finding the proof of energy retrofits | snapshot | the sallan foundation

8/8/2019 Finding the Proof of Energy Retrofits | Snapshot | The Sallan Foundation

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SnapshotFinding the Proof of Energy Retrofits

By: Michael Bobker, Director, Building Performance Lab, CUNY

For: The Sallan Foundation

Date: September, 2010


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1 2010 The Sallan Foundation, Inc. All rights reserved. http://www.sallan.org

Snapshot

Finding the Proof of Energy Retrofits

Introduction:NYCLeadershiponEnergyEfficiencyinExistingBuildings

NewYorkCityispoisedtoexertgloballeadershiponenergyefficiencyinexisting

buildings.MuchhasbeenmadeoftheGreenerGreaterBuildingslawsthatspell

outanarrayofenergyrequirementspursuanttothegoalsofPlaNYC2030.Overthe

nextdecadewewillseewhatresultsareachievedinimplementinglegal

requirementsforenergycodecompliance,benchmarking,audits,retro

commissioning,andlightingimprovements.Keyplayers,ledbyNYCgovernment

itself,havecommittedtoearlyimplementationby2017.Thecurrent

administrationisbudgeting10%ofitmunicipalenergyexpenseforannualfunding

ofenergyefficiencyimprovementprojectsinmunicipalbuildings.Thisamountsto

$100millionperyear.

Bynewconstructionstandards,wherecostseasilyrunto$300persquarefoot,this

isnotahugesum.Butbystandardsofenergyconservationprograms,where

fundingtypicallyismorelike$10persquarefoot,ithisisindeedalargebudgetand

asubstantialopportunitywithglobalimplications.Theprogramisunderthe

managementoftheNYCDepartmentofCitywideAdministrativeServices,utilizingawellthoughtoutapproachthatfollowstheconventionalpracticeoftheenergy

servicesindustry:benchmark,audit,implement,train,operateandmaintain,meter

andmonitor.ii

Givenitshighstakesandpublicprofile,dueconsiderationmustbegiventothe

reliabilityofoutcomes.Thisleadstothequestionofwhatexperienceisavailable

thatcouldprovideinsightintolikelyprogramperformance.


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Experience-basedGuidance.fromTexas

Thebestplacetolook,perhapssurprisinglytosome,isTexas.Since1988theTexas

EnergyOfficehasoperatedLoanSTAR,anenergyefficiencyrevolvingloanfundfor

municipalandstategovernmentfacilities.From$98.6millionincorefunding

(basedonpetroleumviolationescrowfunds),191loanstotalingover$240million

havebeenmadethrough2007iiithefundscapitalhasbeenrepaidtwiceover

andrecycledintonewloans.Theloanstargetpublicbuildingsschooldistricts,

governmentbuildings,highereducation,andhospitalsmakingitaportfoliomix

notunlikewhatcanbeanticipatedunderNYCsprogram.

WithTexasLoanSTARsmixoffacilities,rangeofretrofittechnologiesdeployed,

leveloffundingandsustainedmultiyeareffort,onecouldhardlyhavedesigneda

betterpilotprogramforNYCseffort.Mostimportantly,theprogramincludeda

rigorousevaluationeffortconductedbytheEnergySystemsLabatTexasA&M

University(ESLTAMU).TheESLTAMUappliedengineeringandarchitecture

facultyandgraduatestudentresourcesatasignificantlevelformorethantenyears.

Atanygiventimefourorfiveseniorresearchers,PrincipalInvestigatorsassignedtostatecontractedprogramtasks,wouldbeoverseeingtheworkoftentofifteen

facultyresearcherssupportedbythirtytofortygraduatestudentsandtechnical

staff.

Thisprogramproducedthenationsbestdocumentedanalysisofabodyofenergy

efficiencyretrofitstodate.AcomprehensivecatalogoftheESLspapersandreports

isavailablefordownloadfromTexasA&MUniversity.Theworkwasanimportant

precursortotheemergenceofenergyefficiencymeasurementandverification

(M&V).ESLTAMUstaffbecameimportantcontributorstothefieldskeydocuments,


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theInternationalPerformanceMeasurementandVerificationProtocol(IPMVP)and

ASHRAEGuideline14.

FindingsonAuditsandActualPerformance

Sowhatwaslearned?

Evaluationofthismultiyearretrofitexperienceshowedthatenergysavingsfrom

retrofitsacrossaportfoliocouldberealized,documented,andmaintained.The

engineeringpredictionsfromenergyauditscouldbetrusted.Findingsfromstudies

conductedin1995and1996,iv

basedonover150buildingretrofits,showedthefollowing:

Savingsfrombaselineof24%26%atretrofitcostsof$23persquarefoot Overallaverage5.1yearactualpaybackversus3.8yearprojectedbyaudits

Butthereisacatch.Whiletheresultsfortheoverallsetweregood,theoutcomefor

anyparticularbuildingfellwithinawiderangefrompredicted.Savingsvoutcomes

wereseentofallalmostequallyoneithersideofalinerepresentinga1:1

correspondenceofpredictedtoactualsavings,oftenwithsubstantialvariation.

(SeeFigure1)

Wasthisuncertaintyinoutcomesafunctionofauditerror(prediction)orofretrofit

performance?

Theanswerturnsouttobesomeofboth.Audits,doneundertheLoanSTAR

programbyindependentengineeringconsultants,weresubjecttoTAMUstandards

butneverthelessproblemsinsavingsestimateswerefoundinsome2030%of


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casesreviewed.Suchsavingsestimatesweremadesubjecttoposthocadjustment,

whichistosaythatnewpredictionsweredevelopedbasedonengineeringanalysis

andusedforcomparisontoactualresults.Butitwasalsofoundthatsystemswere

oftennotoperatingasintendedandthatperformancecouldbeimprovedby

adjustment.

Wasthisuncertaintyinoutcomesafunctionofauditerror(prediction)orofretrofit

performance?

Figure1:MeasureSavingsComparedtoEstimatedSavings

Source:TexasA&MEnergySystemsLab


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Theanswerturnsouttobesomeofboth.Audits,doneundertheLoanSTAR

programbyindependentengineeringconsultants,weresubjecttoTAMUstandards

butneverthelessproblemsinsavingsestimateswerefoundinsome2030%of

casesreviewed.Suchsavingsestimatesweremadesubjecttoposthocadjustment,

whichistosaythatnewpredictionsweredevelopedbasedonengineeringanalysis

andusedforcomparisontoactualresults.Butitwasalsofoundthatsystemswere

oftennotoperatingasintendedandthatperformancecouldbeimprovedby

adjustment.

Inthefollowingplotofasampleofbuildings(againwiththeblacklineshowinga

1:1correspondenceofauditprojectedsavingstoactualperformance),verticallines

showsiteswheresavingsestimateswereadjustedwithoutchangeinperformance

andhorizontallinesshowsiteswheresavingsestimateswereunchangedbut

performancewasimprovedbysystemadjustment.Figure2addstothepicture

fromFigure1byshowingadjustmentsovertime.Wecanseeinthischartthe

significantopportunitytoimprovepostretrofitsystemperformance.Interestingly,

performanceimprovementcanbeachievedalmostasfrequentlyincasesthatwereexceedingpredictedperformanceasinthosecasesthatwereunderperformingin

relationtoprediction.

Oneimportantlessonherewasthatthepredictabilityofsavingsforanyspecificsite

couldbeimprovedbyfollowupbasedonMeasurementandVerification(M&V),

actingasfeedbackontheimplementationprocessandongoingoperations.A

secondlessonlearnedisthatbeyondjustpredictabilityinmeetingauditprojections,

absoluteprojectperformancecouldbeimproved.Thetendencyofproject

performancetodegradeovertime(ascontrolsandsettingsslipoutofadjustment,

forexample)couldbereversedbykeepingoperatorsalerttoperformance.With


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M&Vbasedmonitoringappliedinthisway,theoverallportfolioperformedover

timeby20%betterthan(thetotalof)theauditprojections.vi

ContinuousCommissioning

ThevalueofM&VappliedasprocessfeedbackledtotheconceptofContinuous

Commissioning,eventuallytrademarkedbyESLTAMU.Commissioningsavings

couldbeattributedtotheadjustmentwork,independentlyoftheretrofitproject

andwereunderstoodtoconstituteasmuchas25%ofportfoliosavingsandat

muchlowercost.

Figure2:Multi-yearestimatedsavingsvsactualsavingsforLoanSTARbuildings19912000



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IntheLoanSTARprogram,commissioningwasdeployedinretrofitprojectsto

improvetheirperformance.Withthissuccessitbecamenaturaltowonderwhether

acommissioningapproachcouldbeappliedtoexistingsystems,withouttheretrofit.

Thus,theContinuousCommissioningexperienceledtoemergenceofthefieldof

ExistingBuildingCommissioning,RetroCommissioning,andOngoing

Commissioning.vii

Thiskindofmonitoringprocessreliesonintensivedataacquisitionandanalysis.On

anindividualbuildingbasis,itmaybeaccomplishedusingthecomputerbased

BuildingAutomationSystemsupplementedasnecessarybyportabledataloggers

andotherinstrumentation.Butforalarge,programmaticbuildingset,acoordinatedsystemisrequiredthatwillcollectdataandrecognizepatterns.We

havebecomeveryfamiliarwithextensive,complexnetworksintegratingmultisite

dataacquisition,storage,andautomatedanalysis.ESLsLoanSTARproject

Figure3:AnnualsavingsfromtheLoanSTARProgram

includingContinuousCommissioning,19902002



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pioneeredsuchanapplicationforenergymonitoring.Patternrecognitionofactual

versusperformancemodeledisalsoanongoingfieldthatiscriticaltokeepingtrack

oflargenumbersofsites.

Figure4:Pre-andpost-retrofitperformancedatapoints

plottedagainstboundedmodelprediction



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Conclusions

SowhataretheimplicationsforNYC?

Aprocessthatwillachieveitstargetedenergyandcarbonreductionentailsmore

thaninvestinretrofitsbecausethatwouldleavetheinvestmentopento

significantriskofunderperformance.NYCsplanincludesmeteringand

monitoring,butforthisefforttoreallypayoff,substantialinfrastructureisrequired,

intermsofbothhardwareandhumanknowledgeresources.Performancedepends

onfeedbackthroughsuchasystem.Itwillnotpaytoskimponthisphase.

TheCitysbudgetprocessissaidtobeskewedtowardscapitalimprovements.But

aswehaveseen,operations,whicharepaidforintheexpensebudget,reallymatter.

Completingbothretrofitsandthedataacquisitioninfrastructurewillnotmatterif

weareunabletoeffectivelyintegratethemintooperations.Hereisaprimecase

wherethebalanceofallocationbetweenthecapitalandexpensebudgets,can

significantlyaffectperformanceandoutcomes.TheCIUSBuildingPerformanceLab

hasdevelopedasimplespreadsheetthatallowsalternativeallocationstobe

exploredquantitatively.viii

References

iSeeMcGrawHillcitedinNREIResearchPaperTheEvolvingLandscapeofEnergyRetrofitsiiA.Maron,presentationatNREIconferenceonBenchmarkinginNYCBuildings,March2010iiihttp://www.seco.cpa.state.tx.us/ls/ivTAMUESLpublications951101and060702vSavingsarediscussedinenergyunits,notdollarsinordertoeliminatethevariabilityofenergyprices.vihttp://www.seco.cpa.state.tx.us/ls/


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viiSeePortlandEnergyConservationInc.,PECI.orgforacomprehensiveresourcelibraryonbothnewandexistingbuildingcommissioning.viiiM.BobkerIntegratingEnhancedBuildingOperationsintoMunicipalSustainabilityProgrammingProceedingsoftheInternationalConferenceonEnhancedBuildingOperations(ICEBO),2007SanFrancisco,CA.MichaelBobkerisDirectorofBuildingPerformanceLab,CUNYInstitutefor

UrbanSystems

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