system drop in tests of r 410a, r 22, and r 134a in...r410a/r22 alt’s considered compositions o...
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SystemDrop‐inTestsofR‐410A,R‐22,andR‐134aAlternativeRefrigerantsinChillers
KenSchultzThermalSystemsEngineerLaCrosse,WI
2System Drop‐in Tests of R‐410A, R‐22, and R134a Alternative Refrigerants in Chillers at Trane
ChillersUsedForTesting
R410A/R22Alternativeso Air‐CooledWater‐Chiller“Koolman”CGAR‐0605
o Nominaldesigncapacity~4.4RT(15.6kW)
o ScrollCompressorso EvaporatorisBPHEo CondenserisRTPFCoil(8circuits)
R134aAlternativeso Water‐CooledWaterChiller~230RT“RTWD”(prototype)
o DualRefrigerantCircuits~ Rantestsononlyonecircuit
o ScrewCompressor(highlift)o FallingFilmEvaporatoro CuNi TubesinCondenser
rear viewfront view
R410A:DanfossSH090A4ALB
R22: CopelandZR81KC‐TFD‐950
3System Drop‐in Tests of R‐410A, R‐22, and R134a Alternative Refrigerants in Chillers at Trane
TestingConditions
R410A/R22Alternativeso Majorityoftestingdoneatproduct’sdesignoperatingcondition:~ TChWo =45°F =7°C~ VChW =14gpm =53L/min~ Tair =95°F =35°F
o Firstsequencewasusedtodetermine“best”refrigerantchargeasthatgivinghighestCOP.
o TestpointsalsorunatotherTChWo’s andTair’s.~ Thoseresultsnotshownhere.
R134aAlternativeso Majorityoftestingdoneatproduct’sdesignoperatingcondition:~ TChWo =44°F =6.7°C
~ VChWa =2.4gpm/ton=9.1L/min/ton
~ VChWb =550gpm=2080L/min
~ TClWi =85°F =29.4°F~ VClWa =3.0gpm/ton
=11.4L/min/ton~ VClWb =700gpm
=2650L/min
o Firstsequencewasusedtodetermine“best”refrigerantchargeasthatgivinghighestCOP.
o TestpointsalsorunatotherTClWi’s.~ Thoseresultsnotshownhere.
(“Std”)
(“BL”)
(“Std”)
(“BL”)
4System Drop‐in Tests of R‐410A, R‐22, and R134a Alternative Refrigerants in Chillers at Trane
RefrigerantsTested
R410AAlternatives(8+1)o R32 class A2L GWP~675o DR‐5 A2L 490o DR‐4 A2L 296o ARM‐70a A2L 482o L‐41a A2L 494o L‐41b A2L 494o ARM‐32a A1 1577o HPR1D A2L 407
R134aAlternatives(5+1)o XP10 class A1 GWP~631o N‐13a A1 604o N‐13b A1 604o R1234ze(E) A2L 6o ARM‐42a A2L 143o D4Y (quantityneedednotavailable)
R22Alternatives(7+1)o DR‐7 A2L 246o ARM‐32a A1 1577o L‐20 A2L 331o LTR4X A1 1295o LTR6A A2L 206o DR‐4 A2L 296o D52Y A2L 979
5System Drop‐in Tests of R‐410A, R‐22, and R134a Alternative Refrigerants in Chillers at Trane
R410A/R22Alt’sConsidered
Compositionso ThemoreR32,thehigherthepressure.o Alsoresultsin“A2L”classification.
R410A‐likeblendshaveGWPs~500. R22‐likeblendshaveGWPsaslowas200‐250.
A1 1295
A2L 206
A2L 407
A2L 979
A1 1577
A2L 482
A2L 331
A2L 494
A2L 494
A2L 246
A2L 296
A2L 490
A2L 675
A1 2088
6System Drop‐in Tests of R‐410A, R‐22, and R134a Alternative Refrigerants in Chillers at Trane
R134aAlt’sConsidered
Primaryconstituentso R1234yf GWP=4 class=A2Lo R1234ze 6 A2L
Secondaryconstituentso R134a GWP=1430 class=A1o R152a 124 A2
The new “HFO’s”.
“Mildly” flammable.
tested here
A1
A2Lb
7System Drop‐in Tests of R‐410A, R‐22, and R134a Alternative Refrigerants in Chillers at Trane
SimpleThermodynamicModel
Basedonlyonthermodynamicproperties.o Sameconditionsusedforallrefrigerants(R410A&R22asbaselines).o MatchaverageofglidetobaselineTsat’s.o Propertiesasprovidedbytherefrigerantsuppliers.
ID734 = DR-7
8System Drop‐in Tests of R‐410A, R‐22, and R134a Alternative Refrigerants in Chillers at Trane
Comparisons– R410AAlt’sCapacity
measuredresults
simplemodel
comparedtoexpectations(model) largeglide
9System Drop‐in Tests of R‐410A, R‐22, and R134a Alternative Refrigerants in Chillers at Trane
Comparisons– R410AAlt’s
measuredresults
simplemodel
comparedtoexpectations(model) largeglide
COPorEER
10System Drop‐in Tests of R‐410A, R‐22, and R134a Alternative Refrigerants in Chillers at Trane
Comparisons– R410AAlt’s
measuredresults
simplemodel
comparedtoexpectations(model)
DischargeTem
perature
11System Drop‐in Tests of R‐410A, R‐22, and R134a Alternative Refrigerants in Chillers at Trane
Comparisons– R22Alt’s
measuredresults
simplemodel
comparedtoexpectations(model)verylargeglide
Capacity
12System Drop‐in Tests of R‐410A, R‐22, and R134a Alternative Refrigerants in Chillers at Trane
Comparisons– R22Alt’s
measuredresults
simplemodel
comparedtoexpectations(model)
COPorEER
13System Drop‐in Tests of R‐410A, R‐22, and R134a Alternative Refrigerants in Chillers at Trane
Comparisons– R410A&R22Alt’sTemperatureGlide
14System Drop‐in Tests of R‐410A, R‐22, and R134a Alternative Refrigerants in Chillers at Trane
Comparisons– R410A&R22Alt’sRefrigerantCharge
15System Drop‐in Tests of R‐410A, R‐22, and R134a Alternative Refrigerants in Chillers at Trane
Comparisons– R134aAlt’s
Allrefrigerantshadsimilarbehavioratpartload.o Maximumcapacityissetbycompressordisplacementandrefrigerantspecificvolumeatcompressorsuction.
Firsttests,May2012
Repeattest,Oct2012
LoadLines
16System Drop‐in Tests of R‐410A, R‐22, and R134a Alternative Refrigerants in Chillers at Trane
Comparisons– R134aAlt’s
o Measurementsmatchpredictionsverywell.
measuredresults
simplemodel
Maximum
Capacity
o LowerperformanceofN‐13aandN‐13bduetopoorevaporatorperformance.
17System Drop‐in Tests of R‐410A, R‐22, and R134a Alternative Refrigerants in Chillers at Trane
Comparisons– R134aAlt’s
o Measurementsmatchpredictionsreasonablywell.o Lowerefficienciesduetopoorerheatexchangerperformance.o BetterefficiencyforR1234ze(E)dueto“larger”heatexchangers.
measuredresults
simplemodel
Efficiency(COPorEER)
18System Drop‐in Tests of R‐410A, R‐22, and R134a Alternative Refrigerants in Chillers at Trane
Conclusions(A)
LowerGWPalternativestoR410A …
o R32offerspotentialforchargereductionandsmallincreasesincapacityandefficiency(notrealizedhere,though).Mainhurdleislargeincreaseincompressordischargetemperatures(40°F+atnominalratingconditions).Miscibilitywithoilsisalsoanissue.
o DR‐5andtheL‐41’soffer“neardrop‐in”capacitiestoR410Awithpotentialforslightincreasesinefficiencies.However,compressordischargetemperaturesincreasesignificantly(14°F‐22°Fatnominalratingconditions),butnotasmuchasR32.
o ARM‐70aandDR‐4offerpotentialforimprovedefficienciesifsmallreductions(10%‐15%)incapacitiescanbeaccommodated.CompressordischargetemperaturesaresimilartoorslightlyelevatedfromR410A.
o GWP’srangefromonly400to675– notexactly“verylow”.o TheyareallclassA2L(mildlyflammable).NoA1blendswithlowerGWPcanbemadewiththecurrentlyknownverylowGWPrefrigerants.
o Thebestcapacitymatchesproduceelevatedcompressordischargetemperatures,especiallyR32.
19System Drop‐in Tests of R‐410A, R‐22, and R134a Alternative Refrigerants in Chillers at Trane
Conclusions(B)
LowerGWPalternativestoR22 …
o CapacitieswithL‐20(A2L,GWP~330)andLTR4X(A1,GWP~1300)closelymatchR22capacity.However,COP’sweredownby5%‐10%,respectively.
o ARM‐32a(A1,GWP~1575),DR‐7(A2L,GWP~250),andDR‐4(A2L,GWP~300)provideincreasedcapacities,butalsolowerefficiencies(11%‐15%).
o GWP’scanrangeaslowas250‐300.However,theseblendsarealsoA2L.o ClassA1blendscanbemade,however,thereductioninGWPfromR22isverymodest(1800 1300‐1600)– butnoODP.
o Theyallhavesignificantlylowerthermodynamicefficiencies.Equipmentdesignswillneedtomakeupforthisthroughextraheatexchangerarea,improvedcompressorefficiency,etc.(SimilarchallengewhenmovedtoR410A.)
o Theyallhavelargertemperatureglides.Thisagainwillimpactheatexchangerandsystemdesigns.
o CompressordischargetemperaturesaresimilartoorlowerthanwithR22.
20System Drop‐in Tests of R‐410A, R‐22, and R134a Alternative Refrigerants in Chillers at Trane
Conclusions(C)
LowerGWPalternativestoR134a …
o ForclassA1blends,GWP’srangefromonly575‐600– notexactly“verylow”.~ XP10providedacapacityveryneartoR134a.~ TheN‐13’swerenegativelyimpactedbyverypoorperformanceintheevaporator,likelyattributabletotheirsmalltemperatureglide(~1°F/~0.6°C).
o VerylowGWPs(4‐6)canbehadbyusingR1234yfandR1234ze(E)bythemselves.TheseareclassA2L(mildlyflammable)andhaveefficiencyorcapacitypenalties.~ Super‐solubilityofR1234ze(E)inPOEisanissue.
o CapacityandefficiencycanberecoveredifGWPisallowedtobe120‐150(withintheEuropeanMAClimit),eg ARM‐42a– butisA2L.~ NeedtounderstandpoorbehaviorofARM‐42aincondenser.