AHRI’sResearchonRooftopPackagedHeatPumps
XudongWangandKarimAmraneAir-Conditioning,Heating,andRefrigerationInstitute(AHRI)
Overview
Ø IntroductionØ LowGWPrefrigerantperformancetestingØ RiskassessmentonrooftopunitsusingA2LrefrigerantsØ Industryupdateonflammablerefrigerantresearch(outsidethepapercontent)
Introduction
Ø Air-Conditioning,Heating,andRefrigerationInstitute(AHRI)– Representingover300HVACRandwaterheatingmanufacturerswithintheglobalindustry
– Administersrigorouscertificationprograms– Establishesinternationalstandards– Representstheindustrydomestically&globally
Low-GWPAREPIntroduction
Ø Cooperativeresearch&testingprogramtoidentifysuitablealternativestohighGWPrefrigerants
Ø EvaluationofcandidatesstronglydesiredbyOEMs– assessresearch&developmentneeds– accelerateindustry’sresponsetoenvironmentalchallenges– avoidduplicativework
Ø TheprogramisNOTtoprioritizerefrigerants,rathertestandpresentobjectiveresultsinaconsistentmanner
Ø PhaseIItestingwascompletedin2016– newrefrigerants– highambienttestingupto125°F(52°C)
Ø Finalreportsavailabletothepublic
SummaryofTestedHeatPumpsinPhaseIIUnitNo.
EquipmentType RefrigerantsTested Testtype TestStandard
1 3-tonairsource,splitsystem ARM-71a,DR-5A,HPR2A,L-41-1,L-41-2(R410Abaseline)
drop-in AHRIStandard210/240
2 3-tonairsource,splitsystem R-32,DR-5A(R410Abaseline)
drop-in AHRIStandard210/240
AHRIStandard210/2403 4-tonairsource,rooftop unit R-32,DR-5A,DR-55(R410Abaseline)
soft-optimization
4 1-tonwater-to-waterheatpump
R-32,L-41-1,L-41-2(R410Abaseline)
drop-in ISOStandard13256-2andENStandard14511-2
5 1-ton,single packagedverticalheatpump(SPVH)
R-32(R410Abaseline)
drop-in AHRIStandard390
6 3-tonwater-toair heatpump R-32,DR-5A,DR-55,L-41-2(R410Abaseline)
drop-inandsoftoptimization
ISOStandard13256-1
7 4.5tonair-to-waterheatpump DR-3,L-20a,R-290(R407Cbaseline)
drop-in ENStandards14511and14825
TestedLow-GWPRefrigerantsinPhaseII
Baseline Refrigerant Composition (Mass%)Classification
(Note1)GWP100(Note2)
R-407CR-290 R-290 100 A3 <5DR-3 R-32/R-1234yf 21.5/78.5 A2L 148
L-20a(R-444B) R-32/R-1234ze/R-152a 41.5/48.5/10 A2L 295
R410A
R32 R-32 100 A2L 675ARM-71a R-32/R-1234yf/R-1234ze(E) 68/26/6 A2L 460
DR-5A(R-454B) R-32/R-1234yf 68.9/31.1 A2L 466DR-55(R-452B) R-32/R-125/R-1234yf 67/7/26 A2L 698
HPR2A R-32/134a/1234ze(E) 76/6/18 A2L 600L-41-1(R-446A) R-32/R-1234ze/Butane 68/29/3 A2L 461L-41-2(R-447A) R-32/R-1234ze/R-125 68/28.5/3.5 A2L 583
Notes:1. Refrigerants’ classifications or intended classifications according to the ASHRAE Standard 34 [3].2. GWP values are calculated based on IPCC AR-4 100 year.
TestTypes
Ø Drop-inTest– onlyminormodificationsareallowed,e.g.adjustingchargeorsuperheatsetting.
Ø System“soft-optimization”test– systemsaremodifiedforthealternativerefrigerantsusingstandardproductionline
components– UnitNo.3:
• thecompressorwasfittedwithavariablefrequencydrive(R-410AandDR-55at60Hz,R-32at55HzandDR-5Aat61Hztoachieveequalcapacityatstandardratingconditionforcoolingapplication.)
– UnitNo.6:• TXVwasre-sizedfrom3-tonto4-ton.
HeatPumpsHeatingPerformance
Needtounderstandtheresults
Ø Whencomparingtestresults,carefullyreviewwhetherchargequantity,expansiondevice,and/orcompressorspeedwereadjusted.
Ø Resultsmayvarysignificantlybasedonthecriteriausedtomakeadjustments.– Chargeoptimizationmaytargetmaximumcapacity,ormaximumefficiency(eitherfull
loadorpartloadseasonalvalue),orneither(suchasmatchingatargetsubcoolingvalue).
– Compressorspeedadjustmentaccommodatesdifferencesinvolumetriccapacityofeachrefrigerant.
RiskAssessmentofA2LRefrigerantsinRooftopUnitsØ AHRI’scontractorNavigantconductedariskassessmentforsixscenarios,
includingthreesizesofrooftopunitsusingtwodifferentlow-GWPrefrigerants.
Scenario Refrigerant Equipment Building Description
A R-3215TonRoof Commercial
Kitchen
Two-circuitRTU(5Tand10T)mountedontheroofabovetheconditioned space,whichconsistsonlyofthekitchen.B R-1234yf
C R-3225TonRoof Office
Two-circuitRTU(12.5T each)mountedontheroofabovetheoffice;returnandsupplyductsservemultipleoffices.D R-1234yf
E R-32
5TonGround Office
Single-circuitRTUmountedonthegroundadjacenttotheoffice;multiplereturn ductingconfigurationsareanalyzed,includingdirectlyductedhorizontallyandductedverticallyupintotheroof.F R-1234yf
RefrigerantDispersionModeling
# Did a substantial plume accumulate with a flammable concentration?
Inside the RTU/Ventilation
In Conditioned Space Outside the RTU
1 2 3 4 5 6 7 8 9 10 Legend:
- Substantial Flammable Plume - Small Flammable Plume - No Flammable Plume
RefrigerantDispersionModeling
# Did a substantial plume accumulate with a flammable concentration?
Inside the RTU/Ventilation
In Conditioned Space Outside the RTU
1 2 3 4 5 6 7 8 9 10 Legend:
- Substantial Flammable Plume - Small Flammable Plume - No Flammable Plume
FaultTreeAnalysis
(Chartsource:NavigantreportingslidestoAHRI)
PotentialIgnitionSources
(Tablesource:NavigantreportingslidestoAHRI)
AnnualIgnitionRisk
(Tablesource:NavigantreportingslidestoAHRI)
CommonSafetyHazardRisk Risk(unit/year)
Fatalinjuryriskforworkerinthemining,quarrying,andoilandgasextractionindustry
1.2E-4
Occupantfatalityriskintrafficcrash(perpersoninU.S.) 8.5E-5
FatalinjuryriskonthejobforemployedpeopleintheU.S. 3.3E-5
Non-occupantfatalityriskintrafficcrash(perpersoninU.S.) 1.8E-5
Injuryriskforparkattendeeonamusementparkride 4.7E-6
Summary
ØHeatpumptestinginLow-GWPAREP– alternativecandidatesdemonstratedcomparableperformance.
– furtherperformanceimprovementispossiblethroughfulloptimization.
– Theresultsshouldnotbeviewedasuniversallyapplicableandneedtobeinterpretedcarefully.
Ø Rooftopunitriskassessment– theignitionrisksoftheA2LrefrigerantsinRTUsaresignificantlylowerthancommonhazardevents.
IndustryUpdateonFlammableRefrigerantResearch
Ø Acollaboratedresearchprogramissupportedby– AHRI($1million)– ASHRAE($1.3million)– CaliforniaAirResourceBoard($0.3million)– USDepartmentofEnergy($3million)
Ø Theobjectiveisto– producepubliclyavailabletechnicalresultstosupportcodeand
standardactivitiesrelatedtotheuseofflammablerefrigerants.• Ensureatimelycompletionofrelevantstandardrevision.
Summer2017:draft
ASHRAE15completedforPPR
Endof2017:publicationoftheupdatedASHRAE15including2Lrefrigerants
Jan2018:2021IMC:changeproposalsaredue
AHRTI&ASHRAEResearchto
supportthe15revision
IdentifiedanddevelopedhighpriorityprojectsØ AHRTIConducting:
– AHRTI-9007:BenchmarkingRiskbyRealLifeLeaksandIgnitionsTesting– AHRTI-9008:InvestigationofHotsurfaceIgnitionTemperature(HSIT)forA2L
Refrigerants– AHRTI-9009:LeakDetectionofA2LRefrigerantsinHVACREquipment
Ø ASHRAEconducting:– ASHRAE-1806:FlammableRefrigerantsPost-IgnitionSimulationandRiskAssessment
Update– ASHRAE-1807:GuidelinesforFlammableRefrigerantHandling,Transporting,Storing
andEquipmentServicing,InstallationandDismantling– ASHRAE-1808:ServicingandInstallingEquipmentusingFlammableRefrigerants:
AssessmentofField-madeMechanicalJointsØ DOEfunding:
– ORNL:InvestigatetheproperbasisforsettingchargelimitsofA2L,A2,andA3forvarioustypesofproducts
– NIST:Modelingtoolsforlow-GWPrefrigerantblendsflammability
CommercialkitchenwithrooftopAC
Contact
KarimAmrane,XudongWangEmail:[email protected],[email protected]
Tel:703-600-0305
AHRIResearchReportscanbedownloadedattheAHRIwebsite:www.ahrinet.org
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