ContentslistsavailableatScienceDirect
Sustainable
Cities
and
Society
j o ur n a l ho me p a g e :w w w . e l s e v i e r . c o m / l o c a t e / s c s
Towards
regenerative
and
positive
impact
architecture:
A
comparison
of
two
net
zero
energy
buildings
Shady
Attia
∗SustainableBuildingsDesignLab,DepartmentArGEnCo,FacultyofAppliedSciences,UniveristédeLiège,Belgium
a
r
t
i
c
l
e
i
n
f
o
Articlehistory:
Received16February2016
Receivedinrevisedform23April2016
Accepted23April2016
Availableonline7May2016
Keywords:
Sustainablebuildings
Climatechange
Net-zeroenergy
Embodiedcarbon
Lifecycleassessment(LCA)
a
b
s
t
r
a
c
t
Regenerativedesignholdsgreatpromiseforaneweraofsustainableandpositiveimpactarchitecture, sparkingconsiderableinterestamongarchitects,buildingprofessionalsandtheirclients.However,the translationalarmofregenerativedesigninpracticeisinarelativelyprimitivestate.Althougha num-beroftheoreticaldefinitionsandstudieshavebeeninitiated,theearlyreturnspointtoseveralinherent applicationproblems.Inthisregard,theprofessionalandscientificpotentialofregenerativearchitecture canonlybefullyrealizedbytheidentificationofthekeybarrierstoprojectsdesign,constructionand operation.Inthispaper,wecomparetwostateoftheartbuildingstoaddressthecriticalstepsinthe transitionfromthenegativeimpactreductionarchitecturetothepositiveimpactregenerative architec-ture,utilizinglifecycleanalysis.Thecasestudiesanalysisandcomparisoncanserveasaninspiringeye openerandprovideavisionforarchitectsandbuildingprofessionalsinthefieldsofhighperformance buildingsandregenerativearchitecture.
©2016ElsevierLtd.Allrightsreserved.
1. Introduction
Theecologicalandeconomiccriseshavebeenpresentformany
yearsnow.Theeconomicsystemisshowingitsweakpointsina
dramaticfashion,unemploymentisgrowingatafastrate,theend
ofourfossilenergyandotherresourcesareapparent.Thereare
morepeoplewhoarebecomingawareoftheconsequencesofthe
climatechangeandthespeedatwhichthebiodiversityis
dimin-ishingisfarbeyondhumanimagination.Historically,buildingsand
architectureinparticularhadacentralmeaningforthesustainable
developmentofthesociety.Remnantsofthebuiltenvironmentof
manyculturessuggestthatarchitectureplayedanimportantrolein
thesocial,economicandenvironmentallife,butareviewofthelast
centuryrevealsthatarchitecturetendedtodiminishinimportance
whileotherformsofdiscourse,suchasthepolitical,economic,
tech-nological,mediahadamoredefinitiveimpactonculture.Looking
todaytothechallengesforplanninganddesignofsustainablebuilt
environmentincluding,carbonemissions,climatechange,human
health,waterproblems,biodiversity,scarcityofresources,
deple-tionoffossilfuel,populationgrowthandurbanization;sustainable
architecturewillplayakeyroleforthesustainabledevelopment
∗ Correspondenceto:UniveristédeLiège,SustainableBuildingsDesignLab,Office
+0/542,AlléedelaDécouverte9,4000Liège,Belgium.
E-mailaddress:shady.attia@ulg.ac.be
ofsocietyasawhole.Citiesandbuildingscanbeseenas
micro-cosms,apotentialtestinggroundformodelsoftheecologicaland
economicrenewalofthesociety.
Buildingconstructionandoperationcontributegreatlytothe
resourceconsumptions andemissionsofthesociety.In Europe,
buildingacclimatizationaloneaccountsforroughly40%ofthetotal
energyconsumption(Huovila,2007).Whentheeffortrequiredfor
construction,maintenance and demolitionaddsup,itis safeto
assumethatroughlyhalfoftheoverallenergyconsumptioncanbe
attributeddirectlyorindirectlytobuildings.Accordingtoestimates
nearlyhalfoftheallrawmaterialsareemployedinbuildings,anda
staggering60%ofallwasteistheresultofconstructionand
demoli-tion.Thegreatsignificanceofbuildingsanddwellingsisevidentin
thewaythebuildingsectoroccupiesinnationaleconomies.Private
householdsspendroughlyonethirdoftheirdisposableincomeon
housing(Eurostat,2012).InWesternEurope,75%offixedassetsare
investedinrealestate(Serrano&Martin,2009).
Thustheresources(land,water,energy,materialsandair)we
needtoprovide fordecenthousingand highquality lifein the
built environment are in decline because they are being used,
exhaustedor damaged fasterthan naturecanregeneratethem.
In the same time, our demand for these resources is growing.
Theindustrialisationexhaustedtheplanet’scarryingcapacityand
destroyedecosystemfunctionsandservices.Populatinggrowthin
manyregionsoftheplanethasbroughtwithittheneedfordecent
housingwithlowgreenhouseemissions,whileinthosecountries
http://dx.doi.org/10.1016/j.scs.2016.04.017
Nomenclature
AIA Americaninstituteofarchitects
ASES Americansocietyenergysociety
ASHRAE Americansocietyforheatingandrefrigerationand
air-conditioningengineers
BPS Buildingperformancesimulation
DOE U.S.departmentofenergy
EU Europeanunion
EUI Energyuseintensity
GWP Globalwarmingpotential
HVAC Heating,ventilationandairconditioning
IEA Internationalenergyagency
IDP Integrateddesignprocess
IPCC Internationalpanelforclimatechange
LCA Life-Cycleassessment
LCI Life-Cycleinventory
LEED Leadershipinenergyandenvironmentaldesign
MINERGIE-ECO
NRE Non-renewableenergy
NREL Nationalrenewablesenergylaboratory
NZEB Netzeroenergybuildings
PE Primaryenergy
PLEA Passiveandlowenergyarchitecture
PV Photovoltaic
RSF Researchsupportfacility
SHGC Solarheatgaincoefficient
Vlt Visibletransmittance
WWR Windowtowallratio
USGBC UnitedStatesgreenbuildingcouncil
U-value Thermalconductivity
withconsolidatedurbandevelopmentprocessitistheexistingbuilt
environmentthatdemandstransformation.Whensettingoutthe
issueofsatisfyingtheseneeds,wemustconsiderbothlocaland
globalenvironmentallimitations.However,duringthelast50years
architectsandbuildingprofessionalshavebeenmainlyconcerned
byonlyreducingtheenvironmentalimpactofthebuilt
environ-ment(Meadows,Meadows,Randers,&Behrens,1972).Eventoday
thedominantoperatingparadigmtofacetheeconomicand
ecolog-icalcrisisremainsthesamereductionsresourceefficiencybased
paradigm.
Inthiscontext,itisnotenoughtoaspiretomitigatetheeffects
ofhumanactivity.Ontheoppositeweneedtoincreasethecarrying
capacitybeyondpre-industrialconditionstogenerateecosystems
functionsand servicestoreversethe ecologicalfootprint. This
approach is promotedthrough theregenerative paradigm that
seekstodeveloprenewable resourcesinfrastructure anddesign
buildingwith a positive environmental impact. Therefore, this
researchexploresthetwoparadigmsandpresentstwostateofthe
artcasestudiesthatrepresenteachtheefficiencyandregeneration
paradigm.Thepurposeofthestudyistoprovidean
understand-ingofbothparadigmsthroughpracticalexamplesanddemonstrate
tobuildingdesignerstheiradequacyinmeetingthechallengesof
thedesignandoperationofthebuiltenvironment.Theresearch
methodologyisbasedonthelifecycleanalysisandevaluationof
twocasesstudiesthroughcomparison.Comparisonis the
high-est cognitivelevel analysis involving synthesis and evaluation.
ThefirstcasestudyistheResearchSupportFacility(RSF)ofthe
NationalRenewableEnergyLab(NREL) representingthe
reduc-tionistparadigm.ThesecondcasestudyistheGreenOfficeshigh
performancebuildingrepresentativetheregenerativeparadigm.
Thepaperexploresthedifferencebetweentwodifferentparadigms
regardingtheirembodiedenergyandmonitoredperformance.The
comparisonoftwostateofthearthighperformancebuildingsis
valuablebecauseitpermitsresearchestomeasureconstructsmore
accuratelyandasaconsequenceshapeaneffectivetheory-building
ofsustainablearchitecture.Ithelpsustoanswerthemainresearch
questionofthisstudy:Cantheresourceefficiencyandimpact
neu-tralityparadigms help us tosolvetheeconomic and ecological
crisisweareliving?Thejuxtapositionofbothbuildingperformance
resultsallowedtheresearchintoa morecreative,frame
break-ingmodeofthinking.Theresultwasadeeperinsightintoboth
paradigms.Thesignificanceofthestudydocumentsaparadigm
shiftanditsincreasinginfluenceonthearchitecturaland
build-ingdesignandconstructionpracticethroughtwostateoftheart
examples.
Theresultsofthisstudyareconsideredasaneyeopenerand
guidelinesforbuildingprofessionalsincludingdesigners,owners
andarchitects.Theaccurateandspecificdeterminationof
regen-erative characteristicsof buildings can help designersto make
fundamental choicesin thedesign and construction of
sustain-ablearchitecture.Choicesthatachievethermalcomfort,occupant’s
wellbeingsenhancesustainabilitybyworkingtogethertowarda
positivefootprint.Onthelongtermthisarticlecanleadto
refor-mulatingandrethinkingthedefinitionofsustainablearchitecture
whileincreasetheuptakeofpositiveimpactbuildingsinpractice
andconsequentlyleadtoaparadigmshift.Thepaperisdividedinto
sectionsections.Thefirsttwosectionsintroducetheresearch
prob-lemandexplorethehistoricalbackgroundofsustainabilityinthe
architecturalpracticeduringthelastcenturywhilesettinga
defini-tionfornegativeandpositiveimpactbuiltenvironment.Thethird
sectionexplainsthecomparisonmethodologyandtheassumption
usedforthelifecycleassessment(LCA).Then,sectionfourandfive
presentthetwocasestudiesandtheircomparisonresults.Finally,
sectionsixprovidesanextendeddiscussionandconclusiononthe
paperfindings.
2. Definitionsandparadigmshift
Inordertounderstandthechangesthataccruedinthefieldof
architectural,buildingdesignandurbanisationpracticesduringthe
lasthundredyearswemustfollowthehistoryofsustainabilityin
thebuiltenvironment.Wecanclassifythishistoryunderfivemajor
phasesthatshapedthearchitecturaldiscourseandpracticeweare
witnessingtoday.Fouroutoffiveofthosephaseswereinfluenced
mainlybyamajorreductionistparadigmthatdefinedsustainability
forarchitectureandbuildingsdesign.Thereductionistparadigmis
seekingmainlythereductionofnegativebuildingimpactthrough
environmentalefficiency.However,weareonavergeofaparadigm
shiftthatoperatesfromadifferentparadigm.Thefollowing
sec-tionsdescribethehistoricalprogressandphasesofthemodern
sustainablearchitectureandexplorethesustainabilityparadigms
associatedwiththosephases.
2.1. Historicalbackground
Fromthebeginningofthe20thcenturytherehavebeenfive
influentialparadigmsthatshapedsustainabilityinarchitectureand
thebuiltenvironment.Areviewofthelast120yearsrevealsthat
thearchitecturaldiscoursewasinfluencedsignificantlybythe
eco-nomicandecologicalcrisisassociatedwithindustrialisation(see
Table1).Thisclassificationisnotrigidandshouldnotbeinterpreted
asarigidclassificationthatcreatesbordersitisatrialof
categori-sationofthoughtsthataimstoprovideabetterunderstandingof
theevolutionandrelationbetweensustainabilityandthecreation
ofthebuiltenvironment.Thusforthinkingonsustainabilitywe
Table1
SustainabilityParadigmsinfluencingArchitecturein20thand21thcentury.
Paradigm Years Influencer Paradigm
BioclimaticArchitecture 1908–1968 Olgay,Wright,Neutra Discovery
EnvironmentalArchitecture 1969–1972 IanMcHarg Harmony
EnergyConsciousArchitecture 1973–1983 AIA,Balcomb,ASES,PLEA EnergyEfficiency SustainableArchitecture 1984–1993 Brundtland,IEA,Faust ResourceEfficiency
GreenArchitecture 1993–2006 USGBC,VanderRyn Neutrality
CarbonNeutralArchitecture 2006–2015 UNIPCC,Mazria Resilience
RegenerativeArchitecture 2016–Future Lyle,Braungart,Benyus Recovery
ThefirstparadigmnamedBioclimaticArchitecture was domi-natedbyideasofFrankLloydWright(1906)onorganicarchitecture (Uechi, 2009), Corbusier and Breuer (1906) on sun shading (Braham, 2000), Atkinson on hygiene (Banham, 1984), Meyer
(1926) on thebiological model (Mertins,2007), Neutra (1929)
onbioregionalism(Porteous, 2013), Aalto(1935)onhealth and
precautionaryprinciple(Anderson,2010)untilformulationofthe
Bioclimatic Architecture paradigm by theOlgay Brothers (1949)
(Olgyay,1953).Buildingsofthosearchitectsshowedatendencyof
rationalismandfunctionalismwhilebeingfascinatedbythebeauty
ofnature.Bioclimaticadaptation,hygiene,safetyandthenotionof
experimentalandempiricaldesignwasnotdeveloped.Untilthe
brothersOlgaysetupthefirstarchitecturelabinthe1950ies
com-biningacademicresearchandpractice.Thisiswasamajorchange
thatmovedarchitectureintothescientificworld.
Thesecond paradigmnamed Environmental Architecturewas
dominated by theideas of Ian McHarg (1963) on design with
nature(McHarg&Mumford,1969),Ehrenkrantz(1963)onsystems
design (Ehrenkrantz, 1989), Schumacher (1972)on appropriate
technology (Stewart, 1974) and Ron Mace (1972) onuniversal
design(Thompson,Johnston,&Thurlow,2002).Buildingsofthose
architectsshowedatendencyofinclusivenessofenvironmentand
biologyfromthebuildinginteriortourbanandplanningscale.
Thethirdparadigmfollowedthefirstenergycrisisandwas
dom-inatedbytheideasoftheAmericanInstituteofArchitecture(AIA)
(1972)onenergyconsciousarchitecture(Villecco,1977),the
Amer-icanSolarEnergySociety(ASES)includingtheworkofBalcomb
(Balcomb(1972)onpassiveandactivesolararchitecture(Balcomb,
1992), thePassive and Low EnergyArchitecture (PLEA) society
(1980)andThomasHerzog(1980)(Herzog,Flagge,Herzog-Loibl,
&Meseure,2001).Buildingsofthosearchitectsshowedatendency
ofinclusivenessofsolarandenergysavingdesignstrategies.The
firstideasofenergyneutralbuildingsandrenewableenergy
inte-gratedsystemswereintroducedinseveralbuildingprototypesand
concepts.Theuseof empiricalsimulation andmeasuringbased
techniquetoquantifybuildingperformancewasbasedonenergy
codesandstandardsthatwerecreatedinthisphase.
ThefourthparadigmnamedSustainableArchitecturewas
dom-inatedbytheideasofBrundtland(1987),rangingfromBakeron
sustainabledesigns(Bhatia,1991),Fathy’scongruentwithnature
designstobuildarchitecturefromwhatbeneathourfeet(Fathy,
1973)toSamMockbee.Alongwithmanyothers,theyexpandedthe
purviewofsustainabledesignbyembracingaestheticsandhuman
experienceinadditiontoenvironmentalperformance.
ThefifthparadigmnamedGreenArchitecturewasdominatedby
theideasoftheUSGreenBuildingCouncil(1993)ongreenand
smartdesign,VanderRyn(1995)onecologicalcommunitydesign
(VanderRyn&Calthorpe,1991),ARUP(1996)onintegrateddesign (Uihlein,2014)andFaust(1996)onPassiveHausConcept(Feist
etal.,1999).Withtheemergenceofthisparadigmthegreeningof
architectureproliferatedgloballywithmorecomplexandbroader
environmentalconsiderations(Deviren&Tabb,2014).
Thesix’sparadigmnamedCarbonNeutralArchitecturewas
domi-natedbytheideasoftheKyotoProtocol(1997)oncarbonneutrality
(Protocol,1997)andUNIPCCreport(2006)onclimatechange.The
workofBillDunsteronZeroEnergyDevelopmentandEdMazriaon
the2030Challengehadastrongimpactonarchitecturalresearch
and practice. With theEU 2020 nearly zeroenergy targetsfor
28 memberstates,energy neutralarchitecturebecameareality
embracingresilience,dynamism,andintegration.
In thecoming20 years wewillbe onthevergeofthe
sev-enthparadigmnamedRegenerativeArchitecture.Thisparadigmwill
bedominatedbytheideasofLyle(1996)onregenerativedesign
(Lyle,1996), MichaelBraungartand DonaldMcDonough(2002) (McDonough&Braungart,2010)oncradle tocradledesign and
Benyus(2002)onBiomimicry(Benyus,2002).Weareonaverge
ofaparadigmshiftthatoperatesfromapositiveimpactcreation
throughenvironmentallyeffectivesustainablebuildings.Oneofthe
presentedcasesstudiesinthisreachisashowcaseforapositive
impactcreation.
Inconclusionthisclassificationallowsusidentifytheideasand
trendsinthefieldofsustainabilityofarchitectureandthebuilt
environment.Inthelasthundredyearsarchitecturewasinfluenced
bythesustainabilitydiscourseandmanyarchitecturaland
build-inginnovationsweretiedtoprogressofideaslistedearlier.The
influenceofthesevenphaseswasprofoundonarchitectural
prac-tice,drivenbynewconstructiontechnologiessuchasinsulation
materials,renewable systems and efficient heating and cooling
technologies.Sustainabilityrepresentedavisionfornewpractice
andperformancedrivenarchitectureandresultedinnew
produc-tion and performance calculation indices and methods. Several
paradigmsdominatedthearchitecturalandbuildingpractice.The
mostrecenttwoare:ultra-efficiencyandeffectiveness.Beingin
a transitionalvergebetweenbothparadigms thefollowingtwo
sectionsexplainthedifferentbetweenbothparadigms.
2.2. Negativeimpactreductionviaincreasedefficiency
With the emergence of the ecological and economic crises
duringthelasthundredyearsthearchitectural,engineeringand
constructioncommunityrealizedthenegativeimpactofthe
indus-trializationofthebuiltenvironmentontheplanet.Buildingsare
responsiblefor40%ofcarbonemission,14%ofwaterconsumption
and60%ofwasteproductionworldwide(Petersdorff,Boermans,&
Harnisch,2006).AccordingtotheEuropeanUnionDirective,land
isthescarcestresourceonearth,makinglanddevelopmenta
fun-damentalcomponentineffectivesustainablebuildingpractice(EU,
2003;EEA,2002).Worldwideover50%ofthehumanpopulationis
urban.Environmentaldamagecausedbyurbansprawland
build-ingconstructionissevereandwearedevelopinglandataspeed
thattheearthcannotcompensate.Buildingsaffectecosystemsin
avarietyofwaysandtheyincreasinglyovertakeagriculturallands
andwetlandsorbodiesofwaterandcompromiseexistingwildlife.
Energyisthebuildingresourcethathasgainedthemost
atten-tionwithinthebuiltenvironmentresearchcommunity.Building
materialsareanotherlimitedresourcewithinabuilding’slifecycle.
Incontrasttoenergyandwater,materialscirculatewithinanear
Fig.1. EvolutionofbuildingenergyperformancerequirementsintheEUandUS.
incurrentbuildingconstructionisextremelylongsincetheywere
millionsofyearsinthemaking.Waterisakeyresourcethat
lubri-catesthebuildingsectoras muchasoildoes. Buildingsrequire
waterduringconstructionandduringoccupancy.Theenormous
negativeimpactsofecologyandthedeterioratingecosystem
func-tionsandservicesandthelargeecologicalfootprint,duetofossil
fuelconsumption andpollution resultedinlargeenvironmental
deterioration.
Asaresultoftheseproblemstheresourcesefficiencyparadigm
dominatedthepracticeaimingtothereduction ofthenegative
impactofthebuiltenvironment.Forexample,theenergycrisisin
1973resultedinthedevelopmentofenergyefficiencymeasures
inthebuiltenvironment.TheInternationalEnergyAgency(IEA),
EuropeanUnion(EU)andtheAmericanSociety forHeatingand
RefrigerationandAir-conditioningEngineers(ASHRAE)legalized
andpublishedstandardsandperformancetargetsfortheenergy
consumptionofbuildingshaveimprovedbyafactoroffivetoten
since1984(seeFig.1)(EU-Directive,2005).Intryingtoachievean
environmentalfriendlybuiltenvironmentthroughreduction,the
sustainablearchitecturalandbuildingpracticeforaresource
effi-ciencygoalsmeaningtoreducetheconsumptionanduseresources
efficiently.However,thechangesthatinfluencedthefieldemerged
allfromanefficiencyparadigmfocusingonthereductionofthe
useofdepletingorpollutingresources.Eventhezeroenergy
build-ingsandzerocarbonbuildingsgoalsthatseekmaximumefficiency
derivefromthenotionofneutralizingtheresourceconsumption
anddefinethisaszeroenergyconsumption(Marszal&Heiselberg,
2009).Infact,the“breakeven”approachisverylimited.Restricting
thebuildingimpactboundariesto‘zero’or“netzero’ismisguided,
the‘zero’goallimitsachievinglong-termsustainablebuilding
prac-tices.Ifenergygeneratedonsiteprovetobeanabundantresource,
whythenshouldwelimitourobjectivestozero?Moreover,the
efficiencyparadigmdiscouragesthepotentialtoreachfossilfuel
independentbuildings. Thedeclineintheavailability ofoil,gas
andcoalandthedangerofnuclearenergymeansthatthecostof
blackfuelswillbecomeincreasinglyvolatile.Peakoilwillhavea
hugeimpactthroughouttheeconomy.Thustheenergyefficiency
paradigmhasreacheditslimitbyproposingzeroenergyorzero
emissionsasthe‘holygrail”,becausethisreductionist approach
operateswithinablackfossilfuelparadigmthatdoesnotrecognize
theimportanceofrenewable,regenerativeresourcesandbuilding
designmechanismthatcanreversetheclimatechangerootcause.
Withtheadventofthe2013IPCCreportitbecameevidentto
thescientificandpubliccommunitythattheefficiencyparadigm
isfailingtosolvetheproblem.Eveninarchitecturewewitnessed
severalmanifestationsregardingitschangingroleandcrucial
char-actertooursurvival(seeTable1).Theacceleratedimpactofclimate
changeandtheincreasingnegativeimpactofthebuiltenvironment
areexceedingtheplanetscapacitybysixtimes(Stevenson,2012).
Theefficiencyparadigmcannolongerfacetheproblem.Weneedto
reversethenegativeimpactofthebuiltenvironmentandgobeyond
theefficiencyparadigm.
2.3. Positiveimpactviaincreasedregenerativeeffectiveness
Fromthediscussionabovewecanconcludethattheincreasing
populationgrowthandecologicaldestructionrequiresincreasing
theecologicalcarryingcapacitybeyondpre-industrialconditions.
Wearelookingforsustainablepositivedevelopmentthat
incorpo-ratemaximizingtheviabilityofharnessingrenewableresources
andbecomeindependentfromdepletingandpollutingresources.
Inorder,toachievepositivebuildingfootprintwemustmovefrom
thecradletograveparadigmthataimstoreduce,avoid,minimize
orpreventtheuseoffossilenergytoaregenerativeparadigmthat
aimstoincrease,support,andoptimizetheuseofrenewable(Lyle,
1996).AsshowninFig.2,thepreviousefficiencystrategieshave
beenoperatingwithinacarbonnegativeorneutralapproachthat
willneverreachapositiveandbeneficialbuildingfootprint.Even
theexistingnetbalanceapproachassumesafundamental
depen-denceonfossilfuels.Therefore,wedefinethepositiveimpactof
thebuiltenvironmentfromarenewableself-efficiencyparadigm.
Aregenerativesustainablebuildingseeksthehighestefficiency
inthemanagement of combinedresourcesand maximum
gen-erationofrenewableresources.Itseekspositivedevelopmentto
increasethecarryingcapacitytoreverseecologicalfootprint(see
Fig.3).Thebuilding’sresourcemanagementemphasizesthe
viabil-ityofharnessingrenewableresourcesandallowsenergyexchange
andmicrogenerationwithinurbanboundaries(Attia&DeHerde,
2010,2011).Overthepastyears,regenerativepositive
develop-ment paradigmhasbeengarnering increasing influenceonthe
evolutionof architecture.Theprogress isdramatic:plusenergy
plus,earthbuildings,healthybuildings,positiveimpactbuildings.
Thisnewwayofthinkingentails theintegrationofnatural and
humanlivingsystemstocreateandsustaingreaterhealthforboth
accompaniedtechnologicalprogress.
3. Methodology
Inordertoanswertheresearchquestioninbroadtermsonthe
effectivenessoftheefficiencyparadigmversustheeffectiveness
regenerativeparadigmitisimportanttobuildtheoryfromcase
studies.Twospecificcasestudieswereselectedtorepresentthe
paradigms.Welookedforselectingtwoappropriatehigh
perfor-mancebuildingswithextraneousvariationstodefinethelimitfor
generalisingthefindings.Thetwoselectedbuildingsprovide
exam-plesoftwopolartypesclassifiedasstateofthearthighperformance
buildingsinUSandSwitzerland.Thegoaloftheselectiontochoose
caseswhicharelikelytoreplicate.IndeedtheUScaseisLEED
Plat-inumzeroenergybuildingandtheSwisscaseisaMINERGIE-ECO
ecologicalbuilding.Thecomparisonfocusedmainlyonenergy
dur-ingthephaseofconstruction,operationanddemolitioninorderto
avoidtheoverwhelmingvolumeofdata.Thetwocasesweremeant
tobeusedasasourceforafirmerempiricalgroundingforanswer
Fig.2. Paradigmshifttowardsabeneficialpositiveimpactfootprintofthebuilt.
Fig.3. Aregenerativesustainablebuildingseeksthehighestefficiencyinthemanagementofcombinedresourcesandamaximumgenerationofrenewableresources.
• Screeningandanalysingbothbuildingsothat wecanseethe
magnitudeofimpacts.
• PerformingadetailedLCAespeciallyforcarbonemissionsand
primaryenergy.
Forthefirstpartofthestudymultipledatacollectionmethods
werecombinedtocomparethetwocasesstudies.Thedata
col-lectionincludedliteraturereviews,interviews,observations,field
studiesand accesstosimulationmodelsand monitored
perfor-mancedata.Theresearcherhadthechancetointerviewthedesign
teamsand visitbothbuildingsand performforbothbuildingsa
modellinganalysisandpostoccupancyevaluation.
3.1. Lifecyclestandardsandsystemboundary
Thesecondpartofthestudycomprisedalifecycleassessment
analysis.Theinterestinevaluatingenergyuse,consumptionof
nat-uralresourcesandpollutantemissions,especiallyfornewandlow
energybuildingsisincreasing(Hernandez&Kenny,2010;Leckner
impactsofbuildingsismaterialsandresources.Accordingtothe
USGBCProjectsDatabasematerialscountfor35%ofthetotalenergy
consumedduringthebuildinglifecycle(Turner,Frankel,&Council,
2008).Amorerecentstudypointedoutthatembodiedenergycan
beupto60%ofthebuildinglifecycle(Huberman&Pearlmutter,
2008).Therefore,weoptedforalifecycleassessmenttocompare
theenergyconsumption,materialembodiedenergyandCO2
emis-sionsaccordingtoISO14040and14044standards(ISO14040ISO,
2006;ISO14044ISO,2006;Vogtländer,2010).
TheCEN/TC350“SustainabilityofConstructionworks”standard
recommendsconsiderationoffourlifecyclestagesforbuilding:
productstage(rawmaterialssupply,transportandmanufacturing),
constructionstage(transportandconstructioninstallationonsite
process),usestage(maintenance,repairandreplacement,
refur-bishment,operationalenergyuse:heatingcooling,ventilation,hot
waterandlightingandoperationalwateruse)andend-lifestage
(deconstruction,transport,recycling/re-useanddisposal)(Blengini
&DiCarlo,2010;CEN,2005).Table2illustratesthelifecycle
sub-systemsconductedforthisstudy.Tofacilitatethecomparisonof
resourcesforarchitectsweclassifiedouranalysisunderenergyuse
(operationalenergy)materials(embodiedenergy).
3.2. Functionalunit,year,toolsandindicators
Thefunctionalunittocomparebothbuildingswas1m2/year.
Forthecalculationmodelweexpectedtheoccupancyfor100years.
InSwitzerlandtheusualvalueofLCAlifetimeis100years.
Numer-ousexamplesofusingLCAfor100yearscanbefound(Fay,Treloar,
&Iyer-Raniga,2000;Bribián,Capilla,&Usón,2011;Pajchrowski, Noskowiak,Lewandowska,&Strykowski,2014).Alsoglobal
warm-ingpotentialareavailablefordifferenttimehorizons,andachoice
of100yearsisusuallyassessedonthisbasis(Forsteretal.,2007).
ThecradletograveLCAwasmadeonthebasisofdirectlycollected
datafromthedesign-buildteamsandintegratedwithliterature
data.Aninventorydatasetformaterialswasdevelopedand
com-pletedusingtheEcoinvent2database.Thelifecycleinventorywas
performedusingtheSimaPro7softwareapplications.Inorderto
calculatetheenvironmentalimpactresultedfromthebiogenicCO2
circulation,anapproach ofCO2storageinthebuildingsfor100
yearswasused.Thenegativevaluesoftheglobalwarming
indica-torresultswereobtainedforacradle(forest)andpositiveonesfor
thefinaldisposalstageofwoodenwaster(incinerationandreuse).
TheLCAindicatorsweresummarizedinagroupofthreeenergy
andenvironmentalindicatorsasfollow:
• Primaryenergy(PE),asanindicatoroflifecycleenergyuse
• Non-renewableenergy(NRE),asthenon-renewablepartofPE
Globalwarmingpotential(GWP),asanindicatorofgreenhouse
emissions,includingthecontributionofbiogeniccarbondioxide.
BiogenicCO2iscapturedinbiomassduringthegrowthofaplant
ortreeand,consequently,inabiologically-basedproduct.
3.3. Lifecycleinventory
Within the scope of the LCA an inventory have been
cre-ated,which referred tobuildingmaterialsofthefourlife cycle
stagesmentionedearlier.Duringdatacollection,theexpertiseof
architectsandbuildingengineershavebeenusedextensivelyas
describedinTable2.FortheCaseStudy1and2theasbuilt
draw-ingswereusedtosizemostbuildingfeaturesandtheirsizeand
weight.Theenergyconsumption wascollectedfrommonitored
databetween2010and2014andsimulatedintwomodelswith
thesamelegislativerequirements(inSwitzerlandandtheUS)of
envelopeandHVACsystemstoneutralizetheclimaticvariability
andestimateaverageoperationenergyusingEnergyUseIntensity
(EUI)Index.Themaindifferencebetweenbothcasestudiesisthose
relevanttothebuildingmaterial,envelopethicknessandtypeof
insulationandglazing.AlsotheHVACsystemsareverydifferent
andthefueltypehasdifferentassociatedcarbonemissions.The
simulationmodelshelpedinelaboratingthebuildingcomponents
andweightsandlaterfeedintheEcoinventdatainventory.
Table3listsdataconcerningtheweightofmajorbuilding
mate-rialsforbothbuildings.Byinspectingthematerialstructureofthe
RSFwecanseethatconcreteisdominatingthetotalbuildingweight
reachingalmost80%oftheweightshare.Theprecastpanelsthat
makeuptheexteriorwallsoftheRSFwerefabricatedinDenver
usingconcreteandaggregatefromColoradosources.Thebuilding
cores,basementthermallabyrinthandbasementandfloorslabs
areresponsibleforthishighvalue.Thisincludesrecycledrunway
materialsfromDenver’sclosedStapletonAirportusedfor
aggre-gateinfoundationsandslabs).Metalsrepresent4%andinclude
steelbarsforconcretereinforcementandreclaimedsteelgaspiping
usedasstructuralcolumns.InthecaseoftheGreenOffices
build-ingmaterialsarealsodominatedbyconcreteproducedfromalocal
concretemixingplant30km fromthesite.Concretehasalmost
thehighestweightshareconstitutingmainlyfoundations.Wood
isthesecondmostcommonmaterialreachingalmost14%.Table4
presentsthebasicassumptionsrelatedtothedurabilityofelements
subjecttoreplacementandrepairs.Flooringandfinishingiscarried
outwiththehighestfrequencybutitwasassumedthatthe
previ-ousfinishinglayersarenotremovedbeforesubsequentpainting.
Woodendoorsandwindowsaresubjecttoreplacementandare
calculatedwithintheusestage.Theassumptionsincludethe
cal-culatedmassflowsofmaterialsandwastegeneratedin100year
periodandresultingfromthereplacementandrepair.
3.4. Limitations
AlthoughISO14040recommendsthatLCAsendwithasetof
mid-pointenvironmentalindicatorsweproposedthenarrowset
ofindicatorslistedabove.Architectsoftenexpresstheirneedfor
practicalandsimple performanceindicatorsthatmightsimplify
thedecisionmaking.TheLCAscopewaslimitedtothesubsystems
mentionedinTable2.Alsowehadlimitedquantitative
informa-tionontheactualdemolitionprocess.Therefore,wereferredto
few studiesthat containsomequantitativeand methodological
informationontheroleofend-of-lifeinbuildingsintheUSand
Switzerland(BAFU,2016;Thormark,2002,2006;Werner&Richter,
2007;Spoerri,Lang,Binder,&Scholz,2009;Boschmann&Gabriel, 2013;Spiegel&Meadows,2010).
For this study we excluded water installations and sewage
installation including roof gutter systems were excluded from
the study. Also the damage categories such as human health,
ecosystemquality,climatechange,resourcesandimpactcategories
(carcinogens,non-carcinogens, respiratory inorganics, ionising
radiation, ozone layer depletion, respiratory organics,
aquter-restrial ecotoxicity, terrestrial acidification/nitrification, land
occupation, aquatic acidification, aquatic eutrophication, global
warming,atic ecotoxicity) wereexcluded. Needless to say,the
energymixofbothbuildingswastakenintoaccountforcalculations
inregardtotheelectricitymixandwillbeelaboratedinfollowing
casestudiessections.
4. Casestudies
The selection of both case studies was based on their
sim-ilar office function and the awards they received in the USA
and Switzerland.Both projectsrepresentthe excellencein
sus-tainable architecture and green construction in their countries
Table2
Lifecyclephasesanddatasources.
Lifecyclephase Subsystem Casestudy1 CaseStudy2
ProductStage −Shellandbuildingservicesmaterials production
−Quantitiesestimatedfrombuildingdrawings −Quantitiesestimatedfrombuildingdrawings −Analysisincludegrossamount,i.e.including
themateriallossduringbuildingprocess
−Literaturedata(Guggemosetal.,2010) −UnpublisheddatafromUniversityde
Lausanne(Lehmann,2011)
−Inventoryinformationprocessformost
materialshasbeencollectedfromecoinvent
database.
−Inventoryinformationprocessformost
materialshasbeencollectedfromecoinvent
databasewithexceptionofwoodandcellulose
insulationforwhichspecificdatahavebeen
available.
−TransportationandBuildingProcess −Informationaboutthetypeofmeansof
transportusedfortransportingindividual
typesofbuildingmaterialshasbeenbasedon
personalcommunicationwithDesign-Build
team
−UnpublisheddatafromUniversityde
Lausanne(Lehmann,2011)
−Distancesfromtheproductionlocationfor
themainmaterialstothebuildinglocation
basedoncalculatedweight
−Distanceshavebeencalculated −Distanceshavebeencalculated
−Typeoftransportandmeansoftransport −Informationaboutthetypeofmeansof
transportusedfortransportingindividual
typesofbuildingmaterialshasbeenrevised
throughapresentationofthearchitect
ConstructionStage −Constructionofbuildingcomponentsand
constructionofthewholebuilding
−Assumptionsaboutconstructionmachinery
havebeenmadebasedontheliterature
−Assumptionsaboutconstructionmachinery
havebeenmadebasedonconsultationwith
architect
−Energyconsumptionbyconstruction
machinery
−Calculatedwiththesoftwareapplication
SimaPro
−Calculatedwiththesoftwareapplication
SimaPro
UseStage −EnergyuseforHVAC −Literature(USDOE,2012)andmonitored
datafromNREL(CarpenterandDeru.,2010)
−Literature(Lehmann,2011)andmonitored
datafromarchitectConradLutzbetween2010
and2014
−Energyuseforlightingandplugloads −DataconcerningHVAChavebeencollected
between2010–2014
−Asimplesimulationmodelwascreatedto
assesstheenergyconsumptionandfuel
breakdownandneutralizetheclimate
varaiablity
−Asimplesimulationmodelwascreatedto
assesstheenergyconsumptionandfuel
breakdownandneutralizetheclimate
varaiablity
End-of-lifeStage −Dismantling,demolition,
recycling/reuse/landfill
−Literaturedata(CarpenterandDeru.,2010) −Literature[(BAFU,2016)]andunpublished
datafromUniversitydeLausanne(Lehmann,
2011)
−Typeofwastedisposal −Typeodmeansoftransportusedfor
transportingbuildingmaterialshasbeenbased
onliterature
−Typeodmeansoftransportusedfor
transportingbuildingmaterialshasbeenbased
onliterature
−Distancesfromdemolitionsitetothefinal
disposalsites
−Typeoftransportandmeansoftransport
Table3
Weightshareofmaterialgroupsintheanalysedbuildings.
BuildingMaterialCategory RSF GreenOfficea
Amount[kg] Share[%] Amount[kg] Share[%]
Concrete 32500000 79 788650 73.4
Brick – – 10890 1
Gravel 6000000 14.6 50000 4.6
Ceramics 84000 0.2 – 0
Mineralbindingmaterials 82600 0.2 2000 0.1
Woodandwoodbasedmaterials 10000 0.2 144200 13.5
Insulationmaterials 110000 0.3 55000 5.1
Metals 1904762 4.7 12600 1
Glass 53460 0.1 5680 0.05
PaintsandPreservatives 48240 0.1 1340 0.1
PlasterandGypsumboard 229680 0.5 2000 0.1
aAnnex1.1Lehmann(2011).
Minergie-P-ECO. The RSF received the award of Excellence for
GreenConstructionfromtheAmericanConcreteInstituteAIA.Also
itreceivedthe2011AIA/COTETopTenGreenProjectAward.The
GreenOfficereceivedtheWattd’Or2008andPrixLignumHolzpreis
2009inSwitzerland.Moreinterestingly,bothprojectsrepresent
thereductionistandregenerativeparadigmandareseenaspilot
projectsbytheprofessionalcommunitiesintwodifferent
Table4
Durabilityofelementssubjecttoreplacementandrepairsin100years.
Building RSF GreenOffice
Inventoryelement Durability[years] Numberofreplacements Durability[years] Numberofreplacements
Constructionelements 100 0 100 0 Windows 25 3 25 3 Internaldoors 30 3 30 3 Externaldoors 30 3 30 3 Woodflooring – – 50 1 HeatingInstallations 30 3 30 3 Ceramictiles 20 4 20 4 Electricinstallations 50 1 50 1 Ventilationsystem 25 3 25 3 Roofing 50 1 50 1 Roofinsulation 50 1 50 1 Wallsinsulation 60 1 30 2 BuildingFacade 60 1 60 1
Paintinginternalwalls 5 19 5 19
Paintingexternalwalls 25 3 25 3
VarnishingofFloors 25 3 25 3
PVpanels 30 2 30 2
4.1. Casestudy1:efficiencyparadigm
Theresearchsupportfacility(RSF)isa stateof theart office buildingtohost researchers of theNational RenewableEnergy (NREL)Lab.TheRSFinGolden,Coloradowasdesignedand con-structedbetween2006and2010,afteraprocessofproposalscalls andselection.Thevisionoftheselectedprojectoperateswithinthe energyefficiencyparadigmaimingtobuildanenergyneutraloffice buildingor aNZEB.The designbriefemphasizedan integrative designapproachtodesign,buildandoperatethemostenergy effi-cientbuildingintheworld.Thecallhadadesign-buildacquisition strategythatconnectsthebuildingtotheelectricitygridforenergy balancethroughapowerpurchaseagreement.TheDesign-Build TeamcomprisesHaseldenConstruction,RNLArchitectand Stan-tecasSustainabilityConsultantandMEPengineering.Thedesign processinvolvedanintegrativeapproachlookingto:
1avoidneedsforenergybyintegratingpassiveheatingandcooling andventilation;
2improveenergyefficiencyand
3incorporaterenewableenergyandgreenpower.
Thebuildingislocatedinlatitude39.74andlongitude−105.17 andis151mabovesealevel.Thesitereceives660mmofrainper yearwithanaveragesnowfallof1371mm.Thenumberofdays withanymeasurableprecipitationis73.Onaverage,thereare242 sunnydaysperyearinGolden,Colorado.TheJulyhighisaround 30◦andJanuarylowis−8whilehumidityduringthehotmonths,is a58outof100.Thebuildingisa20.400squaremeterhosting800 person.Thebuildingenergyuseintensityhadtoperformlessthan 80kWh/m2/yearandadditional20kWh/m2peryearwasallowed foralargedatacentrethatservestheentireNRELCampus.TheRSF facilityhadtoperform50%betterthatASHRAE90.1-2007energy performancerequirements.Theprojectisanetzeroenergy build-ingandobtainedtheLEEDPlatinumCertificate(V.2)andEnergy StarPluscertification.Thedesignbriefalsorequiredmaximumuse ofnaturalventilationand90%offloorspacefullydaylit.
Withthehelpofbuildingperformancesimulation(BPS)several passivedesignstrategieswereoptimized.Thebuildingformand masswasshapedtohostthemainbuildingfunctionsinfluenceby anenergysavingapproach.TheRSFbuildinghastwowingssized andpositionedtoallownaturalventilationandlighting.The orien-tationofthetwowingsiselongatedontheeast-westaxetoallow aneasycontrolofsolaraccessduringsummer.Toachieveenergy
performancegoals,theworkspacelayoutisopen,withlowcubicle wallsandlight-colouredfurniturethatallowairtocirculateand daylighttopenetrateintothespace.Theaspectratiois13.5andthe windowtowallratiois25%withalow-etriplevisionglazing (U-value0.17,SHGC0.22).Thedaylightglassisalow-edoublepaneday lightingglazing(U-value0.27,SHGC0.38,Vlt65%).Theenvelope comprisesmodularstructuralinsulatedpanelsof2.5cmexterior concretewithrigidfoaminsulation(polyisocyanurateR-13)and aninternalthermalmassof15cminteriorconcrete.
Regardingactivesystemsthebuildinghasahybridoperating system.Thevisionglassismanuallyoperableandgets automati-callycontrolleddependingonindoorandoutdoorenvironment.A radiantheatingandcoolingsystemisinstalledintheroofslab. Nat-uralventilationisachievedduringdaythroughmanualwindows controlandduringnightthroughautomatedcontrolfornight cool-ingandthermalmassactivation.Mechanicalventilationisdemand basedandairisdisplacedthroughanunderfloorairdistribution system.Aheatrecoverysystemisinstalledonoutsideairintake andexhaustfromrestroomsandelectricalrooms.Thewhole build-ingenergyuseis283continuouswattsperoccupant.Laptopsof 60Wwith35Wthinscreensareusedinworkspaces.Theartificial lightingsystemisbasedonmotionanddaylightintensitysensors. SensorcontrolledLEDtasklightof15Wareusedforworkstations lighting.AthirdpartyownedpowerpurchaseagreementPPA pro-videdfullrooftoparrayof1.7MWofmono-crystallinepanelsof17% efficiency.Thecurrentpowerpurchasedfromafossilmix(60%coal, 22%fromnaturalgas,and18%fromrenewableenergyresources (EIA,2014)).
The construction life-cycle stage included the full
construc-tionofthebuilding.FortheLCAdatafromaproprietaryAthena
Institutedatabasewasusedfortheconstructionofsimilar
commer-cialstructuralsystems(precastconcrete, cast-in-placeconcrete,
andstructuralsteel),aswellaslayersofvariousenvelope
mate-rialsand interior partitions. Annual energy usewas calculated
usingNREL monitoringresults. Themaintenance stageincludes
repairandreplacementofassembliesandcomponentsof
assem-blies throughout the study building’s service life. The primary
sourceofinformationwastheAthenareport,Maintenance,Repair
and Replacement Effects for Envelope Materials (2002).
Stan-dardrecommendationsarebasedondecadesofbuildingenvelope
experience,manufacturers’installationinstructions,material
war-ranties,andindustrybestpractice.Genericindustryassociations’
dataandpublicationsandNorthAmericanindustrypracticeswere
AliteraturereviewandInternetsearchwasconductedbutlittle
detailedinformationregardingconstructionanddemolitionwaste
management practices inDenver urban centrewere foundand
furtherconsideredinthis study.End-of-lifescenarios arebeing
forecastupto100years.Amorecomprehensivedescriptionofthe
productionprocessesandtablesfortheothervarietiescanbefound
in(Guggemos,Plaut,&Bergstrom,2010).Thedetailedcarbon
foot-printaswellasenvironmentalimpactofthevariousprocessesfor
producingtheconcreteconstructionsystemisprovided.
4.2. Casestudy2:regenerativeparadigm
Thevisionoftheselectedprojectwastobuildthemost
eco-logicalandregenerativeofficebuilding.ApproachedbytheFrench
StatethearchitectConradLutzwasaskedtodesignandconstruct
anecologicallyoptimalbuildingwithapositiveimpact.TheGreen
OfficebuildinglocatedinGivisiez,Switzerlandwasdesignedand
constructedbetween2005and2007.Thebuildingislocatedin
lat-itude46.81andlongitude7.12andis99mabovesealevel.The
sitereceives1075mmofrainperyearwithanaveragesnowfallof
627mm.TheJulyhighisaround25◦andJanuarylowis−1while
humidityduringthehotmonths,isa69outof100.Thebuilding
pro-videscommercialofficespacesforcompaniesworkinginthefield
ofsustainabledevelopment.Thebuildinghasthreefloorswitha
totalareaof5391squaremeterandisthefirstMINERGIE-P-ECOin
Switzerland.Thebuildingenergyuseintensityhadtoperformless
than25kWh/m2/yearand10W/m2forthermalairheatingshould
notexceed.Thedesignprocessinvolvedanintegrativeapproach
lookingto:
1avoidneedsforenergybyintegratingpassiveheatingandcooling
andventilationwithafocusoncompactness;
2improve energy efficiency and trace the impact of energy
resources
3Sequestration−thecaptureandstorageofCO2inthe
construc-tionmaterial
Thehighthermalinsulationofwalls,ceilingsandfloorandtriple
glazing wasthearchitect’s passivestrategy toreduce theneed
forbuildingheating.Thevalueu-valueoftheroofis0.10W/m2K,
fac¸ade 0.11W/m2K,windows0.5W/m2Kandfloors 0.10W/m2K
achievedthroughwoodfibreinsulation.Thebuildingformis
opti-misedtoincreasecompactnessandreducetheenvelopesurface
areaandreduceheatlosses.Thebuildingresemblesacubewith
avolumeof5291m3andcomprisesinternalpartitionsthatallow
severalcompaniestosettle,shareandgrow.Naturallightwas
opti-mizedusingdaylightsimulationforoptimalnaturallightingand
avoidanceofoverheatingduringsummer.Theheatingsystemisa
pelletstovewithunderfloorheating.Freecoolingusingan
under-groundtubethatworksaspassiveheatexchanger(puitscanadien)
isusedinsummerthroughventilation.Thehotwaterisproduced
withsolarthermalpanelsandthecurrentpowerpurchasedfroma
renewablemix(60%wind,37%hydro,solar3%(Lehmann,2011)).
However,theroofispreparedforelectricityproductionandwillget
equippedwith270m2Photovoltaic.Theexpectedenergy
genera-tionshouldexceed30%ofthebuildingelectricalenergyneedsand
exporttheadditional305tothegrid.Theplugloadsarecontrolled
buyelectricitycutoffpolicyandallusedequipmentandappliances
includingflatscreensareenergystarrated.
Theconstructionlife-cyclestageincludedthefullconstruction
ofthebuilding. FortheLCAdatafromeconinventdatabasewas
usedfortheconstructionofsimilarcommercialstructuralsystems
(timberand cast-in-placeconcrete),aswellaslayersofvarious
envelopematerialsandinteriorpartitions.Woodwascutin
Sem-sales Region. The raw wood was transported on a direct path
toGivisiez,whilethelaminated timbermade alongthewayto
Burgdorf.ThedistanceshavebeencalculatedfromSwitzerland’s
maps.Mostmaterialsourceswerelocatedbasedonthearchitect’s
identificationofproductsnamesandtheirmanufacturer.Annual
energyusewascalculatedusingGreenOfficesmonitoringresults
(Lehmann,2011).Today,mostmaterialsareburiedattheendof
lifeofabuildinginSwitzerland.ForGreenOffices,thetimber
con-structionandcelluloseinsulationwasassumedtobeburnedina
municipalincineratorforelectricitygeneration,andtheother
dis-trictheating.In100years,theefficiencyofenergyrecoverymaybe
increasedbyreusingtimberaschipsorpelletsinheaters.Concrete
wasassumedtobeburiedintheground,orbecrushedforreuse
asgravelunderroadsorunderconstruction.Manufacturers
indi-catedthatglasspanesarenotrecycledinSwitzerland,butburied
withotherconstructionwaste.Genericindustryassociations’data
andpublicationsandSwissindustrypracticesweretakenin
con-siderationtomodel theend-of-life stagescenarios. Aliterature
reviewandInternetsearchwasconductedbutlittledetailed
infor-mationregardingconstructionanddemolitionwastemanagement
practicesintheSwissurbancentreswerefoundandfurther
con-sideredinthisstudy.End-of-lifescenariosarebeingforecastup
to100years. Amorecomprehensivedescriptionofthe
produc-tionprocessesandtablesfortheothervarietiescanbefoundin
(Lehmann,2011).Thedetailedcarbonfootprintaswellas
environ-mentalimpactofthevariousprocessesforproducingthetimber
constructionsystemisprovided.
5. Results
TheresultsoftheLCAappliedtotwohighperformancebuildings
intheUSandSwitzerlandishighlightedbelow.Whenassessing
thesustainabilityandenvironmentalperformanceofhigh
perfor-mancebuildingsitisveryimportanttouseuniversalindicatorsand
considercarefullyalllifecyclephasesandsubsystems.
5.1. Casestudy1:efficiencyparadigm
TheResearchSupportFacilitiesBuilding(RSF)attheNational
RenewableEnergyLaboratory(NREL)inGolden,Coloradoachieved
a67%reduction inenergyuse(excludingthesolarPVoffset)at
zeroextra costfor theefficiency measures,asthedesign team
wascontractuallyobligedtodeliveralow-energybuildingatno
extracost(Torcellini,Pless,Lobato,&Hootman,2010).Torcellini
andPless(Pless&Torcellini,2012)presentmanyopportunitiesfor
costsavingssuchthatlow-energybuildingscanoftenbedelivered
atnoextracost.Otherexamplesoflow-energybuildings(50–60%
savingsrelativetostandardsatthetime)thatcostlessthan
conven-tionalbuildingsaregiveninMcDonell(2003)andIFE(2005).New
Buildings Institute(2012) reports examples of net-zero-energy
buildingsthatcostnomorethanconventionalbuildings.Evenwhen
low-energybuildingscostmore,theincrementalcostsareoften
smallenoughthattheycanbepaidbackinenergycostsavings
withinafewyearsorless(Harvey,2013).Thekeystodelivering
low-energybuildingsatzeroorlittleadditionalcostarethrough
implementationof theIntegrated Design Process(IDP) and the
design-bid-buildprocess.Vaidyaetal.(2009)discusshowthe
tra-ditional,lineardesign processleadstomissedopportunitiesfor
energysavingsandcostreduction,oftenleadingtotherejection
ofhighlyattractiveenergysavingsmeasures.
5.1.1. Energy
The building energy consumption and production has been
monitoredsinceitsconstruction.Theaverageannualconsumption
is109kWh/m2/yearincludingdatacentreserving1325occupant.
5.1.2. Materials
Materials used in the RSF contain recycled content, rapidly
renewableproducts,orwereregional,meaningtheywereprocured
withina500-mileradiusofGolden(DOE,2012).Theprecastpanels
thatmakeuptheexteriorwallsoftheRSFconsistoftwoinchesof
rigidinsulation(R-14)sandwichedbetweenthreeinchesof
archi-tecturalprecastconcreteontheoutsideandsixinchesofconcrete
ontheinside.Thepanels,whichwerefabricatedinDenverusing
concreteandaggregatefromColoradosources,constitutethe
fin-ishedsurfaceonboththeinsideandoutsideofthewallexceptthat
theinteriorisprimedandpainted.Woodoriginatesfrompinetrees
killedbybeetlesusedforthelobbyentry.Recycledrunway
mate-rialsfromDenver’sclosedStapletonAirportareusedforaggregate
infoundationsandslabs.Reclaimedsteelgaspipingwasusedas
structuralcolumns.About75%ofconstructionwastematerialshave
beendivertedfromlandfills(DOE,2012).Table4summariesthe
mid-pointenvironmentalindicatorsrelevant tothelife cycleof
theRSF.Preuseandmaintenanceimpactsarehigherthanthose
relevanttotheusephase.
5.2. Casestudy2:regenerativeparadigm
The building complies with the MINERGIE-ECO® certificate
which is a complementarystandard tothat of MINERGIE® and
MINERGIE-P®seekingtoensure,inadditiontoabuilding
satisfy-ingtheenergyefficiencyrequirements,ansoundenvironmentally
friendlyconstruction.
5.2.1. Energy
The building energy consumption and production has been
monitoredsinceitsconstruction.Theaverageannualconsumption
is8forheatingplus28kWh/m2/yearforelectricity.Abuildingof
thesamesizewouldhavetherighttoconsume25kWh/m2/yearfor
heatingaccordingtoMINERGIE-P®standard.Thetotalimpactofthe
buildingwouldberelativelylowwhencomparedwithother
build-ingssamefunctionalunit.Buildingmaterialsandrenewablesource
ofheatingdecreasemainlytheimpactonresourcesandclimate
change.
5.2.2. Materials
Therequirementsforhumanhealthandtheimmaterialimpact
ontheenvironmentareobligatory.Thereforethearchitectused
woodasrawmaterialsthatiswidelyavailableandwiththeleast
possibleimpactontheenvironment.450cubicmeterofwoodwere
transportedfroma20kmclosewoodforest.Theforestwoodis
sus-tainablymanagedandeachtreewasselectedexplicitlywiththe
lowerpossiblemoisturecontenttoreducetheenergyofthewood
kiln.AsshowninFig.4,theuseofwoodresultedinacarbon
nega-tivefootprint.Bycarbonnegativewemeananegativeoutcomeof
thecarbonfootprintofwood,i.e.whencarboncreditsthrough
car-bonsequestrationandenergyproductionattheendoflifephaseare
higherthantheemissionscausedbyproductionandtransport.The
architectdesignprefabricatedwoodenpanelsfilledwithwoodfibre
insulation.Thestructuralelementsweremainlygluedlaminated
timbertrussesandbeams.Thewholeconstructionwasdesignedto
beeasilydismantledeasilyandinadditiontomaterialsthatcould
beforthemostpart,reusedorrecycled.Thecompactnessofthe
buildingspacewasnotonlystrategicallyachievedheatloss
reduc-tionbutalsotoreducethematerialtotalquantityandreducethe
embodiedenergyofbuildingmaterials.MINERGIE-ECO®required
theuseofanexclusionlistthatpreventsmaterialsthatendupin
thelandfillandarenotcompatiblewithahealthyindoor
environ-ment.Concretewasusedinthefoundationfromacementfactory
100kmawayandothermaterialsweretransportedfrommaximum
1000kmdistance.Allmaterialsfromadistancelessthan500km
weretransportedwith3.5–20ttrucksmaterialstransportedfrom
furtherawaycameon32ttrucks.Amorecomprehensive
descrip-tionoftheproductionprocessesandtablesfortheothervarieties
canbefoundinVanderLugt(2008)andvanderLugtetal.(2009a,
2009b).Thetotalscores(carbonfootprintaswellaseco-costs)of
thevariousprocessesforproducingtheindustrialbambooproducts
areprovidedinChapter6.Fig.4showstheimportantcontribution
ofthebuildinglifecyclewhichcorrespondstothetwodifferent
designobjectivesandparadigms(Table5).
5.3. Casestudiescomparison
Theresultsinthemostgeneralviewarepresented inFig.4
andTable6.Theimpactshownhererelatestothefunctionalunit,
thereforetheproduction andtransport of theamountof
mate-rialsnecessaryconstructbothbuildingsandusethem,including
replacementsrepairs,demolition,aswellastransportanddisposal
ofthedemolitionwasterafter100years.
InTable6,thederivedbreakdownofembodiedenergy,
oper-ationalenergy andcarbon emission values duringthedifferent
lifecyclesarecomparedforbothbuildingcomponentsconsidered
intheanalysis.Theseindicatorsarelistedintermsofenergyper
squarearea(MJ/m2)ofthegivenmaterial,aswellasunitmassper
squarearea(kgCO2/m2)toaccountforvaryingassociatedmaterial
emissions.Table6presentstheembodiedenergy(pre-usephase)in
materialsoftheentirebuildingbasedontheasbuiltdrawings.The
GreenOfficesbuildingmaterialsareatleast85%lessenergy
inten-siveintheirproductionastheRSF.Thesereductionsaremainlydue
tothewoodenconstructioncomparedtothereinforcedconcrete
andsteelconstructionsystem.Itisinterestingtonotethateven
thoughtheembodiedenergyiscalculatedoveranassumed
100-yearlifespan,thebuildingembodiedenergyremainssignificant
intheRSF(23%)andGreenOffices(10%).Thisisduetothelarge
energyconsumptionduringthecomplicatedproductionprocessof
buildingmaterialsthathappenindoors.
Ontheotherside,thetablerevealedsurprisingfindings
regard-ingoperationalenergy.Twodifferentanalyseswereperformedin
ordertovalidatethefinalresults.Theoperationalenergyoutcomes
werebasedonthemonitoreddatatrackingandthecalculationof
theenergymixinbothstates/cantons.Sincebothbuildingswere
on-gridandachieveda netzeroenergyannualbalancewe had
totakeintoaccounttheprimaryenergyoftheimportedenergy.
The RSF (66%of primary energy is due to operationalenergy)
dependsonnaturalgasforheatingandelectricitytomeetother
loadsandGreenOffices(86%ofprimaryenergyisdueto
opera-tionalenergy)dependonpelletfurnaceandelectricity.Themost
prominentdifferenceseenbetweenbothbuildingswasthe
rela-tivelyhighoperationalenergyconsumptionofRSF,whichexceeds
thatofGreenOfficesbyover7timesifcalculatetheenduseenergy
andbyover40 timesifcalculatetheprimaryenergy.Thereare
tworeasonsforthisremarkableperformancedifferences.Firstof
all,theGreenOfficesiscomplyingwiththeMINERGIE−ECOone
ofthemoststringentbuildingperformancestandardsandcould
becomparedtothePassiveHouseStandard.Thesecondreasonis
thattheimportedenergyfortheRSFoverthecourseoftheyear
iscomingfromablackenergymix,whileGreenOfficesimported
energyisoriginatingfromagreenenergymix.Despitethatboth
facilitiesarerecentlybuiltashighperformancezeroenergy
build-ingssharingthesamefunctionasofficebuildings,however,the
performancelevelandoperationalenergyconsumptiondifference
isunjustifiable.
AnotherrepresentationoftheLCAresultscanfoundinFig.4,
wheretheweightedresultsofimpactcategoryindicatorshavebeen
presentedbasedonTable6.Theprimaryenergyandcarbon
emis-sionscalculationsandprovideanewperspectivefortheoveralllife
cycleassessmentofbothbuildings.Whilebothbuildingssucceeded
Table5
ComparisonofmonitoredperformanceoftheRSFandGreenOfficesbuildings.
RSF GreenOffice
EstimatedAnnualEnergyConsumption 100kWh/m2/yearincludingdatacentre 25kWh/m2/year AnnualEnergyConsumptionMonitored 109kWh/m2/yearincludingdatacentre 36kWh/m2/year
Occupants/Surface 1325/20400m2 50/1299m2
Table6
Mid-pointenvironmentalindicatorsrelevanttothelifecycleoftheRSFandGreenOfficesbuildings.
CaseStudy1 CarbonSequest. Pre-use Operation Endoflife Lifecycle
PEMJ/m2/a / 274(23%) 785(66%) 131(11%) 1190 NREMJ/m2/a / 274 785 131 880 GWPkgCO2equiv./m2/a / 5620(%) 197(71%) 25(9%) 275 CaseStudy2 PEMJ/m2/a / 27(10%) 168(86%) −14(4%) 181 NREMJ/m2/a / 27 56 5 88 GWPkgCO2equiv./m2/a −5.9(−13%) 6.5(14%) 40(90%) 3.4(7%) 44
Fig.4.Comparisonoftheprimaryenergybalanceandglobalwarmingpotentialforbothcasestudies.
associatedwiththegenerationandimportingofenergywas posi-tive.Thismeansthatatthisdegreeofresultsaggregationevenifa benefitexists,itisneutralizedbythedominatingnegativeimpacts. Asmentionedbefore,themainreasonisduetocarbonemissions associatedwiththeenergyimportedfromthegrid.Eventhough GreenOfficesimportedgreenenergymainlyproducedfrom renew-ables,theuseofpelletsforheating,maintenanceandnumberof replacements(seeTable4)areexpectedtogenerate90%ofthe
car-bonemissionsofthe100yearbuildinglifecycle.Theuseofcellulose
insulationwillrequire2timesreplacement,whichincreasedthe
operationalenergy.Eventheuseofbiobasedconstruction
mate-rialslikewoodorwoodfiberswasnotenough(-13%)tocreatea
carbonnegativeoutcome.However,ifwetakeintoaccountthe
biogenicCO2capturedinwoodandwoodfibersandmakesureto
haveazerocarbonoperationalenergywemightyreachatotal
neg-ativebalanceofcarbon.Thisshowstheimportanceanddominance
ofoperationalenergy(usestage)ontheoverallcarbonemissions
impact.OntheothersidetheRSFisexpectedtogenerate71%ofthe
carbonemissionsduringoperation.
Inthecaseoftotallifecycle,carbonemissionsintensity
consti-tutingabout275kgCO2equivalent/m2/annumfortheRSFbuilding
andabout44kgCO2 equivalent/m2/annumfortheGreenOffices
building,thereisverysignificantdifference.Attentionshouldbe
paidtothefactthattheuseofconcreteandsteelhasaveryhigh
environmentalimpact oncarbon emissions.Even in the Green
Officesbuilding, whichhasverylowemissionvalue,theimpact
offoundationsandconcretewalls(average1400kg/m2)hasbeen
thehighest(73%accordingtoTable3).However,reaching44kgCO2
equivalent/m2/annumfortheGreenOfficesbuildingisaverygood
recordbecauseiftheemissionsassociatedwithoperationcouldbe
neutralizedthroughagreenergridenergymixwherethetotal
car-bonemissionsmightreachanegativebalancetakingintoaccount
thecarbon sequestration or biogeneration ofwood. Therefore,
buildingefficiency improvements(on thelevel of
MINERGIE-P-ECO)andrenewableenergiesmustbeintroducedinthegridand
duringthepre-useandendlifephase.Theroleofreachinga
nega-tiveCO2balanceoverthewholebuildinglifecycleshouldbecome
increasinglyprominent.
6. Discussionandconclusion
6.1. Summaryofmainfindings
Theregenerativeparadigmwasfoundclosertoreversethe
eco-logicalfootprintandprovideapositiveimpactbuilding.Thanksto
thebiogenicCo2calculationapproachthelifecyclestages
responsi-bleforcreatingthepositiveandthenegativeenvironmentalimpact
relatedtoglobalwarmingarepresented,eventhoughthereisno
consensusinliteratureorpracticetousedcarbonsequestration
or carbon bio generation.The regenerative paradigm increased
knowledgeaboutthematerialsandembodiedenergy,generated
amoreconsciousattitudetomaterialsandenergyresources
selec-tionandalmosteliminatedthereductionistparadigmindesign.
ofknowledgeonmaterialsandresources’environmentalimpacts,
succeededtocreateanalmostregenerativebuildingwithapositive
impact.Inorder tocreatea positive impactbuildingthe
build-inghad to producemore than itsrequirementsto compensate
theemissionsreleasedduringfor heatingand DHW.Moreover,
thebuildinghastobebuiltwiththemaximumpossibleamount
ofplantorbiobasedconstructionmaterials.Theuseofplantor
biobasedconstructionmaterialscanhelptooffsetthe
environ-mentaleffectsofclimatechange,providedthewoodisharvested
fromanaturalforestoraplantationcreatedtoimprovedegraded
landsandisprocessedusingrenewableenergy(duringthepre-use
phase).Aftersuccessionofmultiplereusesanddowncycling
cas-cadethemaininsulationandconstructionmaterialwillbefired.
Ontheotherside,thezeroenergyobjectivesachievedthe
environ-mentalneutralityonlyforoperationalenergyandcouldnotguide
thedesignteamtofocusontheoverallenvironmentalimpactof
thebuilding.AfteroneyearoffullmonitoringoftheRSFthebet
zeroenergybalancewasnotachievedandanewparkinglotwas
constructedtohostnewarraysof668kW.Theroofwascovered
withPVpanelsthataremorethan17%efficient.Therooftoparray
alonecouldnotoffsettheRSF’senergyneeds,soseveraladjacent
parkingstructureswerecoveredwithadditionalPV.Moreover,the
reboundeffectassociatedwiththeincreaseofplugloadsand
pan-els’efficiencydegradationfactorof0.7%peryeareradicatedthe
efficiencyandimpactneutralityparadigms.Theresultsarein
accor-dancewithpreviousstudies(Jordan&Kurtz,2013;Phinikarides,
Kindyni,Makrides,&Georghiou,2014).
Thezeroenergyclaimshavepotentialconsequencesof
unsus-tainableapproachestobuildingandplanning.Thisclaimofannual
buildingoperationcarbonfootprintneutralityofzerocarbon
emis-sions/yearfortheRSFbuildingis misleading.Bothcase studies
couldnot overcomethelimitationgiven bya non100% carbon
neutralgridinfrastructureorenergysupply.Therefore,
maintain-ingsuchobjectiveontheshortandlongtermcannotincreasethe
carryingcapacityofnatureandreverseourfootprint.
Bytracingtheenvironmentalimpactofoperationalenergyand
embodiedenergyover 100years fortwo casestudieswecould
proofthatthechoiceofbuildingmaterialscomesinthesecond
place of importance and relevance after the operation energy.
DespitetheslightlydifferentclimaticconditionsbetweenGolden,
ColoradoandGivisiez,Fribourgandthedifferentneedsfor
heat-ing,coolingand DHW,it is worthwhiletoconsideroperational
energyandthesustainabilityofgridenergysupply followedby
building materials when building high performance buildings.
With the mandatory performance requirements of nearly zero
energybuildingsby2020intheEUwecannotremainoperating
underthecurrentefficiencyorenergyneutralityparadigm(Sartori,
Napolitano,&Voss,2012;Attia,Mlecnik,&VanLoon,2011).
There-fore,thisstudyhasdemonstratedthatthesettingtherightgoals
(MINERGIE-ECOasanexample)canplayinmitigatingtheeffects
ofclimatechangeandhelpingarchitectstocreateapositiveimpact
ofthebuiltenvironmentontheirsurroundings. Byhighlighting
thepotentialofregenerativedesignparadigmitcancontributeto
sustainablebuildingpractices,wealsohopetoincreasethe
aware-nessaboutitsimpactofoperationalenergyandembodiedenergy
offoundationandconcreteconstruction.Regenerativedesigncan
leadtobeneficialfootprintandpositiveimpactbuildingsandcan
informarchitectsandbuildingdesignersinaccordancewiththe
UnitedNationsFrameworkConventiononClimateChange.
How-ever,in order tomaximise itsimpact, and benefitthe greatest
numberofcommunicates,itsuseneedstobepromotedamongst
thepublicandbuildingsprofessionals.Theregenerativeapproach
shouldbebasedonmaximumefficiencycoupledwithrenewable
dominatedenergymix.Creatingacirculareconomymeans
shap-ingthebuildingregulatoryandmarketframeworkstostrengthen
regenerativefinanceanddelivery,andtosupportarchitectsand
buildingengineerswithsimpleenvironmentalindicators,
calcu-lationmethodologiesandnationalimplementationstandardsand
strategies.
6.2. Comparisonwithexistingliterature
Thisresearch builds onearlier studiesthat have considered
themitigationof globaland local resource depletionand
envi-ronmental degradation(McHarg &Mumford, 1969; Lyle, 1996;
Cole,2012).Regenerativedesignanddevelopment,aspreviously
notedinthecaseofGreenOffices,hasconsistentlybeenshownto
deliverinnovativebuildingswithbeneficialqualities.Withrespect
to Cole who stated the scarcity to find similar built projects
can show the capability of expanding our environmental
per-formancetargets(Cole,2012;Waldron,Cayuela,&Miller,2013;
Wolpensinger&nachhaltigesBauen,2016).Thisstudyis inline
environmental assessments made for plant based construction
materials(VanderLugt,2008;Prétot,Collet,&Garnier,2014;Ip
&Miller,2012;Wolpensinger&nachhaltigesBauen,2016;Waugh, Wells,&Lindegar,2010).Despitethesmallsampleofcasestudies,
theauthortriedtogointobuildingswithawell-definedfocusand
tocollectspecificbuildingperformancedatasystematically.
6.3. Implicationsforresearchandarchitecturaldesignpractice
Thecontroversysurroundingefficiencyparadigmhasrecently
been reignited by several studies, published simultaneously
(Ankrah,Manu,Hammond,&Kim,2013).Thelargecontribution
ofbuildingtoresourceconsumptionishighlyrelevant,notleast
becauseoptimisationpotentialisequallygreatinthesamesector.
Whatevertheoutcomeofthetechnocraticreductionistefficiency
debate, the fact remains that the resources efficiency and the
reductionsapproachhavesignificantlimitations.Thosearchitects,
buildingdesignersand owners seekingsustainable architecture
in theirpractice requirevaluable informationin order tomake
informeddecisions.Itisestimatedthatbuildingsdesigncost1%
ofthepercentofthelifecyclecostbutitcanreduceover90%oflife
cycleenergycost(Lovins,Lovins,&Hawken,1999).Whileduring
earlydesignphases20%ofthedesigndecisionstakensubsequently,
influence80%ofalldesigndecisions(Bogenstätter,2000).However,
effortspenttopredictorreducebuildingsenvironmentalimpact
shouldbereplacedbyhighqualityregenerative design support
metrics,indicators,tools,strategiesandframeworkfornetpositive
development.Theyneedinformationonhowtoreplacefossilfuel
basedsystemandcomponentswithpassiveornatural/renewable
sourcesonthebuildingandgridlevel.Thisinformationwillneed
tobeeasilyaccessible,and,asshowninthisstudy,basedonwell
establishpredictsandmaterialslifecycleanalysis.
Thisstudy used Life-Cycle Assessment and carbon footprint
calculations toanalysethe environmentalimpactof two states
ofart buildings. Themain limitationofLCA remains inits
cra-dletograveapproachthatmainlymeasurestheenvironmentally
damagingfootprint.TheGreenOfficesconceptwasdesignedfor
disassemblyandadaptationtochangeoffunction.Thestructure
hadmodulardimensionsystems,theskinismadeofdemountable
facadesandtheinternalspacesallowmovableseparationwalls.
Issuessuchasadjustability,versatility,movabilityandscalability
areofgreataddedvalueallowinghighqualityfuturereuse.
How-ever,theLCAapproachcouldnotquantifythosebeneficialdesign
qualities.Therefore,newtoolsand indicatorsareneededinthe
future toassess building’sfunctionallyand which
environmen-tal,social,andhealthbenefitsthatcanbeachievedinparticular
at theend-of-use phase (reuse,recycling, incineration, landfill)
(Boretal.,2011)(Geldermans&Rosen-Jacobsen,2015).Needless
tosaythestudywaslimitedtoonlythreeenergyand
