sus ainabili y
A icle
Li e Cycle Assessmen o Sola Façade Concep s
Based on T anspa en Insula ion Ma e ials
Ka el S uhala, Mi osla ˇ
Cekon * and Richa d Slá ik
Facul y o Ci il Enginee ing, B no Uni e si y o Technology, AdMaS Cen e, 602 00 B no, Czech Republic;
[email p o ec ed].cz (K.S.); [email p o ec ed].cz (R.S.)
*Co espondence: [email p o ec ed].cz; Tel.: +420-541-148-078
Recei ed: 19 Oc obe 2018; Accep ed: 12 No embe 2018; Published: 15 No embe 2018


Abs ac :
Con empo a y a chi ec u e and cons uc ion indus y a e ying o cope wi h inc easing
equi emen s conce ning ene gy e iciency and en i onmen al impac s. One o he a ailable op ions
is he ac i e u iliza ion o ene gy gains om he en i onmen , speci ically sola ene gy gains.
These gains can be u ilized by, o example, sola walls and acades. The sola açade concep
has been unde de elopmen o mo e han a cen u y. Howe e , i has no achie ed widesp ead
use o a ious easons. Ra he ecen ly he concep was enhanced by he applica ion o anspa en
insula ion ma e ials ha ha e he po en ial o inc ease he e iciency o such açades. The p esen ed
s udy e alua es he en i onmen al e iciency o 10 sola açade assemblies in he mild clima e o
he Czech Republic, Cen al Eu ope. The e alua ed açade assemblies combine he p inciples o a
sola wall wi h anspa en insula ion based on honeycomb and polyca bona e panels. The s udy
applies Li e-Cycle Assessmen me hodology o he calcula ion o en i onmen al impac s ela ed o
he li e cycle o he e alua ed assemblies. The esul s indica e ha e en hough he e a e se e al
limi ing ac o s, açade assemblies wi h anspa en insula ion ha e lowe en i onmen al impac s
compa ed o a e e ence assembly wi h s anda d he mal insula ion. The highes achie ed di e ence
is app ox. 84% (in a o o he assembly wi h anspa en insula ion) du ing a modelled 50-yea
açade assembly se ice li e.
Keywo ds:
building; en i onmen al impac s; açade; Li e-Cycle Assessmen ; anspa en insula ion;
low-emissi i y
1. In oduc ion
I is gene ally accep ed ha echnological ad ances combined wi h human popula ion g ow h a e
ha ing a signi ican impac on he en i onmen [
1
]. Some au ho s e en compa e i o he ex inc ion
e en s ha wiped ou mos li e o ms on Ea h in he pas [
2
]. Such s a emen s may seem exagge a ed;
howe e , he slow change in he global clima e (e.g., ising a mosphe ic CO
2
le els [
3
]) is well
documen ed. To add ess he issue, scien is s and poli icians ha e in oduced di e en “sus ainable
de elopmen ” s a egies such as Agenda 21 on sus ainable cons uc ion [
4
] om 1999 o he mo e
ecen p oposals o a “ci cula economy” [
5
]. These s a egies and he esea ch ha suppo s hem
(e.g., [
6
]) indica e ha he building sec o plays an impo an ole in humani y’s ques o sus ainabili y.
The eason is he massi e ene gy and esou ce consump ion connec ed o buildings, along wi h
was e p oduc ion: buildings a e esponsible o app oxima ely 40% o o al ene gy consump ion and
was e p oduc ion [
7
] and 25% o g eenhouse gas emissions [
8
]. Reducing hese nega i e impac s o
he building indus y is he aim o egula ions like Eu opean di ec i e 2010/31/EU on he ene gy
pe o mance o buildings (EPBD [
9
]). This ( ecen ly upda ed) di ec i e s a es ha all new buildings
and majo eno a ion p ojec s in he EU should comply wi h “nea ly-Ze o Ene gy Building” (nZEB)
s anda ds a e 2020. Li e a u e such as [
10
] sugges s ha he in oduc ion o nZEBs will esul in a
Sus ainabili y 2018,10, 4212; doi:10.3390/su10114212 www.mdpi.com/jou nal/sus ainabili y
Sus ainabili y 2018,10, 4212 2 o 16
massi e educ ion in ene gy consump ion (and a ela ed educ ion in en i onmen al impac ) in new
buildings in compa ison wi h buildings comple ed o e he las ew decades.
In he pas , he mos e icien way o imp o e he ene gy consump ion o buildings was o
educe hei hea ing and en ila ion ene gy losses. This was achie ed h ough he addi ion o he mal
insula ion o he building’s en elope and he ins alla ion o HVAC sys ems wi h hea eco e y [
11
].
This led o he de elopmen and p opaga ion o highly e icien “passi e” buildings [
12
]. Howe e ,
li e a u e such as [
13
,
14
] sugges s ha he po en ial o u he sa ings in con empo a y building
designs is limi ed by inc easing in es men cos s and embodied ene gy (as well as o he en i onmen al
impac s). The e o e, he indus y is looking o new solu ions ha will no only minimize ene gy
losses, bu also u ilize he ene gy gains a ailable on-si e. Such solu ions include he in eg a ion o
enewable ene gy sou ces (RES) like pho o ol aics [
15
] o sola he mal collec o s [
16
] o on-si e
ene gy gene a ion. Bo h o he p e iously men ioned e e ences illus a e ha he ield o RES
is al eady well es ablished in he li e a u e. S ill, he esea ch p esen ed in his pape ies o
b ing a di e en pe spec i e on one o he mo e s aigh o wa d ways o using enewable na u al
ene gy: he exploi a ion o sola ene gy gains wi h sola acades based on anspa en insula ion
ma e ials (TIMs).
The di ec u iliza ion o sola gains in buildings is no new. The sola wall p inciples ha
o igina ed in he la e 19 h cen u y we e u he de eloped by F. T ombe in he 1960s [
17
]. The p inciple
behind he sola wall (o he de i ed T ombe wall) is a he simple. I consis s o a massi e wall and
a glass co e on he ex e io side o he wall. The ou e su ace o he wall is pain ed black in o de
o abso b as much sola ene gy as possible. The ai gap be ween he glazing and he wall se es as a
bu e and insula ion laye ha educes he hea losses o he s uc u e [
18
]. The sola wall concep
has been s udied and de eloped wo ldwide o e he pas ew decades [
19
], when di e en s udies
de eloped sola walls whe e TIMs eplaced he o iginal glazing elemen s [
20
]. The applica ion o TIMs
had al eady p o en success ul in he case o sola he mal collec o s [
21
]. Thei in eg a ion in acade
elemen s is s ill in de elopmen , e en hough comme cial p oduc s al eady exis [
22
]. The p esen ed
s udy is pa o a esea ch p ojec ha s i es o add o he exis ing knowledge in his de eloping ield
by e alua ing he e iciency o a ious TIMs in combina ion wi h o he no el elemen s and ma e ials
such as low-emissi i y sola abso be s.
The wo ks e e enced in he p e ious pa ag aph ypically analyze he he mal cha ac e is ics
and ene gy balance o TIMs o sola walls. The e a e only a ew wo ks desc ibing he o e all
en i onmen al impac s ela ed o hese s uc u es and ma e ials. Fo example, Dowson e al. [
23
]
eleased a pape desc ibing he en i onmen al impac s ela ed o anspa en silica ae ogel insula ion.
S azi e al. [
24
] p esen ed a s udy on he en i onmen al impac s o a a he adi ional sola wall concep .
The applicabili y o he esul s o bo h s udies is limi ed as hey do no include compa isons wi h
o he a ailable ma e ials. One o he ew s udies ha p o ide such a compa ison was eleased by de
Ga cia e al. [25]
. I shows ha (unde speci ied bounda y condi ions) he en ila ed sola açade hey
es ed has a 7.5% lowe en i onmen al impac compa ed o a s anda d açade. The s udy p esen ed
in his pape ollows de Ga cia’s example along wi h p e ious wo k by ˇ
Cekon and S uhala [
26
],
which e alua ed he pe o mance o wo TIM-based sola walls and a s anda d açade wi h mine al
wool insula ion. The s udy p o ides an e alua ion o he en i onmen al impac s o 10 TIM-based
açade assemblies and a compa ison wi h a e e ence açade wi h ex e nal he mal insula ion composi e
sys em (ETICS). The e alua ion ocuses on he en i onmen al impac s o he acade assemblies du ing
hei whole li e cycle: om ex ac ion o he aw ma e ials o he inal was e disposal. This should
p o ide a complex unde s anding o he pe o mance o he concep . Fo his pu pose, he s udy also
includes dynamic simula ions o he ene gy pe o mance based on egional clima e da a. The ene gy
pe o mance is modelled o mul iple o ien a ions o he acades o he ca dinal poin s o p o ide
u he insigh in o he e iciency o he desc ibed açade concep s.
Sus ainabili y 2018,10, 4212 3 o 16
2. Me hodology and Ma e ials
The goal o he p esen ed s udy is he e alua ion o he en i onmen al impac s o he TIM-based
açade assemblies de ined in Sec ion 2.1. Li e-Cycle Assessmen (LCA) me hodology is applied o
achie e his goal. LCA me hodology was concei ed in he 1960s in he USA and se e al Eu opean
coun ies, [
27
]. Cu en ly i is well-es ablished in li e a u e (see e.g., [
28
]) as a me hod o complex
mul i-c i e ia e alua ion o p oduc s. I s applica ions in building indus y a y om e alua ion o
indi idual p oduc s o ma e ials o e alua ion o whole sys ems such as buildings o ci ies. I is
especially use ul in compa a i e s udies, whe e i p o ides complex basis o he decision-making
p ocess [29].
LCA p inciples a e in e na ionally s anda dized. The gene al amewo k is de ined in ISO
14040 [
30
]. This ISO s anda d is a he ague o he pu poses o he p esen ed s udy. The e o e,
he bounda y condi ions and speci ica ions o building- ela ed LCAs desc ibed in Eu opean s anda ds
EN 15804 [31] and EN 15978 [32] a e also applied in he p esen ed s udy.
2.1. Assessed Façade Assemblies
A o al o 11 di e en açade assemblies a e e alua ed in he p esen ed s udy. The base o all
he assemblies is a 200 mm hick conc e e wall wi h cemen -based plas e on he in e io su ace.
Conc e e was selec ed in his s udy due o i s hea accumula ion po en ial and hea ans e p ope ies
in o de o maximize he sola gains o assemblies wi h TIMs (see Figu e 1). Fi e di e en ypes o
e ail-a ailable TIMs wi h di e en he mal and op ical p ope ies a e selec ed o e alua ion in he
açade assemblies. Two ypes o e ail-a ailable sola abso be s a e selec ed o enhance he e iciency
o an o e all he mal pe o mance: common black pain (a non-selec i e sola abso be , nSSA) and
aluminum-based shee wi h low-emissi i y coa ing (a selec i e sola abso be , SSA). This decision is
based on au ho s’ p e ious wo k [
33
] ha iden i ied up o 54% be e e iciency o SSA o e nSSA.
The e alua ed açade assemblies a e de ined as ollows:
•Assembly 1
is a e e ence assembly combining a conc e e wall wi h s anda d ETICS. The ETICS
consis s o 220 mm expanded polys y ene (EPS), cemen -based adhesi e mo a and mine al
ex e io plas e . The assembly ep esen s an en elope wall wi h a U- alue o 0.21 W
·
m
−2·
K
−1
ha ul ils he high he mal p o ec ion le el o building.
•Assembly 2
consis s o a conc e e wall, a nSSA, a 25 mm ai gap and a 40 mm TIM sys em
made o honeycomb polyme hylme hac yla e PMMA (HP40; ci cula cells ho izon ally o ien ed,
pe pendicula o he wall; see Figu e 1a) encased be ween glass panes.
•Assembly 3
consis s o a conc e e wall, a nSSA, a 25 mm ai gap and a 10 mm polyca bona e TIM
panel (PC10) wi h a single laye o e ically o ien ed squa e cells pa allel o he wall su ace
(Figu e 1b).
•Assembly 4
consis s o a conc e e wall, a nSSA, a 25 mm ai gap and a 20 mm polyca bona e
TIM panel (PC20) wi h se en laye s o e ically o ien ed squa e cells pa allel o he wall su ace
(Figu e 1c).
•Assembly 5
consis s o a conc e e wall, a nSSA, a 25 mm ai gap and a 25 mm polyca bona e TIM
panel (PC25) wi h wo laye s o e ically o ien ed iangula cells pa allel o he wall su ace
(Figu e 1d).
•Assembly 6
consis s o a conc e e wall, a nSSA, a 25 mm ai gap and a 32 mm polyca bona e TIM
panel (PC32) wi h i e laye s o e ically o ien ed combined cells ( h ee laye s wi h squa e cells,
wo laye s o iangula cells) pa allel o he wall su ace (Figu e 1e).
•Assemblies 7 o 11
eplace he nSSA wi h SSA. O he wise he composi ion o hese assemblies is
he same as he composi ion o assemblies 2 o 6.
Sus ainabili y 2018,10, 4212 4 o 16
Sus ainabili y 2018, 10, x FOR PEER REVIEW 4 o 15
Figu e 1. Schema ic diag am o an e alua ed acade assembly wi h anspa en insula ion ma e ials
(TIM) (le ) and he indi idual ypes o TIMs applied in he e alua ed açade assemblies ( igh ): (a) 40
mm honeycomb cells (HP40), (b) 10 mm single-laye squa e cells (PC10), (c) 20 mm se en-laye squa e
cells (PC20), (d) 25 mm wo-laye iangula cells (PC25), (e) 32 mm i e-laye combined cells (PC32).
2.2. Bounda y Condi ions o he Assessmen
The s udy models he whole li e cycle o açade assemblies om aw ma e ial ex ac ion up un il
inal was e disposal as de ined by [32]. In pa icula , he s udy e alua es he en i onmen al impac s
ela ed o 1 m2 o each assembly du ing an es ima ed se ice li e o 50 yea s. This se ice li e is a
common building design alue in he Czech Republic. Fo he pu poses o he assessmen i is
es ima ed ha only he conc e e load-bea ing pa o he wall would endu e he whole 50-yea se ice
li e. I is assumed ha all o he o he ma e ials would ha e o be eplaced once (a e app ox. 25
yea s) due o hei lowe du abili y. This should mo e accu a ely model he eal use o açade
assemblies.
The li e cycle o he açade assemblies is di ided in o ou s ages acco ding o [32]: he P oduc
s age, he Cons uc ion p ocess s age, he Use s age, and he End o li e s age. The e is a i h s age
de ined in he s anda d ha deals wi h he euse and ecycling o ma e ials. Howe e , his s age is
omi ed om he s udy o educe possible in o ma ion bias and a dis o ion o he esul s. The
s anda d u he di ides he ou li e cycle s ages in o 16 modules (see Table 1).
Table 1. Li e cycle o a building acco ding o EN 15978 [32]. S ages and modules conside ed in he
p esen ed s udy a e highligh ed in bold ace and g ey backg ound colo . 1.
A1 o A3 P oduc S age
A1: Raw ma e ial supply
D
Bene i s and
loads beyond
he sys em
bounda y
(Reuse,
Reco e y and
Recycling
po en ial)
A2: T anspo
A3: Manu ac u ing
A4 o A5 Cons uc ion P oc. S age A4: T anspo
A5: Cons uc ion/Ins alla ion p ocess
B1 o B7 Use S age
B1: Use
B2: Main enance
B3: Repai
B4: Replacemen
B5: Re u bishmen
B6: Ope a ional ene gy use
B7: Ope a ional wa e use
C1 o C4 End o Li e S age
C1: Decons uc ion/demoli ion
C2: T anspo
C3: Wa e p ocessing
C4: Disposal
Figu e 1.
Schema ic diag am o an e alua ed acade assembly wi h anspa en insula ion ma e ials
(TIM) (le ) and he indi idual ypes o TIMs applied in he e alua ed açade assemblies ( igh ):
(
a
) 40 mm honeycomb cells (HP40), (
b
) 10 mm single-laye squa e cells (PC10), (
c
) 20 mm se en-laye
squa e cells (PC20), (
d
) 25 mm wo-laye iangula cells (PC25), (
e
) 32 mm i e-laye combined
cells (PC32).
2.2. Bounda y Condi ions o he Assessmen
The s udy models he whole li e cycle o açade assemblies om aw ma e ial ex ac ion up un il
inal was e disposal as de ined by [
32
]. In pa icula , he s udy e alua es he en i onmen al impac s
ela ed o 1 m
2
o each assembly du ing an es ima ed se ice li e o 50 yea s. This se ice li e is a
common building design alue in he Czech Republic. Fo he pu poses o he assessmen i is es ima ed
ha only he conc e e load-bea ing pa o he wall would endu e he whole 50-yea se ice li e. I is
assumed ha all o he o he ma e ials would ha e o be eplaced once (a e app ox. 25 yea s) due o
hei lowe du abili y. This should mo e accu a ely model he eal use o açade assemblies.
The li e cycle o he açade assemblies is di ided in o ou s ages acco ding o [
32
]:
he P oduc s age, he Cons uc ion p ocess s age, he Use s age, and he End o li e s age. The e is
a i h s age de ined in he s anda d ha deals wi h he euse and ecycling o ma e ials. Howe e ,
his age is omi ed om he s udy o educe possible in o ma ion bias and a dis o ion o he esul s.
The s anda d u he di ides he ou li e cycle s ages in o 16 modules (see Table 1).
Table 1.
Li e cycle o a building acco ding o EN 15978 [
32
]. S ages and modules conside ed in he
p esen ed s udy a e highligh ed in bold ace and g ey backg ound colo .
A1: Raw ma e ial supply
D
Bene i s and loads
beyond he
sys em bounda y
(Reuse, Reco e y
and Recycling
po en ial)
A2: T anspo
A1 o A3 P oduc S age
A3: Manu ac u ing
A4: T anspo
A4 o A5 Cons uc ion P oc. S age
A5: Cons uc ion/Ins alla ion p ocess
B1: Use
B2: Main enance
B3: Repai
B4: Replacemen
B5: Re u bishmen
B6: Ope a ional ene gy use
B1 o B7 Use S age
B7: Ope a ional wa e use
C1: Decons uc ion/demoli ion
C2: T anspo
C3: Wa e p ocessing
C1 o C4 End o Li e S age
C4: Disposal
Sus ainabili y 2018,10, 4212 5 o 16
Se e al o hese modules a e also omi ed in he s udy: Modules A5 (Cons uc ion/Ins alla ion
p ocess) and C1 (Decons uc ion/Demoli ion) a e omi ed because i is expec ed ha en i onmen al
impac s ela ed o hem would be negligible. Use o he açade assemblies should no cause any
en i onmen al impac s and he e o e module B1 is omi ed. No epai o main enance is expec ed
du ing he se ice li e o he açade assemblies. I is expec ed ha pa icula ma e ials will be eplaced a
he end o hei espec i e se ice li es. The e o e, modules B2, B3 and B5 a e omi ed. No ope a ional
wa e use and was e wa e p ocessing is expec ed and so modules B7 and C3 a e also omi ed.
2.3. Inpu Da a In en o y
In o ma ion ega ding he ma e ials applied in indi idual assemblies is ob ained om labo a o y
measu emen s o pu chased samples. Mo e in o ma ion abou he measu emen s can be ound in [
34
].
All he assemblies sha e he same base s uc u e made o 480 kg o conc e e o he pu poses o his
s udy. The in e io o he s uc u e is co e ed wi h 16 kg o cemen plas e (see Figu e 1). The amoun s
o ma e ials equi ed o he ex e io laye s o he açade assemblies (TIMs o ETICS) a e desc ibed in
Table 2. Based on Czech s a is ical da a [
35
] i is expec ed ha a he end o he modelled se ice li e all
ma e ials will be land illed.
Table 2. Ma e ials conside ed in he e alua ed açade assemblies.
EPS
(ETICS)
Cemen Mo a
(ETICS)
Mine al Plas e
(ETICS) SSA nSSA Polyca bona e
(TIM)
Glass Co e
(TIM)
Assembly 1 6.60 kg 8.00 kg 16.00 kg — — — —
Assembly 2 — — — — 0.15 kg 0.86 kg 26.00 kg
Assembly 3 — — — — 0.15 kg 1.70 kg —
Assembly 4 — — — — 0.15 kg 3.00 kg —
Assembly 5 — — — — 0.15 kg 3.40 kg —
Assembly 6 — — — — 0.15 kg 3.60 kg —
Assembly 7 — — — 0.81 kg — 0.86 kg 26.00 kg
Assembly 8 — — — 0.81 kg — 1.70 kg —
Assembly 9 — — — 0.81 kg — 3.00 kg —
Assembly 10 — — — 0.81 kg — 3.40 kg —
Assembly 11 — — — 0.81 kg — 3.60 kg —
The anspo o ma e ials (in modules A2, A4, B4 and C2) is ano he impo an pa o
building- ela ed LCA. T anspo dis ances be ween a hypo he ical building si e in he ci y o B no
(Czech Republic) and he nea es p oduc ion (was e managemen ) acili ies a e conside ed in his s udy
o ep esen a eal-li e anspo scena io. The anspo dis ances be ween he pe inen p oduc ion
acili ies and B no a e: 591 km o he HP40 TIM; 536 km o he SSA; 324 km o he PC10, PC20,
PC25 and PC30 TIMs; 160 km o nSSA; 32 km o he plas e s and mo a s; 15 km o he EPS; 5 km
o he conc e e. The nea es land ill is loca ed 13 km om he building si e.
Ene gy consump ion is he mos impo an pa o he p esen ed LCA as i has a majo impac
on he o al esul s (see Sec ion 3.2). Ene gy consumed du ing he ope a ion o he e alua ed
açade assemblies can be di ided in o wo pa s: (summe ) cooling ene gy and (win e ) hea ing
ene gy. The p esen ed s udy only includes he hea ing ene gy consump ion (see Table 3) necessa y
o main ain an in e io empe a u e o 20
◦
C behind he e alua ed açade assemblies. The eason is
ha p e ious esea ch [
26
] has al eady indica ed he p oblem o o e hea ing in summe . This p oblem
equi es u he echnical solu ions, such as shading o he applica ion o phase-change ma e ials [
25
].
Such addi ions a e conside ed ou side he scope o he p esen ed s udy, which ocuses solely on he
açade assemblies desc ibed in Sec ion 2.1. I should be no ed ha elec ici y is conside ed o be he
ene gy sou ce in he calcula ions.

Sus ainabili y 2018,10, 4212 6 o 16
Table 3. The annual hea ing ene gy consump ion o he e alua ed açade assemblies. Th ee scena ios
wi h di e en açade elemen o ien a ions a e conside ed.
Ene gy Consump ion [kWh·m−2]Sou h (180◦) Eas (90◦) No h-Eas (15◦)
Assembly 1 44.3 46.8 48.3
Assembly 2 5.1 6.8 8.1
Assembly 3 31.1 41.5 47.9
Assembly 4 17.5 24.1 28.3
Assembly 5 18.0 24.8 29.1
Assembly 6 13.9 19.3 22.9
Assembly 7 3.0 4.0 4.7
Assembly 8 18.1 24.1 28.0
Assembly 9 10.5 14.2 16.8
Assembly 10 10.8 14.6 17.3
Assembly 11 8.5 11.6 13.8
2.3.1. Calcula ion o Ene gy Consump ion
The basis o he e alua ion o en i onmen al impac s ela ed o ene gy consump ion is he
dynamic nume ical modelling o he ene gy pe o mance o he açade assemblies. Dynamic modelling
was selec ed as li e a u e such as [
36
] sugges s ha i should p o ide he mos accu a e da a o LCA.
This ype o modelling conside s he he mal and spec al pa ame e s o he e alua ed ma e ials
ha we e ob ained in he cou se o esea ch o p e ious wo ks ([
34
,
37
]) as well as a ying ex e io
condi ions. A summa y o he ma e ial pa ame e s is in Table 4. The nume ical algo i hm applied
o he modelling is based on one-dimensional ini e elemen s. The ime disc e iza ion o he hea
ans e p oblem uses a ully implici scheme. The ansi ion o hea in he solid non- anspa en
laye s conside s conduc i e hea ans e desc ibed by he mal conduc i i y, hea capaci y, and densi y.
Fu he in o ma ion abou hea ans e modelling can be ound in li e a u e such as [
38
] o [
39
].
T anspa en ma e ials like polyca bona e panels a e modelled as single one-dimensional ini e elemen s
wi h equi alen hea ans e p ope ies and anspa ency o sola adia ion. This means ha sola
adia ion pene a es he ma e ial o e a pe iod o ime p opo ional o i s anspa ency. Ai gaps
a e also modelled as single ini e elemen s acco ding o he me hod s a ed in ISO 6946 [
40
] wi h
equi alen he mal esis ance ha akes in o accoun adia i e hea ans e a ec ed by he emissi i y
o su aces and a con ec i e componen in luenced by he hickness o he ai laye . A schema ic
diag am illus a ing he nume ical model is in Figu e 2.
The bounda y condi ions u ilized o he nume ical modelling o he ene gy pe o mance o
açade assemblies a e as ollows: The hea ans e coe icien equals 25 W
·
m
−2·
K
−1
on he in e io
su ace and 7 W
·
m
−2·
K
−1
on he ex e io su ace o he modelled açade assemblies. These alues
a e based on [
41
]. The ex e io su ace is also exposed o sola adia ion, which is conside ed o
be pe pendicula o he su ace o he pu poses o he modelling. The inciden sola adia ion
includes p ojec ed di ec sola adia ion, di used sola adia ion, and e lec ed sola adia ion om
he g ound, which a e based on ela ions om he li e a u e [
41
]. The o al sola ene gy gains depend
on he o ien a ion o he açade assemblies o he ca dinal di ec ions, he sola abso p ion coe icien
o pa icula ma e ials and ime (based on e e ence clima e da a). All possible o ien a ions o he
ca dinal poin s we e conside ed du ing he calcula ions (see Figu e 3). This s udy p esen s h ee ene gy
demand scena ios (see Table 3): a sou hwa d o ien a ion (180
◦
clockwise om no h), an eas wa d
o ien a ion (90
◦
clockwise om no h) and a no h-eas wa d o ien a ion (30
◦
clockwise om no h).
The sou hwa d o ien a ion ep esen s he s a e wi h maximum sola gains. The e o e, he hea ing
ene gy consump ion o he assemblies wi h TIM is he lowes . The eas wa d and no h-eas wa d
o ien a ions a e included in his s udy o e alua e he impac o educed sola gains on he esul s.
Wes -o ien ed acades had lowe ene gy consump ion in he calcula ions and so a e no included in
he p esen ed s udy. The clima e da a conside ed in he calcula ions a e based on a e e ence es
yea o B a isla a “SVK_B a isla a.118160_IWEC” in he hou ime egime [
42
]. This was selec ed
Sus ainabili y 2018,10, 4212 7 o 16
as B a isla a (Slo akia) is geog aphically he closes ci y o he hypo he ical cons uc ion si e in B no
(Czechia), which has he necessa y clima e da a. The ime s ep used o he dynamic modelling is 600 s
and in e media e alues a e linea ly in e pola ed. A 20
◦
C in e io empe a u e is conside ed o he
pu poses o he modelling.
Table 4.
Ma e ials conside ed in he e alua ed açade assemblies and hei physical pa ame e s. *:
equi alen alue. **: measu ed alue acco ding o [34,37].
Thickness
[mm]
Numbe o
Fini e
Elemen s
Densi y
[kg·m−3]
The mal
Conduc i i y
[W·m−1·K−1]
The mal
Capaci y
[kJ·kg−1·K−1]
Sola
Abso bance
The mal
Emissi i y
Sola
T ansmi ance **
Plas e 0.01 2 1600 0.75 840 0.6 0.93 —
Conc e e 0.02 10 2400 1.47 1000 1 0.93 —
Polys y ene 0.22/0.05 10 15 0.040 * 1200 1 0.90 —
PC10 0.010 1 165 * 0.065 * 1000 0.2 0.84 0.82
PC20 0.020 1 144.9 * 0.051 * 1000 0.2 0.84 0.62
PC25 0.025 1 135.5 * 0.066 * 1000 0.2 0.84 0.63
PC32 0.032 1 110.8 * 0.059 * 1000 0.2 0.84 0.53
TIM 0.040 1 1000 0.040 1000 0.2 0.84 0.58
nSSA — — — — — 0.95 0.9 —
SSA — — — — — 0.95 0.1 —
Sus ainabili y 2018, 10, x FOR PEER REVIEW 7 o 15
si e in B no (Czechia), which has he necessa y clima e da a. The ime s ep used o he dynamic
modelling is 600 s and in e media e alues a e linea ly in e pola ed. A 20 °C in e io empe a u e is
conside ed o he pu poses o he modelling.
Table 4. Ma e ials conside ed in he e alua ed açade assemblies and hei physical pa ame e s. *:
equi alen alue. **: measu ed alue acco ding o [34,37].
Thickness
[mm]
Numbe o
Fini e
Elemen s
Densi y
[kg·m−3]
The mal
Conduc i i y
[W·m−1·K−1]
The mal
Capaci y
[kJ·kg−1·K−1]
Sola
Abso bance
The mal
Emissi i y
Sola
T ansmi ance **
Plas e 0.01 2 1600 0.75 840 0.6 0.93 ---
Conc e e 0.02 10 2400 1.47 1000 1 0.93 ---
Polys y ene 0.22/0.05 10 15 0.040 * 1200 1 0.90 ---
PC10 0.010 1 165 * 0.065 * 1000 0.2 0.84 0.82
PC20 0.020 1 144.9 * 0.051 * 1000 0.2 0.84 0.62
PC25 0.025 1 135.5 * 0.066 * 1000 0.2 0.84 0.63
PC32 0.032 1 110.8 * 0.059 * 1000 0.2 0.84 0.53
TIM 0.040 1 1000 0.040 1000 0.2 0.84 0.58
nSSA --- --- --- --- --- 0.95 0.9 ---
SSA --- --- --- --- --- 0.95 0.1 ---
Figu e 2. Calcula ion model based on he ini e elemen me hod o : (a) an opaque s uc u e; (b) a
s uc u e wi h a anspa en elemen on he ex e io side.
Figu e 3. Sola adia ion model based on he ini e elemen me hod; calcula ed educ ion ac o o
he azimu h o he s uc u e and ime o yea : (a) o July; (b) o Janua y.
2.3.2. LCA Calcula ion P ocedu e and Tools
The LCA was pe o med in GaBi so wa e equipped wi h he ecoin en 2.0 [43] da abase. No
da a desc ibing he pe o mance and en i onmen al impac s o he ma e ials we e a ailable a he
ime o he s udy. The e o e he s udy is based on gene ic ecoin en da ase s. The a ailable da ase s
do no desc ibe all o he p oduc s and p ocesses necessa y o he assessmen , which esul s in
se e al simpli ica ions in he LCA models:
Figu e 2.
Calcula ion model based on he ini e elemen me hod o : (
a
) an opaque s uc u e;
(b) a s uc u e wi h a anspa en elemen on he ex e io side.
Sus ainabili y 2018, 10, x FOR PEER REVIEW 7 o 15
si e in B no (Czechia), which has he necessa y clima e da a. The ime s ep used o he dynamic
modelling is 600 s and in e media e alues a e linea ly in e pola ed. A 20 °C in e io empe a u e is
conside ed o he pu poses o he modelling.
Table 4. Ma e ials conside ed in he e alua ed açade assemblies and hei physical pa ame e s. *:
equi alen alue. **: measu ed alue acco ding o [34,37].
Thickness
[mm]
Numbe o
Fini e
Elemen s
Densi y
[kg·m−3]
The mal
Conduc i i y
[W·m−1·K−1]
The mal
Capaci y
[kJ·kg−1·K−1]
Sola
Abso bance
The mal
Emissi i y
Sola
T ansmi ance **
Plas e 0.01 2 1600 0.75 840 0.6 0.93 ---
Conc e e 0.02 10 2400 1.47 1000 1 0.93 ---
Polys y ene 0.22/0.05 10 15 0.040 * 1200 1 0.90 ---
PC10 0.010 1 165 * 0.065 * 1000 0.2 0.84 0.82
PC20 0.020 1 144.9 * 0.051 * 1000 0.2 0.84 0.62
PC25 0.025 1 135.5 * 0.066 * 1000 0.2 0.84 0.63
PC32 0.032 1 110.8 * 0.059 * 1000 0.2 0.84 0.53
TIM 0.040 1 1000 0.040 1000 0.2 0.84 0.58
nSSA --- --- --- --- --- 0.95 0.9 ---
SSA --- --- --- --- --- 0.95 0.1 ---
Figu e 2. Calcula ion model based on he ini e elemen me hod o : (a) an opaque s uc u e; (b) a
s uc u e wi h a anspa en elemen on he ex e io side.
Figu e 3. Sola adia ion model based on he ini e elemen me hod; calcula ed educ ion ac o o
he azimu h o he s uc u e and ime o yea : (a) o July; (b) o Janua y.
2.3.2. LCA Calcula ion P ocedu e and Tools
The LCA was pe o med in GaBi so wa e equipped wi h he ecoin en 2.0 [43] da abase. No
da a desc ibing he pe o mance and en i onmen al impac s o he ma e ials we e a ailable a he
ime o he s udy. The e o e he s udy is based on gene ic ecoin en da ase s. The a ailable da ase s
do no desc ibe all o he p oduc s and p ocesses necessa y o he assessmen , which esul s in
se e al simpli ica ions in he LCA models:
Figu e 3.
Sola adia ion model based on he ini e elemen me hod; calcula ed educ ion ac o o he
azimu h o he s uc u e and ime o yea : (a) o July; (b) o Janua y.
2.3.2. LCA Calcula ion P ocedu e and Tools
The LCA was pe o med in GaBi so wa e equipped wi h he ecoin en 2.0 [
43
] da abase. No da a
desc ibing he pe o mance and en i onmen al impac s o he ma e ials we e a ailable a he ime
o he s udy. The e o e he s udy is based on gene ic ecoin en da ase s. The a ailable da ase s do
no desc ibe all o he p oduc s and p ocesses necessa y o he assessmen , which esul s in se e al
simpli ica ions in he LCA models:
•
The e is no single da ase ep esen ing he TIMs. The PC10, PC20, PC25 and PC30 TIMs a e
ep esen ed by a combina ion o da ase s, hese being RER: polyca bona e, a plan (ma e ial) and
Sus ainabili y 2018,10, 4212 8 o 16
RER: ex usion, plas ic ilm (p ocessing). The HP40 TIM includes bo h hese da ase s plus he
da ase RER: la glass, uncoa ed, a plan ep esen ing he glass casing.
•
The e is also no single da ase ep esen ing he selec i e sola abso be . I is modelled as a
combina ion o da ase s, hese being RER: aluminum, p ima y, a plan (base ma e ial), RER:
shee olling, aluminum (p ocessing) and SK: selec i e coa ing, aluminum shee , nickel pigmen ed
aluminum oxide (coa ing).
•
The anspo o aw ma e ials and incomple e p oduc s du ing he P oduc s age (especially
module A2) is included in indi idual ecoin en da ase s. The A4 and C2 (pa ially also B4)
modules desc ibe he anspo o inal p oduc s and was es espec i ely. Fo he pu poses o he
assessmen i is assumed ha he ma e ials and was es a e anspo ed by oad wi h a uck o
lo y. This is ep esen ed by he da ase RER: anspo , lo y 3.5-16 , lee a e age.
•
Elec ic ene gy in p ocess CZ: Elec ici y—low ol age, a g id ep esen s he ene gy consumed o
co e hea losses o o e hea ing h ough he e alua ed açade assemblies. No da ase ep esen ing
HVAC equipmen is included in he assessmen .
The en i onmen al impac s ela ed o he e alua ed açade assemblies a e calcula ed using
he CML2001 me hod ( e sion No . 10). This me hod was de eloped by he Ins i u e o
En i onmen al Sciences, Uni e si y o Leu en in he Ne he lands [
29
]. I includes 12 impac
ca ego ies: Abio ic Deple ion Po en ial o Elemen s (ADP-el), Abio ic Deple ion Po en ial o Fossil
Fuels (ADP- ), Acidi ica ion Po en ial (AP), Eu ophica ion Po en ial (EP), F eshwa e Aqua ic
Eco oxici y Po en ial (FAETP), Global Wa ming Po en ial (GWP), Global Wa ming Po en ial Excluding
Biogenic Ca bon (GWP-ex), Human Toxici y Po en ial (HTP), Ma ine Aqua ic Eco oxici y Po en ial
(MAETP), Ozone Laye Deple ion Po en ial (ODP), Pho ochemical Ozone C ea ion Po en ial (POCP),
and Te es ial Eco oxici y Po en ial (TETP). No maliza ion o he indi idual esul s is also applied
( e sion No . 10, EU25+3) o enable he agg ega ing o indi idual impac ca ego y esul s and inc ease
he comp ehensi eness o he s udy.
3. Resul s and Discussion
The p esen a ion o he LCA esul s is di ided in o wo pa s o inc eased cla i y. This is due o
he ac ha he majo i y o en i onmen al impac s a e (acco ding o he pe o med calcula ions) ela ed
o he elec ical ene gy necessa y o co e hea losses. Howe e , li e a u e such as [
44
] o [
45
] indica es
he inc easing impo ance o en i onmen al impac s ela ed o ma e ials (embedded o embodied
en i onmen al impac s). The e o e, Sec ion 3.1 ocuses on “embodied” en i onmen al impac s
ela ed o applied ma e ials, hei anspo , eplacemen , and was e p ocessing (modules A1–A4,
B4,
C2 and C4,
acco ding o [
32
]). O e all en i onmen al impac s, including ene gy consump ion
(module B6 acco ding o [32]), a e desc ibed in Sec ion 3.2.
3.1. E alua ion o Ma e ial-Rela ed En i onmen al Impac s
Table 5and Figu e 4show embodied en i onmen al impac s ela ed o he p oduc ion o ma e ials
(modules A1–A3 acco ding o [
32
]) necessa y o he cons uc ion o he e alua ed açade assemblies.
Table 5shows nume ical esul s in all 12 impac ca ego ies. These esul s indica e ha Assembly 3 has
he ewes embodied en i onmen al impac s connec ed wi h he p oduc ion o necessa y ma e ials in
modules A1–A3. On he o he hand, he iden i ica ion om Table 5o he assembly wi h he highes
amoun o embodied en i onmen al impac s in hese modules is impossible as a ious assemblies
ha e he wo s esul s in indi idual impac ca ego ies. Assembly 7 has he highes impac s in six
impac ca ego ies. Re e ence Assembly 1 and Assembly 11 bo h ha e he highes embodied impac s
in h ee ca ego ies. O e all he di e ence be ween he lowes and highes embodied en i onmen al
impac s in he modules a ies be ween 29% (GWP and GWP-ex) and 89% (MAETP) in indi idual
ca ego ies. The easons o hese di e ences a e isible in Figu e 4, which shows s acked no malized
en i onmen al impac s o modules A1–A3 o he e alua ed assemblies.
Sus ainabili y 2018,10, 4212 9 o 16
Table 5. En i onmen al impac s ela ed o he p oduc ion o ma e ials included in he assessed açade assemblies (modules A1–A3 acco ding o [32]).
Assembly 1 Assembly 2 Assembly 3 Assembly 4 Assembly 5 Assembly 6 Assembly 7 Assembly 8 Assembly 9 Assembly 10 Assembly 11
ADP-el [kg Sb-Equi .] 6.5 ×10−42.2 ×10−41.2 ×10−41.4 ×10−41.5 ×10−41.5 ×10−42.7 ×10−41.8 ×10−42.0 ×10−42.0 ×10−42.0 ×10−4
ADP- [MJ] 1.1 8.0 ×10−16.1 ×10−17.3 ×10−17.7 ×10−17.9 ×10−11.1 8.8 ×10−11.0 1.0 1.1
AP [kg SO2-Equi .] 2.7 ×10−13.8 ×10−11.7 ×10−12.1 ×10−12.2 ×10−12.3 ×10−14.9 ×10−12.8 ×10−13.2 ×10−13.3 ×10−13.4 ×10−1
EP [kg Phospha e-Equi .] 5.0 ×10−25.4 ×10−23.6 ×10−23.9 ×10−24.0 ×10−24.1 ×10−26.4 ×10−24.6 ×10−24.9 ×10−25.0 ×10−25.1 ×10−2
FAETP [kg DCB-Equi .] 4.7 3.4 2.8 3.0 3.1 3.1 1.0 ×10 9.7 9.9 1.0 ×10 1.0 ×10
GWP [kg CO2-Equi .] 1.0 ×1028.5 ×10 7.7 ×10 8.8 ×10 9.1 ×10 9.3 ×10 1.0 ×1029.3 ×10 1.0 ×1021.1 ×1021.1 ×102
GWP-ex [kg CO2-Equi .] 9.9 ×10 8.4 ×10 7.6 ×10 8.7 ×10 9.0 ×10 9.2 ×10 9.9 ×10 9.2 ×10 1.0 ×1021.1 ×1021.1 ×102
HTP [kg DCB-Equi .] 1.5 ×10 1.3 ×10 8.5 9.2 9.4 9.5 1.9 ×10 1.5 ×10 1.6 ×10 1.6 ×10 1.6 ×10
MAETP [kg DCB-Equi .] 1.3 ×1043.3 ×1047.2 ×1038.1 ×1038.4 ×1038.5 ×1036.5 ×1043.9 ×1044.0 ×1044.0 ×1044.0 ×104
ODP [kg R11-Equi .] 5.4 ×10−65.5 ×10−63.2 ×10−63.2 ×10−63.2 ×10−63.2 ×10−66.6 ×10−64.3 ×10−64.4 ×10−64.4 ×10−64.4 ×10−6
POCP [kg E hene-Equi .] 8.1 ×10−23.3 ×10−22.2 ×10−22.7 ×10−22.8 ×10−22.9 ×10−24.1 ×10−23.1 ×10−23.5 ×10−23.6 ×10−23.7 ×10−2
TETP [kg DCB-Equi .] 3.7 ×10−12.9 ×10−12.6 ×10−13.0 ×10−13.2 ×10−13.2 ×10−14.4 ×10−14.0 ×10−14.4 ×10−14.6 ×10−14.6 ×10−1
Sus ainabili y 2018,10, 4212 16 o 16
39.
Lewis, R.W.; Ni hia asu, P.; See ha amu, K.N. Fundamen als o The Fini e Elemen Me hod o Hea and Fluid Flow;
John Wiley & Sons, L d.: Chiches e , UK, 2004; ISBN 0-470-84788-3.
40.
ISO. Building Componen s and Building Elemen s—The mal Resis ance and The mal T ansmi ance—Calcula ion
Me hod; ISO 6946; In e na ional O ganiza ion o S anda diza ion (ISO): Gene a, Swi ze land, 2017; p. 40.
41. Hens, H. Applied Building Physics; Wilhelm E ns & Sohn: Be lin, Ge many, 2011; ISBN 978-3-433-02962-6.
42.
Ene gyPlus. Wea he Da a by Loca ion. A ailable online: h ps://ene gyplus.ne /wea he -loca ion/eu ope_
wmo_ egion_6/SVK//SVK_B a isla a.118160_IWEC (accessed on 14 No embe 2018).
43.
F ischknech , R.; Jungblu h, N.; Al haus, H.-J.; Doka, G.; Dones, R.; Hischie , R.; Hellweg, S.; Nemecek, T.;
Rebi ze , G.; Spielmann, M. O e iew and Me hodology. Final Repo Ecoin en Da a 2.0; Swiss Cen e o Li e
Cycle In en o ies: Dübendo , Swi ze land, 2007; p. 77.
44.
Du il, Y.; Rousse, D.; Quesada, G. Sus ainable Building: An e e e ol ing Ta ge . Sus ainabili y
2011
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3, 443–464. [C ossRe ]
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Roh, S.; Tae, S.; Suk, S.J.; Fo d, G. E alua ing he embodied en i onmen al impac s o majo building asks
and ma e ials o apa men buildings in Ko ea. Renew. Sus ain. Ene gy Re . 2017,73, 135–144. [C ossRe ]
©
2018 by he au ho s. Licensee MDPI, Basel, Swi ze land. This a icle is an open access
a icle dis ibu ed unde he e ms and condi ions o he C ea i e Commons A ibu ion
(CC BY) license (h p://c ea i ecommons.o g/licenses/by/4.0/).