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AnalysesoftheR404ahotgasby‐passattheAccumulatorspiral
BartVerlaatNikhef/CERNDT
8October2010VL209
AC110
HT110
VL206
HX206
Hotgasby‐pass
AccuControl
TT101
TT110
PT110
6
7
8October2010 [email protected]
114.55kJ/kg 67.5kJ/kg
178kJ/kg 67.5kJ/kg
Withsubcooling(InternalHEX)Withoutsubcooling
Hotgasby‐passanalyses(Wheretogetthe840baseloadfrom?
HotgasinjecYoninAccuspiralinlet
R404a
8October2010 [email protected]
MathcadcalculaYonofthemassflowsandinletcondiYonoftheaccumulatorspiral
MathcadcalculaYonoftherequiredhotgasinjecYonvalveCv
8October2010 [email protected]
8October2010 [email protected]
CalculaYngpressuredropandheattransferinthecoolingspiralwiththeWolverineEngineeringdatabookIIIcalculator
8October2010 [email protected]
CalculaYngpressuredropandheattransferinthecoolingspiralwiththeWolverineEngineeringdatabookIIIcalculator
Hotgasby‐passvalveCv(‐)
Hotgasmassflow(g/s)
Liquidmassflow(g/s)
Totalmassflow(g/s)
Vaporqualityatinlet(‐)
Pressuredrop(bar)
Heattransfercoefficient(W/m2K)
AxialdT(duetodP)(°C)
RadialdT(DuetoHTC)(°C)
Maximumcoiltemp.(°C)
Nosubcooling
Hotgasby‐passonly(840W)
0.068 4.6 2.7 7.3 1 0.14 ‐ 1.6 ‐ ‐28.4
500Waccuand840WHotgasby‐pass
0.068 4.6 7.0 11.6 0.82 0.48 7268 5.2 0.6 ‐24.2
500WaccuandreducedHotgasby‐pass(340W)
0.027 1.9 5.4 7.3 0.68 0.21 4437 2.4 0.9 ‐26.7
20°CSub
coo
ling Hotgasby‐passonly
(840W)0.052 3.4 1.3 4.7 1 0.06 ‐ 0.7 ‐ ‐29.3
500Waccuand840WHotgasby‐pass
0.052 3.4 4.1 7.5 0.87 0.19 3959 2.2 1.0 ‐26.8
500WaccuandreducedHotgasby‐pass(340W)
0.021 1.4 3.3 4.7 0.67 0.09 1770 1.0 2.3 ‐26.7
Resultsfora5mlong3/8”coil
Nosubcooling:Tcondenser=30°C,Tevaporator=‐30°C,Tliquid=30°C,Tcoldgas=‐20°C,Tdischarge=70°C
Withsubcooling:Tcondenser=30°C,Tevaporator=‐30°C,Tliquid=10°C,Tcoldgas=20°C,Tdischarge=100°C
8October2010 [email protected]
Hotgasby‐passvalveCv(‐)
Hotgasmassflow(g/s)
Liquidmassflow(g/s)
Totalmassflow(g/s)
Vaporqualityatinlet(‐)
Pressuredrop(bar)
Heattransfercoefficient(W/m2K)
AxialdT(duetodP)(°C)
RadialdT(DuetoHTC)(°C)
Maximumcoiltemp.(°C)
Nosubcooling
Hotgasby‐passonly(840W)
0.068 4.6 2.7 7.3 1 0.27 ‐ 3.1 ‐ ‐26.9
500Waccuand840WHotgasby‐pass
0.068 4.6 7.0 11.6 0.82 0.96 7258 9.7 0.3 ‐20.0
500WaccuandreducedHotgasby‐pass(340W)
0.027 1.9 5.4 7.3 0.68 0.42 4444 4.6 0.5 ‐24.9
20°CSub
coo
ling Hotgasby‐passonly
(840W)0.052 3.4 1.3 4.7 1 0.13 ‐ 1.4 ‐ ‐28.6
500Waccuand840WHotgasby‐pass
0.052 3.4 4.1 7.5 0.87 0.38 3938 4.2 0.5 ‐25.3
500WaccuandreducedHotgasby‐pass(340W)
0.021 1.4 3.3 4.7 0.67 0.17 1761 2.0 1.2 ‐26.9
Resultsfora10mlong3/8”coil(LikeVTCSaccumulator)
Nosubcooling:Tcondenser=30°C,Tevaporator=‐30°C,Tliquid=30°C,Tcoldgas=‐20°C,Tdischarge=70°C
Withsubcooling:Tcondenser=30°C,Tevaporator=‐30°C,Tliquid=10°C,Tcoldgas=20°C,Tdischarge=100°C
8October2010 [email protected]
Preliminaryconclusions
Hotgasbypassvalve.ValveCvvaluesarerangingfrom0.021to0.068UnfortunatelytheCVvaluesfortheselectedDanfoss/SaginomiyaKVexpansionvalvesarenotlisted.TosizethevalveacomparisonwiththeDanfossAKV‐10expansionvalveismadewhichhascoolingpowerandCvlisted.
TheAKV10‐5showacoolingpowerforR404aof4.9kW.ThenearestvalveintheKVexpansionseriesistheUKV‐18D02.TheexpansionvalveforthecoolinginjecYonwillbeUKV‐10D85.
AccumulatorspiralandcontrolThespiralintheaccumulatorcanbea3/8”5mlongtube.Thisissufficienttoremovethe500wahfromtheaccumulatorincludingthehotgasbypass.Thereducedhotgascontrolseemtobethemostpromising.ForthecontrolthismeansthatfirstthehotgasvalveisclosedbeforetheliquidinjecYonisincreased.
8October2010 [email protected]
114.55kJ/kg 67.5kJ/kg
178kJ/kg 67.5kJ/kg
Withsubcooling(InternalHEX)Withoutsubcooling
Hotgasby‐passanalyses(Wheretogetthe840baseloadfrom?
HotgasinjecYoninAccumulatorspiralinlet
R404a
8October2010 [email protected]
CalculaYonofthemassflowsandinletcondiYonoftheaccuspiral
CalculaYonoftherequiredhotgasinjecYonvalveCv
8October2010 [email protected]
8October2010 [email protected]
8October2010 [email protected]
Hotgasby‐passvalveCv(‐)
Hotgasmassflow(g/s)
Liquidmassflow(g/s)
Totalmassflow(g/s)
Vaporqualityatinlet(‐)
Pressuredrop(bar)
Heattransfercoefficient(W/m2K)
AxialdT(duetodP)(°C)
RadialdT(DuetoHTC)(°C)
Maximumcoiltemp.(°C)
Nosubcooling
Hotgasby‐passonly(840W)
0.068 4.6 2.7 7.3 1 0.14 ‐ 1.6 ‐ ‐28.4
500Waccuand840WHotgasby‐pass
0.068 4.6 7.0 11.6 0.82 0.48 7268 5.2 0.6 ‐24.2
500WaccuandreducedHotgasby‐pass(340W)
0.027 1.9 5.4 7.3 0.68 0.21 4437 2.4 0.9 ‐26.7
20°CSub
coo
ling Hotgasby‐passonly
(840W)0.052 3.4 1.3 4.7 1 0.06 ‐ 0.7 ‐ ‐29.3
500Waccuand840WHotgasby‐pass
0.052 3.4 4.1 7.5 0.87 0.19 3959 2.2 1.0 ‐26.8
500WaccuandreducedHotgasby‐pass(340W)
0.021 1.4 3.3 4.7 0.67 0.09 1770 1.0 2.3 ‐26.7
Resultsfora5mlong3/8”coil
Nosubcooling:Tcondenser=30°C,Tevaporator=‐30°C,Tliquid=30°C,Tcoldgas=‐20°C,Tdischarge=70°C
Withsubcooling:Tcondenser=30°C,Tevaporator=‐30°C,Tliquid=10°C,Tcoldgas=20°C,Tdischarge=100°C
8October2010 [email protected]
Hotgasby‐passvalveCv(‐)
Hotgasmassflow(g/s)
Liquidmassflow(g/s)
Totalmassflow(g/s)
Vaporqualityatinlet(‐)
Pressuredrop(bar)
Heattransfercoefficient(W/m2K)
AxialdT(duetodP)(°C)
RadialdT(DuetoHTC)(°C)
Maximumcoiltemp.(°C)
Nosubcooling
Hotgasby‐passonly(840W)
0.068 4.6 2.7 7.3 1 0.27 ‐ 3.1 ‐ ‐26.9
500Waccuand840WHotgasby‐pass
0.068 4.6 7.0 11.6 0.82 0.96 7258 9.7 0.3 ‐20.0
500WaccuandreducedHotgasby‐pass(340W)
0.027 1.9 5.4 7.3 0.68 0.42 4444 4.6 0.5 ‐24.9
20°CSub
coo
ling Hotgasby‐passonly
(840W)0.052 3.4 1.3 4.7 1 0.13 ‐ 1.4 ‐ ‐28.6
500Waccuand840WHotgasby‐pass
0.052 3.4 4.1 7.5 0.87 0.38 3938 4.2 0.5 ‐25.3
500WaccuandreducedHotgasby‐pass(340W)
0.021 1.4 3.3 4.7 0.67 0.17 1761 2.0 1.2 ‐26.9
Resultsfora10mlong3/8”coil(LikeVTCSaccu)
Nosubcooling:Tcondenser=30°C,Tevaporator=‐30°C,Tliquid=30°C,Tcoldgas=‐20°C,Tdischarge=70°C
Withsubcooling:Tcondenser=30°C,Tevaporator=‐30°C,Tliquid=10°C,Tcoldgas=20°C,Tdischarge=100°C
8October2010 [email protected]
Conclusions
Hotgasbypassvalve.ValveCvvaluesarerangingfrom0.021to0.068UnfortunatelytheCVvaluesfortheselectedDanfoss/SaginomiyaKVexpansionvalvesarenotlisted.TosizethevalveacomparisonwiththeDanfossAKV‐10expansionvalveismadewhichhascoolingpowerandCvlisted.
TheAKV10‐5showacoolingpowerforR404aof4.9kW.ThenearestvalveintheKVexpansionseriesistheUKV‐18D02.TheexpansionvalveforthecoolinginjecYonwillbeUKV‐10D85.
AccumulatorspiralandcontrolThespiralintheaccumulatorcanbea3/8”5mlongtube.Thisissufficienttoremovethe500wahfromtheaccumulatorincludingthehotgasbypass.Thereducedhotgascontrolseemtobethemostpromising.ForthecontrolthismeansthatfirstthehotgasvalveisclosedbeforetheliquidinjecYonisincreased.
8October2010 [email protected]