United States Air and EPA/430/R-92/007

Environmental Protection Radiation September 1992

Agency (ANR-445)

= EPA Experimental Investigation of R-22

Replacement Refrigerants in a SplitSystem Residential Air Conditioner

EE-RM-93-801 COMMENT OR10

&EPA 

United States 

Environmental Protection 

Agency 

Air and 

Radiation 

(ANR-445) 

EPAJ430/R-92/007 

September 1992 

Experimental Investigation of R~22 

Replacement Refrigerants in a SplitSystem Residential Air Conditioner 

HCFC-22 

.~ 

. 

G 

I 

HFC-32 

HFC·134a 

@ Printed on Recycled Paper 

l 'u 
Experimental Investigation of R-22 Replacement

Refrigerants in a Split-System Residential Air Conditioner

Prepared for

U.S. Environmental Protection Agency

Technology & Substitutes Branch Global Change Division

Office of Atmospheric and Indoor Air Programs

Office of Air and Radiation

Washington D.C. 20460

by

Sekhar N. Kondepudi

September 1992

EE-RM-93-801 COMMENT OR10

Experimental Investigation of R·22 Replacement 

Refrigerants in a Split.System Residential Air Conditioner 

Prepared for 

U.S. Environmental Protection Agency 

Technology & Substitutes Branch Global Change Division 

Office of Atmospheric and Indoor Air Programs 

Office of Air and Radiation 

Washington D.C. 20460 

by 

Sekhar N. Kondepudi 

September 1992 
CONTENTS

Acknowledgements ................................................................................ 3

Major Findings ......................................................................................... 4

Refrigerants and the Environment ....................................................... 6

Choosing the Best Alternatives ............................................................. 7

Project Objectives .................................................................................... 8

Previous Work .......................................................................................... 9

Testing Details ........................................................................................ 10

Results and Discussions ....................................................................... 13

Performance Results ....................................................................... 13

Normalized Results ........................................................................ 16

Retrofit and New Equipment Applications ................................ 16

Refrigerant Charge and Mass Flow ............................................. 19

Comparisons with Simulations and Breadboard Testing ................ 20

Conclusions and Further Work ........................................................... 23

References ............................................................................................... 23

2

EE-RM-93-801 COMMENT OR10

CONTENTS 

Aclcnowledgements ................................................................................ 3 

Major Findings ......................................................................................... 4 

Refrigerants and the Environment ....................................................... 6 

Choosing the Best Alternatives ............................................................. 7 

Project Objectives ......... ........ ............................. ................... ..... ...... ........ 8 

Previous Work .......................................................................................... 9 

Testing Details ........................................................................................ 10 

Results and Discussions ....................................................................... 13 

Perfol"Ill.ance Results ............................................................... ........ 13 

NOl"Ill.alized Results ........................................................................ 16 

Retrofit and New Equipment Applications ................................ 16 

Refrigerant Charge and Mass Flow............................................. 19 

Comparisons with Simulations and Breadboard Testing ................ 20 

Conclusions and Further Work ........................................................... 23 

References ............................................................................................... 23 

2 
ACKNOWLEDGMENTS

This project was completed successfully as a result of many people contributing to it. These include:

Sekhar Kondepudi

Bill Kopko

Jean Lupinacci

Len Van Essen

Charles Ellis

Oved Hanson

Byron Horak

Dusty Stillman

Project Coordinator:

Drexel University

U.S. EPA

U.S. EPA

Lennox Industries

Lennox Industries

Lennox Industries

ETL Testing Laboratories

ETL Testing Laboratories

Sekhar Kondepudi, Drexel University

3

EE-RM-93-801 COMMENT OR10

ACKNOWLEDGMENTS 

This project was completed successfully as a result of many people contributing to it. These include: 

Sekhar Kondepudi 

Bill Kopko 

Jean Lupinacci 

Len Van Essen 

Charles Ellis 

OvedHanson 

Byron Horak 

Dusty Stillman 

Project Coordinator: 

Drexel University 

U.S. EPA 

U.S. EPA 

Lennox Industries 

Lennox Industries 

Lennox Industries 

ETL Testing Laboratories 

ETL Testing Laboratories 

Sekhar Kondepudi, Drexel University 

3 
MAJOR FINDINGS

• Experimental testing of five blends of R-32/R-134a and

R-32/R-152a, potential R-22 replacements, was performed

in a 2-ton split-system residential air conditioning system.

The only change made to the original R-22 system was a

non-production hand-operated expansion device and a

different lubricant.

• The R-32 mixtures provided similar efficiency and capacities to R-22 with minimal hardware changes.

• The 40/60% mass fraction blend of R-32/R-134a had

capacity and steady-state efficiency 1% greater than R-22.

• The 30/70% blend of R-32/R-134a had a 5% lower capacity and a steady-state efficiency within 1% of R-22 performance. The seasonal energy efficiency levels were within

2% of the R-22 values.

• Since capacity is a driving force for retrofit applications,

the 40/60% of R-32/R-134a may be a good retrofit refrigerant for existing R-22 systems.

• All the blends of R-32/R-134a and R-32/R-152a had

steady-state efficiency levels within 2% of R-22 performance levels but lower capacity levels.

• The R-32/R-152a blends (30/70% and 40/60%) had

steady-state efficiency levels within 1.5% of R-22 but had a

capacity reduction between 8 and 12%. Simulations have

shown these blends to have the most promising energy

performance potential, and with appropriate hardware

modifications and optimization, it may be possible to

improve efficiency and capacity levels considerably.

4

EE-RM-93-801 COMMENT OR10

MAJOR FINDINGS 

4 

• Experimental testing of five blends of R-32/R-134a and 

R-32/R-152a, potential R-22 replacements, was performed 

in a 2-ton split-system residential air conditioning system. 

The only change made to the original R-22 system was a 

non-production hand-operated expansion device and a 

different lubricant. 

• The R-32 mixtures provided similar efficiency and capacities to R-22 with minimal hardware changes. 

• The 40/60% mass fraction blend of R-32/R-134a had 

capacity and steady-state efficiency 1% greater than R-22. 

• The 30/70% blend of R-32/R-134a had a 5% lower capacity and a steady-state efficiency within 1% of R-22 performance. The seasonal energy efficiency levels were within 

2% of the R-22 values. 

• Since capacity is a driving force for retrofit applications, 

the 40 / 60% of R-32/R-134a may be a good retrofit refrigerant for existing R-22 systems. 

• All the blends of R-32/R-134a and R-32/R-152a had 

steady-state efficiency levels within 2% of R-22 performance levels but lower capacity levels. 

• The R-32/R-152a blends (30/70% and 40/60%) had 

steady-state efficiency levels within 1.5% of R-22 but had a 

capacity reduction between 8 and 12%. Simulations have 

shown these blends to have the most promising energy 

performance potential, and with appropriate hardware 

modifications and optimization, it may be possible to 

improve efficiency and capacity levels considerably. 
Table 1: Overview of Steady-State Results

(2 ton, 10.25 SEER Split System Air Conditioner)

(ARI Rating Condition 80-67/95)

Refrigerant Capacity ("A" Test)

% CHANGE

EER ("A" Test) SEER

R-22 Base Base Base

R-32/R-134a -10% -1% -3%

(20/80 Mix)

R-32/R-134a -5% 0% -2%

(30/70 Mix)

R-32/R-134a +1 % +1% -1%

(40/60 Mix)

R-32/R-152a -12% +1% -5%

(30170 Mix)

R-32/R-152a -8% -1.5% -2%

(40/60 Mix)

• Assumptions made in computer simulation, such as system optimization and counterfiow heat exchangers,

resulted in differences between the modeling and experimental results. The thermodynamic properties used in the

simulations may have also contributed to the variation in

the results.

• With appropriate hardware modifications and optimization, it is expected that systems using the R-32/R-134a and

R-32/R-152a blends could achieve performance levels similar to that predicted by simulations.

• Independent tests conducted by Lennox Industries on similar equipment using the same refrigerant blends confirmed trends and results reported above.

• The present set of tests were for a cooling only, split-system air conditioner. The next immediate step should be a

study of refrigerant blends in heat pumps operating in

both heating and cooling modes.

• The results from these tests form the basis of preliminary

"drop-in" tests of R-22 substitutes in operating residential

air conditioning equipment. While the results are encour5

EE-RM-93-801 COMMENT OR10

Table 1: Overview of Steady-State Results 

Refrigerant 

R-22 

R-321R-134a 

(20180 Mix) 

R-321R-134a 

(30170 Mix) 

R-321R-134a 

(40160 Mix) 

R-321R-152a 

(30170 Mix) 

R-321R-152a 

(40160 Mix) 

(2 ton, 10.25 SEER Split System Air Conditioner) 

(ARI Rating Condition 80-67/95) 

% CHANGE 

Capacity ("Art Test) EER (fAA" Test) 

Base Base 

-10% -1% 

-5% 0% 

+1% +1% 

-12% +1% 

-8% -1.5% 

SEER 

Base 

-3% 

-2% 

-1% 

-5% 

-2% 

• Assumptions made in computer simulation, such as system optimization and counterflow heat exchangers, 

resulted in differences between the modeling and experimental results. The thermodynamic properties used in the 

simulations may have also contributed to the variation in 

the results. 

• With appropriate hardware modifications and optimization, it is expected that systems using the R-32/R-134a and 

R-32/R-1S2a blends could achieve performance levels similar to that predicted by simulations. 

• Independent tests conducted by Lennox Industries on similar equipment using the same refrigerant blends confirmed trends and results reported above. 

• The present set of tests were for a cooling only, split-systern air conditioner. The next immediate step should be a 

study of refrigerant blends in heat pumps operating in 

both heating and cooling modes. 

• The results from these tests form the basis of preliminary 

Jldrop-in" tests of R-22 substitutes in operating residential 

air conditioning equipment. While the results are encour5 
aging, a considerable amount of further work needs to be

done prior to commercialization. Future work should

include evaluation of-

• Counterflow Heat Exchangers for Air Systems

• Charge, Superheat, and Subcooling Optimization

• Expansion Devices

• Heat Pumps--Cooling and Heating Modes

• Composition Shifts of the Refrigerant Blends

• Accumulators and Reversing Valve Dynamics

• Compressor Life

• Materials Compatibility (long term)

• Flammability

• Servicing Issues

REFRIGERANTS AND THE ENVIRONMENT

• The environmental problems of ozone-depleting chlorofluorocarbons (CFCs) have been identified and are restricted

worldwide by the Montreal Protocol. Fully halogenated

CFCs, including the widely used refrigerants R-11, R-12,

R-114 and R -50Z are being phased out by the end of 1995

in the United States.

• A similar CFC phaseout, including restrictions on HCFC-22,

will be negotiated under the Montreal Protocol in

November 1992.

• R-22 is presently used in a wide variety of applications

(Figure 1). The concern that continued use of HCFC-22

will lead to increased levels of stratospheric chlorine and

to more significant ozone depletion, has lead to calls for an

R-22 phaseout between the years 2000 and 2010.

• The Rio convention framework indicates that global warming is the next dominant environmental issue and that CFC

and HCFC alternatives will be included in efforts to minimize global warming effects.

• Industry, government, and academia are concentrating

efforts to develop alternatives for R-22.

6

EE-RM-93-801 COMMENT OR10

aging, a considerable amount of fwther work needs to be 

done prior to commercialization. Future work should 

include evaluation of: 

e Counterflow Heat Exchangers for Air Systems 

• Charge, Superheat, and Sub cooling Optimization 

• Expansion Devices 

e Heat Pumps-Cooling and Heating Modes 

• Composition Shifts of the Refrigerant Blends 

• Accumulators and Reversing Valve Dynamics 

• Compressor Life 

• Materials Compatibility (long term) 

• Flammability 

• Servicing Issues 

REFRIGERANTS AND THE ENVIRONMENT 

6 

• The environmental problems of ozone-depleting chlorofluorocarbons (CFCs) have been identified and are restricted 

worldwide by the Montreal Protocol. Fully halogenated 

CFCs, including the widely used refrigerants R-ll, R-12, 

R-114 and R-502, are being phased out by the end of 1995 

in the United States. 

• A similar CFC phaseout, including restrictions on HCFC-22, 

will be negotiated under the Montreal Protocol in 

November 1992. 

• R-22 is presently used in a wide variety of applications 

(Figure 1). The concern that continued use of HCFC-22 

will lead to increased levels of stratospheric chlorine and 

to more Significant ozone depletion, has lead to calls for an 

R-22 phaseout between the years 2000 and 2010. 

• The Rio convention framework indicates that global warming is the next dominant environmental issue and that CFC 

and HCFC alternatives will be included in efforts to minimize global warming effects. 

• Industry, government, and academia are concentrating 

efforts to develop alternatives for R-22. 
Figure 1: Multiple Uses of HCFC-22

Other

(refrigerated transport,

industrial,

household ice making)

Retail food 1%

11% L' 'I _ Reciprocating chillers

Unitary-heat

pumps/central air

32%

Other

(centrifugal chillers,

packaged terminal)

>1%

67% Air Conditioning - 33% Refrigeration

CHOOSING THE BEST ALTERNATIVES

• Several refrigerants and replacements are being evaluated

as R-22 replacements.

• To achieve a significant net reduction in global warming

effects when substituting R-22 with alternatives, it is

important that the alternatives have both a low direct

global warming potential and are at least as energy-efficient as R-22.

• Energy efficiency is especially significant domestically,

since unitary air conditioners and heat pumps must meet

the 1992 Department of Energy (DOE) minimum energy

efficiency standard [11 of 10.00 Seasonal Energy Efficiency

Ratio (SEER).

• Flammability, toxicity, and human health risks, as well as

system performance, materials compatibility, and costs,

must be carefully evaluated before the best alternatives

can be determined.

18%

7

EE-RM-93-801 COMMENT OR10

Figure 1: Multiple Uses of HCFC·22 

Other 

Cold 

storage 

21% 

Retail food 

11% 

Residentialwindow units 

16% 

(refrigerated transport, 

industrial, 

household ice making) 

1% 

Other 

Reciprocating chillers 

18% 

Unitary-heat 

pumps/central air 

32% 

(centrifugal chillers, 

packaged terminal) 

>1% 

~ 67% Air Conditioning _ 33% Refrigeration 

CHOOSING THE BEST ALTERNATIVES 

• Several refrigerants and replacements are being evaluated 

as R-22 replacements. 

• To achieve a significant net reduction in global warming 

effects when substituting R-22 with alternatives, it is 

important that the alternatives have both a low direct 

global warming potential and are at least as energy-efficient as R-22. 

• Energy efficiency is especially significant domestically, 

since unitary air conditioners and heat pumps must meet 

the 1992 Department of Energy (DOE) minimum energy 

efficiency standard [1] of 10.00 Seasonal Energy Efficiency 

Ratio (SEER). 

• Flammability, toxicity, and human health risks, as well as 

system performance, materials compatibility, and costs, 

must be carefully evaluated before the best alternatives 

can be determined. 

7 
• Computer simulations and breadboard tests have indicated that chlorine-free refrigerant blends of R-32/R-134a

and R-32/R-152a can deliver capacities and energy efficiency levels greater than that of R-22.

• These simulations and breadboard type tests have only a

limited value beyond which actual, "drop-in" tests must

be performed to test actual viability.

PROJECT OBJECTIVES

• Evaluate the "drop-in" performance of potential R-22

alternatives blends in an actual full scale 2-ton residential

split-system air conditioner.

• Measure the Capacity, Steady-State, and Seasonal Efficiency

of the air conditioner.

• Demonstrate that comparable capacity and efficiency can

be achieved with minimal hardware changes.

• Provide direction for evaluating engineering design changes

in R-22 systems to achieve optimized energy performance.

• Test refrigerant blends of R-32/R-134a and R-32/R-152a

based on results obtained by Radermacher and Jung [21

and Pannock and Didion [3] (Table 2).

• Measure differences in performance between different

refrigerant compositions.

Table 2: List of Refrigerant Blends Tested

Refrigerant Blend Composition Ratio (Mass)

R-32/R-134a 20/80%

R-32/R-134a 30/70%

R-321R-134a 40/60%

R-32/R-152a 30/70%

R-32/R-152a 40/60%

8

EE-RM-93-801 COMMENT OR10

• Computer simulations and breadboard tests have indicated that chlorine-free refrigerant blends of R-32/R-134a 

and R-32/R-152a can deliver capacities and energy efficiency levels greater than that of R-22. 

• These simulations and breadboard type tests have only a 

limited value beyond which actual, II drop-in" tests must 

be performed to test actual viability. 

PROJECT OBJECTIVES 

8 

• Evaluate the 1/ drop-in" performance of potential R-22 

alternatives blends in an actual full scale 2-ton residential 

split-system air conditioner. 

• Measure the Capacity, Steady-State, and Seasonal Effidency 

of the air conditioner. 

• Demonstrate that comparable capacity and efficiency can 

be achieved with minimal hardware changes. 

• Provide direction for evaluating engineering design changes 

in R-22 systems to achieve optimized energy performance. 

• Test refrigerant blends of R-32/R-134a and R-32/R-152a 

based on results obtained by Radermacher and Jung [2] 

and Pannock and Didion [3] (Table 2). 

• Measure differences in performance between different 

refrigerant compositions. 

Table 2: List of Refrigerant Blends Tested 

Refrigerant Blend Composition Ratio (Mass) 

R-321R-134a 20180% 

R-321R-134a 30170% 

R-321R-134a 40160% 

R-321R-152a 30/70% 

R-321R-152a 40160% 
PREVIOUS WORK

• Vineyard, Sands, and Statt [4] found that refrigerant mixtures with high potential for improved performance over

R-22 included R-32/R-124, R-32/R-142b, R-143a/R-124,

R-143a/R-142b, and R-143a/C-318.

• Radermacher and Jung [2] conducted a simulation study

of potential R-22 replacements in residential equipment.

They found that the most promising mixtures were R-32/

R-152a mixture in a 40/60% blend by mass and

R-32/R-134a in a 30/70% blend by mass.

• Sands, Vineyard, and Nowak [5] compared R-22, R-12, and

R-114 with 11 single component non-CFC refrigerants to

estimate heat pump performance potential. The study concluded that R-152a, R-143a, R-134a, and R-134 had the best

performance of the 11 refrigerants evaluated.

• Other studies [6,7,8,9] suggest that when heat transfer fluids

exchange heat with a refrigerant mixture in a counterflow

mode, the thermodynamic irreversibilities could be reduced

by matching the temperature glide on the refrigerant side

against the drop in the air side. This will result in an

improved efficiency or COP for heat pumps and air conditioners. Other advantages of NARMs include capacity control and increased capacity at lower ambient temperatures.

• Pannock and Didion [3] performed a set of simulations

followed by tests using chlorine-free refrigerant mixtures

on a mini-breadboard heat pump system. They found that

two refrigerant mixtures, R-32/R-134a and R-32/R-152a,

performed better than R-22 for certain composition ranges

using counterflow heat exchangers.

• Shiflett, Yokozeki, and Bivens [10] conducted "drop-in"

tests of a 32/68% mass ratio blend of R-32/R-134a in a

room air conditioner. The test results showed comparable

capacity and efficiency to R-22. They also concluded that

R-32/R-134a mixtures with less than 25% R-32 by mass are

non-flammable for almost all conditions.

• Treadwell [11] performed laboratory tests using Propane

(R-290) and found that by increasing compressor displacement it was possible to attain capacities and efficiencies

similar to that of R-22.

• The Air Conditioning and Refrigeration Institute (ARI)

[12], in consultation with various equipment and refriger9

EE-RM-93-801 COMMENT OR10

PREVIOUS WORK 

• Vineyard, Sands, and Statt [4] found that refrigerant mixtures with high potential for improved performance over 

R-22 included R-32/R-124, R-32/R-142b, R-143a/R-124, 

R-I43a/R-l42b, and R-143a/C-318. 

• Radermacher and Jung [2] conducted a simulation study 

of potential R-22 replacements in residential equipment. 

They found that the most promising mixtures were R-32/ 

R-152a mixture in a 40/60% blend by mass and 

R-32/R-134a in a 30/70% blend by mass. 

• Sands, Vineyard, and Nowak [5] compared R-22, R-12, and 

R-114 with 11 single component non-CFC refrigerants to 

estimate heat pump performance potential. The study concluded that R-152a, R-143a, R-l34a, and R-l34 had the best 

performance of the 11 refrigerants evaluated. 

• Other studies [6,7,8,9] suggest that when heat transfer fluids 

exchange heat with a refrigerant mixture in a counterflow 

mode, the thermodynamic irreversibilities could be reduced 

by matching the temperature glide on the refrigerant side 

against the drop in the air side. This will result in an 

improved efficiency or COP for heat pumps and air conditioners. Other advantages of NARMs include capacity control and increased capacity at lower ambient temperatures. 

• Pannock and Didion [3] performed a set of simulations 

followed by tests using chlorine-free refrigerant mixtures 

on a mini-breadboard heat pump system. They found that 

two refrigerant mixtures, R-32/R-I34a and R-32/R-152a, 

performed better than R-22 for certain composition ranges 

using counterflow heat exchangers. 

• Shiflett, Yokozeki, and Bivens [10] conducted "drop-in" 

tests of a 32/68% mass ratio blend of R-32/R-134a in a 

room air conditioner. The test results showed comparable 

capacity and efficiency to R-22. They also concluded that 

R-32/R-134a mixtures with less than 25% R-32 by mass are 

non-flammable for almost all conditions. 

• Treadwell [11] performed laboratory tests using Propane 

(R-290) and found that by increasing compressor displacement it was possible to attain capacities and efficiencies 

similar to that of R-22. 

• The Air Conditioning and Refrigeration Institute (ARI) 

[12], in consultation with various equipment and refriger9 
ant manufacturers, has identified a set of 10 refrigerants

that the member companies will screen as potential R-22

replacements (Table 3).

Table 3: ARI Recommended List of Potential R-22 Replacements

Refrigerant % Composition By Weight

R-32/R-125 60/40

R-32/R-134a 30170

R-32/R-125/R-134a 10/70/20

R-290 (Propane) --

R-134a --

R-717 (Ammonia) --

R-32/R-125/R-134a/R-290 20/55/20/5

R-32/R-125/R-134a 30/10/60

R-125/R-143a 45/55

R-125/R-143a/R-134a 40/45/15

TESTING DETAILS

• Tests were conducted for the U.S. EPA, at the facilities of

ETL Testing Laboratories in Cortland, NY. To verify the

tests conducted at ETL, similar tests were conducted at

Lennox Industries in Dallas, TX.

• All tests were conducted in accordance with the ARI

Standard 210/240 and ASHRAE Standards 37-1988 and

116-1989 for testing unitary equipment [13,14,15].

• A 2-ton split-system air conditioner manufactured by

Lennox Industries with a rated Seasonal Energy Efficiency

Ratio (SEER) of 10.25 was tested. Details of the condenser

and evaporator section are given in Tables 4 and 5.

10

EE-RM-93-801 COMMENT OR10

ant manufacturers, has identified a set of 10 refrigerants 

that the member companies will screen as potential R-22 

replacements (Table 3). 

Table 3: ARI Recommended Ust of Potential R-22 Replacements 

Refrigerant % Composition By Weight 

R-321R-125 60/40 

R-321R-134a 30nO 

R-321R-1251R-134a 10n0l20 

R-290 (Propane) -

R-134a - R-717 (Ammonia) -

R-321R-1251R-134a1R-290 20/55/2015 

R-321R-1251R-134a 30/10160 

R-125/R-143a 45/55 

R-125/R-143a1R-134a 40/45/15 

TESTING DETAILS 

10 

• Tests were conducted for the U.S. EPA, at the facilities of 

ETL Testing Laboratories in Cortland, NY. To verify the 

tests conducted at ETL, similar tests were conducted at 

Lennox Industries in Dallas, TX. 

• All tests were conducted in accordance with the ARI 

Standard 210/240 and ASHRAE Standards 37-1988 and 

116-1989 for testing unitary equipment [13,14,15]. 

• A 2~ton split-system air conditioner manufactured by 

Lennox Industries with a rated Seasonal Energy Efficiency 

Ratio (SEER) of 10.25 was tested. Details of the condenser 

and evaporator section are given in Tables 4 and 5. 
Table 4: Geometrical Specifications of Condenser Unit

Manufacturer

Face Area

Tube Diameter

No. of Tube Rows

Tube Material

Fins Per Inch

Fin Type

Fan Specs

Air Flow

Fan RPM

Fan Power

Fan Motor

Compressor

Lennox Industries

12.60 ft2

0.375 inches

1

Copper

20

Enhanced, rippled aluminum

20 inch diameter, 3 Blades

2500 cfm

850

200 watts

1/6 HP

Copeland CR22K6-PFV

Table 5: Geometric Specifications of Evaporator Coil

Manufacturer

Coil Type

Face Area

Tube Diameter

No. of Tube Rows

Tube Material

Fins Per Inch

Fin Type

Lennox Industries

A Coil (or V Coil) with 2 slabs

3.44 ft2 (1.72 ft2 per slab)

0.375 inches

2

Copper

15

Enhanced, rippled aluminum

11

EE-RM-93-801 COMMENT OR10

Table 4: Geometrical Specifications of Condenser Unit 

Manufacturer Lennox Industries 

Face Area 12.60 ft2 

Tube Diameter 0.375 inches 

No. ofTube Rows 

Tube Material Copper 

Fins Per Inch 20 

Fin Type Enhanced. rippled aluminum 

Fan Specs 20 inch diameter. 3 Blades 

Air Flow 2500cfm 

Fan RPM 850 

Fan Power 200 watts 

Fan Motor 1/6HP 

Compressor Copeland CR22K6-PFV 

Table 5: Geometric Specifications of Evaporator Coil 

Manufacturer Lennox Industries 

Coil Type A Coil (or V Coil) with 2 slabs 

Face Area 3.44 ft2 (1.72 ft2 per slab) 

Tube Diameter 0.375 inches 

No. of Tube Rows 2 

Tube Material Copper 

Fins Per Inch 15 

Fin Type Enhanced. rippled aluminum 

11 
• No hardware changes were made except for the use of a

non-production hand-operated expansion device. This

allowed for a "drop-in" comparison of the refrigerant

blends.

• The following parameters were measured:

1. System Capacity-as measured on the evaporator coil

2. Power Consumption-Compressor and Fan

3. System Efficiency-EER and SEER

4. Refrigerant Pressures and Temperatures

5. Refrigerant Mass Flow Rate

6. Airside and Refrigerant Side Energy Balances

• Figure 2 is a test schematic showing the test setup and

locations of thermocouple and pressure tap locations,

along with other instrumentation such as mass flow meter

and hand-operated expansion device.

• A hand-operated needle valve was used as the expansion

device to allow for a continuous control over the level of

refrigerant expansion.

Figure 2: Schematic of Test Configuration

12

EE-RM-93-801 COMMENT OR10

12 

• No hardware changes were made except for the use of a 

non-production hand-operated expansion device. This 

allowed for a II drop-in" comparison of the refrigerant 

blends. 

• The following parameters were measured: 

1. System Capacity-as measured on the evaporator coil 

2. Power Consumption-Compressor and Fan 

3. System Efficiency-EER and SEER 

4. Refrigerant Pressures and Temperatures 

5. Refrigerant Mass Flow Rate 

6. Airside and Refrigerant Side Energy Balances 

• Figure 2 is a test schematic showing the test setup and 

locations of thermocouple and pressure tap locations, 

along with other instrumentation such as mass flow meter 

and hand-operated expansion device. 

• A hand-operated needle valve was used as the expansion 

device to allow for a continuous control over the level of 

refrigerant expansion. 

Figure 2: Schematic of Test Configuration 

NMdIeVetwe 

(Expen8lon Device) 

A Tempereture & Pressure 

D. Tempereture Only 
• Thermodynamic properties for the refrigerant blends used

were based on a modified version of REFPROP 3.0, which

includes data on R-32 and R-32 mixtures.

• The original mineral oil lubricant used with R-22 is not

compatible with R-134a. Therefore, a polyol ester-based

lubricant developed for use with R-134a was used with the

R-32/R-134a blends. Flushing of the system was performed to ensure that minimal traces of the original lubricant were present. The same polyester lubricant was used

with the R-32/R-134a blends was used with the R-32/R152a blends.

• The amount of refrigerant charge was based on a 15°F

superheat setting at the compressor suction. The charge

was adjusted to attain the best EER at the "80/67-95" test

condition. In order to maintain consistency, the same

superheat setting was used for all the blends.

• The same test facilities, instrumentation, and test personnel were used for all the tests. This minimized any uncertainty and inaccuracy in the measurements.

RESULTS AND DISCUSSIONS

PERFORMANCE RESULTS

• Capacity, power, EER, and SEER for each refrigerant tested

are summarized in Tables 6 and 7.

• The results show that only the 40/60% R-32/R-134a

blend had better performance than the R-22 baseline. In

all other cases, the EER values were all within 2% of the

R-22 baseline.

• The capacities of the other blends were less than the R-22

baseline and it is expected that with appropriate hardware

changes and optimization, performance can be improved.

• The energy balance between the refrigerant side and the

airside were typically within 5% of one another. All references to capacity are based on air side measurements.

• The results obtained from the ETL and Lennox tests are

within 3 to 5% of each other. This range is well within

expected range of experimental error considering that the

tests were conducted on different test units in different

test facilities.

13

EE-RM-93-801 COMMENT OR10

• Thermodynamic properties for the refrigerant blends used 

were based on a modified version of REFPROP 3.0, which 

includes data on R-32 and R-32 mixtures. 

• The original mineral oil lubricant used with R-22 is not 

compatible with R-l34a. Therefore, a polyol ester-based 

lubricant developed for use with R-l34a was used with the 

R-32/R-134a blends. Flushing of the system was performed to ensure that minimal traces of the originallubricant were present. The same polyester lubricant was used 

with the R-32/R-134a blends was used with the R-32/R152a blends. 

• The amount of refrigerant charge was based on a 15°F 

superheat setting at the compressor suction. The charge 

was adjusted to attain the best EER at the "80/67-95" test 

condition. In order to maintain consistency, the same 

superheat setting was used for all the blends. 

• The same test facilities, instrumentation, and test personnel were used for all the tests. This minimized any uncertainty and inaccuracy in the measurements. 

RESULTS AND DISCUSSIONS 

PERFORMANCE RESULTS 

• Capacity, power, EER, and SEER for each refrigerant tested 

are summarized in Tables 6 and 7. 

• The results show that only the 40/60% R-32/R-134a 

blend had better performance than the R-22 baseline. In 

all other cases, the EER values were all within 2% of the 

R-22 baseline. 

• The capacities of the other blends were less than the R-22 

baseline and it is expected that with appropriate hardware 

changes and optimization, performance can be improved. 

• The energy balance between the refrigerant side and the 

airside were typically within 5% of one another. All references to capacity are based on air side measurements. 

ED The results obtained from the ETL and Lennox tests are 

within 3 to 5% of each other. This range is well within 

expected range of experimental error considering tha t the 

tests were conducted on different test units in different 

test facilities. 

13 
Table 6: Summary of ETL Results

(AU Percentage Compositions Are by Mass)

R-22 R-32/R-134a Mixture R-32/R-152a Mixture

DOE "A" Test (80/67-95) (Baseline) 20/80% 30/70% 40/60% 30/70% 40/60%

Airside Capacity (Btuh) 23690 20610 22390 23870 20630 21550

Total Power (W) 2489 2179 2345 2498 2152 2297

EER (Btuh/W) 9.52 9.46 9.55 9.56 9.59 9.38

Comp Disch Pressure (psig) 260.5 221 250 276 209 231.5

Comp Suct Pressure (psig) 81 62.5 71 79.5 60 66

Comp Disch Temperature (F) 185.5 169 175 181 186 190

Comp Suct Temperature (F) 63 65 64 63 68.5 66.5

R-22 R-32/R-134a Mixture R-32/R-152a Mixture

DOE "B" Test (80/67-82) (Baseline) 20/80% 30/70% 40/60% 30/70% 40/60%

Net Capacity (Btuh) 25320 22390 24210 25610 21250 23060

Total Power (W) 2319 2059 2195 2349 2009 2135

EER (Btuh/W) 10.92 10.87 11.03 10.90 10.58 10.80

Comp Disch Pressure (psig) 225 190.5 215 238 178.5 197

Comp Suct Pressure (psig) 77 60 68 75.5 57.5 63.5

Comp Disch Temperature (F) 170.5 156.5 162 167 171 174

Comp Suct Temperature (F) 59.5 62.5 62.5 60.5 66 64

SEER 10.10 9.80 9.90 10.00 9.58 9.89

14

EE-RM-93-801 COMMENT OR10

Table 6: Summary of ETL Results 

(All Percentage Co"1>ositions Are by Mass) 

R-22 R-321R-134a Mixture 

DOE "A" Test (80/67-95) (Baseline) 20/80% 30/70% 40/60% 

Airside Capacity (Btuh) 23690 20610 22390 23870 

Total Power 0N) 2489 2179 2345 2498 

EER (BtuhlW) 9.52 9.46 9.55 9.56 

Comp Disch Pressure (psig) 260.5 221 250 276 

Comp Suet Pressure (psig) 81 62.5 71 79.5 

Comp Disch Temperature (F) 185.5 169 175 181 

Comp Suet Temperature (F) 63 65 64 63 

R-22 R-321R-134a Mixture 

DOE "8" Test (80/67-82) (Baseline) 20/80% 30170% 40/60% 

Net Capacity (Btuh) 25320 22390 24210 25610 

Total Power 0N) 2319 2059 2195 2349 

EER (BtuhlW) 10.92 10.87 11.03 10.90 

Comp Disch Pressure (psig) 225 190.5 215 238 

Comp Suet Pressure (psig) n 60 68 75.5 

Comp Disch Temperature (F) 170.5 156.5 162 167 

Comp Suet Temperature (F) 59.5 62.5 62.5 60.5 

SEER 10.10 9.80 9.90 10.00 

14 

R-321R-152a Mixture 

30170% 40/60% 

20630 21550 

2152 2297 

9.59 9.38 

209 231.5 

60 66 

186 190 

68.5 66.5 

R-321R-152a Mixture 

30170% 40/60% 

21250 23060 

2009 2135 

10.58 10.80 

178.5 197 

57.5 63.5 

171 174 

66 64 

9.58 9.89 
Table 7: Summary of Lennox Results

(All Percentage Compositions Are by Mass)

R-22 R-32/R-134a Mixture R-32/R-152a Mixture

DOE "A" Test (80/67-95) (Baseline) 20/80% 30170% 40/60% 30170% 40/60%

Net Capacity (Btuh) 24134 21181 21996 23933 20522 22136

Total Power (W) 2468 2186 2342 2538 2174 2337.49

EER (Btuh/W) 9.78 9.69 9.39 9.43 9.44 9.47

Comp Disch Pressure (psig) 257 221 .7 249 281 205.4 -232

Comp Suct Pressure (psig) 76.6 60.8 70.3 79.6 58.9 66.3

Comp Disch Temperature (F) 183.6 167.3 174.5 181 .8 182.5 189

Comp Suct Temperature (F) 60.5 62 63.5 62.8 66.8 66.8

R-22 R-32/R-134a Mixture R-32/R-152a Mixture

DOE "B" Test (80/67-82) (Baseline) 20/80% 30170% 40/60% 30170% 40/60%

Net Capacity (Btuh) 25543 22756 23795 26313 22231 23919

Total Power (W) 2319 2076 2230 2396 2049 2217

EER (Btuh/W) 11.01 10.96 10.67 10. 98 10.85 10.79

Corm Disch Pressure (psig) 223 190 214 241 .7 175.9 200.8

Comp Suct Pressure (psig) 74.4 59.6 676 76.3 56.9 64.8

Comp Disch Temperature (F) 155. 1 160.7 160.7 168.6 169.1 174.4

Comp Suct Temperature (F) 59.5 62.7 61.6 61 . 1 65.7 66

SEER 10.16 10.08 9.68 10.24 10.00 9.94

15

EE-RM-93-801 COMMENT OR10

Table 7: Summary of Lennox Results 

(All Percentage Compositions Are by Mass) 

R-22 R-321R-134a Mixture 

DOE "A" Test (80/67-95) (Baseline) 20/80% 3OnO% 40/60% 

Net Capacity (Btuh) 24134 21181 21996 23933 

Total Power (W) 2468 2186 2342 2538 

EER (BtuhlW) 9.78 9.69 9.39 9.43 

Comp Disch Pressure (psig) 257 221.7 249 281 

Comp Suet Pressure (psig) 76.6 60.8 70.3 79.6 

Comp Disch Temperature (F) 183.6 167.3 174.5 181.8 

Comp Suet Temperature (F) 60.5 62 63.5 62.8 

R-22 R-321R-134a Mixture 

DOE "B" Test (80/67-82) (Baseline) 20/80% 30nO% 40/60% 

Net Capacity (Btuh) 25543 22756 23795 26313 

Total Power (W) 2319 2076 2230 2396 

EER (BtuhlW) 11.01 10.96 10.67 10.98 

Comp Disch Pressure (psig) 223 190 214 241.7 

Comp Suct Pressure (psig) 74.4 59.6 676 76.3 

Comp Disch Temperature (F) 155.1 160.7 160.7 168.6 

Comp Suet Temperature (F) 59.5 62.7 61.6 61.1 

SEER 10.16 10.08 9.68 10.24 

R-321R-152a Mixture 

30nO% 40/60% 

20522 22136 

2174 2337.49 

9.44 9.47 

205.4 "232 

58.9 66.3 

182.5 189 

66.8 66.8 

R-321R-152a Mixture 

30nO% 40/60% 

22231 23919 

2049 2217 

10.85 10.79 

175.9 200.8 

56.9 64.8 

169.1 174.4 

65.7 66 

10.00 9.94 

15 
NORMALIZED RESULTS

• Tables 8 and 9 present the data from ETL and Lennox normalized against the R-22 baseline. This allows for a more

direct comparison of the results obtained in the different

laboratories.

• The data shows that the capacities and power consumption decreased by the same percentage (except for the

40/60% R-32/R-134a blend). Hence, efficiencies remain

effectively constant. This indicates that if a capacity boost

could be achieved with an appropriate increase in power

consumption, then results loser to the R-22 baseline could

be achieved.

RETROFIT & NEW EQUIPMENT APPLICATIONS

• For the R-32/R-134a blends, 30/70 and 40/60% compositions appear to have good potential . Both capacities and

efficiencies are within 5% of the R-22 system for both

these blends. Since the seasonal efficiencies measured in

the ETL tests are within 2% of one another (ETL results),

it can be assumed that the use of these blends will have a

minimal impact on SEER. This can be achieved with minimum hardware changes and forms the basis of a good

retrofit refrigerant.

• Simulations indicate that the R-152a blends have a high

performance potential and it is expected that with appropriate hardware changes in the compressor , heat exchanger, and expansion devices, and other system optimization,

it may be possible to achieve higher capacity and efficiency levels than were measured in these tests.

16

EE-RM-93-801 COMMENT OR10

NORMALIZED RESULTS 

• Tables 8 and 9 present the data from ETL and Lennox normalized against the R-22 baseline. This allows for a more 

direct comparison of the results obtained in the different 

laboratories. 

• The data shows that the capacities and power consumption decreased by the same percentage (except for the 

40/60% R-32/R-134a blend). Hence, efficiencies remain 

effectively constant. This indicates that if a capacity boost 

could be achieved with an appropriate increase in power 

consumption, then results closer to the R-22 baseline could 

be achieved. 

RETROFIT & NEW EQUIPMENT APPLICATIONS 

16 

• For the R-32/R-134a blends, 30/70 and 40/60% compositions appear to have good potential. Both capacities and 

efficiencies are within 5% of the R-22 system for both 

these blends. Since the seasonal efficiencies measured in 

the ETL tests are within 2% of one another (BTL results), 

it can be assumed that the use of these blends will have a 

minimal impact on SEER. This can be achieved with minimum hardware changes and forms the basis of a good 

retrofit refrigerant. 

• Simulations indicate that the R-152a blends have a high 

performance potential and it is expected that with appropriate hardware changes in the compressor, heat exchanger, and expansion devices, and other system optimization, 

it may be possible to achieve higher capacity and efficiency levels than were measured in these tests. 
Table 8: Performance Relative to R-22: ETL Results

(All Percentage Compositions Are by Mass)

R-22 R-321R-134a Mixture R-3218-152a Mixture

DOE "A" Test (80/67-95) (Baseline) 20/80% 30/70% 40/60% 30/70% 40/60%

Net Capacity (Btuh) 1 .000 0.870 0.945 1.008 0.871 0.910

Total Power (W) 1.000 0.875 0.942 1 .004 0.865 0.923

EER (Btuh/W) 1.000 0.994 1.003 1 .004 1.007 0.986

R-22 R-32/R-134a Mixture R-32/R-152a Mixture

DOE "B" Test (80/67-82) (Baseline) 20/80% 30/70% 40/60% 30/70% 40/60%

Net Capacity (Btuh) 1.000 0.884 0.956 1 .011 0.839 0.911

Total Power (W) 1.000 0.888 0.947 1.013 0.866 0.921

EER (Btuh/W) 1.000 0.996 1.010 0.999 0.969 0.989

SEER 1.000 0.970 0.980 0.990 0.949 0.979

17

EE-RM-93-801 COMMENT OR10

Table 8: Performance Relative to R-22: ETL Results 

(All Percentage Compositions Are by Mass) 

R-22 R-321R-134a Mixture R-321R-152a Mixture 

DOE "A" Test (80/67-95) (Baseline) 20180% 3OnO% 40/60% 3OnO% 40/60% 

Net Capacity (Btuh) 1.000 0.870 0.945 1.008 0.871 0.910 

Total Power (W) 1.000 0.875 0.942 1.004 0.865 0.923 

EER (BtuhlW) 1.000 0.994 1.003 1.004 1.007 0.986 

R-22 R-321R-134a Mixture R-321R-152a Mixture 

DOE "B" Test (80/67-82) (Baseline) 20180% 3OnO% 40/60% 30170% 40160% 

Net Capacity (Btuh) 1.000 0.884 0.956 1.011 0.839 0.911 

Total Power (W) 1.000 0.888 0.947 1.013 0.866 0.921 

EER (BtuhlW) 1.000 0.996 1.010 0.999 0.969 0.989 

SEER 1.000 0.970 0.980 0.990 0.949 0.979 

17 
Table 9: Performance Relative to R-22: Lennox Tests

(All Percentage Compositions Are by Mass)

R-22 R-32/R-134a Mixture R-32/R-152a Mixture

DOE "A" Test (80/67-95) (Baseline) 20/80% 30/70% 40/60% 30/70% 40/60%

Net Capacity (Btuh) 1.000 0.878 0.911 0.992 0.850 0.917

Total Power (W) 1.000 0.886 0.949 1.028 0.881 0.947

EER (Btuh/W) 1.000 0.991 0.960 0.964 0.965 0.968

R-22 R-32/R-134a Mixture R-32/R-152a Mixture

DOE "B" Test (80/67-82) (Baseline) 20/80% 30/70% 40/60% 30/70% 40160%

Net Capacity (Btuh) 1.000 0.891 0.932 1.030 0.870 0.936

Total Power (W) 1.000 0.895 0.962 1.033 0.884 0.956

EER (Btuh/W) 1.000 0.995 0.969 0.997 0.985 0.980

SEER 1.000 0.992 0.953 1.008 0.984 0.978

18

EE-RM-93-801 COMMENT OR10

Table 9: Performance Relative to R-22: Lennox Tests 

(All Percentage Co!11)ositions Are by Mass) 

R-22 R-321R-134a Mixture R-321R-152a Mixture 

DOE "A" Test (80/67-95) (Baseline) 20180% 30170% 40160% 30170% 40160% 

Net Capacity (Btuh) 1.000 0.878 0.911 0.992 0.850 0.917 

Total Power fYI) 1.000 0.886 0.949 1.028 0.881 0.947 

EER (BtuhlW) 1.000 0.991 0.960 0.964 0.965 0.968 

R-22 R-321R-134a Mixture R-321R-152a Mixture 

DOE "8" Test (80/67-82) (Baseline) 20180% 30170% 40160% 30170% 40160% 

Net Capacity (Btuh) 1.000 0.891 0.932 1.030 0.870 0.936 

Total Power fYI) 1.000 0.895 0.962 1.033 0.884 0.956 

EER (BtuhlW) 1.000 0.995 0.969 0.997 0.985 0.980 

SEER 1.000 0.992 0.953 1.008 I 0.984 0.978 

18 
REFRIGERANT CHARGE

Tables 10 and 11 show the amount of refrigerant charge

and mass flow rates measured in the tests.

Table 10: Amount of Refrigerant Charged/Reciaimed (ETL Tests)

Refrigerant Ratio

(% Mass)

Charge Amt

(lbs-oz)

Reclaim Amt

(lbs-oz)

R-22 - 4-05 4-05

R-32/R-134a 20/80 4-12 4-08

R-32/R-134a 30/70 4-05 4-02

R-32/R-134a 40/60 4-05 4-04

R-32/R-152a 30/70 3-05 3-03

R-32/R-152a 40/60 3- 12 not measured

Table 11: Refrigerant Mass Flow Rates ("80/67-95 Condition")

Refrigerant Blend Mass Ratio Mass Flow Rate (Lb / Hr)

ETL Lennox

R-22 - 375 352

R-32/R-134a 20/80% 291 295

R-32/13-134a 30/70% 302 300

R-32/R-134a 40/60% 305 305

R-32/R-152a 30/70% 196 206

R-32/R-152a 40/60% 212 219

19

EE-RM-93-801 COMMENT OR10

REFRIGERANT CHARGE 

• Tables 10 and 11 show the amount of refrigerant charge 

and mass flow rates measured in the tests. 

Table 10: Amount of Refrigerant ChargedlReclaimed {ETL Tests} 

Refrigerant Ratio ChargeAmt ReciaimAmt 

(% Mass) (Ibs-oz) (Ibs-oz) 

R-22 - 4 -05 4 - 05 

R-321R-134a 20/80 4 -12 4 - 08 

R-321R-134a 30nO 4-05 4 - 02 

R-321R-134a 40/60 4-05 4-04 

R-321R-152a 30nO 3-05 3 - 03 

R-321R-152a 40/60 3-12 not measured 

Table 11: Refrigerant Mass Flow Rates ("80/67-95 Condition"') 

Refrigerant Blend Mass Ratio Mass Flow Rate (Lb / Hr) 

ETL Lennox 

R-22 - 375 352 

R-321R-134a 20180% 291 295 

R-321R-134a 30170% 302 300 

R-321R-134a 40160% 305 305 

R-321R-152a 30170% 196 206 

R-321R-152a 40160% 212 219 

19 
COMPARISONS WITH SIMULATIONS

AND BREADBOARD TESTS

• Table 12 and Figures 3 and 4 compare the simulation and

breadboard testing conducted at the University of Maryland

and the NIST to the "drop-in" results. The simulations predict that the refrigerant blends tested differently. There are

several reasons for the difference in results.

• Counterflow heat exchangers were used in simulations

and NIST test rig to better utilize temperature glide of the

refrigerant mixture. The system tested at ETL was a standard production unit and had crossflow heat exchangers

which could have impacted the performance.

• The breadboard test used water to refrigerant heat exchangers to obtain a constant capacity and the associated impact

on the energy efficiency. In an actual operating system, the

heat exchangers are air-to-refrigerant type and capacity is

not easily controlled.

• Simulations assumed minimal subcooling and superheat

since thermodynamically, these would be desirable.

Practically, this could lead to incomplete condensation and

evaporation. The EPA tests had 15°F superheat and 5-10°F

subcooling, which could impact performance.

• Coefficients used for thermodynamic properties used in

the University of Maryland simulations differed from the

EPA tests.

• Better performance from the refrigerant blends tested is

expected with further optimization such as optimum superheat settings, counterflow heat exchangers, and better transport and thermophysical properties of refrigerant blends.

20

EE-RM-93-801 COMMENT OR10

COMPARISONS WITH SIMULATIONS 

AND BREADBOARD TESTS 

20 

• Table 12 and Figures 3 and 4 compare the simulation and 

breadboard testing conducted at the University of Maryland 

and the NIST to the II drop-in" results. The simulations predict that the refrigerant blends tested differently. There are 

several reasons for the difference in results. 

• Counterflow heat exchangers were used in simulations 

and NIST test rig to better utilize temperature glide of the 

refrigerant mixture. The system tested at BTL was a standard production unit and had crossflow heat exchangers 

which could have impacted the performance. 

• The breadboard test used water to refrigerant heat exchangers to obtain a constant capacity and the associated impact 

on the energy efficiency. In an actual operating system, the 

heat exchangers are air-ta-refrigerant type and capacity is 

not easily controlled. 

• Simulations assumed minimal subcooling and superheat 

since thermodynamically, these would be desirable. 

Practically, this could lead to incomplete condensation and 

evaporation. The EPA tests had 15°F superheat and 5-lOoF 

subcooling, which could impact performance. 

• Coefficients used for thermodynamic properties used in 

the University of Maryland simulations differed from the 

EPA tests. 

• Better performance from the refrigerant blends tested is 

expected with further optimization such as optimum superheat settings, counterflow heat exchangers, and better transport and thermophysical properties of refrigerant blends. 
Table 12: Comparison of Experimental and Simulation Results

(Simulation Data from Radermacher & Jung [4], Experimental Data from ETL)

ARI "A" Test Conditions

% Change in Capacity % Change in COP

Refrigerant Test Simulation Test Simulation

R-22 Base Base Base Base

R-3218-134a -13 -10 -0.5 +5

(20/80 Mix)

R-3218-134a -5 +2 +0.5 +6

(30/70 Mix)

R-32/R-134a +1 +13 +0.5 +6

(40/60 Mix)

R-32/R-152a -12 -9 +1 +12

(30/70 Mix)

R-32/R-152a -9 +2 -1.5 +12

(40/60 Mix)

21

EE-RM-93-801 COMMENT OR10

Table 12: Comparison of Experimental and Simulation Results 

(Simulation Data from Radermacher & Jung [4]. Experimental Data from Ell) 

ARI "A" Test Concfrtions 

% Change in Capacity % Change in COP 

Refrigerant Test Simulation Test Simulation 

R-22 Base Base Base Base 

R-321R-134a -13 -10 -0.5 +5 

(20180 Mix) 

R-321R-134a -5 +2 +0.5 +6 

(3anO Mix) 

R-321R-134a +1 +13 +0.5 +6 

(40/60 Mix) 

R-321R-152a -12 -9 +1 +12 

(3anO Mix) 

R-321R-152a -9 +2 -1.5 +12 

(40160 Mix) 

21 
Figure 3: Comparison of Capacity

(ARI "A" Test Condition)

ETL Tests

Lennox Tests

UMd Simulation

NIST Simulation

Refrigerant Blends

Figure 4: Comparison of COP

(ARI "A" Test Condition)

- ETL Tests

Lennox Tests

- UMd Simulation

NIST Simulation

NIST Tests

Refrigerant Blends

22

EE-RM-93-801 COMMENT OR10

Base 

Base 

1.2 

1.0 

0.8 

22 

Figure 3: Comparison of Capacity 

(ARI "An Test Condition) 

R-321R-134a R-321R-152a 

20/80% 30170% 40160% 30170% 4OISOOio 

Refrigerant Blends 

Figure 4: Comparison of COP 

(ARI "An Test Condition) 

R-32/R-134a R-32/R-152a 

20/80% 30nO% 40/60% 30nO% 40/60% 

Refrigerant Blends 

_ETL Tests 

_ Lennox Tests 

_ UMd Simulation 

o NIST Simulation 

_ETL Tests 

~ Lennox Tests 

_ UMd Simulation 

D NIST Simulation 

0NISTTests 
CONCLUSIONS AND FURTHER WORK

• R-32 based refrigerant mixtures have been shown to be

promising potential R-22 replacements in a split-system

air conditioner. These tests were conducted in accordance

with the ARI Rating Conditions and parameters measured

included capacity, efficiency, and seasonal efficiency.

• The tests demonstrate that these refrigerants can achieve

comparable performance levels to that of existing R-22

systems. With additional work and optimization, it should

be possible to improve the performance levels beyond that

of R-22.

• While the results of this test program are encouraging,

considerable work is needed to better evaluate these alternatives. The following further work is recommended:

a. Use of Counter Flow Heat Exchangers to optimize

performance of blends with temperature glide.

b. Optimize Charge, Superheat, and Sub Cooling levels

c. Use larger capacity compressors to make up capacity

shortfall-experimental verification needs to be done.

d. Investigate the use of chemical additives to R-22

based lubricants for compatibility with new blends

e. Conduct Heating Tests on heat pumps

f. Conduct Composition Shifts Study for optimization

in heating and cooling

g. Investigate Accumulators and Reversing Valve Dynamics

h. Study Compressor Life and Materials Compatibility

i. Study Flammability Aspects including Risk Analysis

j. Investigate Serviceability Issues

REFERENCES

1. National Appliance Energy Conservation Act (NAECA), Public Law 100-12,

January 1987.

2. Radermacher R. and Jung D, 1991, "Theoretical Analysis for Replacement

Refrigerants for R-22 For Residential Uses," U.S. Environmental Protection

Agency Report, U.S. EPA/400/1-91/041.

23

EE-RM-93-801 COMMENT OR10

CONCLUSIONS AND FURTHER WORK 

• R-32 based refrigerant mixtures have been shown to be 

promising potential R-22 replacements in a split-system 

air conditioner. These tests were conducted in accordance 

with the ARI Rating Conditions and parameters measured 

included capadty, efficiency, and seasonal efficiency. 

• The tests demonstrate that these refrigerants can achieve 

comparable performance levels to that of existing R-22 

systems. With additional work and optimization, it should 

be possible to improve the performance levels beyond that 

ofR-22. 

• While the results of this test program are encouraging, 

considerable work is needed to better evaluate these alternatives. The following further work is recommended: 

a. Use of Counter Flow Heat Exchangers to optimize 

performance of blends with temperature glide. 

b. Optimize Charge, Superheat, and Sub Cooling levels 

c. Use larger capacity compressors to make up capacity 

shortfall-experimental verification needs to be done. 

d. Investigate the use of chemical additives to R-22 

based lubricants for compatibility with new blends 

e. Conduct Heating Tests on heat pumps 

f. Conduct Composition Shifts Study for optimization 

in heating and cooling 

g. Investigate Accumulators and Reversing Valve Dynamics 

h. Study Compressor Life and Materials Compatibility 

i. Study Flammability Aspects including Risk AnalysiS 

j. Investigate Serviceability Issues 

REFERENCES 

1. National Appliance Energy Conservation Act (NAECA), Public Law 100-12, 

January 1987. 

2. Radermacher R. and Jung D, 1991, "Theoretical Analysis for Replacement 

Refrigerants for R-22 For Residential Uses," U.S. Environmental Protection 

Agency Report, U.S. EPA/400/1-91/041. 

23 
3. Pannock J. and Didion D., 1991 , "The Performance of Chlorine-Free Binary

Zeotropic Refrigerant Mixtures in a Heat Pump ," National Institute for

Standards and Technology Report, NISTIR 4748 . (NTIS #PB92-149814/AS)

4. Vineyard E.A., J.R. Sands and T.G. Statt, 1989, "Selection of Ozone -Safe NonAzeotropic Refrigerant Mixtures for Capacity Modulation in Residential

Heat Pumps," ASHRAE Transactions, Paper #3199, Vol 95, Part 1.

5. Sands J.R., E.A. Vineyard and R.J. Nowak, 1990, "Experimental Performance

of Ozone-Safe Alternative Refrigerants," ASHRAE Transactions, Paper #3399

Vol. 96, Part 2.

6. Hogberg M. and T. Berntsson, 1991, "A Residential Heat Pump Working with

the Non-Azeotropic Mixture HCFC-22/HCFC142 b-Experimental Results

and Evaluation," Paper #492, XVIII International Congress of Refrigeration,

Montreal, Canada.

7. Goto M., N. Inque and J. Nakamura, 1991, "Performance of Vapor Compression

Heat Pump System Using a Non-Azeotropic Refrigerant Mixture," Paper #62,

XVIII International Congress of Refrigeration, Montreal, Canada.

8. Takamatsu H., Sh. Koyama, Y. Ikegami and T. Yara, 1991, "An Experiment on

a Vapor Compression Heat Pump System Using Non-Azeotropic Refrigerant

Mixtures," Paper #105, XVIII International Congress of Refrigeration,

Montreal, Canada.

9. Galloway J.E. and V.W. Goldschmidt, 1991 , "Air to Air Heat Pump

Performance with Three Different Non-Azeotropic Refrigerant Mixtures,"

ASHRAE Transactions, Paper #3473, Vol. 97, Part 1.

10. Shiflett M.B., Yokozeki A, and Bivens D.B., 1992, "Refrigerants as HCFC-22

Alternatives," Proceedings of the 1992 International Refrigeration

Conference-Energy Efficiency and New Refrigerants, July 1992. pp. 35-44.

11. Treadwell D.W. "Application of Propane (R-290 ) to a Single Packaged

Unitary Air Conditioning Product," Proceedings of the International CFC

and Halon Alternatives Conference , pp. 348-351. December 1991.

12. Air Conditioning and Refrigeration Institute , 1992: R-22 Alternative

Refrigerants Evaluation Program (AREP)-Participants Handbook, ARI,

Arlington, VA.

13. ASHRAE Standard 116, 1989 : Methods of Testing for Seasonal Efficiency of

Unitary Air-Conditioners and Heat Pumps (1989).

14. ASHRAE Standard 37, 1988 : Methods of Testing for Rating Unitary AirConditioners and Heat Pump Equipment (1988).

15. ARI Standard 210/240 Unitary Air-Conditioning and Air -Source Heat Pump

Equipment (1989).

24

EE-RM-93-801 COMMENT OR10

3. Pannock J. and Didion D., 1991, "The Performance of Chlorine-Free Binary 

Zeotropic Refrigerant Mixtures in a Heat Pump," National Institute for 

Standards and Technology Report, NISTIR 4748. (NTIS #PB92-149814/ AS) 

4. Vineyard E.A., l.R Sands and T.G. Statt, 1989, "Selection of Ozone-Safe NonAzeotropic Refrigerant Mixtures for Capacity Modulation in Residential 

Heat Pumps," ASHRAE Transactions, Paper #3199, Vol 95, Part 1. 

5. Sands J.R, E.A. Vmeyard and RJ. Nowak, 1990, "Experimental Performance 

of Ozone-Safe Alternative Refrigerants," ASHRAE Transactions, Paper #3399 

Vol. 96, Part 2. 

6. Hogberg M. and T. Berntsson, 1991, II A Residential Heat Pump Working with 

the Non-Azeotropic Mixture HCFC-22/HCFCl42 b-Experimental Results 

and Evaluation," Paper #492, XVIII International Congress of Refrigeration, 

Montreal, Canada. 

7. Goto M., N. Inque and J. Nakamura, 1991, "Performance of Vapor Compression 

Heat Pump System Using a Non-Azeotropic Refrigerant Mixture," Paper #62, 

XVIII International Congress of Refrigeration, Montreal, Canada. , 

8. Takamatsu H., Sh. Koyama, Y. Jkegami and T. Yara, 1991, "An Experiment on 

a Vapor Compression Heat Pump System Using Non-Azeotropic Refrigerant 

Mixtures," Paper #105, XVIII International Congress of Refrigeration, 

Montreal, Canada. 

9. Galloway J.E. and V.W. Goldschmidt, 1991, "Air to Air Heat Pump 

Performance with Three Different Non-Azeotropic Refrigerant Mixtures," 

ASHRAE Transactions, Paper #3473, Vol. 97, Part 1. 

10. Shiflett M.B., Yokozeki A, and Bivens D.B., 1992, "Refrigerants as HCFC-22 

Alternatives," Proceedings of the 1992 International Refrigeration 

Conference--Energy Efficiency and New Refrigerants, July 1992. pp. 35-44. 

11. Treadwell D.W. "Application of Propane (R-290) to a Single Packaged 

Unitary Air ConditiOning Product," Proceedings of the International CFC 

and Halon Alternatives Conference, pp. 348-351. December 1991. 

12. Air Conditioning and Refrigeration Institute, 1992: R-22 Alternative 

Refrigerants Evaluation Program (AREP)-Participants Handbook, ARI, 

Arlington, VA. 

13. ASHRAE Standard 116, 1989: Methods of Testing for Seasonal Efficiency of 

Unitary Air-Conditioners and Heat Pumps (1989). 

14. ASH RAE Standard 37, 1988: Methods of Testing for Rating Unitary AirConditioners and Heat Pump Equipment (1988). 

15. ARI Standard 210/240 Unitary Air-Conditioning and Air-Source Heat Pump 

Equipment (1989). 

24