Urban microclimate parameters for buildings energy strategies

X The mal map o u ban space, www.ped obo jamunoz-a qui ec o.es, modi ica ion: cu Vi u io In e na ional jou nal o A chi ec u e Technology and Sus ainabili y Volume 2 1 ABSTRACT 1 Uni e si à degli S udi “G. d’Annunzio” di Chie i-Pesca a, Dipa imen o di A chi e u a Today, he ci ies need o inc ease ene gy e iciency, educe pollu ing emissions and achie e a su icien le el o sus ainabili y. The u ban mic oclima e plays an impo an ole on he buildings ene gy consump ion and he eeling o com o in he spaces. The mic oclima e pa ame e s a e o cen al impo ance o he ac i i ies ha a e ca ied ou in he open spaces and o a la ge ex en de e mine he use. The esponses o he mic oclima e may be unconscious bu e y o en esul in a di e en ia ed use o open spaces jus as unc ion o he di e en clima ic condi ions. Fo his eason, he aim o his wo k is ocused on he en i onmen al pa ame e s and on he me hodology o analysis aiming a he es ablishmen o bioclima ic s a egies o buildings on he basis o mo pho- ype o he componen s o he geome ies and su ace quali y o he ma e ials used in u ban spaces and in unc ion o he consequen mic oclima ic condi ions ob ained. KEYWORDS u ban mic oclima e, com o , ene gy e iciency, bioclima ic design U ban mic oclima e pa ame e s o buildings ene gy s a egies Michele Lepo e1 h p://dx.doi.o g/10.4995/ i u io-ija s.2016.6944 2 1. ENVIRONMENTAL DESIGN IN URBAN CONTEXT The en i onmen al pa ame e s ha a ec he ou side com o he mal condi ions, al hough simila o hose ela ing o he in e io spaces, a e cha ac e ized by a g ea e and mo e complex a iabili y. The e o e, because o his a iabili y and he b oad di e si ica ion o ac i i ies in which people a e in ol ed, he e ha e been so a ew a emp s o unde s and he com o condi ions on he ou side bu especially as he clima ic e ec s ou side could ha e an impac on he echnologies o he building en elop and consequen ly on he condi ions o com o wi hin he con ined spaces. One o he objec i es o en i onmen al design in u ban con ex s is he c ea ion o dis ic s wi h com o able open spaces. The mic oclima e pa ame e s a e he e o e o cen al impo ance o he ac i i ies ha a e ca ied ou in he open and o a la ge ex en de e mine he use. Fo his eason, unde s and he ichness o he mic oclima ic ea u es in o u ban spaces ou side, and he implica ions in e ms o com o o he people who use hem, opens up new possibili ies o he design o hese spaces bo h in e ms o new in e en ions, bo h in he e aining o exis ing agglome a ions. The s udy o he dis ic s mus be con igu ed h ough a se ies o analysis de eloped in successi e s ages o deepening he spa ial cha ac e is ics, echnological and en i onmen al conce ns bo h he se lemen s scale, is a ypological bo h echnological. In pa icula : sȩ analysis o geog aphical con ex and clima e; sȩ analysis o he mo phological cha ac e is ics o he building scale; sȩ analysis o he condi ions o com o ou side in he esiden ial se lemen s; sȩ analysis o he echnological cha ac e is ics o he building en elop; sȩ he sys em building-plan . 1.1 METHODOLOGY The me hodology is based on an e alua ion o he clima ic condi ions and he he mal com o in di e en condi ions. The clima ic pa ame e s a e ob ained by pa ame ic e alua ions and compu e simula ions based on luid dynamics, he modynamics and i adia ion in an u ban en i onmen using nume ic app oach. The g ea ad an age in he use o compu ing sys ems is he abili y o e alua e di e en scena ios. F om a ca e ul analysis on he ex e nal clima e condi ions and he mal com o in he immedia e neighbo hood o he esiden ial se lemen s, you wan o loca e he app op ia e echnologies o he ede elopmen o he indi idual uni s by imp o ing he pa ame e s o he mal com o inside o he dwellings hemsel es. P ima y objec i e, he e o e, is he sea ch o a me hodology o assess he quali y o he mic oclima ic public space, ha is epea able in cases and di e en places wi h e i ying he possible in luences o he ex e nal clima e on he o e all ene gy e iciency o he se lemen and he consequen iden i ica ion o app op ia e echnologies ha a e no based only on clima e class e e ing o he locali y. Speci ic objec i es: sȩ Analyze u ban spaces acco ding o he physical aspec s en i onmen al, h ough a sys em o indica o s ha cha ac e ize s udy a eas. sȩ De ine indica o s o analysis o he aspec s o mic oclima ic space, able o pu in ela ion he en i onmen al condi ions o he com o o use s in o de o de ine ce ain minimum quali y equi emen s. sȩ The iden i ica ion o a me hodology o he calcula ion capable o assessing he quali y mic oclima es o public space in an objec i e manne and eplicable in o he cases in o he places, e alua ing speci ic so wa e o he simula ion o he phenomena ha occu in he u ban space ou side. Vi u io In e na ional jou nal o A chi ec u e Technology and Sus ainabili y Volume 2 3 2. URBAN MICROCLIMATE U ban a eas ha e pa icula clima ic condi ion as esul s o complex u ban mic oclima es, whe e many ac o s come in o play. I is impo an o desc ibe how and why he u ban clima e di e s om he clima ic condi ion o he su ounding u al a eas. U ban and indus ial g ow h has caused signi ican changes in he adian balance o he u ban spaces, he con ec i e hea exchange be ween he g ound and i s buildings, he ai lowing abo e he u ban a ea and he hea gene a ion wi hin he ci y. The main consequence is di e ences in alue o ai empe a u e and in wind condi ions be ween u ban and u al a eas. Ai empe a u e in dense u ban a eas a e highe hen empe a u es in he su ounding coun yside. This di e en is known as he “u ban hea -island e ec and cha ac e ised almos e e y ci y o own in he wo ld. The hea ha is abso bed du ing he day by all u ban cons uc ions (buildings, oads, e c.) is e- emi ed a e sunse , and he g ea es empe a u e di e ences a e obse ed du ing he nigh . Fu he mo e, addi ional hea is gi en by all human hea sou ces. U ban space c ea es unique clima ic condi ions called he u ban mic oclima e. The i s conside a ion is ha i is possible associa e he u ban mo phology o mic oclima ic beha iou , o in o he wo ds, o de ine a mic oclima ic pa e ns cha ac e is ic o each u ban ypology. The second one, as men ioned be o e, is based on he obse a ion ha he en i onmen al condi ions in luence he use o u ban ou doo s spaces. I i is possible o quan i y he he mal com o h ough he s udy o clima ic pa ame e s, he modi ica ion o he u ban mic oclima e will a ec s he he mal com o o people. The con i ma ion o he wo assump ions leads o he de ini ion o he hi d hypo hesis: i is possible o mi iga e he impac o he mic oclima e h ough he modi ica ion o he cons uc ed u ban space, and consequen ly, imp o e ci izens he mal com o condi ions. The speci ic objec i es o achie e his aims a e: 1. De ine a sys em o indica o s o cha ac e ize and desc ibe he physical and en i onmen al aspec s o s udy a eas. These indica o s should be able o desc ibe he cu en si ua ion and guide e u bishmen p ojec . 2. De ine indica o s o he analysis o mic oclima ic aspec s o ou doo spaces, able o es ablish a ela ionship wi h en i onmen condi ions and com o sensa ion, in o de o ind a minimum quali y a ge . 3. Es ablish a calcula ion me hodology able o e alua e he mic oclima ic quali y and com o o public space in an objec i e way and sui able o he applica ion on o he cases and o he loca ions. 4. Elabo a e he guidelines o he e u bishmen o buil spaces om he pe spec i e o mic oclima ic and en i onmen al imp o emen o u ban a eas. 5. E alua e speci ic so wa e o he simula ion o clima ic phenomena which occu in ou doo u ban space. Figu e 1. Hea island e ec 4 2.1 ANALYSIS OF THERMAL COMFORT The en i onmen al pe o mance ela i e o he u ban space in i s en i e y is he desc ip ion o he he mohyg ome ic beha io mixed as a esul o he combina ion o mo phological pa ame e s, ma e and mic oclima e in ela ion o a speci ic use. This ype o desc ip ion i is use ul o make i h ough he use o he indica o o com o , because he indica o con ains in i sel he mixe o he pa ame e s in he game. I is impo an o use o com o indica o s in ela ion o en i onmen al equi emen s, whe he hey a e exp essed by use s o ha a e unawa e. To assess he en i onmen al pe o mance o an u ban space as a whole he e can be no limi o he analysis o he mic oclima ic condi ions in poin , as i canno be limi ed o e alua e he a ious pa ame e s indi idually. A good esul is ob ained by p o iding he a eal dis ibu ion o he com o condi ions h oughou he a ea. The maps o com o ep esen an e alua ion o he exis ing condi ions o a check o he design choices. F om he obse a ion o hese maps you can ge u he in o ma ion on he p ojec , which ela e in pa icula o he placemen o he u ban equipmen ha allow he ca ying ou o ac i i ies compa ible wi h he en i onmen al pe o mance in he gi en ime in e al. F om he e alua ion o he pe o mance in he momen in which hey we e no cong uen wi h he en i onmen al equi emen s o use s, we de i e guidance on speci ic equi emen s ha de ine he p ojec and cha ac e ize i . 2.2 THE ANALYTIC INDICATORS The analy ic indica o s a e calcula ed by ollowing he pa h o he hea low om he human me abolism o he en i onmen ice e sa whe eas he a ia ions o his low in ela ion o he a ia ion o en i onmen al ac o s. They de i e om he equa ion o ene gy balance based on models which conside all he clima ic pa ame e s signi ican . These models use a balance equa ion o hea wi h a models mo e o less simpli ied o e alua e he mean adian empe a u e. The he mal com o can be desc ibed wi h he use o ce ain indices: sȩ WBGT akes only clima ic da a in o accoun such as ai empe a u e, adian hea , sola adia ion, ai mo emen . sȩ PMV has solid base in he indoo en i onmen bu akes in o accoun ele an ac o s and he a ec he mal sensa ion. sȩ PET and ou SET a e o ou doo en i onmen s. PET does no calcula e indi idual pa ame e s and ou SET akes pe sonal pa ame e s o one s anda d ype o pe son. The ISO 7730 de ines he mal condi ions o ou doo en i onmen in which he p obabili y o nega i e o e is minimised. The index “P edic ed Mean Vo e - PMV” and he index “P edic ed Pe cen age Dissa is ied - PPD” a e based on ISO 7730 and a e aking in o accoun he clima ic pa ame e s in conjunc ion wi h he ele an ac o s a ec ing he he mal sensa ion o each esponden (clo hing, me abolic a e, ea ing o d inking). The PMV-index desc ibes he com o le els wi h he p edic ion o he possible o es aking in o accoun me eo ological ac o in combina ion wi h human biome eo ology alues. The alue o he index is be ween -7 which means oo cold and +7 wi h means ho and he alue o ze o ep esen he com o o e. Wi h his scale he close s he alue o he PMV index is o 0 he be e a e he com o le els o he human. S ill his index canno ake in o accoun he psychological ac o s desc ibed and ha is he why he e a e ce ain di e ences o he alue o he PMV and he eal o es on he ield su eys (Fange , 1992). Common mic oclima ic da a wi h he PMV (P edic ed Mean Vo e) equi e wo o he indexes: PET (Physiologically Equi alen Tempe a u e) and ou SET (S anda d E ec i e Tempe a u e). All hose he mal indices a e well documen ed and include impo an me eo ological and he mo-physiological pa ame e s so as o de ine he o al com o . The scale ha a e measu ed is in °C bu he Vi u io In e na ional jou nal o A chi ec u e Technology and Sus ainabili y Volume 2 5 pa ame e s equi ed in he model a e bo h clima ic (ai empe a u e, humidi y, adia ion en i onmen , wind speed and di ec ion) bu also physical cha ac e is ics o e e y in e iewee (age, sex, weigh , heigh , clo hes, me abolism a e). A ull applica ion o hese he mal indices on he ene gy balance o he human body gi es de ailed in o ma ion abou he e ec o he he mal en i onmen on e e y human (Van Hoo , 2010). In he case o a eas wi h a g ea a ie y o spaces, anging om dense ege a ion and ex ensi e shading, o a eas comple ely exposed o he sun and wind, he da a om he me eo ological s a ion canno adequa ely ep esen he mic oclima ic condi ions in he si e. Com o models should be able o app oach he mic oscale o design pu poses, dis inguishing Figu e 2. Rela ion be ween PMV and PPD, and o he sensa ion he mal indices, as ound by Fange be ween sunny and shaded a eas, o a eas p o ec ed and exposed o he wind, which ul ima ely di ec ly a ec s he mal com o condi ions in a gi en space. I is he e o e o alue o de ise a way o include design ela ed pa ame e s in o en i onmen al da a. Iden i ying simpli ied co ec ion ac o s be ween locally measu ed condi ions and hose o he nea by me eo ological s a ion, du ing he ield su eys, can e lec he modi ica ion o he mic oclima e. Such co ec ion ac o s can be used as modi ica ion pa ame e s o design o ien ed com o models, e lec ing he mic oscale, hus o alue o designe s. In his con ex , ege a ion can a ec he mic oclima e in a numbe o ways, educing ai empe a u e compa ed o ha d su aces, shading and p o iding wind p o ec ion (C es, 2014). 6 Figu e 3. Gi oni bioclima ic cha o com o e alua ion 2.3 WIND One o he mos impo an ac o s in luencing pedes ian com o condi ions in ou doo open spaces is he wind. Wind en i onmen is di icul o o esee and con ol because i is in luenced by a numbe o global, egional and local ac o s. On a global scale wind comes om ai mo ing om high-p essu e a eas o low-p essu e a eas. The wind eloci y and di ec ion p oduced by he global wea he sys ems a e subsequen ly in luenced by he egional and local landscape ypology. I is he e o e impo an o unde s and ha he e can be la ge di e ences in he wind en i onmen om one pa o a ci y o ano he o e en on mic o scale om one pa o a space o ano he . Wind is no a cons an phenomenon. I a ies momen ously in di ec ion and s eng h (wind gus s) and a ia ions can be seasonal o annual. The di ec e ec s o he wind can be di ided in o wo main ca ego ies, mechanical and he mal e ec s: sȩ mechanical e ec s o wind can be el wi h wind eloci ies abo e 4-5 m.s-1. Abo e 10m.s-1 i will be unpleasan o walk and abo e 15m.s-1 he e is a di ec isk o acciden s; sȩ o he mal e ec s he 5 m.s-1 com o c i e ia used p esumed ha people will adap hei beha iou and clo hing le el o he season. I should be no ed ha depending on clima e a ce ain le el o wind could be ega ded as undesi able o desi able. In cold clima es wind will almos always dec ease ou doo com o condi ions, whe eas he opposi e is he case in ho clima es (Ghiaus, 2007). Vi u io In e na ional jou nal o A chi ec u e Technology and Sus ainabili y Volume 2 7 2.4 THE IMPACT OF MATERIALS In o de o educe he hea island in ensi y, he i s me hod is o design he ex e nal en i onmen in o de o minimise sola hea gains. In gene al, his can be achie ed by inc easing he sola e lec i i y o cons uc ion ma e ial su aces and educing e insula ion o suscep ible s uc u es. Du ing his p ocedu e, he albedo o he a ious ma e ials and su ace is a c ucial ac o (San amou is, 2006). The albedo o a su ace is de ined as he e lec ed sola adia ion di ided by he inciden sola adia ion. U ban a eas and ci ies a e cha ac e ized, in gene al by a ela i ely educed e ec i e albedo. This is due o he g ea e abso p ion o sola adia ion by u ban cons uc ion ma e ials and mul iple e lec ion inside u ban canyons. Thus, he op ical cha ac e is ics o used ma e ials ha e an impo an impac - hei albedo- o-sola adia ion and emissi i y o long- wa e adia ion being he key pa ame e s. High albedo ma e ial educe he amoun o sola adia ion abso bed h ough building en elopes and u ban s uc u es, and in his way keep hei su aces coole . Respec i ely, ma e ials wi h high emissi i y a e good emi e s o long-wa e ene gy and elease he ene gy ha has been abso bed as sho -wa e adia ion. In his way hei su ace empe a u e is lowe and con ibu es o he educ ion o ambien empe a u es h ough he mechanism o hea con ec ion (San amou is, 2001). Figu e 4. In e ac ion be ween he wind and buildings 3. ENERGY AUDITS TO SCALE SETTLEMENTS The i s ac ion is cons i u ed by he s ipping " he mal" o he isola e o assess sepa a ely he en i onmen al quali y o he con ex bo h unde he p o ile o he mo-hyg ome ic ( empe a u es, le els o ela i e humidi y) and is epo ed o he clima e wellness, e alua ing he le els o bo h he mal sensa ion ha he index o eeling on he pa o he inhabi an s o he se lemen building. These pa ame e s we e e alua ed by compa ing wo calcula ion me hods: he ASV (Guidelines Ru o s) and PMV (Fange ). The main c i ical poin s ound o scale se lemen s a e o ype "physiological", linked o he le els o he mal sensa ion on he pa o he inhabi an s o he dis ic e e s o he ou doo spaces. In he case o s udy (Mon icchio in he p o ince o L'Aquila) o which has been applied his me hodology, compa ing he wo me hods o calcula ing he ASV and PMV show, bo h coincidence o esul s bo h while nego ia ing on clima ic condi ions in win e ha e highligh ed de iciencies in he summe pe iod, gi ing as a esul a eeling o "ho ", abno mal done in a moun ain eso . Figu e 5. G ound e lec ed i adiance wi h a ying Albedo 8 3.1 6%2)&)#Ø4)/./&4(%35.Ø)2)-0Ø#4 A ca e ul analysis o he impac he sun-ai has highligh ed he objec i e ela ionship be ween se lemen and en i onmen al con ex and clima e. In he p elimina y s ages, he quali y checks ha e he aim o assess he ela ionship be ween clima e and he mo phology o he se lemen wi h espec o he o ien a ion o he compac ness o he in e en ion, in addi ion o he clima ic pa ame e s speci ic o he si e. In de ail disman ling “ he mal” o se lemen s and iden i ica ion o ex e nal su aces deemed mo e bu densome om he poin o iew o ene gy consump ion and com o o he occupan s. Fo e i ica ion o en i onmen al pe o mance ela ed o he s a e o ac , he i s s ep was he “ he mal decomposi ion” o he agglome a e, associa ing o each elemen a he mal ole as o example: sȩ buildings = he mal mass; sȩ g een spaces p i a e loggias, e c. = mic oclima ic niches; sȩ spaces pa ed impe meable, pa ed, e c. = he mal ampli ie s; sȩ ga ages, ga ages, box, cella s, e c. = bu e space. 3.2 ANALYSIS OF THE CONDITIONS EXTERNAL COMFORT IN RESIDENTIAL SETTLEMENTS. The mic oclima e pa ame e s a e o cen al impo ance o he ac i i ies ha a e ca ied ou in he open and o a la ge ex en de e mine he use. The esponses o he mic oclima e may be unconscious bu e y o en esul in a di e en ia ed use o open spaces acco ding o he di e en clima ic condi ions. The ypological dimension, diagnosis has ocused on pe o mance e i ica ion esidual he mal building sys em-ins alla ions o buildings, highligh ing he poo quali y o he he mal insula ion and ene gy managemen in pe iod bo h win e and summe in addi ion o an o e all ine iciency o he sys em enginee ing. All homes a e in class G. Also, e i ica ion o en i onmen al quali y inne is consis en wi h ha ca ied ou he u ban scale o , in summe le els a e ob ained signi ican discom o . The i s esul s show ha a pu e physiological app oach is inadequa e in cha ac e izing he condi ions o com o ou doo s and an unde s anding o he dynamics o he human pa ame e is equi ed in he design o spaces o public use. The he mal en i onmen is o undamen al impo ance because hey in luence he pe sons o use hese spaces, bu he psychological adap a ion (choice a ailable, en i onmen al s imula ion, he mal his o y, expec a ions) is equally impo an . The esponses induced by mic oclima e may be unawa e, bu hey o en ansla e in o a di e en use o he u ban space as he clima ic condi ions a y. Bes mic oclima ic condi ions in u n ha e impo an implica ions o he de elopmen o he ci y. Th ough he con ol o he sou ces o discom o , a e a o ed seden a y ac i i ies, as well as he use o public anspo , mo emen on oo and he use o he bicycle. The same image o he ci y can bene i om he quali y o he ex e nal spaces. In San F ancisco, he planning laws s ipula e ha new buildings mus be placed in such a way as no o p omo e ai mo ions o e 5 m/s, 90% o he hou s o ligh , in a eas whe e people can si . The shading o whole s ee s is achie able wi h he sha s wi h he ad an age o ob ain a cooling h ough e apo anspi a ion h ough he lea es. - always in he case o Mon icchio, diagnosis has ocused on pe o mance e i ica ion esidual he mal building sys em-ins alla ions o buildings, highligh ing he poo quali y o he he mal insula ion and o ene gy managemen in he win e pe iod in addi ion o an o e all ine iciency o he sys em enginee ing. All homes a e in class G.