Case Study

Deep Energy Savings in Existing Buildings

Overview

Site Details

• Owner:LovejoyBuildingLLC

• Location:Portland,OR

• BuildingType:Office

• ProjectDescription:MajorRenovation

• SizeSF:20,000

• Stories:2

• ProjectCompletion:2004

• YearBuilt:1910

Recognition:

• LEED-NCGold

THE LOVEJOY BUILDINGOriginallybuiltin1910asthestablesfortheMarshall-WellsHardwareCompany,theLovejoyBuildingisthehomeofOpsis,anarchitecturaldesignfirmpracticingsustainabledesign.ThebuildingislocatedinNorthwestPortlandinanareaknownas“Slabtown,”formerlyhometoearlylumbermillworkers.Theownerarchitectspurchasedandrenovatedthehistoricbuildingin2003tohousetheirgrowingbusinessandtoprovideground-floorofficeleasespaceandsecond-floorofficesfortheirfirm.Retrofitoftheexistingload-bearingbrickstructurerequiredamajorseismicupgrade.Thearchitectsusedthisasanopportunityforanintegratedresponsetoadvancedstructuralupgrades,enhanceduserthermalcomfortandimprovedenergysavings.

Opsiswantedtousethebuildingtoexperienceanddemonstratethetechnologiesandpracticesitpromoteswithclients.Creatinganopen,comfortableandresource-efficientofficespacewasapriority;incorporatingupgradedefficiencyfeatureswasconsideredanintegralpartofthenormalprojectbudget.

Thebuilding’sactualenergyuseis40kBtu/sf/yr,57%betterthantheaverageforofficebuildingsintheU.S.ThebuildingalsoqualifiedfortheU.S.GreenBuildingCouncil’sLeadershipinEnergyandEnvironment(LEED)certificationataGoldlevelin2006.

MotivationsProject goal: ThegoaloftheprojectwastocreateabuildingthatalignedwiththecultureandprofessionalobjectivesofOpsis.Theownersdesignedtheirspacetoformulatealivinglaboratorytoshowcase,andexperience,thevariousenergy-efficientandsustainabledesignfeaturestheyincorporateintotheirwork.

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Accordingtooneoftheowners,JamesMeyer:

“There can be a disconnect for architects to understand the real world and what it means to be the one to write the check. We wanted to ‘walk the talk’ as proponents of green building design for our clients.”

Rationale and economic criteria for selecting energy efficiency options: ThearchitectsatOpsisplacedpriorityonalargeuninterruptedofficespacesupportinganopencollaborativeworkenvironment.Anin-floorhydronicheatingandcoolingsystemwaschosentooptimizeopenspaceaswellastoprovidegreaterindividualthermalcomfort.Verticalandhorizontalglazingofferedeveryoneaccesstoaneffectivelydaylitworkenvironmentandenhancedviewstotheoutside.Opsisrecognizedthecommontendencytoconsiderenergyefficiencymeasuresas“add-ons”thatcanbevalue-engineeredoutduringcost-cuttingsessions.Thefirm’sdesignapproachdemonstratedaholisticintegrationofallcomponents,withefficiencyasanimbeddedpartinseparablefromthedesignandprojectprogram.

Barriers and resolutions to energy efficiency measures:Opsiswantedtoincorporateasmanyenergyefficientmeasuresintothebuildingaspossible,anditwasabletoincludealmosteverythingitconsidered.Lightingcontrols,operablewindowsandnightflushweresomeofthemeasuresforwhichtheownerswerewillingtopaymore.Radiantconcretewallswerestudiedbutweredeterminedtobecost-ineffective.

Technologies and Design StrategiesTheprojectincludedawhole-buildingenvelopeupgrade(thebuildingwasnotoccupiedduringtherenovation).Theadditionalefficiencystrategiesoutlinedbelowwereincorporatedintothe13,660sfoccupiedbyOpsis.Asubtenant

Creatinganopen,comfortableandresource-efficientofficespacewasapriority.

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leasestheremainingarea,whichhasthreedifferentmechanicalsystems;theownerscurrentlyhaveefficiencyorgreentenantleaserequirements.

HVAC:Anin-floorPEXpipehydronicsystemprovidesthebuilding’sprimaryheatingandcooling,coupledwithanintegratednaturalventilationstrategyusingwindows,skylightsandventilators.Inthewinter,waterrunsthroughthethermalmass,creatingastabletemperaturerangewhileintroducingheatlowinthespace.Inthesummer,thebuildingissetforanightpurge:coolnightairintroducedintothebuildingremovestheheatgainsofthepreviousday,leavingthespacecoolforthenextmorning.Inaddition,theradiantslabhydronicsystemcollectsheatoutoftheslab,runningthewaterthrougharooftopchillerwheretheheatisremoved;thecoolwateristhenrecycledbackthroughthein-slabpipingsystem.Theradiantfloorstrategyrequiressignificantlylessspaceforequivalentheatingandcoolingthanamaterial-andenergy-intensiveforcedairsystem,withtheadditionalbenefitoflessrecirculatedair,resultinginimprovedairqualityandhumancomfort.

Envelope: Aseismicupgraderequiredaddingtothethermalmassofthebuilding.Newhighfly-ashconcreteperimeterwallsandaconcretefloorsystemwerepouredinplace,withtheaddedbenefitofimprovingtheefficiencyofheatingandcoolingthebuildingbyincreasingitsthermalmass.Theoriginalwindowswereenlargedtoimproveviewsandbringlightdeepintothespace.Theadditionof14skylightsprovidesadditionalnaturallighttothetopfloorofthebuilding.Low-Ehigh-efficiencyglassisusedtominimizeheat,andoperablewindowsarecontrolledbythebuildingmanagementsystemtomaintaintemperatureandairquality.Automatedsunshadesonthewestfaceofthebuildingblockunwantedlightandheatgains.

Lighting: Theprimarylightingsystemissuspendeddirect/indirectT8fixtureswithdimmableballasts.Thelightingsystemincludesintegrateddaylightingcontrolstoautomaticallydimelectricallight.

Daylighting: TheofficespacewasmodeledforuniformnaturalbalanceddaylightusingaheliodonattheEnergyStudiesandBuildingsLaboratoryinPortland.Daylightingstrategiesincludeopenofficespace,enlargedwindows,skylightsandawhiteceilingforreflectivepurposes.Daylightcontrolsreduceelectriclighting,andwestfacingexteriorautomatedsunshadesreduceglareandheatgain.

Controls: ThelightingandHVACsystemsarecontrolledbyawholebuildingEnergyManagementControlSystem(EMCS)andsensors.Thedigitalsystemmodulateslightingaccordingtodaylightlevelswithzonedphotocellsensorslocatedontheopenofficeceiling.Automatedsunshadesonthewestfaceofthebuildingarecontrolledbyphotocellssettoanastronomicalclock.Ratherthanusingthestandardfixedventilationratesperpersonbasedonassumedfulloccupancy,Opsisusescarbondioxide(CO2)

Anin-floorhydronicheatingandcoolingsystemwaschosentooptimizeopenspaceaswellastoprovidegreaterindividualthermalcomfort.

Efficiency Measures

• Highthermal-massenvelope

• In-floorradiantslabwithhydronicheatingandcooling

• Nightcoolairpurge

• Low-Eglazing

• Automatedsunshades

• Skylights

• Dimmableballastswithintegrateddaylightcontrols

• DemandcontrolventilationwithCO2sensors

• Openofficewithlightsurfaces

• Energymanagementcontrolsystem

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sensorsintheofficetointerpretoccupancydensity.ThissystemofCO2sensors,knownasDemandControlVentilation(DCV),sendsdatatothebuildingmanagementsystemtomodulateventilationair(whichrequiresenergyforconditioning)toaccommodateactualoccupancyneeds.

Plug Load Management:WhenthestaffatOpsismovedintotheirnewspace,theyreplacedtheiroldCRTmonitorswithmoreenergy-efficientflatscreens.Opsisrecentlyinstalledanelectricitymanagementmonitoringsystemtoreviewplugloadsandenergyusageinrealtime.

Commissioning:Theprojectincludedenhancedcommissioning,andtheelectricitymanagementmonitoringsystemallowsforfeedbacktodirectongoingcommissioning.

Monitoring systems: Thebuildinghastwoelectricalmeters,oneforOpsisandtheotherforitstenant.

Post-Renovation Additional Measures: TheoriginalDirectDigitalControls(DDC)purchasedforthebuildingwerereasonably-priced,buttheylackedclearfeedbackandguidance.Afterthreeyears,Opsisboughthigher-end,moreuser-friendlycontrols.

Renewables:Aphotovoltaicsystemontheroofprovides2,500-wattmaximumoutput–enoughtopowersixworkstationcomputerenvironments.

Energy Performance

Energy Performance

%BetterthanBaseline 57%Baseline Average for

U.S. Offices*

MeasuredEnergyUse(KBtu/SF/yr) 40

EnergyStarScore 92

* CBECS – U.S. DOE Energy Information Agency’s Commercial Building Energy Use Index 2003

* Comparable office average energy use from the Energy Star Portfolio Manager program based on like type, size, occupancy, hours, and climate - determined from statistical analysis of the CBECS dataset

**Average energy use for all U.S. Office buildings through the Commercial Building Energy Consumption Survey (CBECS)

Lovejoy Measured Energy Use

Energy Use per square foot Comparison

Energy Use Index (EUI) kBtu/sf/yrZero0 10 20 30 40 50 60 70 80 90 100

Average for comparable office buildings (Energy Star)*

65

40

93

57% less energy

38% less energy

Average for all US Office Buildings (CBECS**)

Daylightcontrolsreduceelectriclighting,andwestfacingexteriorautomatedsunshadesreduceglareandheatgain.

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Energyperformance/savings:Opsishasbeentrackingitsmonthlygasandelectricbillssince2008.In2010,energyusewas40kBtu/sf/yr(EUI1)fortheOpsisofficespacearea–57%lessenergypersquarefootthantheaverageforofficesintheU.S.2TheU.S.officeenergyaverageisagoodbasisforquicklycomparingbuildingsofthesametype.AmorespecificcomparisoncanbemadethroughtheEnergyStarPortfolioManagerprogram,whichdeterminestheenergyuseofcomparablebuildingsofliketype,size,hoursofuseandclimate.Inthisexample,theEnergyStarprogramcalculationshowedthatcomparablebuildingswoulduselessenergythantheaverageU.S.officebuilding,yettheLovejoyperformsevenbetter–using38%lessenergythantheEnergyStarestimate.

TheLovejoyBuildingearnedanENERGYSTARscoreof92(outof100),placingitinthetop10%ofofficebuildingsintheU.S.forenergyperformance.During2010theownerscalculatedacostsavingsofover$5,000inenergy(gasandelectric)comparedtothepredictedenergycostsfortherenovatedbuildingthroughtheLEEDdesignmodel.

TheLovejoyBuildingshowcasestheenergyefficiencypotentialofanolderbuildingupgradedwithreadily-availableenergytechnologiesandthoughtfuldesign.Theowners’interestintheenergyfeaturesandcontinualmonitoringincreasesthelikelihoodofsuccessandprovidesareal-worldexampletotheirclients.

FinancialTotal project cost: $2,300,000,$115/sf

Funding:Theownersusedaconstructionloantofinancethebuilding,receivinganOregonBusinessEnergyTaxCredit(BETC),butfelttheywerenotasaggressiveastheycouldhavebeeninpursuingadditionaltaxcredits.Theydecidedagainstregisteringthebuildingasahistoriclandmark,thusgivinguptheassociatedtaxcredits,inordertoretaintheflexibilitytoenlargetheexteriorwindowsandaddsunshades.OpsisalsochosenottogobeyondLEED-NCGoldduetocost.AccordingtoJamesMeyer:

“We took everything as far as we could within a tight budget and were able to prove that if you are smart with the design, you can achieve LEED-Gold cost-effectively.”

Project ResultsCompetitive positioning in the market: BecausethebuildingisLEED-Gold,Opsishasbeenabletoattracttenantscommittedtosustainability.Whilethisdoesnotnecessarilymeanhigherrents,thespacehasbeen

1 AnEnergyUseIntensity(EUI)isthetotalenergy(gasandelectric)usedinthousands(k)ofBritishthermalunits(Btu)dividedbythesquarefeet(sf)ofthespace–resultinginacommonly-usedmetricofkBtu/sf.

2 CBECS–TheEnergyInformationAgency’sCommercialBuildingsEnergyConsumptionSurvey2003.

During2010theownerscalculatedacostsavingsofover$5,000inenergy(gasandelectric)comparedtothepredictedenergycostsfortherenovatedbuildingthroughtheLEEDdesignmodel.

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continuouslyoccupiedsinceitwasconstructed.Thecurrenttenantisanopensourcewebdesignsoftwarecompany.

Staff education/user satisfaction: Opsishasastaffpolicyregardingturningofflightsandcomputerswhennotinuse.TheydidaPost-OccupancySurveyandfoundthemajorityoftheiremployeeswere“satisfied”or“verysatisfied”withtheirrenovatedworkenvironment.Daylightingreceivedthemostpositiveresponsefromusers.Whenaskedtheirlevelsofsatisfactionwiththequalityofdaylightinginthebuilding,70%ofemployeesresponded“verysatisfied”and30%“satisfied.”Eightypercentofemployeessurveyed“stronglyagreed”thatworkinginabuildingthatuseslessenergyandfewerresourceswasimportanttothem,andthebalance(20%)“agreed”thatitwasimportant.

Innovation and Lessons Learned:ThearchitectsatOpsisbelievethemostinnovativeaspectoftheirbuildingisthein-floorhydronicheatingandcoolingsystem,asitisnotcommonpracticetoincorporateboth.Theenergyefficiencyofthesystemhasmatchedtheirhighexpectationsandtheusercomforthasexceededthem.Althoughthestraightforwarddaylightingstrategyisnothigh-tech,theyconsiderthisaspectoftheprojectverysuccessfulandmostenjoyable.

Acknowledgements and SourcesProject Team:

• OwnerandArchitect:OpsisArchitectureLLP

• GeneralContractor:GrayPurcell

• MechanicalEngineer:InterfaceEngineering,Inc

• ElectricalEngineer:GreenwayElectric

• SustainabilityConsultant:Brightworks

Sources:

• Opsis:JamesMeyer,ownerandprincipal

• Opsis:RandallHeebandChrisBrown,architects

• LovejoyOpsisBuildingcasestudy

• IntegratedDesigninContemporaryArchitecturebyKielMoe

Photos:CourtesyofOpsisArchitecture/GeneFaulkner

Research and Development:

• NewBuildingsInstitute(NBI):LizWhitmore,CathyHiggins,MarkLyles

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Funding:

• TheBetterBricksprogramoftheNorthwestEnergyEfficiencyAlliance(NEEA):PeterWilcox,JohnJennings,andMarkRehley

• NBI’sworkisalsosupportedbytheDorisDukeCharitableFoundationandtheKresgeFoundation

Existing Building Renewal InitiativeThisworkispartofNEEA’sregionalExistingBuildingRenewalinitiativetoacceleratethemarket’sadoptionofdeep,integratedenergy-efficientrenovations.Theinitiativecurrentlyfocusesonofficebuildingsbutwilladdothermarketsectorswithlargepotentialenergysavings.Thisisoneofthewaystheregioncanrapidlyrevampexistingstocktoachieve30–60%energysavings—onthewaytonetzero-energyusebycommercialbuildings.

For more information on the Existing Building Renewal Initiative contact:PeterWilcoxpwilcox@neea.orgorwww.betterbricks.com

For additional case studies highlighting high performance commercial buildings, visit NBI’s Getting to 50 Database: buildings.newbuildings.org/

For more information about NBI’s efforts to improve the energy performance of existing buildings, visit: newbuildings.org/advanced-design/existing-buildings

New Buildings Institute

NewBuildingsInstitute(NBI)isanonprofitorganizationworkingcollaborativelywithcommercialbuildingprofessionalsandtheenergyindustrytoimprovetheenergyperformanceofcommercialbuildings.