evaluation of r-449a as a replacement for r-22 in low and

July 11 -14, 2016

Evaluation of R-449A as a Replacement for R-22 in Low and Medium

Temperature Refrigeration

Andrew Pansulla, The Chemours Company

Charles Allgood, The Chemours Company

Agenda

� Regulations

� HFOs/R-449A introduction

� Thermodynamic modeling

� Calorimeter testing

� System testing in an environmental chamber

� TXV considerations

� Conclusions

July 11-14, 2016 2Purdue Conferences

Environmental Considerations

Global Warming Potential (GWP)

The potential effect that certain substances have on climate change.

Ozone Depletion Potential (ODP)

The potential for a refrigerant to reduce the amount of ozone in the

stratosphere.

The Regulatory Challenge: R-22 is going away

The EPA has published a final rule on the amount of virgin R-22 allowed to be consumed until production ceases in 2020.

The Montreal Protocol is an

international treaty designed to protect the ozone layer by phasing

out the production of numerous substances that are responsible for

ozone depletion.

Refrigerant History : > 85 years of Enabling Technology

1930s

CFCs(R-12)

ChlorineSingle Bond

High ODPHighest GWP

1950s

HCFCs(R-22)

Less ChlorineSingle Bond

Lower ODPHigh GWP

1990s

HFCs(R-134a)

No ChlorineSingle Bond

No ODPHigh GWP

TODAY

HFOs(R-1234yf)

No ChlorineDouble Bond

No ODPVery Low

GWP

What is an HFO

HFCHydro fluorocarbon

HFCHydro fluorocarbon

HFOHydro fluoro olefin

HFOHydro fluoro olefin

1234yf – The Base HFO Molecule

R-134a HFO-1234yf

Formula CH 2FCF3 CF3CF=CH2

Molecular Weight 102 114

ODP 0 0

GWP100 (AR5) 1300 < 1

T Critical Point 102 ºC 95ºC

Boiling Point -26ºC -29ºC

� Same operating conditions as 134a (similar P/T curve)

� Thermally stable under extreme use conditions

� Capacity and efficiency similar to R-134a

� Mildly flammability (A2L)

0

0.5

1

1.5

2

2.5

3

3.5

-40 -20 0 20 40 60 80 100

134a

1234yfPre

ssur

e, M

Pa

Temperature, oC

R-449A Physical Properties

� R-449A is an HFO blend originally developed as a low GWP replacement for R-404A (and R-22)

� Composition (weight percent): R-32 (24.3%)/R-125 (24.7%)/R-1234yf (25.3%)/R-134a (25.7%)

8

Thermodynamic Modeling Assumptions

� R-449A condensing and evaporating pressures calculated to have the same average condensing and evaporating temperatures as R-22

� Superheat and sub cooling calculated from average Tc and Te of R-449A to give the same return gas and liquid line temperatures for all models

� Maximum discharge temperature = 135 oC

� Isentropic efficiency = 0.70

� All models had the same theoretical compressor displacement


R-22 and R-449A Thermodynamic Modeling

Low Temperature 1 Medium Temperature 2

ASHRAE# R-223 R-449A R-22 R-449A

Relative Capacity 1.00 1.00 1.00 1.03

Relative COP 1.00 0.96 1.00 0.94

Relative Mass Flow

1.00 1.14 1.00 1.11

Suction Pressure

(kpa [abs])

171.7 182.2 398.5 436.4

Discharge Pressure

(kpa [abs])

1554 1785 1554 1785

Discharge Temp (°C) 135 121 98.4 84.6

1LT Conditions: -30°C Evap/40°C Cond/3.89 K Sub Cool/-10°C Return Gas Temperature

2MT Conditions: -10°C Evap/40°C Cond/3.89 K Sub Cool/10 oC Return Gas Temperature

3Assumes liquid injection to maintain a maximum discharge temperature of 135 oC

R-449A Performance:

• Equivalent to 3% larger capacity

• 4-6% lower COP

• 11-14% larger mass flow

Compressor Calorimeter Testing

� Semi hermetic compressor

� Compartment temp = 35oC

� LT Evaporator condition = -31.6 oC

� MT evaporator condition = -6.7 oC

� Sub Cool Amount = 5.5 K

� Maximum discharge temp = 135 oC

� Return gas and condensing temperatures were varied

July 11-14, 2016 Purdue Conferences 11

July 11-14, 2016 12

Low Temperature Capacity and COP

Purdue Conferences

13

Medium Temperature Capacity and COP

System Testing in an Environmental Chamber

14

Semi-Hermetic Compressor with a single condensing unit

Med/Low Temp Open Display Case

Environmental Chamber System Testing

� Experimental set up was run in accordance with ASHRAE standard 72

� All tests were run with POE lubricant

� EEV was used to regulate evaporator superheat

� Defrost every 12 hours

� Charge was optimized based on the equivalent liquid volume ratio for the recommended charge

� Performance measurements were taken every six seconds for over a 24 hour period

� “Indoor” temperature/humidity = 23.9 ± 0.27 oC dry bulb and 14.4 ± 0.27 oC wet bulb

� “Outdoor” temperature/humidity = 27.8 ± 0.27 oC dry bulb and 13.3 ±0.27 oC wet bulb


Display Case Performance Data

Condition Refrigerant Discharge Pressure

(kpa) Discharge Temperature

(oC) Evap Superheat

(K) Evaporator Discharge Air Temp

(oC)

LT R-22 1225 96.1 5.8 -25.8

LT R-449A 1435 86.2 3.2 -26.8

MT R-22 1236 93.0 6.4 -0.2

MT R-449A 1492 76.8 3.3 -2.0


Product temperatures


-15.

56

-19.

41

-11.

84

-21.

61

-7.4

5

4.19

2.13

6.17

1.83

6.48

-15.

82

-19.

84

-11.

22

-21.

41

-7.2

3

3.11

1.06

5.39

0.89

5.61

-25.00

-20.00

-15.00

-10.00

-5.00

0.00

5.00

10.00

15.00AT CTSA WTSA CTS WTS AT CTSA WTSA CTS WTS

Low Temp Medium Temp

Tem

pera

ture

[°C

]

R-22 R-449AAT = Average temperature of all test simulators

CTSA = Coldest test simulator average temperature

WTSA = Warmest test simulator average temperature

CTS = Minimum temperature recorded of the coldest simulator

Energy comparison


30.4

88

26.4

06

30.3

29

25.5

80

0.000

5.000

10.000

15.000

20.000

25.000

30.000

35.000

Low Temp Medium Temp

Ene

rgy

Con

sum

ptio

n [k

Wh/

24h]

Energy Consumption

R-22

R-449A

Med/Low TempOpen Display Case with EEV inEnvironmental Chamber

Background on adjustments

� During refrigeration operation, a TXV balances three pressure forces

� P1 – Opening force of the powerhead

� P2 – Closing force of the suction pressure

� P3 – Closing force of the spring pressure

Adjustable R-22 TXVs

� Suction pressure differences for the same average evaporator temp

» LT: 13.8 kpa higher

» MT: 34.5 kpa higher

� TXVs may need to be opened to reach target superheats

� Mass flow of R-449A is roughly 14% higher than R-22

» No changes to properly sized valves/powerhead are necessary

0.0

100.0

200.0

300.0

400.0

500.0

600.0

-40.0 -30.0 -20.0 -10.0 0.0 10.0

Pre

ssur

e (k

pa)

Temperature (oC)

Set point pressure to reach the same average evaporator temperature for

R-22 and R-449A

R-22

R-449A

Field Data


0.00

10.00

20.00

30.00

40.00

50.00

60.00

0.00 5.00 10.00 15.00 20.00 25.00

Ene

rgy

(Kw

h)

Hourly Temperature ( oC)

MT R-22 retrofit to R-449A Rack Energy vs Ambient Temperature

R-22

R-449A

Conclusions

� R-22 is being phased out

� HFOs were developed as low GWP and zero ODP alternatives to current HFCs

� R-449A is a HFO containing blend that has exhibited similar or better performance relative to R-22 in:

- Cycle Modeling

- Calorimeter Testing

- System Testing

� During retrofits, minor adjustments to valves might be needed to reach target superheats


References

� AHRI, Standard 210/240-2008, Unitary A/C and Air Source Heat Pump Standard, Arlington, VA, 2008.

� ASHRAE, Standard 23.1 Methods of Testing for Performance Rating Positive Displacement Refrigerant Compressors and Condensing Units That Operate at Subcritical Temperatures of the Refrigerant, American Society of Heating, Refrigerating and Air-Conditioning Engineers, 2010.

� ASHRAE, Standard 72 Method of Testing Open and Closed Commercial Refrigerators and Freezers, American Society of Heating, Refrigerating and Air-Conditioning Engineers, 2014.

� IPCC. 2013. Climate Change 2013: The physical Science Basis. Contribution of Working Group I to the Fifth Assessment Report of the Intergovernmental Panel on Climate Change. Cambridge University Press, Cambridge, United Kingdom and New York, NY, USA.

� J. Steven Brown, Piotr A. Domanski, Eric W. Lemmon. (2015). Cycle D Version 5.0. National Institute of Standards and Technology.

� Powell, P. (2014). EPA Finalizes R-22 Phaseout Plan. ACHR News. http://www.achrnews.com/articles/127966-epa-finalizes-r-22-phaseout-plan

� UNEP. 2000. The Montreal Protocol on Substances that Deplete the Ozone Layer. The Vienna Convention for the Protection of the Ozone Layer & The Montreal Protocol on Substances that Deplete the Ozone Layer. UNON, Nariobi, Kenya.


QUESTIONS


evaluation of r-449a as a replacement for r-22 in low and

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