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 

# &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 

## @ Printedon 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 

### Experimental Investigation of R·22 Replacement Refrigerants in a Split.System Residential Air Conditioner

Prepared for

U.S. Environmental ProtectionAgency Technology & SubstitutesBranch GlobalChange Division Office ofAtmospheric and Indoor AirPrograms Office ofAirand Radiation

WashingtonD.C. 20460


### by

Sekhar N. Kondepudi

September 1992CONTENTS 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 

### CONTENTS Aclcnowledgements
................................................................................ 3 Major Findings
......................................................................................... 4 Refrigerants and the Environment
....................................................... 6 Choosing the Best Alternatives
............................................................. 7 Project Objectives
............................................................................ ........ 8 PreviousWork
.......................................................................................... 9 Testing Details
........................................................................................ 10 Results and Discussions
....................................................................... 13 Perfol"Ill.ance Results
....................................................................... 13 NOl"Ill.alized Results
........................................................................ 16 Retrofit and New EquipmentApplications
................................ 16 Refrigerant Charge and Mass Flow............................................. 19 Comparisons withSimulations and BreadboardTesting
................ 20 Conclusions and FurtherWork
........................................................... 23 References
............................................................................................... 23

2

### ACKNOWLEDGMENTSThis 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 

### ACKNOWLEDGMENTS This projectwas completed successfully as a result ofmany people contributing to it.These include:
Sekhar Kondepudi Bill Kopko Jean Lupinacci LenVan 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 hadsteady-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 

## 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 withminimalhardware 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% ofthe 

### R-22 values. • Since capacity is a driving force for retrofit applications, the 40/ 60% ofR-32/R-134a may be 

### a good retrofit refrigerantfor 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% ofR-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 andR-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 residentialair conditioning equipment. While the results are encour5 

### 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 predictedbysimulations. • Independent tests conducted by Lennox Industries on similar equipment using the same refrigerant blends confirmed trends andresults 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 bothheating 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 encour5aging, 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 CFCand 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 

### aging, a considerable amount of fwther work needs to be done prior to commercialization. Future work should include evaluationof:
e 

### Counterflow Heat Exchangers for Air

### Systems • Charge, Superheat, and Subcooling Optimization • Expansion Devices e 

### Heat Pumps-Coolingand Heating Modes • Composition Shifts ofthe 

### Refrigerant Blends • Accumulators andReversing Valve Dynamics • Compressor Life • Materials Compatibility (long term) • Flammability • Servicing Issues 

## REFRIGERANTS AND THE ENVIRONMENT

6 

### • The environmentalproblems ofozone-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 inthe 

### United States. • A similarCFC phaseout,including restrictions onHCFC-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 phaseoutbetweenthe 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 mini

### mize 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 directglobal 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 

### 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-134aand 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 

### • 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 ofR-22. • These simulations and breadboard 

### type tests have only a limited value beyond which actual, II

### drop-in" tests must beperformed to test actualviability. 

## 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 ofthe air

### conditioner. • Demonstrate that comparable capacity and efficiency can

be achieved withminimal

### hardware changes. • Provide direction for evaluating engineering designchanges inR-22 systems to achieve optimized energyperformance. • Test refrigerant blends of R-32/R-134a and R-32/R-152a based on results obtained by Radermacher and Jung [2] and Pannock andDidion [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 toestimate 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 animproved 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 

## 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 promisingmixtures were R-32/ R-152a mixture in a 40/60% blend by mass and R-32/R-134a ina 30/70%blendby mass. • Sands,Vineyard, and Nowak [5] compared R-22, R-12, and R-114 with 11 single component non-CFC refrigerants to estimate heatpumpperformancepotential. The studyconcluded that R-152a, R-143a, R-l34a, and R-l34 had thebest performance ofthe 11 refrigerants evaluated. • Other studies [6,7,8,9] suggest thatwhenheattransfer fluids exchange heat with a refrigerant mixture in a counterflow mode,the thermodynamic irreversibilities couldbe 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 andincreased capacityatlowerambienttemperatures. • 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, performedbetter than R-22 for certain composition ranges usingcounterflow 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 withless 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 ofR-22. • The Air Conditioning and Refrigeration Institute (ARI) [12], in consultation with various equipment and refriger9ant 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 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 inDallas,TX. • All tests were conducted in accordance with the ARI Standard 210/240 and ASHRAE Standards 37-1988 and 116-1989 for testingunitaryequipment [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 giveninTables 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 

### 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 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-asmeasured onthe evaporator coil 2. Power Consumption-Compressorand Fan 3. System Efficiency-EERandSEER 4. Refrigerant Pressures andTemperatures 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 andhand-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 theR-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 usedwith 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 theairside 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 

### • 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 withR-l34a wasused with the R-32/R-134a blends. Flushing of the system was performed to ensure that minimal traces ofthe originallubricant were present. The same polyester lubricant was used with the R-32/R-134a blends was used with the R-32/R152ablends. • 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 settingwasused for all

### theblends. • The same test facilities, instrumentation, and test personnel were used for all the 

### tests. This minimized any uncertainty and inaccuracy inthe 

### measurements. 

### RESULTS AND DISCUSSIONS PERFORMANCE RESULTS

• Capacity, power, EER, and SEER for eachrefrigerant tested are summarizedinTables 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 withappropriate hardware changes and optimization, performance canbe 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 ofexperimental error considering that 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 

### 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 

### 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 highperformance 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 

### 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, thenresults 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 ofthese blends will have a minimalimpact onSEER. This can be 

### achieved with mini

### mum 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 thanwere measured inthese 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% 30/7

## 0% 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% 30/7

### 0% 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 

### 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 

### Table 9: Performance Relative to R-22: LennoxTests (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 

### REFRIGERANT CHARGE

• Tables 10 and 11 show the amount of refrigerant charge andmass 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 therefrigerant 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 isexpected with further optimization such as optimum superheat settings, counterflow heat exchangers, and better transport and thermophysical properties of refrigerant blends.

20 

## COMPARISONS WITH SIMULATIONS AND BREADBOARD TESTS

20 • Table 12 and Figures 3 and 4 compare the simulation and breadboard testing conducted atthe University ofMaryland and the NIST to the IIdrop-in" results. The simulations predict that the refrigerant blends tested differently. There are severalreasons for the difference inresults. • Counterflow heat exchangers were used in simulations and NIST test rig to better utilize temperature glide ofthe refrigerant mixture. The system tested at BTL was a standard production unit and had crossflow heat exchangers whichcould have impacted theperformance. • Thebreadboard test used water to refrigerant heatexchangers 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 noteasily 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,whichcould impactperformance. • 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, andbetter transportand thermophysicalproperties ofrefrigerantblends.

### 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 

### 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 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 _ETLTests

_ 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 

## 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 seasonalefficiency. • 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 workis recommended: a. Use of Counter Flow Heat Exchangers to optimize performance ofblends withtemperature glide. b. Optimize 

### Charge, Superheat,and Sub Cooling levels c. Use larger capacity compressors to make up capacity shortfall-experimentalverificationneeds tobe done. d. Investigate the use of chemical additives to R-22 based lubricants for compatibility withnewblends e. Conduct Heating Tests onheatpumps f. Conduct Composition Shifts Study for optimization inheating andcooling g. InvestigateAccumulatorsandReversing

### ValveDynamics 

### h. StudyCompressor Life and Materials Compatibility i. Study FlammabilityAspects includingRisk 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.

233. 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 

### 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 

### andT.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 ofOzone-Safe Alternative Refrigerants," ASHRAE Transactions, Paper#3399 Vol. 96, Part 2. 6. Hogberg M. andT. Berntsson, 1991, II

### A Residential Heat PumpWorking 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 ofVapor Compression Heat Pump System Using a Non-Azeotropic Refrigerant Mixture," 

### Paper #62, XVIII International Congress ofRefrigeration, Montreal, Canada. , 8. Takamatsu H., Sh. Koyama, Y. 

### Jkegami andT. 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