ene gies
A icle
Es ima ion o he Hea Loss Coe icien o Two
Occupied Residen ial Buildings h ough an
A e age Me hod
I a i U ia e 1,*, Ai o E ko eka 1, Pablo Eguia 2, En ique G anada 2
and Koldo Ma in-Escude o 1
1
ENEDI Resea ch G oup, Depa men o Ene gy Enginee ing, Uni e si y o he Basque Coun y (UPV/EHU),
Plaza To es Que edo 1, 48013 Bilbao, Spain; ai o [email p o ec ed] (A.E.);
[email p o ec ed] (K.M.-E.)
2Depa men o Mechanical Enginee ing, Hea Engines and Fluid Mechanics, School o Indus ial Enginee ing,
Uni e si y o Vigo, 36310 Vigo, Spain; [email p o ec ed] (P.E.); [email p o ec ed] (E.G.)
*Co espondence: [email p o ec ed]; Tel.: +34-946-017-322
Recei ed: 14 Sep embe 2020; Accep ed: 29 Oc obe 2020; Published: 2 No embe 2020
Abs ac :
The exis ing pe o mance gap be ween he design and he eal ene gy consump ion o a
building could ha e h ee main o igins: he occupan s’ beha iou , he pe o mance o he ene gy
sys ems and he pe o mance o he building en elope. Th ough he es ima ion o he in-use Hea
Loss Coe icien (HLC), i is possible o cha ac e ise he building’s en elope ene gy pe o mance
unde occupied condi ions. In his esea ch, he es ima ion o he HLC o wo indi idual esiden ial
buildings loca ed in Gainsbo ough and Loughbo ough (UK) was ca ied ou using an a e age
me hod. This a e age me hod was de eloped and success ully es ed in p e ious esea ch o
an occupied ou -s o y o ice building wi h e y di e en cha ac e is ics o indi idual esiden ial
buildings. Fu he mo e, one o he analysed esiden ial buildings is a new, well-insula ed building,
while he o he ep esen s he old, poo ly insula ed semide ached esiden ial building ypology.
Thus, he moni o ed da a p o ided we e il e ed in o de o apply he abo emen ioned a e age
me hod. E en wi hou ul illing all he a e age me hod equi emen s o hese wo esiden ial
buildings, he me hod p o ides eliable HLC alues o bo h esiden ial buildings. Fo he house in
Gainsbo ough, he bes es ima ed HLC alue was 60.2 W/K, while he bes app oach o Loughbo ough
was 366.6 W/K. Thus, despi e he unce ain y sou ces ound du ing he analysis, he me hod seems
p omising o i s applica ion o esiden ial buildings.
Keywo ds: hea loss coe icien ; a e age me hod; building en elope’s in-use ene gy pe o mance
1. In oduc ion
The majo i y o buildings cons uc ed in he Eu opean Union in he pas we e buil wi hou
conside ing any he mal egula ions, since ene gy e iciency was no conside ed a majo issue un il
he 1970s [
1
]. I is well known ha buildings in he EU a e esponsible o a conside able pe cen age
o he ene gy consump ion and CO
2
emissions in acco dance wi h H2020 Ene gy E icien Buildings.
The e o e, he building sec o is cu en ly in a deca bonisa ion p ocess o educe he p oblem [2].
Howe e , achie ing an ene gy e icien building is no a simple ask. Se e al buildings designed o
ob ain a conside able educ ion in ene gy consump ion ha e ailed du ing his p ocess. This is because
he e is s ill an impo an di e ence be ween he eal pe o mance and he heo e ical pe o mance gi en
by he designe s [
3
]. A conside able numbe o s udies ha e shown ha he eal ene gy consump ion
can be up o wo o i e imes highe han he p edic ed ene gy consump ion [4,5].
Ene gies 2020,13, 5724; doi:10.3390/en13215724 www.mdpi.com/jou nal/ene gies
Ene gies 2020,13, 5724 2 o 17
The ene gy pe o mance di e ence, commonly known as he pe o mance gap, has nume ous
di e en causes. Some a e due o such ac o s as he cons uc ion o ope a ion [
6
]; o he s de i e
om such da a unce ain ies as he clima e condi ions a ec ing he building, o he beha iou o he
occupan s. Se e al analyses ha e been ca ied ou o s udy how a speci ic clima e and he beha iou o
he occupan s can a ec he ene gy beha iou o he building [
7
,
8
]. Mo eo e , he shape o he building
is also linked o i s ene gy e iciency [
9
]. Hemsa h and Bandhosseini [
10
] and Mon aze i e al. [
11
] ha e
done esea ch in o how he ela ion be ween he heigh and he wid h o a building can a ec he hea
ans e . Howe e , one o he main easons o his pe o mance gap is he ene gy pe o mance o he
building’s en elope [12]. Se e al wo ks o esea ch ha e ocused on he moni o isa ion o he indoo
ene gy o a building in o de o es di e en e o i solu ions unde di e en clima ic condi ions [
13
].
Las bu no leas , he high cos o moni o ing buildings o ces esea che s o de elop me hods ha can
ob ain obus esul s wi h a limi ed numbe o a iables [14].
Achie ing an accu a e es ima e o he eal ene gy consump ion is a complex ask. This is due o he
nume ous p oblems ound when es ima ing each o he di e en causes ha c ea e unce ain ies in he
ene gy consump ion calcula ion. These p oblems can di ec ly a ec he modelling and simula ions in
he es ima ion p ocess o an accu a e ene gy consump ion alue. In o de o sol e he cu en p oblems
in he building sec o , he In e na ional Ene gy Agency IEA-EBC P og amme [
15
] has been de eloped.
This p og amme in ol es ene gy esea ch and inno a ion wi h collabo a ion om se e al coun ies.
The e o e, he in o mal g oup o med by di e en o ganiza ions, named DYNASTEE [
16
], is aking
pa in he IEA-EBC Annex 71 [
17
] p ojec called “Building Ene gy Pe o mance Assessmen Based
on In-si u Measu emen s”. This Annex is he s ep ha ollows he p e iously de eloped IEA-EBC
Annex 58 i led “Reliable building ene gy pe o mance cha ac e iza ion based on ull scale dynamic
measu emen s”, whe e he cha ac e iza ion o buildings’ ene gy pe o mance based on dynamic
measu emen s was in es iga ed. The e o e, he aim o he IEA-EBC Annex 71 is o imp o e e en
u he he cha ac e iza ion me hods o he eal ene gy pe o mance o building en elopes and
o p o ide in-si u quali y assu ance me hods. The aim is o de elop s eady-s a e and dynamic
da a analysis echniques, along wi h good quali y in-si u measu emen s. The e o e, he aim o he
P og amme is o moni o in-use buildings o ob ain eliable, quali y da a and hus be able o p o ide
accu a e and eliable Key Pe o mance Indica o s (KPIs) o he building’s en elope ene gy pe o mance
using di e en me hods [17].
One o he mos impo an analyses ca ied ou wi hin he p e ious Annex 58 was he Round
Robin Box es [
18
], in which he pa icipan s es ed he he mal beha iou o he box by shipping i
o di e en coun ies. Then, he ob ained da a was analysed using ou main me hods. On he one
hand, a e aging me hods and simple o mul iple linea eg ession [
19
–
21
] we e used o es ima e he
s a iona y he mal p ope ies o he box en elope. In his case, he HLC (Hea Loss Coe icien ) is
he main KPI ha was es ima ed. This pa ame e conside s he building’s hea ansmission h ough
he en elope and he en ila ion and/o in il a ion losses pe empe a u e deg ee di e ence be ween
indoo s and ou doo s in [W/K]. On he o he hand, he ARX (Au o-Reg ession models) (ARMAX) [
22
]
and S a e Space models [
23
] we e used o es ima e he s a iona y and dynamic he mal p ope ies o
he box en elope [24].
The ongoing Annex 71 is now ocused on he in-si u es ima ion o he he mal beha iou o in-use
building en elopes. The e o e, he aim o his pape is o demons a e he alidi y o he a e age
me hod de eloped in [
25
,
26
] o an occupied o ice building in o wo esiden ial buildings, as ne e
done be o e. The beha iou o he hea ing sys em, he in e nal hea gains and he sola gains is e y
di e en in o ice buildings compa ed o esiden ial buildings. Howe e , due o he di e ence ound in
he weigh o he hea gain sou ces wi hin an o ice building, i is possible ha some o he a e age
me hod equi emen s ha limi he aluable moni o ing pe iods o accu a e HLC es ima ion canno
be ul illed o esiden ial buildings. Thus, he limi s he me hod ound when wo king in a esiden ial
building a e also analysed.
Ene gies 2020,13, 5724 3 o 17
The me hod is applied o wo case s udy indi idual esiden ial buildings wi h di e en sizes,
occupa ion, in e nal gains, use, moni o ing pe iod and en elope insula ion cha ac e is ics. The da a
om he analysed esiden ial buildings is p o ided by he Annex 71. The i s building is in
Gainsbo ough (UK) (see Figu e 1a) and is a well-insula ed, occupied building. I is one o he ou social
houses moni o ed in [
27
] and he HLC ‘ heo e ical alue’ gi en by he Annex 71 is 49.9 W/K. The la e
alue is es ima ed based on he building design cha ac e is ics. The Gainsbo ough case ep esen s a no
e y de ailed moni o ing sys em o a eal in-use house, bu wi h a e y long moni o ing pe iod o h ee
yea s. Howe e , he second house, in Loughbo ough (UK) (see Figu e 1b), is inhabi ed by syn he ic
occupan s. Mo eo e , i is a adi ional uninsula ed semide ached esiden ial building. This house
has al eady been es ed h ough he co-hea ing me hod in [
28
] and he HLC ‘ heo e ical alue’ is
382 W/K. The da ase used o he house analysed in Loughbo ough can be ound in [
28
], whe e he
house 1 (HT1)
iles we e s udied. The Loughbo ough case ep esen s a e y de ailed moni o ing
sys em o a syn he ic occupan s’ in-use house, bu wi h a sho moni o ing pe iod o one mon h.
Ene gies 2020, 13, x FOR PEER REVIEW 3 o 17
social houses moni o ed in [27] and he HLC ‘ heo e ical alue’ gi en by he Annex 71 is 49.9 W/K.
The la e alue is es ima ed based on he building design cha ac e is ics. The Gainsbo ough case
ep esen s a no e y de ailed moni o ing sys em o a eal in-use house, bu wi h a e y long
moni o ing pe iod o h ee yea s. Howe e , he second house, in Loughbo ough (UK) (see Figu e 1b),
is inhabi ed by syn he ic occupan s. Mo eo e , i is a adi ional uninsula ed semide ached esiden ial
building. This house has al eady been es ed h ough he co-hea ing me hod in [28] and he HLC
‘ heo e ical alue’ is 382 W/K. The da ase used o he house analysed in Loughbo ough can be ound
in [28], whe e he house 1 (HT1) iles we e s udied. The Loughbo ough case ep esen s a e y de ailed
moni o ing sys em o a syn he ic occupan s’ in-use house, bu wi h a sho moni o ing pe iod o one
mon h.
(a) (b)
Figu e 1. (a) No h side o Gainsbo ough house; (b) on side o Loughbo ough house [28].
Bo h houses show wo ex eme building si ua ions: The i s showing occupied, well-insula ed,
esiden ial building condi ions wi h a no e y de ailed moni o ing sys em, bu moni o ed o a long
pe iod; while he second is a syn he ic occupan con olled, uninsula ed esiden ial building wi h a
e y de ailed moni o ing sys em, bu moni o ed o a sho pe iod. Thus, hese wo cases a e
conside ed sui able o his esea ch wo k, since hey ep esen he ex eme opposi e si ua ions o
es ing he a e age me hod in he esiden ial building le el.
2. Ma e ials and Me hods
2.1. A e age Me hod
The a e age me hod can be used o he HLC es ima ion o in-use whole buildings. The o mulas
de eloped in [25,26], and used o es ima e he HLC, a e:
HLC =∑()
∑(,,)
=
∑()
∑(,,)
=
[W/K] (1)
HLC = ∑(,)
∑(,,)
=
∑(,)
∑(,,)
=
[W/K] (2)
whe e Qk is he hea ing sys em hea inpu in [W], Kk is he o al elec ici y consump ion o he building
in [W], Sa is a ixed equi alen sola ape u e o ob ain he sola gains o he building in [m2] ega ding
Vsol,k ( ha is, he sou h global e ical sola i adiance [W/m2]). Mo eo e , Tin,k [°C] and Tou ,k [°C] a e
he indoo and ou doo ai empe a u es. The e a e N measu emen poin s in he analysed pe iod
and k is he measu emen co ela i e index.
The a e age me hod should only be used o pe iods wi h e y low sola adia ion and high
space hea ing demand. Fo such pe iods, i is possible o ensu e ha he sola hea gains compa ed
o he es o he hea gains wi hin he building (space hea ing plus all o he in e nal gains excluding
Figu e 1. (a) No h side o Gainsbo ough house; (b) on side o Loughbo ough house [28].
Bo h houses show wo ex eme building si ua ions: The i s showing occupied, well-insula ed,
esiden ial building condi ions wi h a no e y de ailed moni o ing sys em, bu moni o ed o a long
pe iod; while he second is a syn he ic occupan con olled, uninsula ed esiden ial building wi h a e y
de ailed moni o ing sys em, bu moni o ed o a sho pe iod. Thus, hese wo cases a e conside ed
sui able o his esea ch wo k, since hey ep esen he ex eme opposi e si ua ions o es ing he
a e age me hod in he esiden ial building le el.
2. Ma e ials and Me hods
2.1. A e age Me hod
The a e age me hod can be used o he HLC es ima ion o in-use whole buildings. The o mulas
de eloped in [25,26], and used o es ima e he HLC, a e:
HLCsimple =PN
k=1(Qk+Kk)
PN
k=1(Tin,k −Tou ,k)=
PN
k=1(Qk+Kk)
N
PN
k=1(Tin,k−Tou ,k)
N
=Q+K
Tin −Tou
[W/K](1)
HLC =PN
k=1(Qk+Kk+SaVsol,k)
PN
k=1(Tin,k −Tou ,k)=
PN
k=1(Qk+Kk+SaVsol,k)
N
PN
k=1(Tin,k−Tou ,k)
N
=Q+K+SaVsol
Tin −Tou
[W/K](2)
whe e Q
k
is he hea ing sys em hea inpu in [W], K
k
is he o al elec ici y consump ion o he building
in [W], S
a
is a ixed equi alen sola ape u e o ob ain he sola gains o he building in [m
2
] ega ding
V
sol,k
( ha is, he sou h global e ical sola i adiance [W/m
2
]). Mo eo e , T
in,k
[
◦
C] and T
ou ,k
[
◦
C]
Ene gies 2020,13, 5724 4 o 17
a e he indoo and ou doo ai empe a u es. The e a e N measu emen poin s in he analysed pe iod
and k is he measu emen co ela i e index.
The a e age me hod should only be used o pe iods wi h e y low sola adia ion and high space
hea ing demand. Fo such pe iods, i is possible o ensu e ha he sola hea gains compa ed o he
es o he hea gains wi hin he building (space hea ing plus all o he in e nal gains excluding sola
adia ion) a e less han 10%. By es ima ing HLC
simple
and HLC, he weigh o he sola gains in he
HLC es ima e can be analysed. By compa ing he HLC o he HLC
simple
o an analysed pe iod, i is
possible o check whe he he sola gains ep esen a conside able pa o he o al hea gains wi hin he
building. Since he no di ec ly measu able sola gains, oge he wi h he me abolic hea gene a ion,
a e he main unce ain y sou ces o he me hod, while i is in e es ing o es ima e he HLC
simple
, i has
no physical meaning.
The a e age empe a u e di e ence be ween he indoo and ou doo ai du ing he es ing pe iod
mus be high ( alues close o o highe han 15
◦
C a e ecommended). Thus, measu ing e o s in
empe a u e di e ence calcula ions will be minimized and high hea ing demands will also pe mi he
hea ing supply o be accu a ely measu ed.
Acco ding o [
25
,
26
], in o de o check he eliabili y o he HLC es ima es o he whole building
using he a e age me hod, i is in e es ing o es i he HLC accumula ed a e age alue is s abilised
du ing he las 24 h o he selec ed pe iods h ough plo ing he accumula ed a e age o he HLC. I he
es ima e is s abilised wi hin a
±
10% band o e he las 24 es ing hou s (see accumula ed HLC a e age
plo s in Appendix A), i can be assumed ha he ob ained HLC wi h he a e age me hod is alid.
Finally, due o he complexi y o accu a ely es ima ing he accumula ed hea o he building, i is
manda o y o ha e he same a e age building empe a u e a he beginning and end o he selec ed
pe iods o es ima ing he HLC. This empe a u e will be he a e age empe a u e be ween he indoo
and ou doo empe a u es. I his is ul illed, i can be assumed ha he e will be no accumula ed hea
in he building in he analysed pe iods, since he s a and end poin s o he analysis will ha e he
same he mal le el. Then, simila condi ions o s a iona y condi ions could be assumed. This issue is
ully demons a ed in Sec ion 2.1 o [26].
2.2. Inpu Da a
The moni o ing sys ems o each gi en building measu ed di e en pa ame e s. A combina ion o
sma me e s and dedica ed senso s we e used in bo h buildings o moni o each o he pa ame e s
in Table 1wi h a leas a 5 min equency. The moni o ing sys em o Gainsbo ough is desc ibed in
de ail in [
27
], while he moni o ing sys em o Loughbo ough is desc ibed in de ail in [
28
]. Howe e ,
he inpu da a p o ided we e il e ed in o de o ob ain common inpu pa ame e s o bo h houses,
as shown in Table 1. The il e ing p ocedu es we e no he same due o he di e en cha ac e is ics o
he moni o ing sys ems.
Fo he Gainsbo ough house, only he o al gas consumed by he boile was p o ided. Howe e ,
he mains wa e consump ion o he house was also p o ided. The boile was p o iding hea o
bo h he space hea ing and he DHW (Domes ic Ho Wa e ). The Gainsbo ough boile is a Po e on
P omax combina ion boile wi h an e iciency o 91% ega ding he SAP p ocedu e, acco ding o he
manu ac u e [
29
]. Like mos con en ional boile s, i does no p oduce DHW in pa allel wi h space
hea ing. Thus, when DHW is equi ed, he boile s ops he space hea ing supply and all he hea
p oduced by he boile is used o DHW p oduc ion. In o de o es ima e he gas consumed by he
space hea ing om he o al gas consump ion, he ollowing assump ion was conside ed: I he e
was gas consump ion a he same ime as he e was mains wa e consump ion, all his consumed gas
was conside ed as gas consump ion solely o DHW. In o he wo ds, only he gas consump ion while
no mains wa e was consumed was conside ed as space hea ing. This il e was applied on a i e
minu e basis.
Mo eo e , o he Gainsbo ough building, only he elec ici y consump ion was conside ed
when es ima ing he in e nal gains (K). The occupancy hea c ea ed by he occupan s’ me abolic
Ene gies 2020,13, 5724 5 o 17
gene a ion was neglec ed (pa o K), as no enough in o ma ion was p o ided o make an es ima ion.
Di e en occupan s li ed in his building o e he h ee win e s o he da a p o ided. Due o his,
achie ing occupancy pa e ns o he inhabi an s o es ima e he me abolic hea gain hey p oduced was
e y complica ed.
Howe e , he Loughbo ough house is a adi ional uninsula ed building occupied by moni o ed
syn he ic occupan s. This means ha he house beha es as i eal people we e li ing inside.
Thus, he me abolic hea gain p oduced by hese syn he ic use s was also conside ed as a hea
gain. All he in e nal hea gains, including he me abolic gene a ion o he syn he ic occupan s,
we e measu ed by means o se e al wa me e s ha measu ed all he elec ical consump ions
occu ing wi hin he building. Mo eo e , o he Loughbo ough house, he hea ou pu o he boile o
he space hea ing sys em was di ec ly measu ed. In o he wo ds, i was no necessa y o use he boile
e iciency o spli he space hea ing and he DHW consump ions. Mo eo e , accu a ely measu ed
syn he ic p o iles we e added o simula e he occupan s’ beha iou . The e o e, all hea gains (Q +K),
as well as he he mos a se ings, we e accu a ely known.
In o de o es ima e he sola gains, since only cloudy pe iods should be used o applying he
a e age me hod, he adia ion could be conside ed pu ely di use and hus simila on all açades.
The e o e, a g- alue o 0.5 could be applied o he o al window a ea, as in [
30
]. Once his oughly
es ima ed sola gain was ob ained, i could hen be compa ed o he a e aged (Q +K) alue o he
selec ed pe iods o see whe he he a e aged pe iod sola gains we e below 10% as compa ed o he
a e aged pe iod (Q +K). Then, he HLC es ima e would mainly be dependen on he measu ed Q and
K ha can be accu a ely measu ed when compa ed o sola gains. Mo eo e , he p opaga ion o he
unce ain y o he senso s was also conside ed when es ima ing he HLC e o bands. The p o ided
senso accu acy o he moni o ing sys ems o he wo houses can be seen in Table 2. No e ha , as in
he a e age me hod [
25
,
26
], o he unce ain y sou ces ela ed o he assump ions made by he me hod
a e no p opaga ed o he HLC es ima ions ca ied ou in his wo k. In he case o he sola gains
unce ain y, apa om he accu acy o he py anome e (conside ed 5% o his analysis), he sola
ape u e unce ain y was also conside ed. As done in [
25
,
26
], despi e he sola ape u e (S
a
) being
unknown, a 10% e o was conside ed o he la e . Thus, he o al unce ain y conside ed o he
sola gains o bo h buildings was 15%.
Table 1. Lis o inpu pa ame e s o applying he a e age me hod.
Senso s Measu ed Pa ame e Desc ip ion
The mocouple/The mis o s
Ou doo empe a u e (◦C)
Tou ,k On-si e ou doo ai empe a u e
Indoo empe a u e (◦C)
Tin,k
Measu ed in di e en ooms o he
house. In o de o achie e a unique
empe a u e o he building, a
non-weigh ed a e age empe a u e
was es ima ed using he ollowing
o mula:
Tin,k =Tin,1+Tin,2+... +Tin,n
n
Ene gy consump ion de ices
Boile hea ou pu (kWh)
Qk
When equi ed, he gas consump ion
was con e ed by boile e iciencies o
space hea ing sys em kWh supply.
Ho wa e ene gy supply is no
conside ed in his e m.
To al elec ici y consump ion (kWh)
Kk
Measu ed o he whole building o in
each o he ooms o he house.
Py anome e
Sola adia ion (global ho izon al
sola i adiance [W/m2])
Hsol
Ob ained om he Wadding on
wea he s a ion. In o de o apply he
a e age me hod, i was con e ed in o
sou h global e ical sola adia ion
(Vsol) [31].
Ene gies 2020,13, 5724 6 o 17
Table 2. Lis o measu emen s and p o ided accu acy o applying he a e age me hod.
Measu emen Gainsbo ough Accu acy Loughbo ough Accu acy
Indoo empe a u e ±0.25 ◦C±0.2 ◦C
Gas me e ±2% ±2%
Elec ici y consump ion ±2% No p o ided (±2% assumed)
Ou doo empe a u e ±0.5 ◦C±0.2 ◦C
In Table 1, due o he high homogenei y o indoo empe a u es du ing he analysed pe iods,
he indoo empe a u e is conside ed as he non-weigh ed a e age o all he measu ed indoo
empe a u es. A ull de elopmen o he p ope ies o he HLC, ega ding i s es ima ion in buildings
comp ising di e en he mal zones wi h di e en indoo empe a u e se poin s, is ma hema ically
de eloped and demons a ed in Sec ion 2.2 om he e e ence [
26
]. The e, he equi emen s o be able
o es ima e he whole building HLC by means o he sum o he zone HLCs a e desc ibed. Such needs
a e basically o know indi idually each zone hea gain (Q +K+S
a
V
sol
) and each zone T
in
. In bo h
o he one amily esiden ial buildings analysed in his wo k, i was only possible o conside one
he mal zone, as he in e nal hea gains (Q +K+S
a
V
sol
) could no be accu a ely spli be ween he
di e en ooms ha make up he dwelling. Mos o he in e nal gains we e measu ed only on he
whole building le el. Fu he mo e, o each indi idual empe a u e measu emen , he pe iod a e aged
alue has been compa ed o he pe iod a e age o he non-weigh ed a e age indoo empe a u e.
Fo all he analysed pe iods, he indoo empe a u e homogenei y o he buildings has been so high
ha he di e ence be ween he pe iod a e aged alues o indi idual indoo empe a u es and he
non-weigh ed indoo empe a u es ha e been wi hin he senso e o band.
In o de o see he beha iou o each o he moni o ed pa ame e s, Figu e 2a shows he
e olu ion o e one mon h o he indoo and ou doo ai empe a u es o he Loughbo ough building.
The e, he empe a u e di e ence be ween he in e io and he ex e io is also plo ed. F om Figu e 2a,
i can be concluded ha he empe a u e di e ence be ween he ex e io and in e io is conside ably
high du ing he selec ed pe iod. A zoom-in o Pe iod 1, used la e o apply he a e age me hod,
is also p esen ed in Figu e 2b. Figu e 3a shows he e olu ion o he sola gains (S
a
V
sol
), he space
hea ing sys ems’ hea inpu (Q) and he o al elec ici y consump ion, including he syn he ic occupan s’
gene a ion (K) o he Loughbo ough building, again including a zoom-in on pe iod 1 in Figu e 3b.
I Figu e 3a is analysed, i can be seen ha i is no possible o ind a h ee-day pe iod whe e he sola
gains emain below 10% when compa ed o he es o he measu able hea gains (Q +K). Finally, as an
example, Figu e 4shows he accumula ed a e age plo o he HLC o pe iod 1 in Loughbo ough.
I can be seen how he HLC alue s abilises along he du a ion o he pe iod and emains wi hin he
10% bands o e he p e ious 24 h.
Ene gies 2020, 13, x FOR PEER REVIEW 6 o 17
Table 2. Lis o measu emen s and p o ided accu acy o applying he a e age me hod.
Measu emen Gainsbo ough Accu acy Loughbo ough Accu acy
Indoo empe a u e ±0.25 °C ±0.2 °C
Gas me e ±2% ±2%
Elec ici y consump ion ±2% No p o ided
(±2% assumed)
Ou doo empe a u e ±0.5 °C ±0.2 °C
In Table 1, due o he high homogenei y o indoo empe a u es du ing he analysed pe iods,
he indoo empe a u e is conside ed as he non-weigh ed a e age o all he measu ed indoo
empe a u es. A ull de elopmen o he p ope ies o he HLC, ega ding i s es ima ion in buildings
comp ising di e en he mal zones wi h di e en indoo empe a u e se poin s, is ma hema ically
de eloped and demons a ed in Sec ion 2.2 om he e e ence [26]. The e, he equi emen s o be able
o es ima e he whole building HLC by means o he sum o he zone HLCs a e desc ibed. Such needs
a e basically o know indi idually each zone hea gain (Q + K + SaVsol) and each zone Tin. In bo h o
he one amily esiden ial buildings analysed in his wo k, i was only possible o conside one
he mal zone, as he in e nal hea gains (Q + K + SaVsol) could no be accu a ely spli be ween he
di e en ooms ha make up he dwelling. Mos o he in e nal gains we e measu ed only on he
whole building le el. Fu he mo e, o each indi idual empe a u e measu emen , he pe iod
a e aged alue has been compa ed o he pe iod a e age o he non-weigh ed a e age indoo
empe a u e. Fo all he analysed pe iods, he indoo empe a u e homogenei y o he buildings has
been so high ha he di e ence be ween he pe iod a e aged alues o indi idual indoo
empe a u es and he non-weigh ed indoo empe a u es ha e been wi hin he senso e o band.
In o de o see he beha iou o each o he moni o ed pa ame e s, Figu e 2a shows he e olu ion
o e one mon h o he indoo and ou doo ai empe a u es o he Loughbo ough building. The e,
he empe a u e di e ence be ween he in e io and he ex e io is also plo ed. F om Figu e 2a, i can
be concluded ha he empe a u e di e ence be ween he ex e io and in e io is conside ably high
du ing he selec ed pe iod. A zoom-in o Pe iod 1, used la e o apply he a e age me hod, is also
p esen ed in Figu e 2b. Figu e 3a shows he e olu ion o he sola gains (SaVsol), he space hea ing
sys ems’ hea inpu (Q) and he o al elec ici y consump ion, including he syn he ic occupan s’
gene a ion (K) o he Loughbo ough building, again including a zoom-in on pe iod 1 in Figu e 3b.
I Figu e 3a is analysed, i can be seen ha i is no possible o ind a h ee-day pe iod whe e he sola
gains emain below 10% when compa ed o he es o he measu able hea gains (Q + K). Finally, as
an example, Figu e 4 shows he accumula ed a e age plo o he HLC o pe iod 1 in Loughbo ough.
I can be seen how he HLC alue s abilises along he du a ion o he pe iod and emains wi hin he
10% bands o e he p e ious 24 h.
(a)
0
5
10
15
20
-5
0
5
10
15
20
25
2014-02-16 2014-02-20 2014-02-24 2014-02-28 2014-03-04 2014-03-08 2014-03-12 2014-03-16
Tempe a u e di e ence [°C]
Tempe a u e [°C]
Tou Tin Tou _P1 Tin_P1 Tin-Tou Tin_P1-Tou _P1
Figu e 2. Con .
Ene gies 2020,13, 5724 7 o 17
Ene gies 2020, 13, x FOR PEER REVIEW 7 o 17
(b)
Figu e 2. Indoo empe a u e, ou doo empe a u e and empe a u e di e ence: (a) o he whole
da ase in Loughbo ough, (b) o pe iod 1 in Loughbo ough.
(a)
(b)
Figu e 3. Sola gains (SaVsol), space-hea ing sys ems’ hea inpu (Q) and o al elec ici y consump ion,
including syn he ic occupan s’ gene a ion (K): (a) o he whole da ase in Loughbo ough, (b) o
pe iod 1 in Loughbo ough.
0
5
10
15
20
-5
0
5
10
15
20
25
2014-02-28 2014-03-01 2014-03-02 2014-03-03
Tempe a u e di e ence [°C]
Tempe a u e [°C]
Tou _P1 Tin_P1 Tin_P1-Tou _P1
0
4000
8000
2014-02-16 2014-02-20 2014-02-24 2014-02-28 2014-03-04 2014-03-08 2014-03-12 2014-03-16
In e nal hea gains [W]
SaVsol Q K SaVsol_P1 Q_P1 K_P1
0
4000
8000
2014-02-28 2014-03-01 2014-03-02 2014-03-03
In e nal hea gains [W]
SaVsol_P1 Q_P1 K_P1
0
50
100
150
200
250
300
350
400
0 5 10 15 20 25 30 35 40 45 50 55 60 65 70 75 80 85
HLC [W/K]
Time [h]
The accumula ed HLC Lowe limi Uppe limi The accumula ed HLC du ing he las 24h
Figu e 2.
Indoo empe a u e, ou doo empe a u e and empe a u e di e ence: (
a
) o he whole
da ase in Loughbo ough, (b) o pe iod 1 in Loughbo ough.
Ene gies 2020, 13, x FOR PEER REVIEW 7 o 17
(b)
Figu e 2. Indoo empe a u e, ou doo empe a u e and empe a u e di e ence: (a) o he whole
da ase in Loughbo ough, (b) o pe iod 1 in Loughbo ough.
(a)
(b)
Figu e 3. Sola gains (SaVsol), space-hea ing sys ems’ hea inpu (Q) and o al elec ici y consump ion,
including syn he ic occupan s’ gene a ion (K): (a) o he whole da ase in Loughbo ough, (b) o
pe iod 1 in Loughbo ough.
0
5
10
15
20
-5
0
5
10
15
20
25
2014-02-28 2014-03-01 2014-03-02 2014-03-03
Tempe a u e di e ence [°C]
Tempe a u e [°C]
Tou _P1 Tin_P1 Tin_P1-Tou _P1
0
4000
8000
2014-02-16 2014-02-20 2014-02-24 2014-02-28 2014-03-04 2014-03-08 2014-03-12 2014-03-16
In e nal hea gains [W]
SaVsol Q K SaVsol_P1 Q_P1 K_P1
0
4000
8000
2014-02-28 2014-03-01 2014-03-02 2014-03-03
In e nal hea gains [W]
SaVsol_P1 Q_P1 K_P1
0
50
100
150
200
250
300
350
400
0 5 10 15 20 25 30 35 40 45 50 55 60 65 70 75 80 85
HLC [W/K]
Time [h]
The accumula ed HLC Lowe limi Uppe limi The accumula ed HLC du ing he las 24h
Figu e 3.
Sola gains (S
a
V
sol
), space-hea ing sys ems’ hea inpu (Q) and o al elec ici y consump ion,
including syn he ic occupan s’ gene a ion (K): (
a
) o he whole da ase in Loughbo ough, (
b
) o pe iod 1
in Loughbo ough.
Ene gies 2020, 13, x FOR PEER REVIEW 7 o 17
(b)
Figu e 2. Indoo empe a u e, ou doo empe a u e and empe a u e di e ence: (a) o he whole
da ase in Loughbo ough, (b) o pe iod 1 in Loughbo ough.
(a)
(b)
Figu e 3. Sola gains (SaVsol), space-hea ing sys ems’ hea inpu (Q) and o al elec ici y consump ion,
including syn he ic occupan s’ gene a ion (K): (a) o he whole da ase in Loughbo ough, (b) o
pe iod 1 in Loughbo ough.
0
5
10
15
20
-5
0
5
10
15
20
25
2014-02-28 2014-03-01 2014-03-02 2014-03-03
Tempe a u e di e ence [°C]
Tempe a u e [°C]
Tou _P1 Tin_P1 Tin_P1-Tou _P1
0
4000
8000
2014-02-16 2014-02-20 2014-02-24 2014-02-28 2014-03-04 2014-03-08 2014-03-12 2014-03-16
In e nal hea gains [W]
SaVsol Q K SaVsol_P1 Q_P1 K_P1
0
4000
8000
2014-02-28 2014-03-01 2014-03-02 2014-03-03
In e nal hea gains [W]
SaVsol_P1 Q_P1 K_P1
0
50
100
150
200
250
300
350
400
0 5 10 15 20 25 30 35 40 45 50 55 60 65 70 75 80 85
HLC [W/K]
Time [h]
The accumula ed HLC Lowe limi Uppe limi The accumula ed HLC du ing he las 24h
Figu e 4.
E olu ion o he accumula ed a e age o he hea loss coe icien o pe iod 1 in Loughbo ough.
Ene gies 2020,13, 5724 8 o 17
3. Resul s
The wo houses p esen ed ha e no been moni o ed o he same da a pe iods. The house in
Loughbo ough [
28
] was only moni o ed om 16 Feb ua y o 15 Ma ch 2014. Un o una ely, he elec ical
consump ion da a s a ed o be collec ed on 25 Feb ua y, which limi s he oppo uni y o ind a sui able
pe iod wi hin he p o ided da a. The house in Gainsbo ough was moni o ed om 1 No embe 2012
un il 30 Ap il 2015. Thus, since a longe moni o ing pe iod was p o ided, i was easie o ind sui able
pe iods o es ima e he HLC ha ul il he a e age me hod equi emen s.
As explained in Sec ion 2, he a e age me hod is able o es ima e he HLC o a building using
sho ime pe iods (a leas 72 h pe iods). Howe e , due o all he equi emen s demanded by he
a e age me hod om he pe iods o analysis, inding sui able pe iods when sho da a se ies a e
p o ided is no s aigh o wa d. In his case, i was necessa y o ease some o he me hod equi emen s,
aking mo e lexible limi a ions o he sola gains 10% weigh equi emen , and his elaxa ion e ec
on he HLC es ima ion was analysed.
In he nex wo subsec ions, bo h building da a se ies a e analysed sepa a ely. In o de o
demons a e he eliabili y o he me hod, se e al use ul independen pe iods should be ound du ing
he s udy o each building’s da a se s. Thus, he indi idual esul s ob ained o each pe iod will be
independen om each o he and can hen be compa ed o he same building. Thus, an a e age HLC
es ima ion alue was calcula ed o each o he houses. Conside ing he cha ac e is ics o each house,
he eliabili y o he esul s a e now discussed.
3.1. Gainsbo ough HLC Es ima ion
Since a la ge da ase was p o ided o he house in Gainsbo ough, h ee consecu i e win e s
a e a ailable o ind sui able cold and cloudy pe iods o apply he a e age me hod. Thus, six use ul
pe iods ha ul il mos o he a e age me hod equi emen s we e ound, see Tables 3and 4.
Table 3.
Necessa y pe iod a e aged a iable alues o es ima e he HLC
simple
(simple Hea Loss Coe icien )
and HLC (Hea Loss Coe icien ) o Gainsbo ough. The a iables included a e he ou doo empe a u e
(T
ou
), he indoo empe a u e (T
in
), he empe a u e di e ence (T
in −
T
ou
), he space hea ing hea
inpu (Q), he elec ical hea gains (K), he in e nal hea gains (Q+K) and he sola gains (SaVsol).
Win e Pe iod
Inpu Da a
Tou
[◦C]
Tin
[◦C]
Tin-Tou
[◦C]
Q
[W]
K
[W]
Q+K
[W]
SaVsol
[W]
2012–2013
Pe iod 1 2012-12-03
18:02 →
2012-12-07
19:02 2.6 21.2 18.6 1066.5 11.9 1078.4 491.7
Pe iod 2 2012-12-11
16:02 →
2012-12-14
11:02 −0.4 16.9 17.3 767.9 22.6 790.5 380.9
Pe iod 3 2012-12-18
23:02 →
2012-12-22
8:02 5.9 16.9 11.0 544.7 9.3 554.0 110.7
2013–2014
Pe iod 4 2013-11-27
2:02 →
2013-11-30
8:02 7.0 21.7 14.7 326.8
459.2
786 336.9
Pe iod 5 2013-12-13
21:02 →
2013-12-17
3:02 9.5 21.7 12.2 393.8
453.7
847.5 282.0
2014–2015 Pe iod 6 2014-11-26
3:02 →
2014-11-30
8:02 8.7 21.9 13.2 322.7
353.8
676.5 139.4
Ene gies 2020,13, 5724 9 o 17
Table 4.
The HLC
simple
(simple Hea Loss Coe icien ) and HLC (Hea Loss Coe icien ) es ima ed
alues o Gainsbo ough.
Win e Pe iod
Ou pu Da a
HLCsimple
[W/K]
HLC
[W/K]
2012–2013
Pe iod 1 57.9 ±3.5 84.4 ±8.5
Pe iod 2 45.9 ±2.9 68.0 ±7.2
Pe iod 3 50.2 ±4.4 60.2 ±6.6
2013–2014 Pe iod 4 53.6 ±3.8 76.6 ±8.4
Pe iod 5 69.6 ±5.7 92.7±10.6
2014–2015 Pe iod 6 51.4 ±3.9 61.9 ±6.1
The a e age alue o he six HLC
simple
es ima ions p esen ed in Table 4is 54.8
±
4.1 W/K,
and 74
±
8.1 W/K o he HLC. As a compa ison e e ence, he Annex 71 has p o ided a “ heo e ical
HLC alue” o 49.9 W/K. No e ha he Gainsbo ough heo e ical alue only conside s he en elope
design ansmi ance alues and design in il a ion/ en ila ion cha ac e is ics, so i is no he “ ue”
HLC alue. Howe e , as p o en by [
12
], when design HLC alues a e compa ed o co-hea ing
expe imen al HLC alues, he co-hea ing HLC alues a e usually conside ably highe han he design
HLC alues. These di e ences ha e been p o en o be up o 100% highe in he co-hea ing HLC when
compa ed o he design HLC alues. Thus, he ob ained esul s ollow his p o en end o ha ing
highe expe imen al HLC alues when compa ed o he design HLC alues.
In o de o analyse he sp ead and eliabili y o he es ima ed in-use HLC esul s o Gainsbo ough,
i is indispensable o ca y ou a mo e de ailed s udy o he da a. As explained in Sec ion 2.2,
Gainsbo ough’s gas consump ion is no only p o iding space hea ing, bu also DHW. Then, al hough a
il e is de eloped o es ima e he gas consump ion o space hea ing and DHW p oduc ion (see Table 5),
his issue in oduces an impo an unce ain y. The o de o magni ude o he es ima ed ene gy
dedica ed o DHW is o he o de o he es ima ed space hea ing equi emen s. Howe e , pe iods 2
and 3 had no main wa e consump ion and gi e e y in e es ing in o ma ion.
Table 5.
Space hea ing (Q), Domes ic Ho Wa e consump ion (Q
DHW
), o al (Q
To
=Q+Q
DHW
) and
co esponding DHW pe cen age o he o al (%QDHW) o he analysed pe iods in Gainsbo ough.
Win e Pe iod
Inpu Da a
Q
[W]
QDHW
[W]
QTo
[W]
%QDHW
[W]
2012–2013
Pe iod 1 1066.5 406.0 1472.5 27.6
Pe iod 2 767.9 0.0 767.9 0.0
Pe iod 3 544.7 0.0 544.7 0.0
2013–2014
Pe iod 4 326.8 404.7 731.6 55.3
Pe iod 5 393.8 431.6 825.5 52.3
2014–2015
Pe iod 6 322.7 46.6 369.2 12.6
I Table 5is analysed, i can be seen how he second and hi d pe iods show null DHW
consump ion (ac ually hey ha e null mains wa e consump ion), while he space hea ing con inues o
wo k. Table 6shows he indi idual indoo empe a u e measu emen s o he bed oom and lounge o
he Gainsbo ough house.
Ene gies 2020,13, 5724 16 o 17
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