RebeccaOlsonNeighborhoodEnergyConnec5on

DuluthEnergyDesignConference2/22/2017

ThisprojectwassupportedinpartbyagrantfromtheMinnesotaDepartmentofCommerce,DivisionofEnergyResourcesthroughtheConserva>onAppliedResearchandDevelopment(CARD)program.

ResearchUpdate:

Con5nuingEduca5on

InaccordancewiththeDepartmentofLaborandIndustry’sstatute326.0981,Subd.11,“Thiseduca5onalofferingisrecognizedbytheMinnesotaDepartmentofLaborandIndustryassa5sfying1.5hoursofcredittowardBuildingOfficialsandResiden>alContractorscon5nuingeduca5onrequirements.”Foraddi5onalcon5nuingeduca5onapprovals,pleaseseeyourcredittrackingcard.

Objec5ves

•  Understandhowresiden5alcondensingboilersarebeinginstalledinMN�

•  LearnaboutHVACcontractorbarriersanda]tudestowardcondensingboilersinresiden5alapplica5ons�

•  Interpretdatafrommonitoringofpreviouslyinstalledcondensingboilers�

•  Learnwhichfactorsaffectcondensingboilerefficiencyinsinglefamilyhomes�

•  Applylessonslearnedfromtheresearchprojectintoboilerinstalla5onprac5ces�

•  Understandtheoverallgoalsofthisresearchproject�•  Getupdatedonnextstepsofop5miza5onproject

Introduc5ontoHydronicHea5ng

Introduc5ontoHydronicHea5ng

•  Non-condensingvs.condensing–  Conven5onalboiler:condensa5onofcombus5ongasescanrustout

heatexchanger–  Condensingboiler:condensa5onofcombus5ongasesisop5mumfor

efficiency•  Differenceinreturntemperaturerequirement

–  Inordertogetcombus5ongasestocondense,thereturnwatertemperatureneedstobebelow~130°

•  Radiatortypes–  RadiatortypesandsizeplayasignificantroleintheΔTbetweensupplyandreturntemps.

•  Issueswithreplacementfromonetoother–  It’simportanttoop5mizeefficiencywhenreplacingaconven5onalboilerwithacondensingboilerbasedontheabovefactors

HydronicHea5nginMN

•  Approximately30%ofMNhomesareheatedbyaboiler

•  Mostoftheseareinolderci5eslikeSt.PaulandMinneapolis

•  Someinnorthernloca5onswherecentralA/Cisinlessdemand

CondensingBoilers

•  Howitworks:–  2ndcondensingheatexchanger

–  Lesswasteheatupthechimney

–  Ifreturnwatertempislow,moreheatisexchangedfromthecombus5ongasestotheboilerwater:increasingefficiency

–  Supplytemperature,flowratesandradiatortype/sizedictatereturnwatertemp.

NeedforCondensingBoilerResearch

•  Lackofmodula5ngcondensingboilersinresiden5almarket

•  EvidencethatHVACcontractorsandu5li5eshaveinconsistentconfidenceinproducts

•  Priorresearchshowinghowimportantreturntemperatureisoncondensingboilers—commercialandhydronicairhandlerstudies

•  Needforqualityinstalla5onprotocolforu5litysavingsandcostbenefitconfidence

ContractorHesitanceandCost

•  Costofcondensingunitsisgenerallyhighandvariable•  $6,500--$15,000installa5oncostrange

•  Lackofconfidenceinopera5onathighefficiency•  Issueswithearlymodelsandmaintenance

callbacks•  Confusionaboutsupplyset-tempsand

condensingrateop5miza5on•  Notasmanymodelop5onsinthismarketas

condensingforcedairsystems

CondensingBoilerRebatesinMN

•  Currentrebatesforcondensingunitsareofferedby:–  CenterpointEnergy(91%+AFUE=$500)– MNEnergyResources(90%+AFUE=$200)–  GreatPlainsNaturalGas(91%+AFUE=$500)–  GreaterMNGas(90%+AFUE=$500)–  Newin2017:XcelEnergy(90%=$300,95%+=$400)

•  2017Federaltaxcredit:TBD?

PriorResearchandInforma5on

•  Conclusions:– Returnwatertempisaprimaryfactor– Flowratescaninfluencereturnwatertemperature

– Outdoorresetneedstobeinstalledandset-upproperly

– NeededmoreinfopertainingtoMNhousingstock,radiatortypes,andclimateaswellasmorefieldimplementa5onguidelines

•  BuildingAmerica—Butcher/Arena•  CommercialBoilerstudy—CEERussLandry•  ASHRAEHandbook

PriorResearchandInforma5on

ResearchProjectStructure

•  FieldandMarketresearch•  Exis5ngcondensingboilermonitoring•  Dratretro-commissioningac5vi5es•  Monitorsavingsaterretro-commissioning•  DevelopmentofQualityInstalla5onProtocolfor

U5lityrebatesbasedonsavingsfromretro-commissioning

•  WorkwithcontractorstoinstallcondensingboilersinhomesusingQIprotocol

•  Informa5ondissemina5onthroughwebinars,presenta5onsandpublishedreports

ResearchProjectTimeline

Task Name1 Assessment2 Existing boiler monitoring

2.2 Exisiting monitoring 2.3 recommissioning2.4 Post monitoring2.5 refinement of recommissioning checklist

3 New boiler installation3.2 Installation3.3 Monitoring 3.4 refinement of installation checklist

4 Final report

Q1 Q2 Q3 Q4 Q1 Q2 Q3 Q4 Q1 Q2 Q3 Q4

MarketResearchStructure

•  InterviewHVACcontractorsaboutinstalla5on•  Procedures•  Pricing•  Barriers•  Incidence

•  Interviewhomeownersaboutperformance•  Comfort•  Maintenance•  Issues

•  InterviewU5li5esaboutrebatedevelopmentandra5onale

EarlyMarketResearchResults

•  InterviewHVACcontractorsaboutinstalla>on•  6companiesinterviewedsofarincludingasupplier•  Lowvolumeofboilerreplacementsandevenlowervolumeof

condensing•  Somehesita5ononcostvs.performance•  Costsseemtobeinconsistentwithequipmentandlabordetails

•  Interviewhomeownersaboutperformanceofexis>ngcondensingBoiler•  Comfortisveryhighinexis5ngsites•  Maintenancedoesnotseemtobeanissuewithanyofthesites•  Mostsitesreliedoncontractortochoosemodel•  All6residentssaidtheywouldrecommendcondensingsystemtoothers

•  InterviewU>li>esaboutrebatedevelopmentandra>onale•  PreliminarydiscussionwithXcelindicatestheywereworriedaboutcost

effec5veness.•  Theymaybege]nghighinstalla5oncostes5mates,andnothavealotof

confidenceintheefficiency

FieldResearchPhaseI

•  Characteriza5onofTypicalMNhouseholds•  Basedonaggregateconsump5ondatafromexis5ngprograms

•  Par5cipantsolicita5on/selec5on•  6siteschosenwithexis5ngmodula5ngcondensingboilers

installedwithinthelast5years•  Siteshavevariedhea5ngloadsandconstruc5oncharacteris5cs•  Allhomeshavecastironradiators

•  Somehaveotherconvectortypes,(i.e.baseboard,in-floor,lowmass)•  3siteshaveindirectwaterheaters•  Monitoring

•  Gasusage•  Supplyandreturnwatertemperature•  Flowrates•  Condensa5onrate

FieldResearchPhaseI

•  1sthalfof2015/2016hea5ngseason,monitoredasinstalled

•  Mademinorchangestoop5mizeefficiency•  Adjustedsupplytemp•  Op5mizedturn-downra5o•  AwemptedtochangeDHWsupplytempandflowrate

•  2ndhalfof2015/2016hea5ngseason,monitoredateradjustments

•  Measuredsavingsfrom1sthalfto2ndhalf•  Developeddratqualityinstalla5onprotocol

SiteSelec5onCriteria•  Atleast1homepertypicalhea5ngloadquar5le(420to700,700to830,

830to1275,and>=1275therms/yr)—basedonMNaggregatedresiden5alu5lityprogramdata

•  Atleast1ofeachofthetop3manufacturers—iden5fiedbyu5lityrebateandlocalsalesinfo

•  Avarietyofinstallers

•  MNprogramdatabasessuggestbetween30-36%ofcondensingboilerinstallshadindirectwaterheaters

•  Na5onalGridstudyfound30-40%ofoutdoorresetwerenotinstalledorinstalledpoorly

•  Avarietyofemiwertypes.Castironradia5on,Lowmassradia5on,baseboards,andin-floorhea5ng

SiteSelec5onandRecruitment•  17recruitedhomeshadsmallerloadsthantypicalhomes(Avg720therm/yr)

–  Inselected6sites,largerusagehomeswereslightlyunderrepresented•  Iden>fied6differentmanufacturersinrecruitment.

–  Topbrandsbasedonsupplierandu5lityrebatedataarerepresentedin6selectedsites

–  Triangletube,Buderus,Bunham,WeilMclainallincluded•  11differentinstallersinrecruitedhomes

–  5differentinstallersinselectedsites

MonitoringSet-up

GasuseFlow

Temp

Temp

Output

Temp

Temp

Run>me

PhaseIPreRetro-commissioningDailyMeasuredPerformance

DailyMeasuredPerformance

PhaseI:As-foundperformance

Site ModeSpaceHeating DHW Combined

SpaceHeating DHW

therms/yr therms/yrd215_ex_02 As-found 837 na na 88.4% nad215_ex_03 As-found 536 112 88.0% 90.5% 76.1%d215_ex_05 As-found 88.0% 91.6% 70.3%d215_ex_06 As-found 669 na na 95.1% nad215_ex_07 As-found 731 na na 89.0% na

AnnualEnergyUse AnnualEfficiency

459 94

Retro-CommissioningAc5ons

•  LoweredSupplyTemperature– Determinedreasonableleveltos5llmeetload,butlowerreturntemp.toop5mizeefficiency

•  AdjustedoverallResetCurve– Maximumsupplytemperatureoutputat-12°vs.defaultof0°

–  Thiswilllowertheslopeofthecurvemakingmorepointsalongthecurveinthecondensingmode

•  AdjustedDHWSupplywhenpossible–  Basedonlowerefficienciesofindirecttanksaswellasindica5onsofunusedcapacity

–  Thiswaseitherimpossible,ordidn’tactuallyhaveaneffectonthereturntempbecauseofheatexchangecapability

PhaseISiteExample(D215_ex_07)

•  Boilerforspacehea5ngonly

•  6Castironradiators•  2lowmassradiators•  3zonesw/3t-stats

Min Max28,500 99,000

at140SupT at180SupT35,000 65,000

CapacityEstimatesandRatings(Btu/hr)

BoilerOutput

Emmiters

DesignHeatingLoad(BillAnalysis)

at-12FOAT38,500

SupplyTemperatureOp5miza5on

•  Calculateores5matethehomehea5ngload•  Calculateores5matetheemiwercapacity•  Minimizethesupplywatertemperaturesothatthehouseloadcans5llbemet

PhaseISiteExample(D215_ex_07)

At0°Fthehouseneeds~25,000Btu/hr

SiteExample(D215ex07)EmiwerCapacity

130°Fwilldelivertheneeded25,000Btu/hrat0°FOAT.

SiteExample(D215ex07)Improvement

Aterretrocommissioningperformance

Addfigure

SiteExample(D215_ex_03)-DHW

•  Boilerandindirect

waterheater•  6Castironradiators•  41GalWHsetat130°F

Min Max22,745 75,200

at140SupT at180SupT22,234 41,997

DesignHeatingLoad(BillAnalysis)

at-12FOAT28,925

CapacityEstimatesandRatings(Btu/hr)

BoilerOutput

Emmiters

SiteExample(D215ex03)

DHWOp5miza5on

•  DoesthecurrentDHWcapacitymeetload?•  Minimizethesupplywatertemperature– ManyolderboilersfixtheDHWtemperature

•  d215_ex_03

•  MinimizetheDHWloopflowrate– Manualpumpadjustment– Orboilerse]ngs

SiteExample(D215ex03)

Aterretrocommissioningperformance

PumpSpeed DHWGPM ReturnWaterT Capacity(Btu/hr) AvgEffAs-Found High 2.8 133 53,100 76.1%Opt_1 Med 2.5 131 49,300 77.3%Opt_2 Low 2 129 45,500 77.9%

ComparisonChart

Site Mode

Annual CombinedEff

Annual SpaceEff

Annual DHWthermal Eff

d215_ex_01 As-found 82.6% 86.2% 62.6%

d215_ex_01 Opt-OATCurved215_ex_02 As-found na 88.4% nad215_ex_02 Opt-OATCurve na 90.2% nad215_ex_03 As-found 88.0% 90.5% 76.1%d215_ex_03 Opt-Clean 88.2% 90.5% 77.1%d215_ex_03 Opt-DHW1 88.4% 90.5% 77.3%d215_ex_03 Opt-DHW2 88.6% 90.5% 77.9%d215_ex_05 As-found 88.0% 91.6% 70.3%d215_ex_05 Opt-NAd215_ex_06 As-found na 95.1% nad215_ex_06 Opt-NAd215_ex_07 As-found na 89.0% nad215_ex_07 Opt-OATCurve 90.4%

AnalysisOn-going

NoOptimizationtobeDone

NoOptimizationtobeDone

ConclusionsOp5miza5on

•  EnablingrecommendedOATreseatcurvewillachievemajorityofsavings– Furtherop5miza5onispossible,butnottypicallycosteffec5ve

•  Waterhea5nghasroomforimprovingefficiency– Howeverthesystemmustbedesignedforlowwatertemperatures(whichappearstobeuncommon)

FieldResearch,PhaseII

•  Selected7homeslookingtoreplacenon-condensingboilerwithcondensingboiler

•  Usedsimilarsolicita5onandselec5oncriteriatoPhaseI

•  Workedwith4contractorstoinstallnewboilerinaccordancewithdratQIprotocolinselectedsites

•  Monitoring(sameasexis5ngsites)•  Gasusage•  Supplyandreturnwatertemperature•  Flowrates•  Condensa5onrate

•  MeasureefficiencyandcomparetoPhaseItoes5matepoten5alsavingsassociatedwithQIprotocol

PhaseIISet-upProcedureleadingtoQIguide

•  BoilersizedaccordingtomanualJ–  Ensureminimumfiringrateisaslowaspossible

•  Ensureoutdoorresetisinstalledandmeetsmanufacturerspecifica5ons.–  Ex.Notlocatedinsunnyloca5onorinexhaustpath

•  Setappropriateresetcurve

ComparisonChartPhaseII

ComparisonofAnnualSpaceHea5ngEfficiency

•  Onaveragecondensingboilerssaved14%annualspacehea5ngcostsover80%AFUEboilers.

•  Indirectwaterheaterswereequivalenttoa0.70EFpowerventWH

PreliminaryConclusions

•  Condensingequipmentmeetexpectedsavings–  Evenboilerswithnon-aggressiveresetcurvesareefficientbecausesettempisreachedbeforesupplywatertempgetstohighlimit

–  1-3%savingspoten5albasedonintensiveset-upprocedure—emiwercapacitymeasurement

– Notcosteffec5ve•  DHWperformanceismorealignedwithPowerventedwaterheaterthancondensing– Notrecommendingunlesscostcompe55vewithpowervent

Dissemina5onPlan

•  Holdseveralwebinarsandlivepresenta5onsaboutprojectfindings

•  Workwithcontractorsinvolvedininterviewsaswellasinstalla5onstoadoptQIprotocolandhoneinonpricing

•  WorkwithWXagenciestodetermineassessmentprotocolforcondensingboilerworkscope

•  Workwithgasu5li5esnotcurrentlyofferingrebatesformodconstoimplementrebatewithQIprotocolrequired

•  PublishfinalresearchreportandsendoutwithDERnewslewersetc.

Futureplans

•  Analyzecosteffec5veness•  Finalizeop5mizedresetcurverecommenda5ons•  Communicatewithu5li5esaboutBasicset-upprotocol

•  Getinforma5onoutbasedonDissemina5onplan•  PublishfinalresearchreportandsendoutwithDERnewslewersetc.

ThisprojectwassupportedinpartbyagrantfromtheMinnesotaDepartmentofCommerce,DivisionofEnergyResourcesthroughtheConserva5onAppliedResearchandDevelopment(CARD)program.

DaveBohacDirectorofResearch

CenterforEnergyandEnvironmentdbohac@mncee.org

612-802-1697

RebeccaOlsonResiden5alEnergyProgramDirector,NeighborhoodEnergyConnec5on

rebeccao@thenec.org651-789-5705

ProjectPartners:

BenSchoenbauerSeniorResearchEngineer

CenterforEnergyandEnvironmentbschoenbauer@mncee.org

612-244-2413