (Figu e 5).
Dayligh simula ions we e un o an annual balance o in e nal ho izon al illuminance unde
wo sky models [65]:
•CIE clea sky model o simula e sunligh condi ions.
•CIE o e cas sky model o conside a ion o he mos un a ou able dayligh si ua ion.
The balance was simula ed o he 21s day o e e y mon h and day ime 12:00.
Finally, he class oom dayligh ing was also simula ed o designed a ia ions and compa ed wi h
s anda d equi emen s acco ding o EN 17037 [61] as ollows:
•
Dayligh illuminance simula ed o he clea sky model on 21s June, a 12:00 was compa ed wi h
a ge illuminance 300 lux.
•
Dayligh ac o simula ion o he o e cas sky model was compa ed wi h a ge dayligh ac o
DT=2%.
Ene gies 2020, 13, x FOR PEER REVIEW 7 o 18
(a) (b)
Figu e 5. O ien a ion o windows in he dayligh model. (a) Pho og aph o a pa o he school
building acade ( he class oom windows a e on he 2nd loo ). (b) Geome ic model o he class oom
(Dayligh Visualize ).
3. Resul s
The abo e men ioned ene gy audi ing e alua ion achie ed no able esul s o he analysis o he
school buildings e iciency. Ou pu s o indoo he mal and dayligh e alua ions in he selec ed
ep esen a i e o school class ooms show po en ial p oblems in he cu en s a e and gi e an
o e iew abou some eno a ion scena ios.
3.1. Resul s o he Ene gy Audi s Analysis
The analysis o selec ed school buildings ene gy audi s gi es an o e iew abou hei en elopes
and hei in luence on hea losses. To al hea ansmission and en ila ion losses o buildings a y
om 61.1 kW o 424.5 kW. To al annual ene gy consump ion in he schools is be ween 265 and 3305
GJ pe yea . Pe cen age o hea ansmission losses o hei building en elopes a e ollowing:
• 23.6% o 57.0% o ex e nal walls (U = 0.57 o 1.83 W m−2 K−1).
• 18.3% o 36.0% o oo s (U = 0.36 o 1.50 W m−2 K−1).
• 17.4% o 55.3% o windows (U = 2.30 o 3.50 W m−2 K−1), ex e nal doo s (U = 3.50 o 6.50 W m−2
K−1).
The annual consump ion o ene gy in dependence o he building olume is be ween 23.7 and
64.7 kWh.m−3 pe yea and consump ion o ene gy o hea ing and domes ic ho wa e a y om 19.8
o 61.7 kWh.m−3 pe yea . The hea ing ene gy consump ion is qui e high in he school buildings
compa ed o demands o low ene gy buildings (less han 50 kWh/m2 pe yea ) and passi e houses
(less han 15 kWh/m2 pe yea ) [5] (Figu e 6).
Figu e 6. Compa ison o hea ing ene gy consump ion in s udied school buildings 1 o 18.
3.2. Resul s o he The mal E alua ion
Figu e 5.
O ien a ion o windows in he dayligh model. (
a
) Pho og aph o a pa o he school
building acade ( he class oom windows a e on he 2nd loo ). (
b
) Geome ic model o he class oom
(Dayligh Visualize ).
Ene gies 2020,13, 2489 7 o 17
3. Resul s
The abo e men ioned ene gy audi ing e alua ion achie ed no able esul s o he analysis o
he school buildings e iciency. Ou pu s o indoo he mal and dayligh e alua ions in he selec ed
ep esen a i e o school class ooms show po en ial p oblems in he cu en s a e and gi e an o e iew
abou some eno a ion scena ios.
3.1. Resul s o he Ene gy Audi s Analysis
The analysis o selec ed school buildings ene gy audi s gi es an o e iew abou hei en elopes
and hei in luence on hea losses. To al hea ansmission and en ila ion losses o buildings a y
om 61.1 kW o 424.5 kW. To al annual ene gy consump ion in he schools is be ween 265 and 3305 GJ
pe yea . Pe cen age o hea ansmission losses o hei building en elopes a e ollowing:
•23.6% o 57.0% o ex e nal walls (U =0.57 o 1.83 W m−2K−1).
•18.3% o 36.0% o oo s (U =0.36 o 1.50 W m−2K−1).
•
17.4% o 55.3% o windows (U =2.30 o 3.50 W m
−2
K
−1
), ex e nal doo s (U =3.50 o 6.50 W m
−2
K
−1
).
The annual consump ion o ene gy in dependence o he building olume is be ween 23.7 and
64.7 kWh.m
−3
pe yea and consump ion o ene gy o hea ing and domes ic ho wa e a y om
19.8 o 61.7 kWh.m
−3
pe yea . The hea ing ene gy consump ion is qui e high in he school buildings
compa ed o demands o low ene gy buildings (less han 50 kWh/m
2
pe yea ) and passi e houses
(less han 15 kWh/m2pe yea ) [5] (Figu e 6).
Ene gies 2020, 13, x FOR PEER REVIEW 7 o 18
(a) (b)
Figu e 5. O ien a ion o windows in he dayligh model. (a) Pho og aph o a pa o he school
building acade ( he class oom windows a e on he 2nd loo ). (b) Geome ic model o he class oom
(Dayligh Visualize ).
3. Resul s
The abo e men ioned ene gy audi ing e alua ion achie ed no able esul s o he analysis o he
school buildings e iciency. Ou pu s o indoo he mal and dayligh e alua ions in he selec ed
ep esen a i e o school class ooms show po en ial p oblems in he cu en s a e and gi e an
o e iew abou some eno a ion scena ios.
3.1. Resul s o he Ene gy Audi s Analysis
The analysis o selec ed school buildings ene gy audi s gi es an o e iew abou hei en elopes
and hei in luence on hea losses. To al hea ansmission and en ila ion losses o buildings a y
om 61.1 kW o 424.5 kW. To al annual ene gy consump ion in he schools is be ween 265 and 3305
GJ pe yea . Pe cen age o hea ansmission losses o hei building en elopes a e ollowing:
• 23.6% o 57.0% o ex e nal walls (U = 0.57 o 1.83 W m−2 K−1).
• 18.3% o 36.0% o oo s (U = 0.36 o 1.50 W m−2 K−1).
• 17.4% o 55.3% o windows (U = 2.30 o 3.50 W m−2 K−1), ex e nal doo s (U = 3.50 o 6.50 W m−2
K−1).
The annual consump ion o ene gy in dependence o he building olume is be ween 23.7 and
64.7 kWh.m−3 pe yea and consump ion o ene gy o hea ing and domes ic ho wa e a y om 19.8
o 61.7 kWh.m−3 pe yea . The hea ing ene gy consump ion is qui e high in he school buildings
compa ed o demands o low ene gy buildings (less han 50 kWh/m2 pe yea ) and passi e houses
(less han 15 kWh/m2 pe yea ) [5] (Figu e 6).
Figu e 6. Compa ison o hea ing ene gy consump ion in s udied school buildings 1 o 18.
3.2. Resul s o he The mal E alua ion
Figu e 6. Compa ison o hea ing ene gy consump ion in s udied school buildings 1 o 18.
3.2. Resul s o he The mal E alua ion
Resul s o he ex e nal wall hyg o- he mal e alua ion a e p esen ed in Figu e 7. The cu en wall
(U =0.43 W m
−2
K
−1
) and eno a ion scena ios (U =0.29 W m
−2
K
−1
) wi h in e nal and ex e nal
he mal insula ion we e s udied. The igu e shows schemes o apou p essu e dis ibu ion wi hin he
wall and speci ica ion o po en ial condensa ion egions. An annual balance o condensed/e apo a ed
amoun inside o he wall is summa ized in g aphs. I is clea ha he in e s i ial condensa ion is ully
elimina ed in he wall wi h ex e nal he mal insula ion ( eno a ion scena io II).
Ene gies 2020,13, 2489 8 o 17
Ene gies 2020, 13, x FOR PEER REVIEW 8 o 18
Resul s o he ex e nal wall hyg o- he mal e alua ion a e p esen ed in Figu e 7. The cu en wall
(U = 0.43 W m−2 K−1) and eno a ion scena ios (U = 0.29 W m−2 K−1) wi h in e nal and ex e nal he mal
insula ion we e s udied. The igu e shows schemes o apou p essu e dis ibu ion wi hin he wall
and speci ica ion o po en ial condensa ion egions. An annual balance o condensed/e apo a ed
amoun inside o he wall is summa ized in g aphs. I is clea ha he in e s i ial condensa ion is ully
elimina ed in he wall wi h ex e nal he mal insula ion ( eno a ion scena io II).
Vapou p essu e dis ibu ion (mon h 11) Annual balance, condensa ion/e apo a ion
Cu en s a e
Reno a ion scena io I
Reno a ion scena io II
No condensa ion occu s in he cons uc ion du ing he model
yea o he annual balance o condensa ion/e apo a ion
a e in acco dance wi h ISO 13,788 [40].
Figu e 7.
Vapou p essu e dis ibu ion wi hin he ex e nal wall and annual balance o
condensa ion/e apo a ion a e acco ding o ISO 13788 [40].
Simula ion ou pu s o wo-dimensional empe a u e dis ibu ion o he window jamb de ails in
he cu en s a e and in he wo eno a ion scena ios a e shown in Figu e 8. I is ob ious ha he
a ia ion o he wall wi h ex e nal he mal insula ion ep esen s be e empe a u e dis ibu ion and
mo e con enien design solu ion.
Ene gies 2020,13, 2489 9 o 17
Ene gies 2020, 13, x FOR PEER REVIEW 9 o 18
Figu e 7. Vapou p essu e dis ibu ion wi hin he ex e nal wall and annual balance o
condensa ion/e apo a ion a e acco ding o ISO 13788 [40].
Simula ion ou pu s o wo-dimensional empe a u e dis ibu ion o he window jamb de ails in
he cu en s a e and in he wo eno a ion scena ios a e shown in Figu e 8. I is ob ious ha he
a ia ion o he wall wi h ex e nal he mal insula ion ep esen s be e empe a u e dis ibu ion and
mo e con enien design solu ion.
Figu e 8. Tempe a u e dis ibu ion o he ex e nal wall de ail a he window jamb.
The mal s abili y o he class oom was e alua ed o win e and summe season condi ions. The
indoo empe a u e d op du ing a 24 h hea ing lapse in win e does no a y signi ican ly when
compa ing he exis ing s a e and wo eno a ion scena ios (Figu e 9). I is because o he ela i ely
small acade a ea compa ed o he big olume o he class oom. Th ee la ge windows o sou heas
o ien a ion ep esen massi e sola gains and indoo empe a u e ise in summe seasons (Table 2).
I could b ing abou o e hea ing p oblems du ing in ensi e sola shining pe iods. Sola gains can
a ec indoo isual discom o . Fo his eason, dayligh ing in he class oom was also e alua ed o
clea sky condi ions.
Figu e 8. Tempe a u e dis ibu ion o he ex e nal wall de ail a he window jamb.
The mal s abili y o he class oom was e alua ed o win e and summe season condi ions.
The indoo empe a u e d op du ing a 24 h hea ing lapse in win e does no a y signi ican ly when
compa ing he exis ing s a e and wo eno a ion scena ios (Figu e 9). I is because o he ela i ely
small acade a ea compa ed o he big olume o he class oom. Th ee la ge windows o sou heas
o ien a ion ep esen massi e sola gains and indoo empe a u e ise in summe seasons (Table 2).
I could b ing abou o e hea ing p oblems du ing in ensi e sola shining pe iods. Sola gains can
a ec indoo isual discom o . Fo his eason, dayligh ing in he class oom was also e alua ed o
clea sky condi ions.
Ene gies 2020, 13, x FOR PEER REVIEW 10 o 18
Figu e 9. Resul s o assessmen o he class oom he mal s abili y in win e .
Table 2. Resul s o assessmen o he class oom he mal s abili y in summe .
Cu en S a e Reno a ed Scena io I, II
To al sola ansmi ance o window g = 0.65 To al sola ansmi ance o window g = 0.53
Sola gains 2141.64 W Sola gains 1746.26 W
Hea gain h ough acade 4857.30 W Hea gain h ough açade 3961.7
Hea en ila ion loss Hea en ila ion loss
( o en ila ion a e 0.5 h
−1
) −32.78 W ( o en ila ion a e 0.5 h
−1
) −32.78 W
To al hea gain 6966.16 W To al hea gain 5675.24 W
Max. indoo empe a u e ise pe day 16.5 °C Max. indoo empe a u e ise pe day 14.7 °C
3.3. Dayligh S udy Resul ss
The class oom dayligh ing was analysed o illuminance and luminance measu ed da a and
dayligh simula ion ou pu s.
3.3.1. Measu ed Da a Analysis
Da a om illuminance measu emen s on he ho izon al wo king plane in he class oom ( om
Figu e 4) a e summa ized in Figu es 10 and 11. The dayligh le el is educed wi h he dis ance om
windows. I is ob ious ha big di e ences in illuminance a e in Row i close o he window line. The
illuminance di e ences a e minimized in he oom dep h. Highe illuminance alues in posi ions o
Line A and B a Row i a e in luenced due o he glossy whi eboa d su ace loca ed nea he big
window (Figu e 3). I is also ob ious om Figu e 11, whe e illuminance is in ensi ied a poin s 8, 9
and 10 o Row i. Illuminance a poin s 2, 6 and 10 is inc eased because o windows posi ions.
Illuminance di e ence be ween window/wall posi ions is educed in he oom dep h—Rows iii o i.
Figu e 10. Class oom dayligh illuminance—dependence on dis ance om windows.
Figu e 9. Resul s o assessmen o he class oom he mal s abili y in win e .
Ene gies 2020,13, 2489 16 o 17
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