2008 sae arss visteon eval

8/12/2019 2008 SAE ARSS Visteon Eval

1/27

R1234yf SystemEnhancements and

Comparison to R134a

R1234yf SystemEnhancements and

Comparison to R134a

June 10, 2008

John Meyer


2/27

R1234yf AgendaR1234yf Agenda

System Performance Evaluation TXV (Egelhof) and MCV (TGK) tuning

Baseline and enhanced system test results

IHX

Oil Separator

High Effectiveness Evaporator

Compressor Durability


3/27

P-T for R134a and R1234yfP-T for R134a and R1234yf

0

500

1000

1500

2000

2500

3000

3500

-10 0 10 20 30 40 50 60 70 80 90

Temperature [C]

Pressure

[kPaA] R134a

R1234yf

Cross at ~30C

R1234yf has lower

saturation pressure

R1234yf has higher

saturation pressure


4/27

R134a Stand EvaluationR134a Stand Evaluation

Production system used for analysis

160cc variable displacement compressor

16mm IRD condenser

2.0T cross-charged TXV 58mm plate-fin evaporator

Slightly modified discharge and liquid line

Modified for installation on stand

Slightly modified SL To allow for in situtorque calibration


5/27

R1234yf Stand EvaluationR1234yf Stand Evaluation

Changes to R134a system hardware Same 16mm IRD condenser

Same 58mm plate-fin evaporator

Same VS16 compressor,new MCV set points

Same 200 cc PAG

2.0T, 2.5T, 1.75T TXVs at high & low SH settingsevaluated

Same slightly modified discharge and liquid line

Same slightly modified SL to allow for torquecalibration


6/27

Evaluation MatrixEvaluation Matrix

Compressor

Temp Flow Temp RH

RPM l/s C l/s C %

1 2500 700 45 140 43 40

2 1800 650 45 140 43 40

3 800 600 45 140 43 404 2500 700 37 140 35 40

5 1800 650 37 140 35 40

6 800 600 37 140 35 40

7 2500 700 27 100 25 40

8 1800 650 27 100 25 40

9 800 600 27 100 25 40

Condenser Airflow Evaporator Airflow


7/27

R134a Charge DeterminationR134a Charge Determination

1800

1850

1900

1950

2000

2050

2100

300 350 400 450 500 550 600 650

Charge [g]

Pressure[

kPaG]

0

4

8

12

16

20

24

Temperatu

re[C]

Disch P

Air out T

SH

SC

560 g chosen


8/27

1650

1700

1750

1800

1850

1900

1950

300 350 400 450 500 550 600 650

Charge [g]

Pressure

[kPaG]

0

4

8

12

16

20

24

Temper

ature[C]

Pdisch Evap SH

SC disch air

R1234yf Charge DeterminationR1234yf Charge Determination

550 g


9/27

35C, 1800RPM (pt 5)

0

2

4

6

8

10

12

14

0 1 2 3 4 5

# of 60 degree CCW turns of the TXV

COP

,SC,SH,Capac

ity

Evap SHSubcool

COP

Capacity

Adjusting R1234yf SHAdjusting R1234yf SH

TXVs have a set screw to adjust SH setting Each valve was evaluated at a high and low

SH setting


10/27

SH comparison

0

2

4

6

8

10

12

14

16

18

9 8 7 6 5 4 3 2 1Point

Temperatur

e[C]

R134a baseline

R1234yf 2T high SH

R1234yf 2T low SH

R1234yf 2.5T high SH

R1234yf 2.5T low SH

R1234yf 1.75T high SH

R1234yf 1.75T low SH

R1234yf vs R134a; Evaporator SH

1.75T TXV (blue) seems to loseControl of SH at high loads

43C35C25C

250018008002500180080025001800800


11/27

R1234yf TXV and MCV EvaluationR1234yf TXV and MCV Evaluation

Cross charge TXVs from Egelhof

2.0, 2.5, and 1.75T valves tested

1.75T TXV is undersized

TXV at low SH

Although no strong indication that low SH leads toimproved performance:

Low SH facilitates IHX integration

Improved evaporator discharge air stratification

MCVs from TGK Initial MCV calibration slightly off

Gen II MCVs better tuned for this system


12/27

R1234yf Evaporator StratificationR1234yf Evaporator Stratification

4x4 thermocouple matrix on evaporator outlet

Stratification = Tmax Tmin

With similar SH settings, R1234yf shows

slightly improved stratification


13/27

Baseline R1234yf System Defined

Same compressor, heat exchangers, lines,

lubricant

2.0T TXV from Egelhof at low SH setting

GEN II MCV from TGK


14/27

R1234yf EnhancementsR1234yf Enhancements

Internal Heat Exchanger (IHX) Production Intent (SOP 09)

Fully validated with R134a

Oil Separator

High efficiency evaporator Tube-fin

Same package

Lower air-side pressure drop


15/27

0

1

2

3

4

5

6

7

8

9 8 7 6 5 4 3 2 1

Point

Capacity

[kw]

R134a baseline

R134a IHX

R1234yf baseline

R1234yf IHX

R134a vs 1234yf IHX; CapacityR134a vs 1234yf IHX; Capacity

MCV controls capacity

43C35C25C

250018008002500180080025001800800


16/27

0.0

0.5

1.0

1.5

2.0

2.5

3.0

3.5

4.0

4.5

5.0

9 8 7 6 5 4 3 2 1

Point Number

COP[-

]

R134a baseline

R134a IHX

R1234yf baseline

R1234yf IHX

R134a vs 1234yf IHX; EfficiencyR134a vs 1234yf IHX; Efficiency

43C35C25C

250018008002500180080025001800800

43C35C25C

250018008002500180080025001800800


17/27

Discharge and Pressure RatioDischarge and Pressure Ratio

0

200

400

600

800

1000

1200

1400

1600

1800

2000

2200

9 8 7 6 5 4 3 2 1Point

Pressure[kPaG]

0

1

2

3

4

5

6

7

8

9

10

11

Pressure

Ratio[-]

R134a

R1234yf

R134a

R1234yf

P [kPaG] R134a [C] 1234yf [C]

1700 62.9 65.0

1800 65.2 67.5

1900 67.5 69.9

2000 69.6 72.2

P-T relationship predicts

~100kPa lower discharge

pressure for R1234yf

43C35C25C

250018008002500180080025001800800


18/27

R134a vs 1234yf IHX; Compressor

Discharge Temperature

R134a vs 1234yf IHX; Compressor

Discharge Temperature

0

10

20

30

40

50

60

70

80

90

100

110

120

9 8 7 6 5 4 3 2 1

Point

Temperature[C]

R134a Baseline

R134a IHX

R1234yf baseline

R1234yf IHX

43C35C25C

250018008002500180080025001800800

43C35C25C

250018008002500180080025001800800


19/27


20/27

0.0

0.5

1.0

1.5

2.0

2.5

3.0

3.5

4.0

4.5

5.0

9 8 7 6 5 4 3 2 1

Point Number

COP[

-]

R134a baseline

R1234yf baseline

R1234yf Oil Sep

R1234yf HE evap

R134a vs 1234yf Oil Separator & High

Efficiency Evaporator; Efficiency

R134a vs 1234yf Oil Separator & High

Efficiency Evaporator; Efficiency

43C35C25C

250018008002500180080025001800800

43C35C25C

250018008002500180080025001800800


21/27

0.00

0.050.10

0.15

0.20

0.25

0.30

0.35

0.40

0.45

0.50

0.55

0.60

0.65

0.70

0.75

20 30 40 50 60 70 80

Condensing Temperature [C]

Quality[-]

R134a

R1234yf

Evaporator Inlet QualityEvaporator Inlet Quality

Higher quality = less liquid = lower capacity

8% Less Liquid

Inputs10C Subcool

5C Evaporation temp

Supercritical R744 high-

side pressure = 13MPa


22/27

0.00

0.050.10

0.15

0.20

0.25

0.30

0.35

0.40

0.45

0.50

0.55

0.60

0.65

0.70

0.75

20 30 40 50 60 70 80

Condensing Temperature [C]

Quality[

-]

R134a

R1234yf

R744

Evaporator Inlet QualityEvaporator Inlet Quality

Higher quality = less liquid = lower capacity

8% Less Liquid

29% Less LiquidInputs10C Subcool5C Evaporation temp

Supercritical R744 high-

side pressure = 13MPa


23/27

R1234yf Performance SummaryR1234yf Performance Summary

Baseline R1234yf system used same tonnage TXV

with modified bulb charge and adjusted MCV

R1234yf has approximately 8-10C cooler

compressor discharge temperature vs R134a As near drop-in, capacity and efficiency fall slightly

short of R134a


24/27

R1234yf Performance Summary

(cont)

R1234yf Performance Summary

(cont)

R1234yf with IHX

~Matches/exceeds R134a baseline capacity

Has slightly higher average efficiency than baseline

R134a across all points

~Matches R134a compressor discharge temperature

R1234yf with Oil Separator Small increase in capacity and efficiency

Falls short of baseline R134a at high ambient

R1234yf with High Efficiency Evaporator

Small increase in capacity and efficiency

Falls short of baseline R134a at high ambient


25/27

R1234yf Compressor TestingR1234yf Compressor Testing

Initial Compressor Durability

High Pressure Low Charge high load and temperature test

Completed initial testing - No issues

High Speed high friction and high temperature test

Completed initial testing No issues


26/27

Durability Teardown ResultsDurability Teardown Results


27/27

AcknowledgementsAcknowledgements

Thanks to. for prototype MCVs

Egelhof for prototype TXVs

JCS for tube-fin evaporator Honeywell and DuPont for R1234yf

2008 sae arss visteon eval

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