Energy Use and Savings Potential for Laboratory Fume HoodsWord格式文档下载.docx
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emills@lbl.gov
DaleSartor,P.E.
Mailstop90-3111
ApplicationsTeam
dasartor@lbl.gov
April2006
LBNL-554002
Abstract
Fumehoodsarecriticalenergyend-usedevices,typicallyrelieduponastheprimary
sourceofventilationinlaboratory-typefacilitieswhileprovidingforsafeconditionsin
areaswhereexperimentsarebeingconducted,Fumehoodscreatelargeamountsof
airflow,whichdrivestheoverallHVACsizingandenergyrequirementsofthebuildings
inwhichtheyarelocated.Forstandardtwo-meter(six-foot)hoods,per-hoodenergycosts
rangefrom$4,600formoderateclimatessuchasLosAngeles,USAto$9,300/yearfor
extremecoolingclimatessuchasSingapore.Withanestimated750,000hoodsinusein
theU.S.,theaggregateenergyuseandsavingspotentialissignificant.Weestimatethe
annualoperatingcostofU.S.fumehoodsatapproximately$4.2billion,witha
correspondingpeakelectricaldemandof5,100megawatts.Therearevariousstrategies
forsavingenergy,eachwithitslimitations.Withemergingtechnologies,per-hood
savingsof50percentto75percentcanbesafelyandcost-effectivelyachievedwhile
addressingthelimitationsofexistingstrategies.
Introduction
Effortstoimproveenergyefficiencymustattendtoahostof“non-energy”
considerations,primarilysafety.Inmanycases,non-energybenefitscanprovidean
additionalimpetusfortechnologyinnovationbeyondthevalueofdirectenergysavings
(MillsandRosenfeld1996;
PyeandMcKane1999;
Worrelletal.2003).Thisiscertainly
thecasewithlaboratoryfumehoods.
Fumehoodsarebox-likestructures,oftenmountedattabletoplevelwithamovable
window-likefrontcalledasash.Fumehoodscapture,contain,andexhaustairborne
hazardousmaterials,whicharedrawnoutofthehoodbyfansthroughaportatthetopof
thehood.Laboratoryfumehoodsareubiquitousinpharmaceuticalandbiotechnology
facilities,industrialshops,medicaltestinglabs,privateresearchlabs,andacademic
settings.Theirfundamentaldesignhasgonelargelyunchangedforthepast60years
(Saunders1993).
AsdepictedinFigure1,overallfumehoodenergyuseistheproductofanumberof
supportsystems,including:
supplyandexhaustfans,space-coolingenergy,space-heating
energy,and(insomecases)humidificationorde-humidificationandterminalreheat.We
developedanengineeringmodel(Figure2)toperformbaselineanalysisandtesttheperhoodandnationalimpactsofenergyefficiencyimprovements.
Figure1.Typicalfume
hoodcross-section,
applicationandrelation
toHVACsystem(TekAir
2003).
Anon-linecalculatorbasedonourmethodologymaybefoundathttp:
//fumehoodcalculator.lbl.gov3
Figure2.Web-basedfumehoodenergyusemodel.
Highlightingthe“systemsnature”offumehooddesignandapplication,hoodsrequire
largeamountsofairflowthattendtodrivethesize,andfirstcostofcentralheating,
ventilatingandair-conditioning(HVAC)systemsinbuildingswherehoodsarelocated.
Asaresult,fumehoodsareamajorfactorinmakingtypicallaboratoriesfour-tofivetimesmoreenergyintensivethantypicalcommercialbuildings(Belletal.2002).Afume
hoodconsumes3.5-timesmoreenergythananaveragehouse.With0.5to1.5million
hoodsinuseintheU.S.(“central”estimate750,000),aggregateenergyuseandsavings
potentialissignificant.Aswillbedescribedbelow,theannualoperatingcostofU.S.
fumehoodsis$4.2billionwithcorrespondingelectricityuseof26TWh,peakelectrical
demandof5,100megawatts,and204Petajoules(193TBTU)ofheatingfuel.
Furtheramplifyingtheneedtoimprovefumehooddesign,recentresearchshowsthat
increasingtheamountandrateofairflow(and,consequently,energyuse)doesnottend
toimprovecontainment.Instead,erranteddycurrentsandvortexescanbeinduced
aroundhoodusersasairflowsaroundworkersandintothehood,reducingcontainment
effectivenessandcompromisingsafety(Belletal.2002).4
BaselineEnergyUseandAnalysisofPotentialSavings
Wehavemodeledtheenergyuseandpotentialsavingsonaper-hoodbasisacrossa
varietyofweatherlocationsaroundtheglobe.Totalenergycostsaremoresensitivetothe
coolingload.Ourcalculationsaccountfortheheating,cooling,andmovementofair
throughthefumehood,andtheassociatedpricesofelectricity,peakelectricitydemand,
andfuel.Dependingonclimate,estimatedcostsrangefrom$100to$325/m
3
-minute($3
to$11/cfm).
Weassumethehoodha