TheextraordinaryEastgateBuildinginHarareZimbabwe’scapitalcityissaidtobetheonlyoneintheworldtousethesamecoolingandheatingprinciplesasthetermitemound(白蚁堆).
ArchitectMickPearceusedpreciselythesamestrategywhendesigningtheEastgateBuildingwhichhasnoair-conditioningandalmostnoheating.Thebuilding—thecountry’slargestcommercialandshoppingcomplex—useslessthan10%oftheenergyofaconventionalbuildingofitssize.TheEastgate’sownerssaved$3.5millionona$36millionbuildingbecauseanair-conditioningplantdidn’thavetobeimported.
Thecomplexisactuallytwobuildingslinkedbybridgesacrossashadyglass-roofedatrium(天井)opentotheair.Fanssuckfreshairinfromtheatriumblowitupstairsthroughhollowspacesunderthefloorsandfromthereintoeachofficethroughbaseboardvents(通风口).Asitrisesandwarmsitisdrawnoutviaceilingventsandfinallyexiststhroughforty-eightbrickchimneys.
Duringsummer’scoolnightsbigfansblowairthroughthebuildingseventimesanhourtocooltheemptyfloors.Bydaysmallerfansblowtwochangesofairanhourthroughthebuildingtocirculatetheairwhichhasbeenincontactwiththecoolfloors.Forwinterdaystherearesmallheatersinthevents.
ThisisallpossibleonlybecauseHarareis1600feetabovesealevelhascloudlessskieslittledampnessandrapidtemperatureswings—daysaswarmas31℃commonlydropto14℃atnight.“Youcouldn’tdothisinNewYorkwithitsfantasticallyhotsummersandfantasticallycoldwinters”Pearcesaid.
TheengineeringfirmofOveArup&Partnersmonitorsdailytemperatures.Itisfoundthatthetemperatureofthebuildinghasgenerallystayedbetween23℃and25℃withtheexceptionoftheannualhotperiodjustbeforethesummerrainsinOctoberandthreedaysinNovemberwhenadoorkeeperaccidentallyswitchedoffthefansatnight.Andtheairisfresh—farmoresothaninair-conditionedbuildingswhereupto30%oftheairisrecycled.
【小题1】WhywasEastgatecheapertobebuiltthanaconventionalbuilding?