Specification of glazings for façades based on spectrophotometric characterization of transmittance

sus ainabili y A icle Speci ica ion o Glazings o Façades Based on Spec opho ome ic Cha ac e iza ion o T ansmi ance Helenice Ma ia Sach 1,*, Luís B agança 2, Manuela Almeida 2and Rosana Ca am 3   Ci a ion: Sach , H.M.; B agança, L.; Almeida, M.; Ca am, R. Speci ica ion o Glazings o Façades Based on Spec opho ome ic Cha ac e iza ion o T ansmi ance. Sus ainabili y 2021, 13, 5437. h ps://doi.o g/10.3390/ su13105437 Academic Edi o : Tomonobu Senjyu Recei ed: 22 Ap il 2021 Accep ed: 11 May 2021 Published: 13 May 2021 Publishe ’s No e: MDPI s ays neu al wi h ega d o ju isdic ional claims in published maps and ins i u ional a il- ia ions. Copy igh : © 2021 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 ps:// c ea i ecommons.o g/licenses/by/ 4.0/). 1La in Ame ican Ins i u e o Technology, In as uc u e and Te i o y (ILATIT), Fede al Uni e si y o La in Ame ican In eg a ion (UNILA), Foz do Iguaçu, PR 85867-970, B azil 2Depa men o Ci il Enginee ing, Uni e si y o Minho, 4800-533 Guima ães, Po ugal; [email p o ec ed] (L.B.); [email p o ec ed] (M.A.) 3 Ins i u e o A chi ec u e and U banism (IAU), Uni e si y o São Paulo (USP), São Ca los, SP 13566-590, B azil; [email p o ec ed] *Co espondence: [email p o ec ed] Abs ac : The co ec speci ica ion o glazings o açades can educe he ene gy consump ion in buildings. The hea exchange occu s h ough anspa en su aces and adia ion eaches he building as ligh and hea . The e o e, glazings signi ican ly con ibu e o he hea ans e be ween ou doo and indoo spaces and ac di ec ly on dayligh ing and he mal com o . This pape epo s on he spec opho ome ic cha ac e iza ion o glazings ansmi ance o he s udy o componen s o a modula açade sys em and i s sui abili y o he clima e o Po ugal ( empe a e clima e). The s udy ocused on esul s o spec opho ome ic measu emen s o op ical p ope ies, speci ically he ansmi ance o some ypes o glazings (sola con ol, sel -cleaning, low-e, loa , and ex a-clea ) and wo ypes o double glazings. The esul s show he pe cen age o ansmission o ul a iole , isible, and nea -in a ed egions and i s impo ance, which enabled he analysis o he glazing e iciency ega ding dayligh ing and he co ela ion o he mal pe o mance. Subsidies and indica ions o he speci ica ion and adequa e uses o anspa en su aces ha e been p esen ed and complemen ed he da ashee s a ailable om he manu ac u es. Keywo ds: açade; glazing; speci ica ion; ansmi ance; spec opho ome e es s; ene gy e iciency 1. In oduc ion A la ge a ie y o anspa en ma e ials is a ailable o use in buildings açades. How- e e , all glazing p ope ies mus be conside ed in he choice o ma e ial. The selec ion o glazings should be a ca e ul p ocess o e alua ion and weighing o adeo s. Among he cha ac e is ics equi ed o he speci ica ion o anspa en ma e ials, he spec opho o- me ic beha io is an impo an ac o o be conside ed, as i enables imp o emen s in he he mal and isual com o o a building. Many s udies ha e been ca ied ou in his espec , bo h o glass and o he anspa en ma e ials, mainly ocused on pene a ion o UV ays h ough he glazings. In o de o cu b excessi e pene a ion o UV ays, op ically unc ional glasses ha e been p oposed and he pe o mance assessmen s o he glazed ma e ials ha e been measu ed and epo ed by Kim e al. [ 1 ]. Resul s ha e shown ha UV p o ec ion glass is mo e e ec i e in con olling he UV ays o na u al ligh ; clea glass ea ed wi h a UV p o ec ion ilm would p o ide excellen con ol o UV pene a ion and a pai o clea and UV p o ec ion glass shee s ea ed wi h a UV p o ec ion ilm should be ecommended; his achie es 96.7% UV p o ec ion pe o mance om na u al ligh . Goia e al. [ 2 ] in es iga ed he spec al and angula beha io o di e en PCM glazing samples, cha ac e ized by di e en hicknesses o PCMs, by means o a comme cial spec- opho ome e , and by means o a dedica ed op ical es bed ha includes a la ge in eg a ing sphe e wi h a diame e o 0.75 m. The expe imen s ha e poin ed ou he highly di usi e Sus ainabili y 2021,13, 5437. h ps://doi.o g/10.3390/su13105437 h ps://www.mdpi.com/jou nal/sus ainabili y Sus ainabili y 2021,13, 5437 2 o 19 beha io o he PCM laye , wi h inc easing weigh o he di ec - o-di use ansmission mode as he PCM laye hickness inc eases. Mo e ia e al. [ 3 ] s udied he he mal and op ical cha ac e iza ion o h ee polyca bon- a e sys ems o buildings (wi h di e en numbe s o chambe s and geome y). The mal ansmi ance measu emen s we e ca ied ou using a ho -box appa a us, in o de o as- sess he impac o he connec ion join s on he e ec i e U- alue and o compa e i wi h da a decla ed by manu ac u e s, usually e e ed o as he cen e o he componen . The in es iga ed polyca bona e sys ems could be a alid solu ion in place o classic windows in comme cial buildings and he s udy p o ides deepened knowledge abou he polyca - bona e panels’ he mal and op ical beha io and a se o use ul da a o accu a e analyses in building in eg a ion. Baldinelli [ 4 ] p esen ed he spec al da a on he wa eleng h ield o in e es o sola adia ion, showing he high anspa ency le els o glazing sys ems made by an in e nal laye (s a i ied glass, ai gap, loa glass) and ex e nal laye (s a i ied glass), as well as he good e lec i e p ope ies o he aluminum in he shading sys em. Acco ding o he same au ho , glazing op ical p ope ies depend on he inciden angle be ween he su ace and he ay di ec ion: as his angle de ia es om he no mal di ec ion (0 ◦ ), ansmissi i y dec eases, e lec i i y inc eases, and abso p i i y inc eases. The a ia ion o op ical p ope ies wi h he incidence angle depends on glass ype and hickness; in pa icula , i is mo e p onounced o mul iple-pane glazing sys ems. Be a di [ 5 ] poin s ou ha wi h ecen ad ances in glazing echnology, manu ac u e s can con ol how glazing beha es in he di e en po ions o he spec um. Coa ings may con ol he passage o long-wa e sola adia ion h ough ansmission and/o e lec ion. In he pas , coa ings on windows ha educed he sola gain also educed he isible ansmi ance and we e ha dly accep ed by occupan s. Howe e , new high-pe o mance in ed glass and low sola -gain (o low-E) coa ings make i possible o educe he sola hea gain wi h li le o no educ ion in he isible ansmi ance. A low-E coa ed glass has a mic oscopically hin anspa en me al coa ing ha e lec s longwa e in a ed ene gy du ing win e and blocks ex e nal sho wa e gains du ing summe . Despi e he e being s udies on he de e mina ion o op ical p ope ies o glazing and o he ma e ials o açades, wi h he de elopmen o new ma e ials, u he s udies a e needed o di e en ypes o glass, as well as conside ing he beha io o double glazings and analyzing he ela ionship be ween hose p ope ies wi h he mal and dayligh ing beha io . 1.1. Glazings and Sola Spec um People ypically spend many hou s in buildings ba hed in he ul a iole , isible, and in a ed adia ion p oduced by na u al o elec ic ligh ing. This adia ion can damage issue ega dless o whe he o no i a ec s he isual and ci cadian sys ems [6] The adia ion ansmission h ough glazings depends mainly on ac o s, such as angle o adia ion incidence, hickness, chemical composi ion, and supe icial cha ac e is ics o he glazing. The angle o adia ion incidence is he angle be ween he di ec ion o he adia ion and he no mal one (90~) o he su ace unde analysis [ 7 ]. The ansmission o glazings also depends on he wa eleng h o he inciden adia ion. The glazing ac s as an opaque ma e ial o ce ain egions o he spec um, o example, i exhibi s opaque beha io and p e en s he c ossing o adia ion o wa eleng hs sho e han 300 nm and longe han 5000 nm [ 8 ]. The main he mal exchanges, as well as he passage o ligh in o he in e io o a building, occu on anslucen o anspa en su aces. The e o e, such su aces ac di ec ly on he mal com o and dayligh ing. Rega ding anspa en glazing, pa o he ene gy om he sola adia ion (Figu e 1a) is di ec ly ansmi ed o he in e io o he en i onmen , which dis inguishes opaque su aces om anslucen ones. Re lec ion, abso p ion, and ansmission also occu on anslucen su aces (Figu e 1b), howe e , he ansmission akes place in a di e en way. The ligh p opaga es when i pene a es anslucen glazing and lea es i as a di use ligh , and no as a di ec one. Sus ainabili y 2021,13, 5437 3 o 19 Sus ainabili y 2021, 13, x FOR PEER REVIEW 3 o 20 he ansmission akes place in a di e en way. The ligh p opaga es when i pene a es anslucen glazing and lea es i as a di use ligh , and no as a di ec one. Figu e 1. Beha io o adia ion on a anspa en su ace (a) and on a anslucen su ace (b). The beha io o anspa en ma e ials when hey ecei e sola adia ion is o eac selec i ely, ha is, he amoun o ene gy hey abso b, e lec , o ansmi depends on he wa eleng h o he inciden ay. When he angle o incidence is no no mal o he plane and is inc eased, he e lec ed ene gy becomes mo e and mo e, while he ansmi ed and abso bed ene gy dec eases, al hough he ela ionship ha co esponds o he no mal in- cidence app oxima ely emains he same be ween hem. The o al alue o he adia ion ansmi ed, e lec ed, and abso bed by glazings is an impo an a iable o he calcula ion o he sola hea gain coe icien , which depends on he op ical p ope ies o he ma e ial, sola ac o , inciden sola adia ion, o e all hea ans e coe icien (U ac o ), and di e ence o empe a u e be ween he ou doo and in- doo en i onmen s. The isible spec um is he mos known sola adia ion. Howe e , wo o he im- po an bands a e ul a iole (UV) and in a ed (IV). Figu e 2 shows he sola adia ion incidence di ided by spec a. Al hough he sun emi s adia ion in an ex ensi e band o elec omagne ic wa es, only a na ow band o he sola spec um is pe cep ible. Wa e- leng hs longe han 1500 nm each he e es ial su ace in small p opo ions. Figu e 2. Sola Spec um [9]. UV Visible IR 0,00 0,25 0,50 0,75 1,00 1,25 1,50 1,75 2,00 250 500 750 1000 1250 1500 1750 2000 2250 2500 2750 3000 3250 3500 3750 4000 Spec al I adiance W m -2 nm -1 Wa eleng h nm ASTM G173-03 Re e ence Spec a E W*m-2*nm-1 Global il W*m-2*nm-1 Di ec +ci cumsola W*m-2*nm-1 Figu e 1. Beha io o adia ion on a anspa en su ace (a) and on a anslucen su ace (b). The beha io o anspa en ma e ials when hey ecei e sola adia ion is o eac selec i ely, ha is, he amoun o ene gy hey abso b, e lec , o ansmi depends on he wa eleng h o he inciden ay. When he angle o incidence is no no mal o he plane and is inc eased, he e lec ed ene gy becomes mo e and mo e, while he ansmi ed and abso bed ene gy dec eases, al hough he ela ionship ha co esponds o he no mal incidence app oxima ely emains he same be ween hem. The o al alue o he adia ion ansmi ed, e lec ed, and abso bed by glazings is an impo an a iable o he calcula ion o he sola hea gain coe icien , which depends on he op ical p ope ies o he ma e ial, sola ac o , inciden sola adia ion, o e all hea ans e coe icien (U ac o ), and di e ence o empe a u e be ween he ou doo and indoo en i onmen s. The isible spec um is he mos known sola adia ion. Howe e , wo o he impo an bands a e ul a iole (UV) and in a ed (IV). Figu e 2shows he sola adia ion incidence di ided by spec a. Al hough he sun emi s adia ion in an ex ensi e band o elec omag- ne ic wa es, only a na ow band o he sola spec um is pe cep ible. Wa eleng hs longe han 1500 nm each he e es ial su ace in small p opo ions. Figu e 2. Sola Spec um [9]. Fo he use o sola ene gy, he only adia ion conside ed is he one whose wa eleng h anges be ween 290 and 1800 nm, o , mo e speci ically, up o 1500 nm [ 10 ], as wa eleng hs longe han hose each he e es ial su ace in a e y educed way and a e abso bed by he wa e apo and ca bon dioxide p esen in he a mosphe e. Wa eleng hs sho e han 290 nm a e abso bed by he ozone laye [7]. Sus ainabili y 2021,13, 5437 4 o 19 The sola spec um is di ided in o he ul a iole UV egion (100 o 380 nm), isible egion (380 o 780), and in a ed egion (780 o 3000). The ansmission o he glazings o each in e al in luences some cha ac e is ics. 1.1.1. Ul a iole (UV) (100–380 nm) The ul a iole band is mo e ene ge ic han he ligh (i has a sho e wa eleng h), he e o e, i pene a es he skin mo e deeply and causes bu ns depending on he ime o exposi ion o he sola adia ion. Al hough only 1 o 5% o he ul a iole adia ion eaches he e es ial su ace, i mus no be igno ed due o he e ec s i exe s. In some si ua ions, such adia ion may no be impo an , as in eco e y a eas in hospi als, as i is esponsible o he syn hesis o Vi amin D h ough he skin and exe s a bac e icide e ec . Howe e , i comp omises he du abili y o ma e ials by he discolo a ion o he issues, as i has pho ochemical capaci y. The ul a iole egion ha causes he discolo a ion o he ma e ials is be ween 315 and 380 nm. Such adia ion is also esponsible o anning. The ul a iole adia ion is subdi ided in o h ee in e als: UV-C (be ween 100 and 280), UV-B (be ween 280 and 320), and UV-A (be ween 320 and 380). The UV-A adia ion (be ween 320 and 380) causes he di ec anning o he skin wi h weak e y hema o sun- bu n. The maximum eac ion o he e y hema occu s 72 h a e he exposi ion o he sun. The con inuous exposi ion causes no only as aging o he skin bu also ca cinogenic implica ions. The UV-B adia ion causes an e y hema esponse and, in associa ion, indi ec anning. Unde in ense and equen adia ion, UV-B may p oduce skin ca cinomas. In such a case, he maximum eac ion occu s be ween 6–20 h a e exposi ion. UV-C adia ion does no each he Ea h, as wa eleng hs below 290 nm a e abso bed by he ozone laye o he a mosphe e. Such adia ion is a ge micide and highly ha m ul o he human skin, due o i s high ene gy con en [11]. 1.1.2. Visible (Vis) (380–780 nm) The isible egion is associa ed wi h he in ensi y o he whi e ligh ansmi ed and in luences di ec ly he deg ee o dayligh o an en i onmen . I is also called luminous and enables he isual sensa ion o days passing. I is he isible po ion o he inciden sola adia ion in he di ec ion no mal o he su ace plane. The isible ligh ca ies enough ene gy o s imula e chemical eac ions in he eyes and he unc ioning o he isual sys em. This wa eleng h ollows he sequence: iole , blue, g een, yellow, o ange, and ed, howe e , he human isual sys em is mo e e ec i e in he wa eleng h ha co esponds o g een and yellow. Besides being undamen al o humans, he isual sys em is indispensable o he de elopmen o ege ables, because o he pho osyn hesis p ocess, which equi es isible ligh . Chlo ophyll, he agen esponsible o he ege able cellula espi a o y p ocess, abso bs speci ic egions o he spec a. 1.1.3. In a ed IR (780–3000 nm) The in a ed egion is in isible o he isual sys em, al hough i is no iced in he o m o hea . I in e e es wi h he indoo condi ions o he en i onmen h ough sola hea gain, he e o e, i canno be igno ed. I is di ided in o h ee bands: sho -wa e in a ed, o nea -in a ed, whose wa eleng hs ange be ween 780 and 1400 nm, mid-wa eleng h in a ed, which anges om 1400 o 3000 nm, and, inally, long-wa eleng h in a ed, which includes he adia ion ha esul s om hea ed bodies, whose wa eleng hs a e longe han 5000 nm. The nea -in a ed co esponds o he la ge pa o he sola spec um ha c osses a colo less glass, o ins ance, in high p opo ions. Re e ences o some speci ie s ega ding such a egion o he spec um include s a emen s as “glass is gene ally opaque o he in a ed”, howe e , his is w ong in o ma ion [8]. A spec opho ome ic cha ac e iza ion o glazings was accomplished o he s udy o componen s o a modula açade sys em in Po ugal. The s udy ocused on esul s o Sus ainabili y 2021,13, 5437 5 o 19 spec opho ome ic measu emen s o op ical p ope ies, speci ically, he ansmi ance o some ypes o simple glazings and wo ypes o double glazings [12–14]. The esul s enabled he e i ica ion o he glazing e iciency in e ms o dayligh and he co ela ion o he mal pe o mance and p o ided subsidies and indica ions o he speci ica ion and adequa e uses o anspa en su aces. They also complemen ed he da ashee s o he manu ac u es. An e alua ion o he ansmission o glazings by spec opho ome ic es s enables he analysis o he di e en egions o he spec um (ul a iole , isible, and in a ed) indi idually and no as a whole, as i occu s wi h pa ame e s, such as sola ac o and shading coe icien , which a e calcula ed in a global way wi hou aking in o accoun he di e ences o beha io pe egion o he spec um. 2. Ma e ials and Me hods The de elopmen o his esea ch included he ollowing asks: I. Cha ac e iza ion o glazing ma e ials; II. P epa a ion o he spec opho ome e ; III. Cleaning, Iden i ica ion, and Fixa ion o he Specimen on he De ice; and IV. Desc ip ion o he Spec opho ome ic Tes s. 2.1. Cha ac e iza ion o he Glazing Ma e ials Samples o 6 mm hick glazings we e used in he spec opho ome ic es s. Ten ypes o simple glazings and wo ypes o double glazings we e analyzed. The double glazings we e moun ed on ha d pape wi h he aid o a de ice (Figu e 3a,b). Sus ainabili y 2021, 13, x FOR PEER REVIEW 5 o 20 The nea -in a ed co esponds o he la ge pa o he sola spec um ha c osses a colo less glass, o ins ance, in high p opo ions. Re e ences o some speci ie s ega ding such a egion o he spec um include s a emen s as “glass is gene ally opaque o he in- a ed”, howe e , his is w ong in o ma ion [8]. A spec opho ome ic cha ac e iza ion o glazings was accomplished o he s udy o componen s o a modula açade sys em in Po ugal. The s udy ocused on esul s o spec opho ome ic measu emen s o op ical p ope ies, speci ically, he ansmi ance o some ypes o simple glazings and wo ypes o double glazings [12–14]. The esul s enabled he e i ica ion o he glazing e iciency in e ms o dayligh and he co ela ion o he mal pe o mance and p o ided subsidies and indica ions o he speci ica ion and adequa e uses o anspa en su aces. They also complemen ed he da ashee s o he manu ac u es. An e alua ion o he ansmission o glazings by spec o- pho ome ic es s enables he analysis o he di e en egions o he spec um (ul a iole , isible, and in a ed) indi idually and no as a whole, as i occu s wi h pa ame e s, such as sola ac o and shading coe icien , which a e calcula ed in a global way wi hou aking in o accoun he di e ences o beha io pe egion o he spec um. 2. Ma e ials and Me hods The de elopmen o his esea ch included he ollowing asks: I. Cha ac e iza ion o glazing ma e ials; II. P epa a ion o he spec opho ome e ; III. Cleaning, Iden i ica ion, and Fixa ion o he Specimen on he De ice; and IV. Desc ip ion o he Spec opho ome ic Tes s. 2.1. Cha ac e iza ion o he Glazing Ma e ials Samples o 6 mm hick glazings we e used in he spec opho ome ic es s. Ten ypes o simple glazings and wo ypes o double glazings we e analyzed. The double glazings we e moun ed on ha d pape wi h he aid o a de ice (Figu e 3a,b). (a) (b) Figu e 3. De ice made wi h ha d pape o he con o ma ion o he double glazing (a); de ice wi h he specimens posi ioned (b). This de ice enabled he con igu a ion o he double glazings wi h an indoo ai laye . The samples we e placed 6 mm om each o he in he spec opho ome e , di e en ly om he usual posi ion, ha is, 12 mm. Howe e , he esul s would be signi ican o he analysis o he in luence o he ai laye on he ansmission o he double glazings. Rec angula samples o 50 mm × 50 mm we e used o all eigh ypes o glazings. The in e al o he spec um was 200 o 1100 nm, which comp ised h ee egions: ul a iole (200 o 380 nm), isible (380 o 780 nm), and nea -in a ed (780 o 1100 nm). Table 1 shows he cha ac e is ics o he samples analyzed. Figu e 3. De ice made wi h ha d pape o he con o ma ion o he double glazing ( a ); de ice wi h he specimens posi ioned (b). This de ice enabled he con igu a ion o he double glazings wi h an indoo ai laye . The samples we e placed 6 mm om each o he in he spec opho ome e , di e en ly om he usual posi ion, ha is, 12 mm. Howe e , he esul s would be signi ican o he analysis o he in luence o he ai laye on he ansmission o he double glazings. Rec angula samples o 50 mm × 50 mm we e used o all eigh ypes o glazings. The in e al o he spec um was 200 o 1100 nm, which comp ised h ee egions: ul a iole (200 o 380 nm), isible (380 o 780 nm), and nea -in a ed (780 o 1100 nm). Table 1shows he cha ac e is ics o he samples analyzed. The glazings we e selec ed mainly acco ding o hei cha ac e is ics ega ding o e all hea ans e (U- alue) and Visible T ansmi ance. The equisi e o he mal quali y is he U- alue, o which accep able maximum alues (Umáx) a e limi ed and e e ence alues (U e ) a e ecommended, acco ding o RCCTE Po uguese Code [ 15 ]. The maximum supe icial U- alues (Umáx) accep able in a cu en zone and he e e ence alues (U e ) o he elemen s o he buildings en elope a e shown in Table 2. Sus ainabili y 2021,13, 5437 6 o 19 Table 1. Cha ac e is ics o he Glass Specimens. Iden i ica ion Type o Glass Thickness Numbe o Specimens Posi ion o Coa ing Dimension 50 ×50 mm Glass A Glass wi h a sola con ol me allic oil ha con e s i s cha ac e is ics o sola con ol. 6 mm 3 Face 2 Glass B G een glass wi h a sola con ol me allic oil ha con e s i s cha ac e is ics o sola con ol. 6 mm 3 Glass C Sel -cleaning glass manu ac u ed by deposi ing a anspa en laye o pho oca aly ic and hyd ophilic mine al ma e ial on o clea glass. 6 mm 3 Face 1 Glass D Glass wi h a low-emissi i y oil. 6 mm 3 Face 2 Glass E Glass wi h an ex emely low-emissi i y oil. 6 mm 3 Face 2 Glass F Clea loa glass, which has been coa ed wi h me allic oxides by magne ically enhanced ca hodic spu e ing unde acuum condi ions. 6 mm 3 Face 2 Glass G High quali y, clea annealed glass, manu ac u ed by he loa p ocess. 6 mm 3 No coa ing Glass H Highly anspa en ex a clea glass, which has e y li le esidual colo . 6 mm 3 No coa ing Glazing 04 Glass B 6 mm 3 Bo h in Face 2 Glass E Glazing 07 Glass C 6 mm 3 Glass C: Face 1 Glass G Faces o Double Glazing Sus ainabili y 2021, 13, x FOR PEER REVIEW 6 o 20 Table 1. Cha ac e is ics o he Glass Specimens. Iden i ica ion Type o Glass Thickness Numbe o Specimens Posi ion o Coa ing Dimension 50 × 50 mm Glass A Glass wi h a sola con ol me- allic oil ha con e s i s cha - ac e is ics o sola con ol. 6 mm 3 Face 2 Glass B G een glass wi h a sola con- ol me allic oil ha con e s i s cha ac e is ics o sola con- ol. 6 mm 3 Glass C Sel -cleaning glass manu ac- u ed by deposi ing a ans- pa en laye o pho oca aly ic and hyd ophilic mine al ma- e ial on o clea glass. 6 mm 3 Face 1 Glass D Glass wi h a low-emissi i y oil. 6 mm 3 Face 2 Glass E Glass wi h an ex emely low- emissi i y oil. 6 mm 3 Face 2 Glass F Clea loa glass, which has been coa ed wi h me allic ox- ides by magne ically en- hanced ca hodic spu e ing unde acuum condi ions. 6 mm 3 Face 2 Glass G High quali y, clea annealed glass, manu ac u ed by he loa p ocess. 6 mm 3 No coa ing Glass H Highly anspa en ex a clea glass, which has e y li le e- sidual colo . 6 mm 3 No coa ing Glazing 04 Glass B 6 mm 3 Bo h in Face 2 Glass E Glazing 07 Glass C 6 mm 3 Glass C: Face 1 Glass G Faces o Double Glazing Ai laye : 6 mm The glazings we e selec ed mainly acco ding o hei cha ac e is ics ega ding o e all hea ans e (U- alue) and Visible T ansmi ance. The equisi e o he mal quali y is he U- alue, o which accep able maximum alues (Umáx) a e limi ed and e e ence alues (U e ) a e ecommended, acco ding o RCCTE Po uguese Code [15]. The maximum su- pe icial U- alues (Umáx) accep able in a cu en zone and he e e ence alues (U e ) o he elemen s o he buildings en elope a e shown in Table 2. Ai laye : 6 mm Table 2. Maximum su ace hea ans e coe icien accep able and e e ence su ace hea ans e coe icien [15]. Elemen s Umáx (W/m2·◦C) Clima ic Zone I1 Clima ic Zone I2 Clima ic Zone I3 Ou doo elemen s in a cu en zone UmáxU e UmáxU e UmáxU e Ve ical Opaque zones 1.80 0.70 1.60 0.60 1.45 0.50 Ho izon al opaque zones 1.25 0.50 1.00 0.45 0.90 0.40 Glazings U e (W/m2·◦C) Clima ic Zone I1 Clima ic Zone I2 Clima ic Zone I3 - 4.30 - 3.30 - 3.30 The e o e, he U- alue o he glazings should no exceed 3.30 W/m 2·◦ C, so as o mee mos zones. Mo eo e , maximum sola ac o s accep able (g Sus ainabili y 2021, 13, x FOR PEER REVIEW 7 o 20 Table 2. Maximum su ace hea ans e coe icien accep able and e e ence su ace hea ans e coe icien [15]. Elemen s Umáx (W/m2·° C) Clima ic Zone I1 Clima ic Zone I2 Clima ic Zone I3 Ou doo elemen s in a cu en zone Umáx U e Umáx U e Umáx U e Ve ical Opaque zones 1.80 0.70 1.60 0.60 1.45 0.50 Ho izon al opaque zones 1.25 0.50 1.00 0.45 0.90 0.40 Glazings U e (W/m2·°C) Clima ic Zone I1 Clima ic Zone I2 Clima ic Zone I3 - 4.30 - 3.30 - 3.30 The e o e, he U- alue o he glazings should no exceed 3.30 W/m2·°C, so as o mee mos zones. Mo eo e , maximum sola ac o s accep able (g┴) a e ecommended. No glazing o any building ha is no no he n-o ien ed (be ween he no hwes and he no heas ) and whose o al a ea does no exceed 5% o he use ul pa emen mus show a sola ac o co esponding o he glazed oid wi h he espec i e p o ec ion de ices 100% ac i e ha exceeds he alues indica ed (Table 3). Table 3. Maximum Sola Fac o accep ed o glazings [15]. The mal Ine ia Maximum Sola Fac o Accep ed Clima ic Zone V1 Clima ic Zone V2 Clima ic Zone V3 Poo 0.15 0.15 0.10 Medium 0.56 0.56 0.50 High 0.56 0.56 0.50 Table 4 [16] shows o he cha ac e is ics o glasses, as he U- alues, sola ac o , shad- ing coe icien , and ela i e hea gain o he glazings s udied. Rega ding he spec opho- ome ic es s, images o he samples will be shown, so as o p o ide he isual aspec o he selec ed ma e ial. The s udied glasses a e: • Glass A is a glass wi h a sola con ol me allic oil ha con e s i s cha ac e is ics o sola con ol; • Glass B is a g een glass wi h a sola con ol me allic oil ha con e s i s cha ac e is ics o sola con ol; • Glass C is sel -cleaning glass manu ac u ed by deposi ing a anspa en laye o pho- oca aly ic and hyd ophilic mine al ma e ial on o clea glass; • Glass D is a glass wi h a low-emissi i y oil; • Glass E is a glass wi h an ex emely low-emissi i y oil; • Glass F is clea loa glass ha has been coa ed wi h me allic oxides by magne ically enhanced ca hodic spu e ing unde acuum condi ions and sola con ol p ope ies; • Glass G is a high quali y, clea annealed glass, manu ac u ed by he loa p ocess; • Glass H is a highly anspa en ex a clea glass, which has e y li le esidual colo ; • Glazings 04 and 07 a e double glazings. ) a e ecommended. No glazing o any building ha is no no he n-o ien ed (be ween he no hwes and he no heas ) and whose o al a ea does no exceed 5% o he use ul pa emen mus show a sola ac o co esponding o he glazed oid wi h he espec i e p o ec ion de ices 100% ac i e ha exceeds he alues indica ed (Table 3). Sus ainabili y 2021,13, 5437 7 o 19 Table 3. Maximum Sola Fac o accep ed o glazings [15]. The mal Ine ia Maximum Sola Fac o Accep ed Clima ic Zone V1 Clima ic Zone V2 Clima ic Zone V3 Poo 0.15 0.15 0.10 Medium 0.56 0.56 0.50 High 0.56 0.56 0.50 Table 4[ 16 ] shows o he cha ac e is ics o glasses, as he U- alues, sola ac o , shading coe icien , and ela i e hea gain o he glazings s udied. Rega ding he spec opho ome ic es s, images o he samples will be shown, so as o p o ide he isual aspec o he selec ed ma e ial. The s udied glasses a e: • Glass A is a glass wi h a sola con ol me allic oil ha con e s i s cha ac e is ics o sola con ol; • Glass B is a g een glass wi h a sola con ol me allic oil ha con e s i s cha ac e is ics o sola con ol; • Glass C is sel -cleaning glass manu ac u ed by deposi ing a anspa en laye o pho oca aly ic and hyd ophilic mine al ma e ial on o clea glass; •Glass D is a glass wi h a low-emissi i y oil; •Glass E is a glass wi h an ex emely low-emissi i y oil; • Glass F is clea loa glass ha has been coa ed wi h me allic oxides by magne ically enhanced ca hodic spu e ing unde acuum condi ions and sola con ol p ope ies; •Glass G is a high quali y, clea annealed glass, manu ac u ed by he loa p ocess; •Glass H is a highly anspa en ex a clea glass, which has e y li le esidual colo ; •Glazings 04 and 07 a e double glazings. Table 4. Cha ac e is ics o he Glazings. Cha ac e is ics Glazings Glass A (Sola Con ol) Glass B (G een Sola Con ol) Glass C (Sel -Cleaning) Pane Ou e 6 mm 6 mm 6 mm U-Value (W/m2K) 5.683 5.683 5.799 Sola Hea Gain Coe icien (SHGC) 0.503 0.432 0.814 Shading coe icien 0.57 0.496 0.936 Rela i e Hea Gain (W/m2)403 351 631 Cha ac e is ics Glazings Glass D (Low-E) Glass E (Ex emely Low-E) Glass F (Clea Floa -Sola Con ol) Pane Ou e 6 mm 6 mm 6 mm U-Value (W/m2K) 5.665 5.665 5.661 Sola Hea Gain Coe icien (SHGC) 0.708 0.617 0.454 Shading coe icien 0.814 0.709 0.521 Rela i e Hea Gain (W/m2)551 485 366 Sus ainabili y 2021,13, 5437 8 o 19 Table 4. Con . Cha ac e is ics Glazings Glass G (Clea Floa Annealed) Glass H (Ex a Clea ) Pane Ou e 6 mm 6 mm U-Value (W/m2K) 5.799 5.799 Sola Hea Gain Coe icien (SHGC) 0.85 0.898 Shading coe icien 0.976 1.032 Rela i e Hea Gain (W/m2)657 692 Cha ac e is ics Glazings Glazing 04 (Double) Glazing 07 (Double) Pane Ou e Glass B Glass C Inne Glass E Glass G U-Value (W/m2K) 2.363 3.102 Sola Hea Gain Coe icien (SHGC) 0.333 0.714 Shading coe icien 0.383 0.821 Rela i e Hea Gain (W/m2)260 543 Table 5shows he samples o he selec ed glazings. The glazings wi h a me allic-o igin coa ing, mainly Glass D, Glass E, and Glass F oxidize in con ac wi h he ai . The e o e, in he composi ions o double glazing, he coa ing mus be placed inside. In he samples, he us y pa co esponds o he ab asion band ha shows he ace wi h he ilm, so ha he glazings could be co ec ly posi ioned in he spec opho ome ic cha ac e iza ion es s. Table 5. Specimens o Glasses. Glass A (Sola Con ol) Glass B (G een Sola Con ol) Glass C (Sel -Cleaning) Sus ainabili y 2021, 13, x FOR PEER REVIEW 9 o 20 Table 5. Specimens o Glasses. Glass (Sola Con ol) Glass B (G een Sola Con ol) Glass C (Sel -Cleaning) Glass D (low-e) Glass E (ex emely low-e) Glass F (clea loa -sola con ol) Glass G (clea loa annealed) Glass H (ex a clea ) 2.2. P epa a ion o he Spec opho ome e Acco ding o he ASTM [17], he spec opho ome e is he ideal equipmen o p o ide he da a o ansmission pe cen age o he ul a iole , isible, and nea -in a ed egions. I also enables a sweeping in he spec um only in he egion o in e es . A spec opho ome e was used in he es s. I enables a monoch oma ic ligh shea o pass h ough a sample and measu es he amoun o ligh abso bed (Figu e 4). Wi h he aid o a p ism, i sepa a es he ligh in o shea es o di e en wa eleng hs (as in he ain- bow, wi h he sepa a ion o he colo s o whi e ligh . The e o e, a monoch oma ic ligh shea (o only one, o almos only one wa eleng h) can pass h ough he sample. The spec- opho ome e shows he amoun o ligh abso bed a each wa eleng h and p o ides da a on abso p ion, e lec ion, and ansmission o he ma e ial o di e en incidence angles. Figu e 4. UNICAM UV/VIS Spec opho ome e . Sus ainabili y 2021, 13, x FOR PEER REVIEW 9 o 20 Table 5. Specimens o Glasses. Glass (Sola Con ol) Glass B (G een Sola Con ol) Glass C (Sel -Cleaning) Glass D (low-e) Glass E (ex emely low-e) Glass F (clea loa -sola con ol) Glass G (clea loa annealed) Glass H (ex a clea ) 2.2. P epa a ion o he Spec opho ome e Acco ding o he ASTM [17], he spec opho ome e is he ideal equipmen o p o ide he da a o ansmission pe cen age o he ul a iole , isible, and nea -in a ed egions. I also enables a sweeping in he spec um only in he egion o in e es . A spec opho ome e was used in he es s. I enables a monoch oma ic ligh shea o pass h ough a sample and measu es he amoun o ligh abso bed (Figu e 4). Wi h he aid o a p ism, i sepa a es he ligh in o shea es o di e en wa eleng hs (as in he ain- bow, wi h he sepa a ion o he colo s o whi e ligh . The e o e, a monoch oma ic ligh shea (o only one, o almos only one wa eleng h) can pass h ough he sample. The spec- opho ome e shows he amoun o ligh abso bed a each wa eleng h and p o ides da a on abso p ion, e lec ion, and ansmission o he ma e ial o di e en incidence angles. Figu e 4. UNICAM UV/VIS Spec opho ome e . Sus ainabili y 2021, 13, x FOR PEER REVIEW 9 o 20 Table 5. Specimens o Glasses. Glass (Sola Con ol) Glass B (G een Sola Con ol) Glass C (Sel -Cleaning) Glass D (low-e) Glass E (ex emely low-e) Glass F (clea loa -sola con ol) Glass G (clea loa annealed) Glass H (ex a clea ) 2.2. P epa a ion o he Spec opho ome e Acco ding o he ASTM [17], he spec opho ome e is he ideal equipmen o p o ide he da a o ansmission pe cen age o he ul a iole , isible, and nea -in a ed egions. I also enables a sweeping in he spec um only in he egion o in e es . A spec opho ome e was used in he es s. I enables a monoch oma ic ligh shea o pass h ough a sample and measu es he amoun o ligh abso bed (Figu e 4). Wi h he aid o a p ism, i sepa a es he ligh in o shea es o di e en wa eleng hs (as in he ain- bow, wi h he sepa a ion o he colo s o whi e ligh . The e o e, a monoch oma ic ligh shea (o only one, o almos only one wa eleng h) can pass h ough he sample. The spec- opho ome e shows he amoun o ligh abso bed a each wa eleng h and p o ides da a on abso p ion, e lec ion, and ansmission o he ma e ial o di e en incidence angles. Figu e 4. UNICAM UV/VIS Spec opho ome e . Glass D (low-e) Glass E (ex emely low-e) Glass F (clea loa -sola con ol) Sus ainabili y 2021, 13, x FOR PEER REVIEW 9 o 20 Table 5. Specimens o Glasses. Glass (Sola Con ol) Glass B (G een Sola Con ol) Glass C (Sel -Cleaning) Glass D (low-e) Glass E (ex emely low-e) Glass F (clea loa -sola con ol) Glass G (clea loa annealed) Glass H (ex a clea ) 2.2. P epa a ion o he Spec opho ome e Acco ding o he ASTM [17], he spec opho ome e is he ideal equipmen o p o ide he da a o ansmission pe cen age o he ul a iole , isible, and nea -in a ed egions. I also enables a sweeping in he spec um only in he egion o in e es . A spec opho ome e was used in he es s. I enables a monoch oma ic ligh shea o pass h ough a sample and measu es he amoun o ligh abso bed (Figu e 4). Wi h he aid o a p ism, i sepa a es he ligh in o shea es o di e en wa eleng hs (as in he ain- bow, wi h he sepa a ion o he colo s o whi e ligh . The e o e, a monoch oma ic ligh shea (o only one, o almos only one wa eleng h) can pass h ough he sample. The spec- opho ome e shows he amoun o ligh abso bed a each wa eleng h and p o ides da a on abso p ion, e lec ion, and ansmission o he ma e ial o di e en incidence angles. Figu e 4. UNICAM UV/VIS Spec opho ome e . Sus ainabili y 2021, 13, x FOR PEER REVIEW 9 o 20 Table 5. Specimens o Glasses. Glass (Sola Con ol) Glass B (G een Sola Con ol) Glass C (Sel -Cleaning) Glass D (low-e) Glass E (ex emely low-e) Glass F (clea loa -sola con ol) Glass G (clea loa annealed) Glass H (ex a clea ) 2.2. P epa a ion o he Spec opho ome e Acco ding o he ASTM [17], he spec opho ome e is he ideal equipmen o p o ide he da a o ansmission pe cen age o he ul a iole , isible, and nea -in a ed egions. I also enables a sweeping in he spec um only in he egion o in e es . A spec opho ome e was used in he es s. I enables a monoch oma ic ligh shea o pass h ough a sample and measu es he amoun o ligh abso bed (Figu e 4). Wi h he aid o a p ism, i sepa a es he ligh in o shea es o di e en wa eleng hs (as in he ain- bow, wi h he sepa a ion o he colo s o whi e ligh . The e o e, a monoch oma ic ligh shea (o only one, o almos only one wa eleng h) can pass h ough he sample. The spec- opho ome e shows he amoun o ligh abso bed a each wa eleng h and p o ides da a on abso p ion, e lec ion, and ansmission o he ma e ial o di e en incidence angles. Figu e 4. UNICAM UV/VIS Spec opho ome e . Sus ainabili y 2021, 13, x FOR PEER REVIEW 9 o 20 Table 5. Specimens o Glasses. Glass (Sola Con ol) Glass B (G een Sola Con ol) Glass C (Sel -Cleaning) Glass D (low-e) Glass E (ex emely low-e) Glass F (clea loa -sola con ol) Glass G (clea loa annealed) Glass H (ex a clea ) 2.2. P epa a ion o he Spec opho ome e Acco ding o he ASTM [17], he spec opho ome e is he ideal equipmen o p o ide he da a o ansmission pe cen age o he ul a iole , isible, and nea -in a ed egions. I also enables a sweeping in he spec um only in he egion o in e es . A spec opho ome e was used in he es s. I enables a monoch oma ic ligh shea o pass h ough a sample and measu es he amoun o ligh abso bed (Figu e 4). Wi h he aid o a p ism, i sepa a es he ligh in o shea es o di e en wa eleng hs (as in he ain- bow, wi h he sepa a ion o he colo s o whi e ligh . The e o e, a monoch oma ic ligh shea (o only one, o almos only one wa eleng h) can pass h ough he sample. The spec- opho ome e shows he amoun o ligh abso bed a each wa eleng h and p o ides da a on abso p ion, e lec ion, and ansmission o he ma e ial o di e en incidence angles. Figu e 4. UNICAM UV/VIS Spec opho ome e . Glass G (clea loa annealed) Glass H (ex a clea ) Sus ainabili y 2021, 13, x FOR PEER REVIEW 9 o 20 Table 5. Specimens o Glasses. Glass (Sola Con ol) Glass B (G een Sola Con ol) Glass C (Sel -Cleaning) Glass D (low-e) Glass E (ex emely low-e) Glass F (clea loa -sola con ol) Glass G (clea loa annealed) Glass H (ex a clea ) 2.2. P epa a ion o he Spec opho ome e Acco ding o he ASTM [17], he spec opho ome e is he ideal equipmen o p o ide he da a o ansmission pe cen age o he ul a iole , isible, and nea -in a ed egions. I also enables a sweeping in he spec um only in he egion o in e es . A spec opho ome e was used in he es s. I enables a monoch oma ic ligh shea o pass h ough a sample and measu es he amoun o ligh abso bed (Figu e 4). Wi h he aid o a p ism, i sepa a es he ligh in o shea es o di e en wa eleng hs (as in he ain- bow, wi h he sepa a ion o he colo s o whi e ligh . The e o e, a monoch oma ic ligh shea (o only one, o almos only one wa eleng h) can pass h ough he sample. The spec- opho ome e shows he amoun o ligh abso bed a each wa eleng h and p o ides da a on abso p ion, e lec ion, and ansmission o he ma e ial o di e en incidence angles. Figu e 4. UNICAM UV/VIS Spec opho ome e . Sus ainabili y 2021, 13, x FOR PEER REVIEW 9 o 20 Table 5. Specimens o Glasses. Glass (Sola Con ol) Glass B (G een Sola Con ol) Glass C (Sel -Cleaning) Glass D (low-e) Glass E (ex emely low-e) Glass F (clea loa -sola con ol) Glass G (clea loa annealed) Glass H (ex a clea ) 2.2. P epa a ion o he Spec opho ome e Acco ding o he ASTM [17], he spec opho ome e is he ideal equipmen o p o ide he da a o ansmission pe cen age o he ul a iole , isible, and nea -in a ed egions. I also enables a sweeping in he spec um only in he egion o in e es . A spec opho ome e was used in he es s. I enables a monoch oma ic ligh shea o pass h ough a sample and measu es he amoun o ligh abso bed (Figu e 4). Wi h he aid o a p ism, i sepa a es he ligh in o shea es o di e en wa eleng hs (as in he ain- bow, wi h he sepa a ion o he colo s o whi e ligh . The e o e, a monoch oma ic ligh shea (o only one, o almos only one wa eleng h) can pass h ough he sample. The spec- opho ome e shows he amoun o ligh abso bed a each wa eleng h and p o ides da a on abso p ion, e lec ion, and ansmission o he ma e ial o di e en incidence angles. Figu e 4. UNICAM UV/VIS Spec opho ome e . Sus ainabili y 2021,13, 5437 9 o 19 2.2. P epa a ion o he Spec opho ome e Acco ding o he ASTM [ 17 ], he spec opho ome e is he ideal equipmen o p o ide he da a o ansmission pe cen age o he ul a iole , isible, and nea -in a ed egions. I also enables a sweeping in he spec um only in he egion o in e es . A spec opho ome e was used in he es s. I enables a monoch oma ic ligh shea o pass h ough a sample and measu es he amoun o ligh abso bed (Figu e 4). Wi h he aid o a p ism, i sepa a es he ligh in o shea es o di e en wa eleng hs (as in he ainbow, wi h he sepa a ion o he colo s o whi e ligh . The e o e, a monoch oma ic ligh shea (o only one, o almos only one wa eleng h) can pass h ough he sample. The spec opho ome e shows he amoun o ligh abso bed a each wa eleng h and p o ides da a on abso p ion, e lec ion, and ansmission o he ma e ial o di e en incidence angles. Sus ainabili y 2021, 13, x FOR PEER REVIEW 9 o 20 Table 5. Specimens o Glasses. Glass (Sola Con ol) Glass B (G een Sola Con ol) Glass C (Sel -Cleaning) Glass D (low-e) Glass E (ex emely low-e) Glass F (clea loa -sola con ol) Glass G (clea loa annealed) Glass H (ex a clea ) 2.2. P epa a ion o he Spec opho ome e Acco ding o he ASTM [17], he spec opho ome e is he ideal equipmen o p o ide he da a o ansmission pe cen age o he ul a iole , isible, and nea -in a ed egions. I also enables a sweeping in he spec um only in he egion o in e es . A spec opho ome e was used in he es s. I enables a monoch oma ic ligh shea o pass h ough a sample and measu es he amoun o ligh abso bed (Figu e 4). Wi h he aid o a p ism, i sepa a es he ligh in o shea es o di e en wa eleng hs (as in he ain- bow, wi h he sepa a ion o he colo s o whi e ligh . The e o e, a monoch oma ic ligh shea (o only one, o almos only one wa eleng h) can pass h ough he sample. The spec- opho ome e shows he amoun o ligh abso bed a each wa eleng h and p o ides da a on abso p ion, e lec ion, and ansmission o he ma e ial o di e en incidence angles. Figu e 4. UNICAM UV/VIS Spec opho ome e . Figu e 4. UNICAM UV/VIS Spec opho ome e . UNICAM UV/VIS was he de ice used o he es s. I p o ides da a on abso p ion, e lec ion, and ansmission o he es ed ma e ials. By i ue o ou objec i e, only he ansmission mode was used. A ungs en lamp was used o he whole spec um. The samples we e es ed a 0 ◦ wi h he no mal incidence (shea pe pendicula o he sample) and he shea incidence was in acco dance wi h he coa ing o he samples, as i ollowed he ecommenda ions o he manu ac u e o bo h simple and double glazings analyzed. In he speci ic case o ansmission, g aphs can be gene a ed wi h he ansmission pe cen age o he ul a iole , isible, and nea -in a ed egions and he esul s can be compa ed among hemsel es o wi h a colo less simple glazing, o example, o he e i ica ion o he e iciency o he glazings ega ding he illuminance le el [7]. The in o ma ion o he glass manu ac u e s is limi ed o alues o mechanical e- sis ance, acous ic insula ion, and ene ge ic ansmission o sola adia ion. The la e is ea ed in a gene alized way and he da a on he isible egion and sola ac o igno e he beha io o he ma e ial in he ul a iole and in a ed adia ion. The da a usually ega d he ansmi ance o he incidence o no mal adia ion o he su ace, which occu s in a minimum pe iod o ime. Some in o ma ion e e s o he sola hea gain coe icien . Howe e , in mos cases, no da a on he in a ed a e p o ided, which hampe s an indi idual and co ec analysis o he spec al beha io o he glass. The highes concen a ion o in a ed is in he 780 o 1500 nm in e al and he pe cen - age o wa eleng hs longe han 1500 nm is e y small. The e o e, analyses o he 780 o 1100 nm in e al used in ou esea ch a e alid. This is he limi ing in e al in which he de ice u ilized pe o ms he sweeping The da a p o ided by he spec opho ome e enabled he c ea ion o cu es wi h he ansmission da a and analysis o he in eg a ion o bo h a eas ha co espond o each egion o he spec um (ul a iole , isible, and in a ed) and he o al a ea o he cu es. The e o e, he ansmission could be compa ed in cha ac e is ic in e als. Sus ainabili y 2021,13, 5437 16 o 19 Sus ainabili y 2021, 13, x FOR PEER REVIEW 17 o 20 Figu e 13. To al T ansmission o Simple and Double Glazings. Besides he Glass H, which can be indica ed o use in T ombe walls, Glass G and Glass C mus be highligh ed, as hey ha e shown he highes alues o o al ansmission in he cha ac e is ic in e als. The o al ansmission o glass 07 (Glass C-sel -cleaning in he ou e pane and Glass G-clea loa annealed, in he inne pane), mainly in he in a ed egion, has also p o en i s e iciency ega ding he dec ease in he hea ene gy needs. The da a o ansmission o sola adia ion a e di ec ly ela ed o he he mal com o condi- ions, mainly in ela ion o he esul s o he in a ed in e al. Figu e 14 clea ly shows he maximum and minimum ansmission alues o Glass H (ex a clea ) and glazing 04, espec i ely. Glass B (g een sola con ol) enables good illumina ion and weakens he in a ed adia ion in he in e al analyzed, educing he hea ing in his egion. G een glasses a e known o always end o dec ease ansmission in longe wa eleng hs. Figu e 14. T ansmission cu es o all glazings. Ano he ac o ha mus be highligh ed is he di e si y o beha io s ega ding he ansmission shown by he glasses (see abo e g aph), e en o ma e ials o simila cha - ac e is ics in e ms o composi ion. Figu e 13. To al T ansmission o Simple and Double Glazings. Besides he Glass H, which can be indica ed o use in T ombe walls, Glass G and Glass C mus be highligh ed, as hey ha e shown he highes alues o o al ansmission in he cha ac e is ic in e als. The o al ansmission o glass 07 (Glass C-sel -cleaning in he ou e pane and Glass G-clea loa annealed, in he inne pane), mainly in he in a ed egion, has also p o en i s e iciency ega ding he dec ease in he hea ene gy needs. The da a o ansmission o sola adia ion a e di ec ly ela ed o he he mal com o condi ions, mainly in ela ion o he esul s o he in a ed in e al. Figu e 14 clea ly shows he maximum and minimum ansmission alues o Glass H (ex a clea ) and glazing 04, espec i ely. Glass B (g een sola con ol) enables good illumina ion and weakens he in a ed adia ion in he in e al analyzed, educing he hea ing in his egion. G een glasses a e known o always end o dec ease ansmission in longe wa eleng hs. Sus ainabili y 2021, 13, x FOR PEER REVIEW 17 o 20 Figu e 13. To al T ansmission o Simple and Double Glazings. Besides he Glass H, which can be indica ed o use in T ombe walls, Glass G and Glass C mus be highligh ed, as hey ha e shown he highes alues o o al ansmission in he cha ac e is ic in e als. The o al ansmission o glass 07 (Glass C-sel -cleaning in he ou e pane and Glass G-clea loa annealed, in he inne pane), mainly in he in a ed egion, has also p o en i s e iciency ega ding he dec ease in he hea ene gy needs. The da a o ansmission o sola adia ion a e di ec ly ela ed o he he mal com o condi- ions, mainly in ela ion o he esul s o he in a ed in e al. Figu e 14 clea ly shows he maximum and minimum ansmission alues o Glass H (ex a clea ) and glazing 04, espec i ely. Glass B (g een sola con ol) enables good illumina ion and weakens he in a ed adia ion in he in e al analyzed, educing he hea ing in his egion. G een glasses a e known o always end o dec ease ansmission in longe wa eleng hs. Figu e 14. T ansmission cu es o all glazings. Ano he ac o ha mus be highligh ed is he di e si y o beha io s ega ding he ansmission shown by he glasses (see abo e g aph), e en o ma e ials o simila cha - ac e is ics in e ms o composi ion. Figu e 14. T ansmission cu es o all glazings. Ano he ac o ha mus be highligh ed is he di e si y o beha io s ega ding he ansmission shown by he glasses (see abo e g aph), e en o ma e ials o simila cha ac- e is ics in e ms o composi ion. Sus ainabili y 2021,13, 5437 17 o 19 Acco ding o he esul s, he sola con ol glasses (colo less, g een, Glass F-clea loa - sola con ol and Glass A- sola con ol) ha e shown li le anspa ency o he ul a iole , he e o e hey can be adequa e o shop windows, comme cial cen e s, museums, and e en esidences. Glazing 04 can be highligh ed in e ms o con ol o ul a iole sola adia ion, wi h he lowes ansmission o his egion. This spec um band has high ene ge ic powe , which de e io a es and discolo s he ma e ials and may e en cause skin diseases. Howe e , in some si ua ions, i s incidence can be impo an , as in eco e y a eas in hospi als, as i is esponsible o he syn hesis o some i amins. Glass C, which has a sel -cleaning coa ing, exhibi ed good he mal beha io , based on he esul s o he mal pe o mance simula ions o o he esea ch s ages [ 14 ]. Such esul s show he pe o mance o his glass is good, ega ding he dec ease in he hea ene gy needs. Figu e 14 also shows a cu e o he possible beha io o an ideal glass in e ms o adia ion ansmission, which a ies in unc ion o he clima e o which he ma e ial will be indica ed. Fo ins ance, he glass conside ed ideal o açades in ho egions and exposed o sola adia ion daily should p esen a good ansmission in he isible egion and ligh ansmission in he in a ed. The ma e ial mus allow he en y o ligh and a oid he en y o hea om he p edominan clima ic condi ions. As he clima e in Po ugal is empe a e, he ideal glazing should wo k as a ba ie agains ul a iole adia ion, enable he passage o he isible ligh o a o dayligh ing, and enable a pa o In a ed ligh o p omo e passi e hea ing, hus he low-e glass use is a good indica ion. Al hough he s udy was done o he clima e o Po ugal, i is emphasized ha i can be consul ed o applica ion in o he loca ions, acco ding o he needs ha a e sough in he applica ion o glazing sui able o he clima e. Fo example, i an applica ion in a chi ec u e equi es minimizing issues ela ed o he ading o su aces, glass wi h he g ea e ansmission in he ul a iole egion should be a oided. I he applica ion objec i es o he glazing a e o imp o e he condi ions o dayligh , g ea e alues o ansmi ance should be sough in he isible egion and, inally, i he main cha ac e is ic o he applica ion o he glass is o minimize he hea ansmi ed o he in e io , glass wi h high ansmi ance in he in a ed egion should be a oided. The e o e, his analysis o wha is necessa y in e ms o speci ying he glazing acco ding o he clima e (mo e o less dayligh ing; mo e o less ansmission o hea ) mus be done i s and, knowing he ansmi ance o he glass o be applied in he h ee egions o he spec um, i is possible o make he speci ica ion mo e app op ia e o he clima e. 5. Conclusions Acco ding o he esul s o he spec opho ome ic es s, he double Glass B (g een sola con ol)—Glass E (ex emely low-e) (glazing 04) has shown a subs an ial ansmission dec ease in all egions o he spec um, especially in he isible egions (25.2%). On he o he hand, he double Glass C (sel -cleaning)—Glass G (clea loa annealed) (glazing 07) ansmi s 70.3% o he isible ligh , which gua an ees be e condi ions o dayligh . The g een double Glass B—Glass E (glazing 04) led o he lowes ansmission alue in he in a ed (2.6%) ega ding hea . The e o e, such glazing can be e icien in he dec ease o he nominal needs o cooling. Double Glass C—Glass G (glazing 07) led o a ansmission simila o ha o low-e (47.9%) in e ms o in a ed adia ion, which indica es i s use will cause s onge hea ing in an indoo habi able space. As he clima e in Po ugal is empe a e, he ideal glazing should wo k as a ba ie agains ul a iole adia ion and enable he passage o he isible ligh o a o dayligh ing. In o he wo ds, such glazing should enable good ansmission in he isible egion and a small amoun o hea om he nea -in a ed so as o help he hea ing o he indoo en i onmen . Low-emissi i y glazings display hose cha ac e is ics as hey usually show good he mal pe o mance o empe a e clima es. The esul s o high ansmission in he in a ed o some ma e ials analyzed show hei adequacy o use in coun ies o p edominan ly cold wea he . Sus ainabili y 2021,13, 5437 18 o 19 Each ype o glazing has led o dis inc ansmissions o each band o he sola spec um. The concep ion o a good dayligh ing sys em and he mal com o equi es a en ion ega ding he localiza ion and o ien a ion o he building, bu also he a ia ions o he dayligh in unc ion o he seasons o he yea , ime, and wea he condi ions. The esul s o he spec opho ome ic es s show de ining ansmission as adequa e only in unc ion o he luminous ansmission (in he isible egion) o he glazing may no be co ec , as he ansmission in he o he in e als will also in luence he he mal com o . The dimension o he glazed a ea, i s geog aphic o ien a ion, la i ude, and ime o he yea mus also be aken in o accoun . In he e alua ion o he dayligh ing condi ions, o ins ance, he le els o illuminance o an en i onmen can be adequa ed by he use o glazings o di e en pe cen ages o isible ansmission h ough he esizing o he windows. The le el o illuminance o an en i onmen is ela ed o no only he ype o glazing bu also o he sola o ien a ion, dimension, and disposi ion o he opening and he ex e nal obs acles, colo s o he in e nal su ace, among o he ac o s. Au ho Con ibu ions: Concep ualiza ion, H.M.S. and R.C.; Me hodology, H.M.S. and R.C.; Fo - mal analysis, L.B. and M.A.; In es iga ion, H.M.S.; Da a cu a ion, H.M.S.; W i ing—o iginal d a p epa a ion, e iew and edi ing, H.M.S.; Supe ision, L.B. and M.A.; P ojec adminis a ion, L.B. and M.A.; Funding acquisi ion, H.M.S. All au ho s ha e ead and ag eed o he published e sion o he manusc ip . Funding: This esea ch was unded by E asmus Mundus Ex e nal Coope a ion Window–ISAC: Imp o ing Skills Ac oss Con inen s (F amewo k Pa ne ship Ag eemen 2008-1021/001 FRAMEECW L16 Coimb a, Speci ic G an Ag eemen 2008-3628/001-001-MUN-ECW). Ins i u ional Re iew Boa d S a emen : No applicable. In o med Consen S a emen : No applicable. Da a A ailabili y S a emen : Da a suppo ing epo ed esul s can be ound a ailable online in: h ps:// eposi o ium.sdum.uminho.p /. Con lic s o In e es : The au ho s decla e no con lic o in e es . Re e ences 1. Kim, G.; Kim, J.T. 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