This is he accep ed manusc ip o he a icle ha appea ed in inal o m in Ene gy
Con e sion and Managemen 126 : 736-747 (2016) , which has been published in inal
o m a h ps://doi.o g/10.1016/j.enconman.2016.08.042. © 2016 Else ie unde CC BY-NC-
ND license (h p://c ea i ecommons.o g/licenses/by-nc-nd/4.0/)
© 2016. This manusc ip e sion is made a ailable unde he CC-BY-NC-ND 4.0 license
h p://c ea i ecommons.o g/licenses/by-nc-nd/4.0/
ENERGY CONVERSION AND MANAGEMENT
h ps://doi.o g/10.1016/j.enconman.2016.08.042
The ole o he design and ope a ion o indi idual hea ing
sys ems o he ene gy e o i s o esiden ial buildings
J. Te és-Zubiaga(1); A. Campos-Celado (2); I. González-Pino(3); G. Dia ce(4)
(1) ENEDI Resea ch G oup, Depa men o The mal Enginee ing, Facul y o Enginee ing
o Bilbao, Uni e si y o he Basque Coun y UPV/EHU, Ra ael Mo eno “Pi xi xi” 2,
48013 Bilbao, Spain.
(2) ENEDI Resea ch G oup, Depa men o The mal Enginee ing, Facul y o
Enginee ing o Gipuzkoa, Uni e si y o he Basque Coun y UPV/EHU, A da. O aola 29,
20600 Eiba , Spain.
(3)ENEDI Resea ch G oup, Depa men o The mal Enginee ing, Facul y o
Enginee ing o Bilbao, Uni e si y o he Basque Coun y UPV/EHU, Alda. U quijo S/N,
48013 Bilbao, Spain.
(4) ENEDI Resea ch G oup, Depa men o Mining and Me allu gical Enginee ing and
Ma e ial Sciences, Facul y o Enginee ing o Bilbao, Uni e si y o he Basque Coun y
UPV/EHU, Ra ael Mo eno “Pi xi xi” 2, 48013 Bilbao, Spain.
ABSTRACT
The easibili y o indi idual na u al gas i ed boile -based hea ing sys ems in he e o i ing o buildings
cons uc ed in he 50-60s in Bilbao (no he n Spain) is e alua ed in his pape . A holis ic app oach
h ough dynamic simula ions using TRNSYS is employed o he pu pose. An exis ing dwelling
p e iously moni o ed and used o alida e he model applied is selec ed as a case s udy. 54 di e en
scena ios a e e alua ed, which a ise om he combina ion o 3 di e en en elope op ions, 2 ypes o
hea p oduc ion uni s, 3 hea p oduc ion empe a u es and 3 com o empe a u e se -poin s. The cases
a e e alua ed in e ms o ene gy esul s, economic aspec s, and he in luence o use beha iou .
Rega ding he la e , he in luence o he po en ial ebound e ec is also e alua ed. The esul s show
ene gy sa ings nea by 10% when condensing boile s a e compa ed wi h high e iciency boile s. In
ela ion o ho wa e p oduc ion empe a u e, ene gy sa ings be ween 5 and 10% a e ound when he
empe a u e is lowe ed om 60 o 50ºC. The g ea es impac on ene gy consump ion is ela ed o he
occupan s’ beha iou : educ ions up o 89% a e achie ed i he indoo empe a u e se -poin is lowe ed
J. Te és-Zubiaga, A. Campos-Celado , I. González-Pino, G. Dia ce. The ole o he design and ope a ion o indi idual hea ing
sys ems o he ene gy e o i s o esiden ial buildings. Ene gy Con e sion and Managemen 2016, 136, 736–747
2
2ºC. This is ein o ced wi h he esul s ela ed o he ebound e ec , which show signi ican di e ences
on ene gy consump ion alues. These e idences demons a e ha he use beha iou is an essen ial
ea u e o be conside ed in s udies ega ding buildings ene gy pe o mance. As a consequence, he
holis ic app oach he ein employed eme ges as a key ool o be applied in u he wo ks ela ed wi h he
opic.
Keywo ds: Ene gy supply sys ems; Holis ic app oach; Building Ene gy Re o i ; Ene gy e iciency;
Rebound E ec
Nomencla u e
BAU
Business as usual
BO
Bes op ion
C
Theo e ical hea ing ene gy consump ion (calcula ed)
C
op
Ope a ing cos
C
en
Cu en cos o ene gy
CB
Condensing boile
DHW
Domes ic Ho Wa e
E
Ac ual ene gy consump ion
e
Annual escala ion a e o ene gy
ESM
Ene gy Sa ing Measu es
I
Cu en cos o in es men
LTB
Low empe a u e na u al gas boile ; High e iciency boile
LCC
Li e Cycle Cos
NR
Non- e o i ed
P
e
E ec i e he mal powe
P
EN442
Nominal he mal powe pe leng h (EN-442)
PLR
Pa load a ion
Discoun ac o
RE
Rebound E ec
T
e
E ec i e empe a u e
TRV
The mos a ic al e
1 In oduc ion
Nowadays, he building sec o is esponsible o 40% o he o e all p ima y ene gy consump ion in
Eu ope as well as one hi d o ela ed global g eenhouse gas emissions [1]. Acco ding o he Uni ed
Na ions En i onmen P og amme, he building ope a ional phase accoun s o 80-90% o hose
emissions, consis ing o he ene gy use o hea ing, cooling, en ila ion, ligh ing and appliances [2];
he e o e, each ac ion di ec ed owa ds inc easing ene gy e iciency o buildings and educing hei
p ima y ene gy consump ion is o g ea impo ance, as i can be in e ed om he nume ous egula ions
se up du ing he las decade [3]. These egula ions we e o iginally ocused on new cons uc ion;
J. Te és-Zubiaga, A. Campos-Celado , I. González-Pino, G. Dia ce. The ole o he design and ope a ion o indi idual hea ing
sys ems o he ene gy e o i s o esiden ial buildings. Ene gy Con e sion and Managemen 2016, 136, 736–747
3
howe e , he exis ing building s ock is he main challenge o a subs an ial educ ion o he ene gy
consump ion. As a esul , conside able wo k has been done h oughou he la es yea s o ge a sui able
no ma i e amewo k o acing his challenge [4].
Fo he speci ic case o Spain [5], 56% o he 26 million dwellings exis ing by 2011 we e buil up be o e
he i s Spanish he mal egula ion on buildings (NBE-CT 79) came in o e ec in 1980. The e o e, he e
is a doub less equi emen o e o i ing in o de o mee he Eu opean objec i es on 20% p ima y
ene gy consump ion educ ion [6]. This can be achie ed applying ene gy sa ing measu es (ESM);
educing he ene gy demand h ough he imp o emen o he he mal pe o mance o he building
en elope, and/ o implemen ing mo e e icien ene gy sys ems.
As a as ene gy sys ems a e conce ned, se e al wo ks ha e been ecen ly published. De u Che e al. [7]
e alua ed he upg ade o a con en ional gas boile in o a condensing boile , ocusing on he boile i sel ,
and lea ing ou o scope i s in e ac ion wi h he building and i s use s. Deng e al. [8] e alua ed ene gy
supply concep s o ze o ene gy esiden ial buildings in wo di e en clima es, by means o simula ions.
M. Ow ak e al. [9] e alua ed expe imen ally and by means o simula ions he he mal pe o mance o a
oom hea ed wi h an a ached sunspace, which included wa e anks wi h he aim o inc easing he hea
s o age capaci y. Focused on he mal ins alla ions, Obyn and an Moeseke [10] e alua ed o he case o
Belgium di e en hea ing sys ems in he eno a ion o an a ached house. They concluded ha o
highly insula ed dwellings, he op imum sys em is he mos simple in e ms o composi ion. Also o
Belgium, V ijde s and Delem [11] unde lined ha condensing gas boile s a e he cheapes hea ing
sys em wi h low emission le el. Tagliabue e al. [12] analyzed h ee solu ions (gas condensing boile , ai
sou ce hea pump and g ound sou ce hea pump) o a esiden ial building in Milan (I aly). I was
p o ed ha hea pumps pe o m be e han gas condensing boile s, being he g ound sou ce hea pump
he mos p o i able solu ion. Anas aselos e al. [13] ca ied ou a compa a i e analysis be ween di e en
echnologies o a semi-de ached house in Ge many. Amongs he cases unde e alua ion, na u al gas
boile s showed o be he bes op ion om an economical and en i onmen al poin o iew. Nagy e al.
[14] demons a ed ha he implemen a ion o a sui able low empe a u e hea ing sys em can be he bes
solu ion o exis ing buildings, e en when no ESM is applied o he en elope.
Use beha iou is an addi ional ac o o be conside ed on ene gy consump ion. I s in luence can be
e en la ge han he building cha ac e is ics o o he ac o s [15-17]. Many s udies ha e poin ed ou
no iceable di e ences in ene gy consump ion o simila buildings [18, 19] due o he occupan s’
J. Te és-Zubiaga, A. Campos-Celado , I. González-Pino, G. Dia ce. The ole o he design and ope a ion o indi idual hea ing
sys ems o he ene gy e o i s o esiden ial buildings. Ene gy Con e sion and Managemen 2016, 136, 736–747
4
beha iou . The exis ing ela ion be ween beha iou al pa e ns, use p o iles and ene gy use was
demons a ed in [20]. To illus a e his poin , he ene gy use ob ained om a ield su ey in 110 simila
dwellings was p esen ed in [21]. The dwelling wi h he maximum consump ion showed an ene gy use 12
imes highe han ha dwelling wi h he minimum. This e ec is e en g ea e when he social building
sec o is analysed, as shown by B unne e al. in [22].
The ebound e ec (RE) [23] is ano he ac o o be aken in o accoun . I is de ined as he di ec
inc ease on demand o an ene gy se ice as a esul o imp o emen s in echnical e iciency in he use
o ene gy [24, 25]. The so-called back i e occu s when he uel use ac ually inc eases as a esul o ha
uel e iciency gain. E en hough empi ical s udies sugges ha back i e is no usual, many esea ch
wo ks p o e ha ac ual ene gy sa ings in building eno a ions a e ha dly e e p opo iona e o he
ene gy e iciency imp o emen . Whe eas RE ocuses on o e -consump ion a e an ene gy eno a ion,
p ebound e ec concep is based on he e idence o unde -consump ion p io o o in he absence o
ene gy eno a ions [26]. The link be ween p ebound e ec and ene gy sa ings sho alls in eno a ions
has been s udied in dep h by R. Gal in [27-29], while implica ions o he RE in building eno a ions
ha e been widely analysed in s udies such as [30-32]. In some cases, he ebound e ec is ecognised as
a co-bene i which in ol es social ad an ages like heal hie condi ions [33]; in o he s, i in ol es an
inc ease o in e nal empe a u es wi hou occupan s demanding i [34]. Despi e he di icul ies o
quan i ying hese e ec s, Gal in and Sunikka asse ed ha i gene ally lies wi hin he ange o 10-35%
[26].
Up o now, no wo k has been ound in he li e a u e dealing wi h he combined analysis o hea ing
sys em and en elope e o i ing; hea ing sys em ope a ion and use beha iou . Thus, he objec i e o
his pape is o e alua e, unde a holis ic app oach, he easibili y o indi idual na u al gas i ed boile -
based hea ing sys ems in he e o i ing o buildings/dwellings cons uc ed in he 50-60s in Bilbao
(no he n Spain). This ype o building s ock has a g ea ene gy pe o mance imp o emen po en ial, as
i has been al eady shown in o he s udies [35, 36]. I should be no iced ha se e al o hese buildings in
no he n Spain, especially social housing, ha e no hea ing sys em and he dwellings a e usually hea ed
up by indi idual elec ical adia o s. Conside ing he absence o a cen al hea ing in as uc u e and he
wide a ailabili y o na u al gas ne wo ks in he a ea, indi idual gas boile s appea as he mos easible
op ion o hea ing ins alla ion upg ade.
J. Te és-Zubiaga, A. Campos-Celado , I. González-Pino, G. Dia ce. The ole o he design and ope a ion o indi idual hea ing
sys ems o he ene gy e o i s o esiden ial buildings. Ene gy Con e sion and Managemen 2016, 136, 736–747
5
The e alua ion is ca ied ou o e a e e ence dwelling selec ed as a case s udy. This dwelling was
p esen ed in a p e ious pape whe e he au ho s analyzed he building en elope ESMs as a i s s ep o
ene gy eno a ion o buildings a he men ioned loca ion [36]. Fo ha pu pose, he dwelling was
modelled in TRNSYS and expe imen ally alida ed [37]. The wo k is he ein ex ended, including he
upg ade o hea ing sys ems and hei ope a ion as a second s ep o ene gy eno a ion. Di e en op ions
will be s udied in combina ion wi h h ee en elope op ions al eady analysed in [36]. An in eg al
dynamic simula ion using a alida ed TRNSYS model will be used o he pu pose. Wi h his aim in
mind, he expe imen ally alida ed TRNSYS model used in [36] will be adap ed and b oadened in o de
o include a de ailed hea ing ins alla ion along wi h he building. The ene gy and economic esul s will
be e alua ed, conside ing he in e ela ionship amongs he na u al gas boile echnology (low
empe a u e and condensing); i s ope a ion (ho wa e p oduc ion empe a u e) and he use beha iou
(indoo ai se -poin empe a u e). Rega ding he la e , he in luence o he ebound e ec will be also
add essed.
The a icle p o ides wo main signi ican con ibu ions o he li e a u e published so a . Fi s , he
exis ing lack o s udies de o ed o hea ing sys em upg ades in social housing buildings unde mild
clima es is aimed o be add essed. The s udy is ocused on e o i ing, which can be conside ed he
ac ual challenge o be aced in he ollowing yea s. Mo eo e , he simula ions a e pe o med unde
ealis ic condi ions by means o an exis ing dwelling and using o a alida ed dynamic model. Second,
he s udy will be ca ied ou using a holis ic app oach, whe e he use beha iou and he (p) ebound
e ec will be e alua ed along wi h ene gy and economic aspec s. The a icle will demons a e ha hese
e ec s, a ely conside ed in he ela ed li e a u e, a e an essen ial ea u e o be aken in o accoun in
u he s udies ocused on buildings ene gy pe o mance.
The emainde o his pape is o ganized as ollows: In Sec ion 2 he me hodology and main
assump ions adop ed and he TRNSYS ene gy modelling a e desc ibed. In Sec ion 3, he case s udy is
de ailed and he scena ios conside ed a e de ined. The e alua ion c i e ia a e desc ibed in Sec ion 4.
Sec ion5 p esen s he esul s, while hei discussion appea s in Sec ion 6. Finally, he main conclusions
a e add essed in Sec ion 7.
2 Modelling app oach
The ene gy eno a ion in a building o dwelling gene ally consis s o he ene gy demand educ ion by
imp o ing he he mal pe o mance o he en elope and, subsequen ly, he p oduc ion o such demand
J. Te és-Zubiaga, A. Campos-Celado , I. González-Pino, G. Dia ce. The ole o he design and ope a ion o indi idual hea ing
sys ems o he ene gy e o i s o esiden ial buildings. Ene gy Con e sion and Managemen 2016, 136, 736–747
6
by mo e e icien ene gy supply sys ems. While he en elope e o i ing was co e ed in [36], in his
pape he hea p oduc ion sys ems upg ade is aced. E e y hea ing sys em consis s no mally o he
ollowing elemen s: (1) hea p oduc ion uni ; (2) e minal uni s and (3) con ol sys em. The in eg a ion
o hese h ee elemen s makes up he hea ing ins alla ion. The cha ac e is ics o each o he elemen s o
he sys em in ol ed a e de ailed nex .
2.1 Hea p oduc ion uni
Conside ing ha he building s ock in no he n Spain is mos ly comp ised by indi idual elec ical
hea ing sys ems [35], only indi idual sys ems a e aken in o conside a ion in his pape . Amongs he
di e en indi idual hea ing sys ems a ailable, na u al gas boile s a e selec ed, owing o he wide na u al
gas ne wo k exis ing in he egion.
Na u al gas boile s can be nowadays di ided in o wo ca ego ies: high e iciency boile s (LTB) o
condensing boile s (CB). Bo h echnologies ha e a common ope a ion basis, being he di e ence ha
condensing boile s eco e pa o he la en hea con en o he exhaus by condensing hei apou
wa e con en h ough hea exchange wi h he wa e e u ning om he load side. Acco dingly, he lowe
he empe a u e o he e u ning wa e , he highe he condensing le el and he e iciency [38]. Besides,
in boile s wi h modula ing bu ne s, he lowe he pa load ope a ion, he highe he e iciency, since he
lowe low a e o umes implies a be e hea eco e y a e. This end is main ained un il a limi PLR
(Pa Load Ra ion) is eached (namely 10-15%). Below ha poin , he e iciency suddenly d ops and
hus, his condi ion is usually p e en ed by he boile bu ne con ol. The dependency be ween he
he mal e iciency and he e u n empe a u e and PLR can be ound in Fig. 1.
Fig. 1. The mal e iciency ela ionship o high e iciency boile s (LTB) and condensing boile s (CB); adap ed
om [39]
J. Te és-Zubiaga, A. Campos-Celado , I. González-Pino, G. Dia ce. The ole o he design and ope a ion o indi idual hea ing
sys ems o he ene gy e o i s o esiden ial buildings. Ene gy Con e sion and Managemen 2016, 136, 736–747
7
As i can be seen, condensing boile s pe o m be e han non-condensing ones, especially when he
e u n empe a u e is lowe ed below he condensing empe a u e (a ound 50ºC-55ºC o na u al gas)
and when pa load ope a ion is boos ed. This is closely ela ed o he selec ion o he e minal uni and
he con ol o he whole ins alla ion, which a e subsequen ly discussed.
2.2 Te minal uni
Radia o ne wo ks a e chosen as e minal uni s, because hey a e he mos common op ion in na u al
gas boile ins alla ions. These uni s we e o iginally sized o a high empe a u e ope a ion; howe e ,
hei design has been upda ed o ope a ion a lowe empe a u e le els wi h inle empe a u es a ound
55-60ºC, being he e u n empe a u e a unc ion o he he mal load and he adia o he mal
e iciency. Thei e ec i e he mal powe can be ela ed o he design pe o mance by Eq. 1 [40], whe e n
is a coe icien conside ed equal o 1.3 o na u al con ec ion.
Eq. 1
The pe o mance alues a e gi en by he manu ac u e s ollowing he EN442 o a 50K empe a u e
di e ence be ween he wa e a e age empe a u e and he oom empe a u e (being commonly 70ºC
and 20ºC, espec i ely) [40]. Acco dingly, an a e age empe a u e o he adia o o 50ºC would gi e a
30K empe a u e di e ence, which esul s in a 50% educ ion o he nominal powe o he uni s. This
makes necessa y o inc ease he adia o leng h in o de o lowe he ope a ion empe a u e when
condensing boile s a e used. The e o e, a ela ion be ween he adia o leng h inc ease and he
ope a ion empe a u es is equi ed. This is p esen ed in Fig. 2, being he low a e assumed cons an .
Fig. 2. Rela ionship be ween adia o a e age empe a u e and adia o leng h inc emen
J. Te és-Zubiaga, A. Campos-Celado , I. González-Pino, G. Dia ce. The ole o he design and ope a ion o indi idual hea ing
sys ems o he ene gy e o i s o esiden ial buildings. Ene gy Con e sion and Managemen 2016, 136, 736–747
8
The shadowed a ea o he plo ema ks he ope a ion poin s whe e condensing occu s (when he e u n
empe a u e (Tou le ) is below 55ºC acco ding o Fig. 1). As i can be seen, i equi es longe adia o
(Δl ad) uni s, which inc ease exponen ially as he ope a ion empe a u e d ops. This means a bigge
in es men o he hea ing sys ems eno a ion which will a ec he economic easibili y.
Ano he al e na i e o eaching low e u n empe a u es is o employ he adian loo echnology as
e minal uni . This sys em wo ks a a lowe empe a u e, being he inle wa e empe a u e a ound
40ºC. This ac ensu es he condensing e ec , bu i also p esen s a highe ini ial in es men and
echnical complexi y. Fo ha eason, his op ion is no e y common on e o i ing wo ks o social
household in Spain, and hus, i has been conside ed ou o he scope o his s udy.
2.3 Con ol sys em
Hea ing sys ems can be con olled ac ing o e one o he ollowing a iables: (1) On/O con ol o he
hea ing sys em; (2) con ol o e he wa e deli e y empe a u e; and (3) con ol o e he wa e mass
low a e.
The On/O con ol is usually made by a he mos a , which is usually placed in he li ing oom. The use
speci ies he empe a u e below which he hea ing sys em is ac i a ed. The con ol p esen s ce ain
hys e esis in o de o a oid oo as On/O sequences. This hys e esis cycle is a ound 1ºC downwa d.
The con ol o e he wa e deli e y empe a u e is egula ed by he boile . Mode n boile s allow pa
load ope a ion wi h he aim o mee ing a gi en se -poin empe a u e. This empe a u e can be modi ied
by he use sepa a ely o space hea ing and DHW. The e o e, om a p ac ical poin o iew, he ho
wa e supply empe a u e can be conside ed as cons an in indi idual boile sys ems and hen, he
bu ne is egula ed in o de o mee i .
Rega ding he con ol o e he wa e mass low a e, his possibili y p esen s wo op ions: ac ing di ec ly
o e he low a e by he use o a iable speed pumps, o ac ing o e he p essu e d op o he hea ing
loop by he use o al es. Howe e , none o hese op ions a e included in his pape since indi idual
boile s in eg a e hei own single speed pump and he p essu e d op-based con ol could imply noise
and highe pump head, and he e o e, highe pumping cos s.
Addi ionally, he low a e o he wa e ha lows h ough each e minal uni can be con olled by a h ee
way al e, bypassing pa o he low. This can ac o e he hea deli e ed by he e minal uni s, bu is
J. Te és-Zubiaga, A. Campos-Celado , I. González-Pino, G. Dia ce. The ole o he design and ope a ion o indi idual hea ing
sys ems o he ene gy e o i s o esiden ial buildings. Ene gy Con e sion and Managemen 2016, 136, 736–747
9
no use ul o educing he empe a u e o he e u n wa e , since he bypassed low is mixed wi h he
wa e exi ing om he e minal uni s.
2.4 TRNSYS ene gy modelling
The dwelling, along wi h he hea ing sys em, is simula ed wi h TRNSYS simula ion so wa e. The main
ea u es o he dwelling will be p esen ed in Sec ion 3. The model and i s expe imen al alida ion we e
al eady de ailed in [36]. In he cu en wo k, he hea ing sys em model is in eg a ed in o i . The analysis
pe o med e alua es he pe o mance o di e en sys ems made up om he combina ion o : high
e iciency and condensing na u al gas boile s as hea p oduc ion uni s; adia o s as e minal uni s; and
di e en wa e supply empe a u es and indoo ai se -poin empe a u es.
The na u al gas i ed boile is simula ed using he Type 700 simple boile model de eloped by TESS
[41]. A he mal powe o 24 kW is conside ed as ypical o his kind o boile s. The he mal e iciency
o bo h high e iciency and condensing boile s a e ob ained om Cock o e al. [39]. The On/O
ope a ion o he boile is con olled by Type 2b ha swi ches i o when he ai empe a u e o he
e e ence oom (li ing oom) is eached. A hys e esis o ±0.5ºC is included in o de o gua an ee a
smoo he ope a ion. The pump is in eg a ed in he boile and modelled wi hin i , being con olled by he
oom he mos a . In he simula ions, only he he mal p oduc ion o space hea ing is conside ed,
neglec ing he ope a ion o he DHW. The ene gy consump ion o DHW p oduc ion is added a
pos e io i o he economic e alua ion, as de ailed in Sec ion 4. This assump ion does no ha e
signi ican in luence on he esul s, since he model does no ake in o accoun he he mal mass o he
boile .
Radia o s a e modelled by a sel - ailo ed ype, implemen ed as Type 211. The model consis s o a
lumped capaci y model which is based on a i s -o de di e en ial equa ion ha accoun s o he
he mal ine ia o he adia o . The hea deli e ed a any ins an by he adia o a di e en ope a ion
condi ions is ob ained by applying Eq. (1). The hea eleased by each adia o is in oduced as hea gains
o each zone, a ypical con ec i e/ adia i e a io o 80/20 can be conside ed.
Piping om he boile o he e minal uni s ac s as hea emi e s ( he mal losses a e eleased o he
ambien ) and adds he mal ine ia o he hea ing ins alla ion. They a e modelled by Type 31, a single-
node pipe model. Radia o ne wo ks in dwellings a e be e a anged by double pipe con igu a ion; hus,
wa e en e s adia o s a he same empe a u e and he mal unbalance is a oided. A wa e low a e o
10 l/min is conside ed and dis ibu ed o he di e en ooms acco ding o he nominal powe o he
J. Te és-Zubiaga, A. Campos-Celado , I. González-Pino, G. Dia ce. The ole o he design and ope a ion o indi idual hea ing
sys ems o he ene gy e o i s o esiden ial buildings. Ene gy Con e sion and Managemen 2016, 136, 736–747
16
Amongs he di e en o ms o ebound e ec exis ing in he li e a u e [50], only di ec e ec s a e
conside ed in his pape . They a e calcula ed by Eq. 4 [26].
𝑃𝑃=𝐿𝐿−𝐸𝐸
𝐿𝐿
Eq. 4
The e, C is he heo e ical hea ing ene gy consump ion (calcula ed), which is ob ained conside ing ha
he indoo empe a u e se -poin a e e o i ing is he same o ha i was be o e. E is he ac ual ene gy
consump ion, and is de e mined assuming a gi en inc emen o he indoo empe a u e se -poin a e
ene gy e iciency upg ades. Two inc emen alues a e conside ed: 1 and 2 ºC. In bo h cases, he assumed
indoo empe a u e se -poin be o e he ene gy e iciency upg ades is 19ºC [35]; hus, he se -poin
empe a u e a e he ene gy e iciency upg ades is conside ed o be 20ºC and 21ºC.
5 Resul s
The gene al esul s o he 54 scena ios a e he ein p esen ed and discussed. P io o he e alua ion, he
com o condi ions we e analyzed o all he cases in o de o check he ac ual beha iou o each
ins alla ion in ela ion o he heo e ical design. The ac ual ai empe a u e was quali a i ely compa ed
o he se -poin , showing good ag eemen . A simple analysis o he com o was made by conside ing he
numbe o hou s in which indoo empe a u e is below 18 ºC. Simila condi ions we e ob ained o all
he scena ios, whe e he numbe o hou s below 18ºC anged be ween 0 and a maximum alue o 37
hou s, depending on he indoo empe a u e se -poin . Thus, i can be s a ed ha all he selec ed designs
we e adequa e.
5.1 Ene gy esul s
Hea ing consump ion o each scena io is depic ed in Fig. 6. Da a a e dis ibu ed by he di e en
en elope e o i ing op ions, ene gy supply sys ems and ho wa e p oduc ion empe a u es.
Addi ionally he e ec o he indoo ai empe a u e se -poin can be seen o each case.
J. Te és-Zubiaga, A. Campos-Celado , I. González-Pino, G. Dia ce. The ole o he design and ope a ion o indi idual hea ing
sys ems o he ene gy e o i s o esiden ial buildings. Ene gy Con e sion and Managemen 2016, 136, 736–747
17
Fig. 6. Final ene gy consump ion ( o hea ing) pe yea
As expec ed, he en elope e o i ing op ion has a signi ican e ec on he ene gy consump ion o he
dwelling. BAU scena io shows, in compa ison o NR, a e age ene gy sa ings be ween 15% (6.5 - 7.5
kWh/m2; 21ºC se -poin ) o 27% (3.5 - 4 kWh/m2; 19ºC se -poin ). When NR and BO scena ios a e
compa ed, a e age sa ings om 45% (19 - 20 kWh/m2; 21ºC se -poin ) o 80% (11 - 13 kWh/m2; 19ºC
se -poin ) a e achie ed. The inal ene gy consump ion alues could be pa ially deduced om he
demand esul s in [36], bu he e he e ec o he seasonal hea ing sys em pe o mance is also
conside ed (which anges o supplying he hea ing demand be ween 0.71 in he case o LTB and a se -
poin empe a u e o 21 ºC o 0.87 in he case o CB and a se -poin empe a u e o 19 ºC) in he
e alua ion.
The g ea es impac on he ene gy consump ion is closely ela ed o he occupan s’ beha iou , i.e. he
indoo empe a u e se -poin . A non-linea ela ion be ween he empe a u e se -poin and he ene gy
consump ion educ ion can be clea ly obse ed. Thus, a signi ican ly highe educ ion in he
consump ion is app ecia ed when changing om a empe a u e se -poin o 21ºC o 20ºC. This
educ ion is also signi ican when changing om 20 o 19ºC. This in luence is quan i a i ely p esen ed
in Table 6. I can be obse ed ha , whe eas ene gy sa ings in absolu e alues dec ease when he
en elope e iciency is highe , he impac in e ms o ela i e alues becomes he bigges in he BO
scena io. This demons a es ha he use in e ac ion plays a ole mo e impo an han o he design
aspec s, and acco dingly i mus be aken in o accoun in his kind o analysis. This end is main ained
0
10
20
30
40
50
60
NR.LTB.60
NR.LTB.55
NR.LTB.50
NR.CB.60
NR.CB.55
NR.CB.50
BAU.LTB.60
BAU.LTB.55
BAU.LTB.50
BAU.CB.60
BAU.CB.55
BAU.CB.50
BO.LTB.60
BO.LTB.55
BO.LTB.50
BO.CB.60
BO.CB.55
BO.CB.50
kWh/m2yea
Se Poin : 21ºC Se Poin : 20ºC Se Poin : 19ºC
NR BO
BAU
LTB CB LTB CB LTB CB
J. Te és-Zubiaga, A. Campos-Celado , I. González-Pino, G. Dia ce. The ole o he design and ope a ion o indi idual hea ing
sys ems o he ene gy e o i s o esiden ial buildings. Ene gy Con e sion and Managemen 2016, 136, 736–747
18
o all he cases e alua ed; hus, o he sake o cla i y, a se -poin o 20ºC is conside ed as he basis o
he analysis o he es o he pape .
NR
BAU
BO
21 ºC 20 ºC
17.86 (40.5%)
16.95 (45.5%)
14.93 (61.4%)
21 ºC 19 ºC
29.21 (66.3%)
26.45 (70.9%)
21.6 (88.7%)
Table 6. Summa y o ene gy sa ings in kWh/m2.yea ela ed o se -poin empe a u e (in b acke s, pe cen age o he
sa ing in ela ion o ene gy consump ion wi h a 21 ºC se -poin )
Rega ding ho wa e p oduc ion empe a u e, a lowe p oduc ion empe a u e means a lowe e u n
empe a u e and, he e o e, a highe e iciency. The ene gy consump ion educ ion is o 4-5% ( om
60ºC o 55ºC) and o 9% ( om 60ºC o 50ºC) o he NR and BAU scena ios. Ene gy sa ings a e highe
in he BO scena ios, 8% ( om 60ºC o 55ºC) and 12% ( om 60ºC o 50ºC). This is explained by he ac
ha he BAU case p esen s sligh ly lowe demand and, he e o e, o a gi en boile nominal powe , he
pa load a ion is lowe , meaning a highe e iciency (Fig. 1). The same end is ge ega dless o he
boile ype. In he case o he hea ing sys em supply, di e ences be ween LTB and CB pe o mance a e
ha dly ound, which is owed o wo main easons: bo h op ions p esen he same mean e u n
empe a u e o 37.6 (60ºC), 33.1 (55ºC) and 28.9ºC (50ºC), and he ene gy e iciency pe cen age
a ia ion be ween hese e u n empe a u es is p ac ically he same o bo h boile s, a ound 8-9% (Fig.
1).
The esul s o he p ima y ene gy consump ion, which a e ob ained adding he DHW consump ion o
he hea ing consump ion, a e p esen ed in Fig. 7. The alues a e ga he ed in wo g oups o he sake o
cla i y: hose ela ed o LTB and hose ela ed o CB. The esul s shown ein o ce he a o emen ioned
in luence o he se -poin empe a u e and, o a lesse ex en , he e ec o educing he ho wa e
p oduc ion empe a u e.
J. Te és-Zubiaga, A. Campos-Celado , I. González-Pino, G. Dia ce. The ole o he design and ope a ion o indi idual hea ing
sys ems o he ene gy e o i s o esiden ial buildings. Ene gy Con e sion and Managemen 2016, 136, 736–747
19
Fig. 7. Ope a ing P ima y Ene gy consump ion pe yea (indoo ai empe a u e se -poin : 20 ºC)
5.2 Economic esul s
Resul s co esponding o he e alua ion App oach (A) a e summa ized in Fig. 8. In he g aph, annual
cos s a e p esen ed, conside ing hem as he sum o he in es men amo iza ion and he yea ly a e age
ope a ing cos o he sys em.
Each en elope eno a ion op ion (BAU and BO) p esen s he in es men (in da k g ay), p o a ed
acco ding o he sys em li espan assumed. Addi ional cos s a e ela ed o he hea ing sys em upg ade:
annual in es men and uel cos s. The o e in es men needed o he condensing boile in ela ion o
he low- empe a u e one can be obse ed, as well as ha equi ed o lowe ho wa e p oduc ion
empe a u e, i.e. la ge adia o s acco ding o he sizing me hod (Table 3). Thus, unde App oach (A),
he join eno a ion ac ion consis ing o BAU en elope and condensing boile b ings he bes economic
esul s. Amongs he di e en ho -wa e p oduc ion se -poin s, no signi ican di e ences a e obse ed,
bu he economics a e be e when he boile ope a es a 60ºC. This means ha he addi ional
in es men o ope a ing a a lowe empe a u e does no compensa e he economic sa ings o a uel
usage educ ion.
0
10
20
30
40
50
60
70
80
60 ºC 55 ºC 50 ºC 60 ºC 55 ºC 50 ºC
P ima y Ene gy
[kWh/m2.yea ]
Boile se poin empe a u e
NR BAU BO
LOW TEMPERATURE BOILER CONDENSING BOILER
J. Te és-Zubiaga, A. Campos-Celado , I. González-Pino, G. Dia ce. The ole o he design and ope a ion o indi idual hea ing
sys ems o he ene gy e o i s o esiden ial buildings. Ene gy Con e sion and Managemen 2016, 136, 736–747
20
Fig. 8. Economic esul s. App oach A. Annual cos o each scena io (amo iza ion o in es men + ope a ing
cos ) conside ing as e e ence case he NR scena io wi h elec ic sys em.
Resul s co esponding o App oach (B) a e depic ed in Fig. 9. The di e ence wi h espec o App oach
(A) is ha , o each case, he en elope e o i ing is assumed o be made by he use p io o he hea ing
sys em upg ade. Thus, he NR scena io is he same ha he one p esen ed be o e in Fig. 8. Fo he BAU
and BO scena ios, bo h annual cos s and sa ings in ela ion o he e e ence case a e lowe .
Fig. 9. Economic esul s. App oach B. Annual cos o each scena io (amo iza ion o in es men + ope a ing
cos ) conside ing as e e ence cases he NR, BAU and BO scena ios wi h elec ical sys ems
The simple payback esul s unde bo h app oaches A and B a e p esen ed in Fig. 10. Payback pe iods in
NR and BAU scena ios a e simila ega dless he eno a ion app oach, anging be ween 8 and 11 yea s.
0
100
200
300
400
500
600
700
NR.LTB.60
NR.LTB.55
NR.LTB.50
NR.CB.60
NR.CB.55
NR.CB.50
BAU.LTB.60
BAU.LTB.55
BAU.LTB.50
BAU.CB.60
BAU.CB.55
BAU.CB.50
BO.LTB.60
BO.LTB.55
BO.LTB.50
BO.CB.60
BO.CB.55
BO.CB.50
Cos [€/yea ]
Ope a ing Cos [20ºC] In es men cos (ene gy sys em)
In es men Cos (en elope) Re Cos [20 ºC]
NR BAU BO
0
100
200
300
400
500
600
700
NR.LTB.60
NR.LTB.55
NR.LTB.50
NR.CB.60
NR.CB.55
NR.CB.50
BAU.LTB.60
BAU.LTB.55
BAU.LTB.50
BAU.CB.60
BAU.CB.55
BAU.CB.50
BO.LTB.60
BO.LTB.55
BO.LTB.50
BO.CB.60
BO.CB.55
BO.CB.50
Cos [€/yea ]
Ope a ing Cos [20ºC] In es men cos (ene gy sys em) Re Cos [20 ºC]
NR BAU BO
J. Te és-Zubiaga, A. Campos-Celado , I. González-Pino, G. Dia ce. The ole o he design and ope a ion o indi idual hea ing
sys ems o he ene gy e o i s o esiden ial buildings. Ene gy Con e sion and Managemen 2016, 136, 736–747
21
In BO scena ios, he eno a ion app oach is o g ea impo ance, especially due o he ela i ely highe
in es men ha i equi es (i.e. windows eplacemen ). Thus, payback anges om 19 o 20 yea s o
app oach A and om 10 o 12 yea s o app oach B.
Fig. 10. Simple payback o each scena io o App oach A and B (indoo ai se -poin empe a u e: 20ºC)
5.3 Use beha iou
The occupan beha iou was pa ially e alua ed in Sec ion 5.1 by means o he analysis o di e en se -
poin empe a u es (Fig. 6); howe e , he same se -poin was assumed be o e and a e eno a ion. Fo
a deepe discussion, he e alua ion o he (p) ebound e ec is ca ied ou . The esul s ob ained a e
p esen ed in Table 7, whe e he pe cen ages shown a e he a io be ween heo e ical and ac ual sa ings.
Se -poin empe a u e
p io o upg ades
Se -poin empe a u e
a e upg ades NR BAU BO
19 ºC
20 ºC
29.9%
31.5%
34.8%
19 ºC
21 ºC
60.5%
59.7%
59.5%
Table 7. Rebound e ec in each scena io, conside ing a empe a u e inc emen o 1 and 2 ºC
As obse ed, an inc emen o 1ºC ( om 19 o 20ºC) in ol es ebound e ec alues a ound 30-35%.
These esul s ag ee wi h p e ious publica ions [26]. An inc emen o 2 ºC om 19 ºC o 21 ºC in ol es a
ebound e ec a ound 60%. No e ha his s udy deals wi h social housings, whe e elec ic hea e s a e
usually employed. These sys ems a e expensi e o ope a e o low-income households, and hey c ea e
empe a u e g adien s o he indoo ai ha make he ac ual oom empe a u e signi ican ly lowe han
he se -poin o he sys em. Acco dingly, inc emen s o 2ºC a e conside ed easible.
0
2
4
6
8
10
12
14
16
18
20
NR.LTB.60
NR.CB.60
NR.LTB.55
NR.CB.55
NR.LTB.50
NR.CB.50
BAU.LTB.60
BAU.CB.60
BAU.LTB.55
BAU.CB.55
BAU.LTB.50
BAU.CB.50
BO.LTB.60
BO.CB.60
BO.LTB.55
BO.CB.55
BO.LTB.50
BO.CB.50
Payback pe iod [yea s]
App oach A App oach B
NR BAU BO
J. Te és-Zubiaga, A. Campos-Celado , I. González-Pino, G. Dia ce. The ole o he design and ope a ion o indi idual hea ing
sys ems o he ene gy e o i s o esiden ial buildings. Ene gy Con e sion and Managemen 2016, 136, 736–747
22
The yea ly sa ings on p ima y ene gy consump ion and payback pe iod alues conside ing he
a e ma h o he ebound e ec a e depic ed in Fig. 11 and Fig. 12. The da k g ey hombus ep esen he
heo e ical alues wi h no ebound e ec (se -poin empe a u e o 19 ºC), while he whi e ec angle
ep esen s he ange o depic ed alues when he inc ease o se -poin empe a u e anges om 1 o 2ºC.
Fig. 11. Range o p ima y ene gy sa ings alues conside ing he ebound e ec
I can be app ecia ed ha anges a e wide in hose case whe e a less in ensi e ene gy e iciency upg ade
is ca ied ou , and e en he a o emen ioned back i e e ec is eached in he NR.LTB.60, whe e nega i e
ene gy sa ings (highe ene gy consump ion) a e ound when se -poin empe a u e inc eases close o
2ºC.
Analogously, payback pe iod alues can be analyzed using a simila me hodology. In his case, as a way
o example, payback pe iod alues unde app oach (A) a e p esen ed conside ing he consequences o
he (p) ebound e ec . Men ioned alues ange be ween 10,5 and 12,5 yea s in NR and BAU scena ios
when no ebound e ec is conside ed (da k g ey hombus), inc easing he payback pe iod up o 17-18
yea s unde some cases when he ebound e ec is conside ed. Simila consequences a e ound in BO
scena io; whils payback pe iod alues a e in all cases close o 24 yea s when no ebound e ec is
conside ed, alues highe han 30 yea s a e ge in some cases, alues ha a e highe ha he conside ed
li espan o he sys em, hus comp omising he easibili y o he eno a ion.
-10
0
10
20
30
40
50
60
70
NR.LTB.60
NR.LTB.55
NR.LTB.50
NR.CB.60
NR.CB.55
NR.CB.50
BAU.LTB.60
BAU.LTB.55
BAU.LTB.50
BAU.CB.60
BAU.CB.55
BAU.CB.50
BO.LTB.60
BO.LTB.55
BO.LTB.50
BO.CB.60
BO.CB.55
BO.CB.50
kWh/m2yea
NR BAU BO
J. Te és-Zubiaga, A. Campos-Celado , I. González-Pino, G. Dia ce. The ole o he design and ope a ion o indi idual hea ing
sys ems o he ene gy e o i s o esiden ial buildings. Ene gy Con e sion and Managemen 2016, 136, 736–747
23
Fig. 12. Range o he payback pe iod alues conside ing he ebound e ec (App oach A)
6 Discussion
The ob ained esul s ha e signi ican ele ance on he planning o ene gy e o i ing o buildings. Fi s ,
i is obse ed ha , om he analysed issues, educing he empe a u e se -poin has he g ea es e ec
on he ene gy consump ion educ ion wi h no addi ional expense, showing a sa ing po en ial o up o
80%. This makes i he measu e ha mo e e ec i ely add esses he ene gy consump ion educ ion
sough bu cu en ene gy policies. Add essing his issue equi es checking he concep o how he
equi ed com o le els a e eached and o emphasize he ole o clo hing in buildings. This need is
especially ema kable in mild clima es as i is he case unde e alua ion.
The use o mo e e icien hea ing sys ems, such as condensing boile s, in ol es sa ings o e
con en ional low- empe a u e ones, bu hese sa ings a e in he o de o 1-2 kWh/m2. Simila sa ings
a e go om educing he ho wa e p oduc ion empe a u e, since i allows a highe e iciency, bu his
could lead o p oblems in mee ing he com o equi emen s. To a oid ha , in his pape he sizing o
he adia o s was pe o med acco ding o ha ope a ing empe a u e. Howe e , he sizing o adia o s is
usually made ega dless o hese issues, and p oblems could a ise when ying o mee he se -poin
empe a u es when educing he ho wa e p oduc ion empe a u e. Finally, he ene gy consump ion
educ ion is simila in pe cen age e ms o all he en elope e o i ing scena ios, which makes i mo e
desi able in e ms o ene gy in ensi y educ ion when he en elope is less e icien .
0
5
10
15
20
25
30
35
NR.LTB.60
NR.LTB.55
NR.LTB.50
NR.CB.60
NR.CB.55
NR.CB.50
BAU.LTB.60
BAU.LTB.55
BAU.LTB.50
BAU.CB.60
BAU.CB.55
BAU.CB.50
BO.LTB.60
BO.LTB.55
BO.LTB.50
BO.CB.60
BO.CB.55
BO.CB.50
Yea s
NR BAU BO
J. Te és-Zubiaga, A. Campos-Celado , I. González-Pino, G. Dia ce. The ole o he design and ope a ion o indi idual hea ing
sys ems o he ene gy e o i s o esiden ial buildings. Ene gy Con e sion and Managemen 2016, 136, 736–747
24
Wi h he excep ion o he empe a u e se -poin , he di e en aspec s e alua ed be o e imply di e en
le els o in es men . Fo example, a condensing boile implies an o e in es men in ela ion o a low-
empe a u e one, while a lowe ho wa e p oduc ion wa e implies a highe adia o su ace and
he e o e, in es men . F om he economic analysis, he BAU en elope wi h condensing boile op ion
and ho wa e p oduc ion a 60ºC o e s he lowes annual cos s. The addi ional in es men needed o
bigge adia o s when educing he ho wa e empe a u e does no compensa e he uel consump ion
educ ion in any case. BO en elope op ion needs o signi ican ly highe in es men ha educes he
economic easibili y. This is mainly due o he windows eplacemen , which makes he in es men
o de s o magni udes highe han he insula ion addi ion. Howe e , windows eplacemen o e s o he
bene i s ha canno be analysed om a pu ely economic poin o iew: com o , acous ics, e c. These
esul s a e di e en i he in es men o he en elope e o i ing is al eady done when he hea ing
sys em upg ade is aced (app oach B). In his case, a be e en elope educes he annual cos s, bu also
he educ ion acco ding o he e e ence case. In gene al, esul s ha e add essed he in e es o
in eg a ed ene gy eno a ions, wi h packages ha include ene gy sa ings measu es wi h sho payback
pe iods and o he measu es wi h highe payback pe iods.
No mally he same ope a ing and com o condi ions a e conside ed be o e and a e he eno a ion.
Howe e , he so-called ebound e ec usually occu s, meaning ha ene gy e iciency measu es lead o
changes in he use ha could imply a highe speci ic use o ene gy. F om he esul s, i is obse ed ha
ebound e ec can play a e y impo an ole, especially conside ing he low pe o mance o he
e e ence hea ing sys em, unde which he com o condi ions we e ha d and expensi e o mee . Thus,
unde a po en ial inc ease o he se -poin empe a u e o 2ºC, some scena ios could lead o no ene gy
sa ings and some e o i ing op ions could be di ec ly economically un easible.
7 Conclusions
A holis ic me hodology based on TRNSYS simula ion has been p esen ed o he e alua ion o indi idual
hea ing sys ems in he ene gy e o i ing o domes ic buildings. I has been subsequen ly applied o a
social housing building loca ed in no he n Spain, o which an al eady alida ed model is a ailable.
Di e en e o i ing scena ios and op ions ha e been analysed. F om all o hem, he empe a u e se -
poin has esul ed in he mos e ec i e o educe he ene gy consump ion which unde lines he ole
played by he building use . The na u e and ope a ion o hea ing sys ems plays a signi ican ole.
Condensing boile o e highe sa ings han con en ional boile s bu he bene i s om he educ ion o
J. Te és-Zubiaga, A. Campos-Celado , I. González-Pino, G. Dia ce. The ole o he design and ope a ion o indi idual hea ing
sys ems o he ene gy e o i s o esiden ial buildings. Ene gy Con e sion and Managemen 2016, 136, 736–747
25
he ope a ing empe a u e do no compensa e he need o he highe in es men o la ge adia o s.
The e en ual e ec s o he (p) ebound e ec ha e been demons a ed e y signi ican and i should be
analysed whe he his inc ease is a bene i o a ea u e no -demanded by he occupan s
The ac ha he use in e ac ion plays he mos impo an ole o ge ing signi ican ene gy sa ings
ein o ces he need o explo ing new ways o achie e he mal com o . This can be ega ded as a key
ac o o educe ene gy consump ion in buildings and should be conside ed in u he wo ks.
8 Acknowledgemen s
The au ho G. Dia ce wan s o hank he inancial suppo o he Basque Go e nmen , h ough he
Depa men o Educa ion, Uni e si ies and Resea ch's Pe sonnel Resea ch T aining P og am (2012
call).
9 Re e ences
[1] Eu os a , S a is ics Da abase - Ene gy s a is ics - Supply, ans o ma ion, consump ion (2010).
[2] Uni ed Na ions. Sus ainable Buildings & Clima e Ini ia i e, Common Ca bon Me ic. P o ocol o
Measu ing Ene gy Use and Repo ing G eenhouse Gas Emissions om Building Ope a ions (2010).
[3] Eu opean Commission, Di ec i e 2010/31/EU on he Ene gy Pe o mance o Buildings (2010).
[4] C. Baek, S. Pa k, Changes in eno a ion policies in he e a o sus ainabili y, Ene gy Build. 47 (2012)
485-496.
[5] Spanish Minis y o Public Wo ks, Dwelling S ock Es ima ion (2013).
[6] Eu opean Commission, Communica ion om he commission. Eu ope 2020. A s a egy o sma ,
sus ainable and inclusi e g ow h (2010) 1-35.
[7] D. Che, Y. Liu, C. Gao, E alua ion o e o i ing a con en ional na u al gas i ed boile in o a
condensing boile , Ene gy Con e s Manage. 45 (2004) 3251-3266.
[8] S. Deng, A. Daliba d, M. Ma in, Y.J. Dai, U. Eicke , R.Z. Wang, Ene gy supply concep s o ze o
ene gy esiden ial buildings in humid and d y clima e, Ene gy Con e s Manage. 52 (2011) 2455-2460.
[9] M. Ow ak, M. Aminy, M.T. Jamal-Abad, M. Dehghan, Expe imen s and simula ions on he he mal
pe o mance o a sunspace a ached o a oom including hea -s o ing po ous bed and wa e anks, Build.
En i on. 92 (2015) 142-151.
[10] S. Obyn, G. an Moeseke, Compa ison and discussion o hea ing sys ems o single- amily homes in
he amewo k o a eno a ion, Ene gy Con e s Manage. 88 (2014) 153-167.
[11] J. V ijde s, L. Delem, Economical and en i onmen al impac o low ene gy housing eno a ion,
REPORT. (2008) 1-117.
[12] L.C. Tagliabue, M. Mais ello, M. Fa o , Technical and Cos -op imal E alua ion o The mal Plan s
o Ene gy Re o i ing o a Residen ial Building, Ene gy P ocedia. 50 (2014) 597-602.
