2014 TOC Refrigeration, A/C and Heat Pumps Assessment Report 1

MONTREAL PROTOCOL

ON SUBSTANCES THAT DEPLETE

THE OZONE LAYER

UNEP

2014 REPORT OF THE

REFRIGERATION, AIR CONDITIONING AND HEAT PUMPS

TECHNICAL OPTIONS COMMITTEE

2014 Assessment
2014 TOC Refrigeration, A/C and Heat Pumps Assessment Report 2

UNEP

2014 REPORT OF THE

REFRIGERATION, AIR CONDITIONING AND HEAT PUMPS

TECHNICAL OPTIONS COMMITTEE

2014 ASSESSMENT
2014 TOC Refrigeration, A/C and Heat Pumps Assessment Report 3

Montreal Protocol

On Substances that Deplete the Ozone Layer

UNEP

2014 REPORT OF THE

REFRIGERATION, AIR CONDITIONING AND HEAT PUMPS

TECHNICAL OPTIONS COMMITTEE

2014 ASSESSMENT

The text of this report is composed in Times New Roman.

Co-ordination: Refrigeration, Air Conditioning and Heat Pumps 

Technical Options Committee

Composition: Lambert Kuijpers and Roberto Peixoto (Co-chairs)

Formatting, 

Reproduction: RTOC co-chairs and UNEP Nairobi, Ozone Secretariat

Date: February 2015

No copyright involved

Printed in Kenya, 2015

ISBN: 978-9966-076-09-0
2014 TOC Refrigeration, A/C and Heat Pumps Assessment Report 4

DISCLAIMER

The United Nations Environment Programme (UNEP), the Technology and Economic Assessment Panel 

(TEAP) co-chairs and members, the Refrigeration AC and Heat Pumps Technical Options Committee, cochairs and members, and the companies and organisations that employ them do not endorse the performance, 

worker safety, or environmental acceptability of any of the technical options discussed. Every industrial 

operation requires consideration of worker safety and proper disposal of contaminants and waste products. 

Moreover, as work continues - including additional toxicity evaluation - more information on health, 

environmental and safety effects of alternatives and replacements will become available for use in selecting 

among the options discussed in this document.

UNEP, the TEAP co-chairs and members, the Refrigeration, AC and Heat Pumps Technical Options 

Committee, co-chairs and members, in furnishing or distributing this information, do not make any warranty 

or representation, either express or implied, with respect to the accuracy, completeness, or utility; nor do they 

assume any liability of any kind whatsoever resulting from the use or reliance upon any information, material, 

or procedure contained herein, including but not limited to any claims regarding health, safety, environmental 

effect or fate, efficacy, or performance, made by the source of information.

Mention of any company, association, or product in this document is for information purposes only and does 

not constitute a recommendation of any such company, association, or product, either express or implied by 

UNEP, the Technology and Economic Assessment Panel co-chairs or members, the Refrigeration, AC and 

Heat Pumps Technical Options Committee co-chairs or members, or the companies or organisations that 

employ them.

ACKNOWLEDGEMENT

The UNEP Refrigeration, A/C and Heat Pumps Technical Options Committee acknowledges with thanks the 

outstanding contributions from all of the individuals and organisations who provided technical support to 

committee members. In developing this report, particularly the chapter lead authors were instrumental.

The names of chapter lead authors, co-authors and contributors are given at the start of each chapter. Addresses 

and contact numbers of the chapter lead authors and all other authors of the UNEP TOC Refrigeration, A/C and 

Heat Pumps can be found in the Annex.

The opinions expressed are those of the Committee and do not necessarily reflect the views of any sponsoring or 

supporting organisations.

Gratitude is expressed to UNEP’s Ozone Secretariat, Nairobi, Kenya for the co-operation in formatting and 

styling of the report and for the reproduction of this report.
2014 TOC Refrigeration, A/C and Heat Pumps Assessment Report 5

UNEP

2014 REPORT OF THE

REFRIGERATION, AIR CONDITIONING AND HEAT PUMPS

TECHNICAL OPTIONS COMMITTEE

2014 ASSESSMENT

Table of Contents

KEY MESSAGES ........................................................................................................................................11

REFRIGERANTS ..........................................................................................................................................11

DOMESTIC APPLIANCES..............................................................................................................................11

COMMERCIAL REFRIGERATION...................................................................................................................11

INDUSTRIAL SYSTEMS ................................................................................................................................12

TRANSPORT REFRIGERATION......................................................................................................................12

AIR-TO-AIR AIR CONDITIONERS AND HEAT PUMPS......................................................................................12

WATER HEATING HEAT PUMPS ...................................................................................................................12

CHILLERS...................................................................................................................................................13

VEHICLE AIR CONDITIONING ......................................................................................................................13

SUSTAINABLE REFRIGERATION ..................................................................................................................13

ABSTRACT EXECUTIVE SUMMARY...................................................................................................15

REFRIGERANTS ..........................................................................................................................................15

DOMESTIC APPLIANCES..............................................................................................................................15

COMMERCIAL REFRIGERATION...................................................................................................................16

INDUSTRIAL SYSTEMS ................................................................................................................................16

TRANSPORT REFRIGERATION......................................................................................................................17

AIR-TO-AIR AIR CONDITIONERS AND HEAT PUMPS......................................................................................17

WATER HEATING HEAT PUMPS ...................................................................................................................18

VEHICLE AIR CONDITIONING ......................................................................................................................19

SUSTAINABLE REFRIGERATION ..................................................................................................................20

EXECUTIVE SUMMARIES OF ALL CHAPTERS................................................................................21

REFRIGERANTS ..........................................................................................................................................21

DOMESTIC APPLIANCES..............................................................................................................................21

COMMERCIAL REFRIGERATION...................................................................................................................22

INDUSTRIAL SYSTEMS ................................................................................................................................23

TRANSPORT REFRIGERATION......................................................................................................................23

AIR-TO-AIR AIR CONDITIONERS AND HEAT PUMPS......................................................................................24

WATER HEATING HEAT PUMPS ...................................................................................................................25

CHILLERS...................................................................................................................................................26

VEHICLE AIR CONDITIONING ......................................................................................................................26

SUSTAINABLE REFRIGERATION ..................................................................................................................28

1 INTRODUCTION ..............................................................................................................................31

1.1 MONTREAL PROTOCOL DEVELOPMENTS...........................................................................................31

1.2 THE UNEP TECHNOLOGY AND ECONOMIC ASSESSMENT PANEL .....................................................32

1.3 THE TECHNICAL OPTIONS COMMITTEE REFRIGERATION, A/C AND HEAT PUMPS ............................35

1.4 REFRIGERATION, AIR CONDITIONING AND HEAT PUMPS....................................................................37

1.4.1 General remarks.....................................................................................................................37

1.4.2 Long term options and energy efficiency................................................................................38

1.4.3 Set up of the 2014 RTOC Refrigeration, A/C and Heat Pumps Assessment Report ...............39

2 REFRIGERANTS ..............................................................................................................................43

2.1 INTRODUCTION.................................................................................................................................43

2.1.1 Refrigerant progression .........................................................................................................43
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2.1.2 Unsaturated hydrofluorochemicals........................................................................................43

2.1.3 Recent assessment on current and future refrigerants and GWP...........................................44

2.1.4 Flammable refrigerants and Safety classification..................................................................44

2.1.5 Climate impact metrics for refrigerants.................................................................................45

2.1.6 ODP and GWP data for regulatory and reporting purposes .................................................46

2.1.7 Selection of refrigerant...........................................................................................................48

2.1.8 HCFC-22 replacements..........................................................................................................49

2.2 REFRIGERANT DESCRIPTIONS ...........................................................................................................49

2.3 DATA SUMMARY...............................................................................................................................54

TABLE 2-9: DATA SUMMARY FOR AZEOTROPIC REFRIGERANT BLENDS ..........................................................57

2.3.1 Data sources...........................................................................................................................57

2.4 CONCLUDING REMARKS ...................................................................................................................59

2.5 REFERENCES.....................................................................................................................................59

ANNEX TO CHAPTER 2 - SAFETY STANDARDS AND REGULATIONS .......................................64

REFERENCES ..............................................................................................................................................68

3 DOMESTIC APPLIANCES..............................................................................................................71

3.1 INTRODUCTION.................................................................................................................................71

3.2 OPTIONS FOR NEW EQUIPMENT.........................................................................................................72

3.2.1 Alternatives for domestic refrigerators..................................................................................72

3.2.2 Conversion of HFC-134a domestic refrigerators to low GWP alternatives ..........................74

3.2.3 Alternatives for tumble dryers................................................................................................75

3.2.4 Not-in-kind alternative technologies......................................................................................76

3.2.5 Product energy efficiency improvement technologies for domestic refrigerators..................76

3.2.6 Product energy efficiency improvement technologies for tumble dryers ...............................77

3.3 OPTIONS FOR EXISTING DOMESTIC REFRIGERATORS .........................................................................78

3.4 END-OF-LIFE DISPOSAL.....................................................................................................................79

3.5 CONCLUDING REMARKS ...................................................................................................................79

3.6 REFERENCES.....................................................................................................................................79

4 COMMERCIAL REFRIGERATION ..............................................................................................85

4.1 INTRODUCTION.................................................................................................................................85

4.2 APPLICATIONS ..................................................................................................................................85

4.3 OPTIONS FOR NEW EQUIPMENT.........................................................................................................86

4.3.1 Stand-alone equipment...........................................................................................................86

4.3.2 Condensing unit systems ........................................................................................................88

4.3.3 Centralized supermarket systems...........................................................................................89

4.4 OPTIONS FOR EXISTING EQUIPMENT..................................................................................................95

4.5 REFERENCES.....................................................................................................................................96

5 INDUSTRIAL SYSTEMS ...............................................................................................................101

5.1 INTRODUCTION...............................................................................................................................101

5.1.1 Background ..........................................................................................................................101

5.1.2 Efficiency and sustainability ................................................................................................102

5.1.3 Refrigeration ........................................................................................................................102

5.1.4 Heat pumps...........................................................................................................................104

5.1.5 Air conditioning ...................................................................................................................104

5.1.6 Rankine cycle ......................................................................................................................104

5.2 APPLICATIONS ................................................................................................................................105

5.2.1 Food processing ...................................................................................................................105

5.2.2 Cold storage .........................................................................................................................106

5.2.3 Industrial cooling in buildings, power plant and IT centres ................................................106

5.2.4 District cooling.....................................................................................................................106

5.2.5 Industrial heat pumps and heat recovery .............................................................................107

5.2.6 Leisure..................................................................................................................................108

5.2.7 Process Refrigeration...........................................................................................................109

5.3 OPTIONS FOR NEW EQUIPMENT.......................................................................................................109

5.3.1 R-717 (Ammonia).................................................................................................................109

5.3.2 Hydrofluorocarbons.............................................................................................................110
2014 TOC Refrigeration, A/C and Heat Pumps Assessment Report 7

5.3.3 Hydrocarbons.......................................................................................................................111

5.3.4 R-744 (Carbon dioxide) .......................................................................................................111

5.3.5 R-718 (Water).......................................................................................................................112

5.3.6 Absorption............................................................................................................................112

5.4 OPTIONS FOR EXISTING EQUIPMENT................................................................................................112

5.4.1 Conversion to HFC blends...................................................................................................113

5.4.2 Conversion to R-744.............................................................................................................113

5.4.3 Conversion to R-717.............................................................................................................113

5.4.4 Conversion to hydrocarbon..................................................................................................113

5.5 SERVICE REQUIREMENTS ................................................................................................................114

5.6 CONCLUDING REMARKS .................................................................................................................114

5.7 REFERENCES...................................................................................................................................114

6 TRANSPORT REFRIGERATION ................................................................................................119

6.1 INTRODUCTION...............................................................................................................................119

6.2 OPTIONS FOR NEW EQUIPMENT.......................................................................................................119

6.2.1 Intermodal containers and road vehicles.............................................................................119

6.2.2 Vessels..................................................................................................................................123

6.3 OPTIONS FOR EXISTING EQUIPMENT................................................................................................124

6.3.1 Road equipment and intermodal containers.........................................................................124

6.3.2 Vessels..................................................................................................................................125

6.4 CONCLUDING REMARKS .................................................................................................................126

6.5 REFERENCES...................................................................................................................................126

ANNEX TO CHAPTER 6 .........................................................................................................................129

A6.1 Requirements........................................................................................................................129

A6.2 Vessels..................................................................................................................................129

A6.3 Trucks, trailers and rail cars................................................................................................130

A6.4 Intermodal containers..........................................................................................................132

A6.5 Temperature profiles............................................................................................................133

7 AIR-TO-AIR AIR CONDITIONERS AND HEAT PUMPS ........................................................137

7.1 INTRODUCTION...............................................................................................................................137

7.2 EQUIPMENT TYPES..........................................................................................................................138

7.2.1 Small self-contained air conditioners...................................................................................138

7.2.2 Split (non-ducted) residential and commercial air conditioners..........................................139

7.2.3 Multi-split air conditioners for commercial and residential ................................................140

7.2.4 Split ducted air conditioners (residential and commercial).................................................140

7.2.5 Ducted commercial packaged (self-contained) air conditioners..........................................140

7.3 OPTIONS FOR NEW EQUIPMENT.......................................................................................................141

7.3.1 HFC-134a ............................................................................................................................142

7.3.2 R-407C.................................................................................................................................142

7.3.3 R-410A .................................................................................................................................143

7.3.4 HFC-32 ................................................................................................................................143

7.3.5 HFC-152a ............................................................................................................................144

7.3.6 HFC-161 ..............................................................................................................................144

7.3.7 HFC-1234yf..........................................................................................................................144

7.3.8 HC-290.................................................................................................................................145

7.3.9 HC-1270...............................................................................................................................146

7.3.10 R-744 ...............................................................................................................................146

7.3.11 R-446A and R-447A.........................................................................................................147

7.3.12 R-444B.............................................................................................................................147

7.3.13 Charge reduction.............................................................................................................148

7.3.14 Not-in-kind alternative technologies ...............................................................................149

7.4 OPTIONS FOR EXISTING EQUIPMENT................................................................................................149

7.4.1 Replacement refrigerants only .............................................................................................150

7.4.2 Retrofit refrigerants .............................................................................................................151

7.4.3 Conversion to flammable refrigerants .................................................................................152

7.5 HIGH AMBIENT CONSIDERATIONS ...................................................................................................152

7.5.1 Performance of alternatives under high ambient temperatures...........................................153
2014 TOC Refrigeration, A/C and Heat Pumps Assessment Report 8

7.5.2 Measures to design and optimise air-conditioners for high ambient conditions..................156

7.6 CONCLUDING REMARKS .................................................................................................................157

7.7 REFERENCES...................................................................................................................................157

8 WATER HEATING HEAT PUMPS ..............................................................................................169

8.1 INTRODUCTION...............................................................................................................................169

8.2 HEAT PUMP TYPES, IMPLICATIONS AND TRENDS .............................................................................169

8.2.1 Heat pump types...................................................................................................................169

8.2.2 Heat pump implications and trends......................................................................................171

8.3 OPTIONS FOR NEW EQUIPMENT.......................................................................................................172

8.3.1 HFC-134a and HFC blends R-407C, R-417A and R-410A..................................................172

8.3.2 HFC-32 ................................................................................................................................173

8.3.3 HFC-1234yf and other low-GWP HFC blends ....................................................................174

8.3.4 R-744 (carbon dioxide) ........................................................................................................174

8.3.5 Hydrocarbons.......................................................................................................................175

8.3.6 R-717 (ammonia) .................................................................................................................175

8.4 REFRIGERANT CHARGE LEVELS......................................................................................................176

8.5 OPTIONS FOR EXISTING SYSTEMS....................................................................................................176

8.6 CONCLUDING REMARKS .................................................................................................................176

8.7 REFERENCES...................................................................................................................................177

9 CHILLERS .......................................................................................................................................181

9.1 INTRODUCTION...............................................................................................................................181

9.2 TYPES OF EQUIPMENT AND APPLICATIONS .................................................................................182

9.2.1 Mechanical vapour compression chillers............................................................................182

9.2.2 Absorption chillers...............................................................................................................182

9.2.3 Chiller capacity ranges........................................................................................................183

9.3 OPTIONS FOR NEW EQUIPMENT.......................................................................................................183

9.3.1 Evaluation of experimental refrigerants for vapour compression chillers...........................183

9.3.2 Options for new vapour compression chillers......................................................................185

9.4 OPTIONS FOR EXISTING CHILLER EQUIPMENT .................................................................................188

9.4.1 Positive displacement chillers..............................................................................................189

9.4.2 Centrifugal chillers ............................................................................................................189

9.4.3 Non-vapor compression chiller replacements – absorption................................................189

9.5 ALTERNATIVES FOR HIGH AMBIENT CONDITIONS.......................................................................190

9.6 CONCLUDING REMARKS .................................................................................................................190

9.7 REFERENCES...................................................................................................................................191

10 VEHICLE AIR CONDITIONING .................................................................................................197

10.1 INTRODUCTION ..........................................................................................................................197

10.2 DESCRIPTION OF SYSTEMS AND CURRENT AND FUTURE APPLICATIONS OF MOBILE AIR CONDITIONING 

SYSTEMS ..................................................................................................................................................197

10.2.1 Refrigerant cost and recharge.........................................................................................198

10.2.2 Future Trends..................................................................................................................198

10.3 OPTIONS FOR NEW AND FUTURE MOBILE AIR CONDITIONING SYSTEMS...................................200

10.3.1 Passenger Car and Light Truck Air Conditioning\ .........................................................200

10.3.2 Bus and Rail Air Conditioning ........................................................................................208

10.4 OPTIONS FOR EXISTING SYSTEMS ..............................................................................................209

10.4.1 Retrofit of CFC-12 systems .............................................................................................209

10.4.2 Hydrocarbon retrofits......................................................................................................209

10.5 CONCLUDING REMARKS ............................................................................................................209

10.6 REFERENCES..............................................................................................................................210

ANNEX TO CHAPTER 10 .......................................................................................................................217

11 SUSTAINABLE REFRIGERATION.............................................................................................225

11.1 INTRODUCTION ..........................................................................................................................225

11.2 SUSTAINABILITY APPLIED TO REFRIGERATION...........................................................................225

11.2.1 Sustainability principles..................................................................................................225

11.2.2 Environmental aspects.....................................................................................................226

11.2.3 Social aspects..................................................................................................................226
2014 TOC Refrigeration, A/C and Heat Pumps Assessment Report 9

11.2.4 Assessment tools..............................................................................................................226

11.2.5 Opportunities for improvement .......................................................................................227

11.3 DIRECT IMPACT OF REFRIGERANTS ............................................................................................228

11.3.1 Design criteria for charge minimization and leak tightness............................................228

11.3.2 Reduction of emissions through installation, servicing and maintenance.......................230

11.3.3 Refrigerant recovery, recycling, reclamation and destruction ........................................230

11.4 INDIRECT IMPACTS DUE TO ENERGY USE....................................................................................233

11.4.1 Energy efficiency improvements......................................................................................234

11.5 EQUIPMENT LIFE CYCLE CONSIDERATIONS: EQUIPMENT DESIGN, OPERATION, MAINTENANCE, AND ENDOF-LIFE 234

11.5.1 Equipment design ............................................................................................................235

ANNEX 1 - TEAP REFRIGERATION, AIR CONDITIONING AND HEAT PUMPS TECHNICAL

OPTIONS COMMITTEE (RTOC) - MEMBERSHIP STATUS 12/14 ................................................239

ANNEX 2 - CONTACT DETAILS FOR AUTHORS, CO-AUTHORS AND CONTRIBUTORS TO THE 

2014 RTOC ASSESSMENT REPORT (TO BE COMPLETED)..........................................................241
2014 TOC Refrigeration, A/C and Heat Pumps Assessment Report 10
2014 TOC Refrigeration, A/C and Heat Pumps Assessment Report 11

Key Messages

Refrigerants

 Whatever refrigerant is chosen will always have to be a balance between several factors, the 

availability and cost of the refrigerant (and the associated equipment), the system energy 

efficiency, the safety and convenience of applicability, environmental issues and many more.

 The perfect refrigerant does not exist, and is unlikely to come into existence. Choices will 

therefore include the existing low GWP refrigerants (e.g. R-717, R-744 or HCs) and the newly 

applied or developed chemicals. Many new alternatives are proposed which create a challenge 

in finding the right refrigerant for each application. One aspect of particular importance is that 

refrigerants with low direct impact on climate change are often flammable to some extent. 

With new refrigerant characteristics comes the need for new technology development and 

increased need for training. 

 21 refrigerants obtained standardized designations and safety classifications since the 2010 

RTOC assessment report, including one new molecule: HCFC-1233zd(E). Approximately a 

quarter of the new refrigerants are blends which are replacements for HCFC-22. Of the new 

refrigerants twelve are blends of saturated HFCs and unsaturated HFCs (HFOs) of which 

seven blends are with class 2L flammability.

Domestic appliances 

 Globally, new refrigerator production conversion from use of ODS was essentially 

completed by 2008. HC-600a or HFC-134a continue to be the refrigerant option for new 

production. 

 It is projected that by 2020 about 75% of new refrigerator production will use HC-600a 

(possibly with a small share applying unsaturated HFC refrigerants) and the rest will use 

HFC-134a.

 Initial efforts to assess the use of HFC-1234yf in domestic refrigeration have begun, but 

they are not being pursued with high priority, due to cost implications and flammability. 

 The heat pump clothe (laundry) dryer (HPCD) sales using HFC-134a are fastly growing in 

the EU. HPCDs using R-407C and HC-290 have also been introduced. Alternative 

refrigerant solutions that are being explored include R-744, HC-600a and low GWP HFCs. 

Commercial refrigeration

 In commercial refrigeration stand-alone equipment, hydrocarbons (HCs) and R-744 are 

replacing HFC-134a and R-404A and represent a significant market share in Europe and in 

Japan. 

 Because of their high GWP, R-404A and R-507 are seen as refrigerants in many non-Article 5 

countries as refrigerants to be replaced and, depending on the refrigeration capacities, 

hydrocarbons, R-744 or HFC refrigerant blends with lower GWP are the current chosen 

options. 

 In supermarkets in Europe, two-stage CO2 systems are recognized as viable option especially 

in moderate temperature countries. The technology is now spreading to other areas and 

development of concepts for hot climates is ongoing.

 Plug-in units with air and/or water cooled condensers are gaining market share. Particularly in 

the USA, distributed systems (condensing units with water cooled condensers installed in the 

sales area) are also installed in large numbers.
2014 TOC Refrigeration, A/C and Heat Pumps Assessment Report 12

Industrial systems

 R-717 is widely used in industrial systems, but its adoption as a low GWP alternative to 

HCFC-22 in Article 5 countries is not universal due to safety concerns. The key 

requirements to facilitate this transition are education and training of designers and 

operators.

 Although HFCs are technically feasible for large industrial systems, the market sector is 

extremely cost sensitive and more expensive refrigerants are not favoured due to the large 

charge quantity required.

Transport refrigeration 

 Low-GWP candidates for transport refrigeration include R-744, hydrocarbons, and HFC 

blends; however, various challenges are currently preventing them from widespread use. 

Intermodal container applications are at the forefront of developments; here the R-744 based 

system is available. 

 In the case of a regulation banning the use of refrigerants above a certain GWP level (as in the 

EU), HFC blends will likely play a role in the 2020 timeframe as a retrofit to R-404A and 

(possibly) HFC-134a: their GWP is significantly lower and performances are close.

 Cryogenic and eutectic systems consist of potentially HFC-free stationary units and 

periodically recharged vehicle systems; they can be used on some transport routes.

Air-to-air air conditioners and heat pumps

 HCFC-22 is still widely used in new and existing systems in Article 5 countries and to some 

extent in existing systems in non-Article 5 countries.

 The majority of new systems using an alternative to HCFC-22 use R-410A; some others are 

using R-407C, HFC-134a, HC-290 and HFC-32.

 There are a growing number of alternatives which have a medium to low GWP and are 

flammable that are being considered and evaluated by research entities and enterprises, 

meaning there is some degree of uncertainty over future selection of alternatives.

Water heating heat pumps

 For water heating heat pumps most systems commercialised today make use of R-410A, HFC134a, R-407C, HC-290, HC-600a, R-717 or R-744. The majority of new equipment uses R410A. 

 In some Article 5 countries HCFC-22 is used. There are no technical barriers for replacing 

HCFC-22 by a non-ODS refrigerant in new systems. The main parameters in the selection of

alternatives when switching over from HCFC-22 are efficiency, cost effectiveness, economic 

impact, safe use and easiness of use. 

 HFC-32 and other medium and low-GWP HFC blends are under way to become commercially

available. R-744 based water heating heat pumps have been mainly developed and 

commercialised in Japan. However, the expansion of this technology to other countries is 

limited by its high cost. R-717 has also been used in a small number of reversible heat pumps 

and absorption heat pumps.
2014 TOC Refrigeration, A/C and Heat Pumps Assessment Report 13

Chillers

 The phase-out of ozone depleting refrigerants in chillers is going well. The use of HCFC-22 in 

chillers has been phased out in developed countries but use still continues in some Article 5 

countries. The primary refrigerants currently used in chillers are HFC-134a, R-410A, and 

HCFC-123. HC-290, R-717 and R-744 are used as refrigerants, however, to a lesser extent.

 A number of new refrigerants with lower global warming potentials have been proposed for 

use in chillers. Evaluations by manufacturers and other laboratories are underway, but it is not 

clear which ones will be selected for commercialization. Tradeoffs are apparent among GWP, 

energy efficiency, safety, and applied costs.

 Climate effects from chillers are dominated by their energy use. Thus, the ultimate goal in 

choosing new chiller refrigerant alternatives is to achieve the highest energy efficiency while 

remaining viable to chiller manufacturers, regulators, and users.

Vehicle air conditioning

 Now, at the end of 2014, it looks like as if more than one refrigerant will be used in the 

coming years for new car and light truck air conditioning. HFC-134a will remain largely 

adopted worldwide, HFC-1234yf will continue its growth in new models at least in the near 

future, and R-744 is expected to be implemented by German OEMs starting in 2017. 

 New refrigerant options have GWPs enabling the GHG credits in US and are below the EU 

threshold of 150; both can achieve fuel efficiency comparable to the existing HFC-134a 

systems with appropriate hardware and control development. 

 The worldwide spread of the two new refrigerants (HFC-1234yf and R-744) will be governed 

significantly by additional aspects like safety, costs, regulatory approval, system reliability, 

heat pump capability (especially for electric driven vehicles) and servicing. 

 At the moment, it cannot be foreseen whether or not the old and new refrigerants will remain 

parallel in the market for a long period of time. It is also unclear if the bus and train sector will 

follow these trends. The use of hydrocarbons or blends of hydrocarbons has not received 

support from vehicle manufacturers due to safety concerns. 

Sustainable refrigeration

 Refrigeration addresses fundamental human needs. In order to become more sustainable, the 

industry may consider the enhancement of current practices to: minimize the extraction of 

natural resources; avoid the emission of man-made substances such as refrigerants and 

solvents; protect fertile ecosystems from mining, water usage, and landfill of waste; promote 

education for sustainable production and consumption.

 From the persepective of refrigeration, air conditioning, and heat pumps, sustainability mainly 

refers to energy efficiency, use of renewable energy, and other options to reduce GHG 

emissions and the use of natural resources. In aparticular, the responsible choice and 

management of refrigerants are important sustainability aspects.
2014 TOC Refrigeration, A/C and Heat Pumps Assessment Report 14
2014 TOC Refrigeration, A/C and Heat Pumps Assessment Report 15

Abstract Executive Summary

Refrigerants

Current status

Whatever refrigerant is chosen will always have to be a balance between several factors, the 

availability and cost of the refrigerant (and the associated equipment), the system energy efficiency, 

the safety and convenience of applicability, environmental issues and many more. The refrigerant 

options emerging today address the phase-out of ODS, especially HCFC-22, as well as concerns about 

climate change. The perfect refrigerant does not exist and is unlikely to come into existence. Choices

will therefore include existing low GWP refrigerants (e.g. R-717, R-744 or HCs) and the newly 

applied or developed chemicals. Many new alternatives are proposed, which create a challenge in 

finding the right refrigerant for each application. One of the important aspects is that refrigerants with 

a low direct impact on climate change are often flammable to some extent.

What is left to be achieved

The industry will keep searching for the right candidate for each application. In some cases this may 

be as simple as changing the refrigerant, while in other cases this will require redesign of the system or 

even a change of system topology. The search is a trade-off between cost, safety, energy efficiency, 

while limiting the need for redesign. One particular concern is the acceptance of flammability in some 

form or the other.

The way forward

There is a complex selection process ahead, where the market will need to find out which of the many 

proposed new and old refrigerants will be used in each application. Part of the complexity is that the 

market is unlikely to be able to support many different refrigerants for the same application. 

This will result in a period in time, likely to last a couple of decades, where the industry will have to 

work with both the currently established refrigerants as well as new refrigerants addressing ozone 

depletion and/or climate change concerns. In the long run, the number of candidates is likely to fall, 

but it is too early to tell which or even how many of the current refrigerant candidates will survive.

Domestic appliances

Current status

Globally, new refrigerator production conversion from the use of ODS was essentially completed 

by 2008. HC-600a or HFC-134a continue to be the refrigerant options for new production. Initial 

efforts to assess the use of HFC-1234yf in domestic refrigeration have begun, but it is not being

pursued with high priority, as in automotive applications, due to cost implications and 

flammability. 

The heat pump clothe (laundry) dryer (HPCD) using HFC-134a is fastly growing in the EU, with 

manufacturers from both the EU and Japan. HPCDs using R-407C and HC-290 have also been 

introduced. 

What is left to be achieved

It is projected that, by 2020, about 75% of new refrigerator production will use HC-600a (possibly 

with a small share applying unsaturated HFC refrigerants) and the rest will use HFC-134a.

Alternative low GWP refrigerant solutions are being explored for HPCDs. This includes R-744, HC600a and low GWP HFCs.
2014 TOC Refrigeration, A/C and Heat Pumps Assessment Report 16

The way forward

A number of improved energy efficiency design options are fully mature, and future improvements 

of these options are expected to be evolutionary. Extension of these to an all-global domestic market 

would yield significant benefit, but is generally constrained by the availability of capital funds and 

related product cost implications.

Commercial refrigeration

 Current status

Commercial refrigeration is one of the application sectors where the refrigerant demand is the highest 

for servicing, due to the large emission level of refrigerants from supermarket systems. The phase-out 

of HCFC-22, being the dominant refrigerant in Article 5 countries, is important for supermarkets, 

where it can be replaced by high-GWP refrigerants such as R-404A or R-507A or lower GWP options 

from the R-407 family (R-407A, C or F) or the low GWP options such as R-744 or HCs. For standalone equipment, large global companies have taken commitments to phase-out, where low GWP 

HFCs, CO2, and hydrocarbons are the leading choices.

What is left to be achieved

In Article 5 countries, the phase-out of HCFC-22 in the case of condensing units and centralized 

systems asks for rapid refrigerant choices. The current low-GWP options require a significant 

technical background to implement, particularly for e.g., two-stage CO2 systems, this in high ambient 

temperature conditions. So the HFC refrigerant blends, with GWPs ranging from 1500 to 2100 are 

possible immediate options, rather than choosing R-404A or R-507A.

The way forward

Low environmental impact, energy efficiency, simple maintenance, low refrigerant emissions and 

costs are the drivers for the next generation of refrigerants in commercial refrigeration. For the low 

refrigeration capacities of stand-alone systems, many of those criteria are currently met by R-744 or 

HCs. For large refrigeration capacities and for all climate conditions there are still a number of options 

open. The phase-out of high GWP refrigerants is a certainty, the replacement options R-744 and 

hydrocarbons are known, but the replacement low-GWP HFCs options are still not well known.

Industrial systems

Current status

Non-fluorinated refrigerants are widely used in industrial systems, particularly in Europe, Scandinavia 

and North America. The most common refrigerant in these systems is R-717, used in a few cases in 

cascade systems with R-744. Safety standards and regulations are well developed in these markets and 

the incidence of serious injury and fatal accidents is extremely low. The HFC use in these markets is 

confined to specialist niches.

What is left to be achieved

R-717 use is less common in some sub-sectors in Europe and North America, for example in France 

and New Jersey, where regulations make it more difficult to construct new ammonia systems; as a 

result, HCFC-22 was favoured in these jurisdictions. This matches the situation in many Article 5 

countries where R-717 is not widely used, due to a lack of expertise in designing and operating 

systems. There is no inexpensive and widely available low GWP alternative to HCFC-22 for industrial 

systems in the currently available group of HFCs and unsaturated HFCs. The options for addressing 

the HCFC phase-out in Article 5 countries are therefore to find ways to use R-717, to accept the higher 

refrigerant cost for existing HFCs or to develop a suitable low GWP fluorinated refrigerant.
2014 TOC Refrigeration, A/C and Heat Pumps Assessment Report 17

The way forward

The main conclusion drawn from this survey is that greater training of designers, installers, operators 

and maintenance crews is required to facilitate the move away from ozone depleting substances in all 

subsectors of industrial systems. New fluids are unlikely to be developed for the majority of industrial 

systems. The low GWP refrigerants R-717, R-744 and HCs are the dominant choices in several of the 

applications covered, and this is expected to remain in the future. However, there are some niche 

applications that use high GWP HFCs, which applications need to be addressed in the future.

Transport refrigeration

Current status

The vast majority of trucks, trailers, vans and intermodal containers uses the non ozone depleting 

refrigerants R-404A and HFC-134a. While most new vessels use HFC refrigerants, new fishing 

vessels increasingly use R-717 or R-744. However, the installed base at sea is still largely dominated 

by HCFC-22. The industry has been focusing on numerous environmental issues, making progress in 

reductions of engine pollution emissions, fuel consumption, noise levels and refrigerant charge. In 

addition, some manufacturers have made commitments to replace the current refrigerants with R-744 

or R-452A in some first applications.

What is left to be achieved

Refrigerated vessels using HCFC-22 will continue being retrofitted with R-417A, R-422D and R427A. In parallel, the industry will be looking for lower GWP alternatives in all sub-segments 

including R-717 and R-744 in shipping vessels. Cooperation between governments and manufacturers

must continue in order to reflect the very specific transport refrigeration requirements. While 

introducing lower GWP solutions, the industry must ensure the best trade-offs among GWP, 

performance, indirect emissions, life cycle costs, etc., while safety and compliance are in no way 

compromised.

The way forward

In the short term, the industry will progressively introduce lower GWP alternatives to R-404A such as 

R-452A (GWP around 2000, it will be introduced in Europe for new production in 2015), R-448A and

R-449A (GWP around 1400), R-744. In a longer time frame, other HFC blends and -within certain 

charge limits- possibly hydrocarbons or other flammable alternatives will be addressed. Lower GWP 

refrigerants will also be gradually applied in vessels when their applications mature in other segments 

and gain more confidence. Cryogenic and eutectic systems are proven solutions, and will continue 

playing a role on road transport.

Air-to-air air conditioners and heat pumps

Current status

Air-to-air air conditioners and heat pumps: HCFC-22 remains the dominant refrigerant in use, where 

the refrigerant bank for unitary air conditioners is estimated to be in excess of 1 million tonnes. In new 

systems, HCFC-22 is only being used in Article 5 countries. The HFC blend R-410A is the most 

common alternative, further, to a limited extent R-407C along with HFC-134a are used in regions with 

high ambient temperatures. HC-290 is being used in split systems, window and portable air 

conditioners. HFC-32 is being used in split systems and is being proposed for larger ducted and multisplit systems. These various alternatives have also been found to achieve performance approaching, as 

good as or better than HCFC-22.
2014 TOC Refrigeration, A/C and Heat Pumps Assessment Report 18

What is left to be achieved

In general there is still a significant proportion of the sector throughout almost all Article 5 countries 

that remains to be shifted from HCFC-22 to a zero ODP alternative. Because of the high GWP of R410A, investigations into medium and low GWP alternatives are continuing. In cooler climates, R-744 

is available for commercially sized systems and the technology is further being explored. There are a 

large number of new mixtures being considered for air conditioning systems primarily consisting of 

HFCs and unsaturated HFCs, such as R-444B, R-446A and R-447A. Although there is concern over 

the use of R-410A in high ambient temperatures, appropriate design measures can be used to help 

remedy the relatively greater degradation in performance; nevertheless, work is underway to 

investigate this and other refrigerants further.

The way forward

The forthcoming direction remains unclear in terms of which alternatives this sector, sub-sectors and 

regions will settle upon. It is likely that different manufacturers and countries will opt for a variety of 

alternatives before any single option is chosen (if at all). In the meantime, investigations will continue 

into medium GWP flammable HFCs, HFC/unsaturated HFC blends and HCs for normal operating 

conditions as well as high ambient temperature conditions.

Water heating heat pumps

Current status

Air-to-water and water-to-water heat pumps have experienced significant growth in Japan, Australia, 

China, and Europe during the last ten years. HCFC-22 is still used in some Article 5 countries. The 

HFC blends R-410A and R-407C are currently used in Europe and other countries. R-744 heat pump 

water heaters were introduced to the market in Japan in 2001 and have seen a steady growth since then

due to strong government support. In the past, the number of HC-290 applications in Europe has 

decreased, due to the Pressure Equipment Directive, however, recently a range of HC-290 

compressors have become available. R-717 is mainly used for large capacity heat pump systems. 

What is left to be achieved

Based on regulations in Europe, the water heating heat pump industry is looking to alternatives with a 

lower GWP than the one for R-410A. 

The main challenge is to come with an efficient, cost effective, safe and easy to use solution. It is 

expected that other regions will follow the tendency to reduce the GWP value of refrigerants.

The way forward

For water heating heat pumps, HFC-32 or blends with unsaturated HFCs will be studied for future use 

by taking into account the performance, costs and the necessary safety regulations in relation to their 

lower flammability. R-744 systems will be optimised and used wherever possible, taking into account 

costs that will apply. HC-290 and R-600a will be used where possible, taking into account the costs 

involved and safety in regards to flammability.

Chillers

Current status

The phase-out of ozone-depleting refrigerants in chillers is moving along well. The CFCs have been 

essentially phased out for new equipment and the CFC banks are decreasing in existing chillers. The 

current generation of chillers using zero-ODP refrigerants had been introduced without a sacrifice in 
2014 TOC Refrigeration, A/C and Heat Pumps Assessment Report 19

reliability or energy efficiency. HC-290, R-717 and R-744 are also being used in chillers. Water as a 

refrigerant is currently being used in absorption chillers and had been recently announced in vapour

compression based chillers. The use of HCFC-22 in new equipment has been phased out in developed 

countries; many Article 5 countries also have stopped its use in new equipment. Limits set for HCFC22 production and its rising costs have contributed to the conversion of new and existing chillers to 

zero ODP refrigerants. 

What is left to be achieved?

The energy consumption of chillers dominates their environmental impact because the latest 

generation of chillers has low leak rates and, therefore, low direct global warming impact. The issue, 

then, is to determine which of the new refrigerants has high energy efficiency in chillers while being 

safe to use and having acceptable application costs. Major efforts have been launched to propose and 

test new lower-GWP refrigerants to replace the higher-GWP refrigerants currently in use. 

The way forward

Testing of new, lower GWP refrigerants started several years ago and is continuing. At this juncture it 

is not clear which refrigerants may be selected for commercialisation. Tradeoffs are apparent among 

GWP, energy efficiency, safety, and applied cost. Refrigerants that are non-flammable with the A1 

refrigerant safety classification generally have GWPs of 600 or more. Refrigerants with low GWP 

(<150) generally are flammable. All flammable refrigerants require special safety considerations. A2L 

refrigerants will not be widely used without changes to safety standards and building codes. 

Vehicle air conditioning

Current status

Today the overwhelming majority of new AC equipped passenger cars world-wide use HFC-134a. 

The transition from CFC-12 is complete for new systems, but there are still cars in use especially in 

Article 5 countries. In order to meet the EU MAC Directive and to harvest potential US EPA CO2 

credits, OEMs evaluated several refrigerant options for new car (and truck) air conditioning systems. 

As a result, some car manufacturers have started to equip certain models with HFC-1234yf. Owing to 

safety concerns regarding the A2L-refrigerant HFC-1234yf, other car manufacturers work on R-744 

systems in order to introduce them into the market by the year 2017. Both options have GWPs 

enabling the GHG credits in US, they are below the EU threshold of 150 and both can achieve fuel 

efficiency comparable to the existing HFC-134a systems with appropriate hardware and control 

development. Also owing to safety concerns the use of hydrocarbons or blends of hydrocarbons has 

not received support from vehicle manufacturers. Most new bus or train air conditioning systems are 

currently equipped with the refrigerants HFC-134a or R-407C; fleet tests of R-744 systems in buses 

are on-going.

What is left to be achieved

At the end of 2014 it looks likely that more than one refrigerant will be used in the coming years for 

car and light truck air conditioning. HFC-134a will remain largely adopted worldwide, HFC-1234yf 

will continue its growth in new models at least in the near future, other new low GWP synthetic 

refrigerants or refrigerant blends (e.g. R-445A) may be implemented, and R-744 is expected to be 

implemented by German OEMs starting in 2017. 

The way forward

Along with the Global Warming Potential issue the future spreading of the two refrigerants HFC1234yf and R-744 in the worldwide vehicle air conditioning market will be significantly governed by 

additional considerations like safety, costs, regulatory approval, system reliability, heat pump 

capability (especially for electric driven vehicles) and servicing. At the moment, it cannot be foreseen 
2014 TOC Refrigeration, A/C and Heat Pumps Assessment Report 20

whether or not the old and the new refrigerants will see parallel use in the market for a long period of 

time. Without existing regulations it is also unclear whether the bus and train sector will follow these 

trends.

Sustainable refrigeration

Current status

Refrigeration, air conditioning, and heat pump equipment are vital means to address the human 

fundamental needs in areas such as food conservation, food security, health care, water heating, and 

thermal comfort worldwide. There are however a number of negative environmental impacts from the 

use of such equipment that need to be minimized through careful consideration of design, operation, 

and end of life aspects of these equipment and the refrigerants they use. 

What is left to be achieved?

Negative environmental impacts from refrigeration, air conditioning, and heat pump equipment must 

be managed through careful and systematic assessment when choosing new refrigerants, by reducing 

CO2 emissions along the equipment life cycle, and through environmentally sound and socially fair 

end of life procedures.

The way forward

Enhancement towards sustainability demands proper national and regional regulation, expansion of 

voluntary programs aiming higher levels of energy efficiency, adoption of state-of-the-art energy 

management technologies, use of life cycle assessment tools, expansion of awareness and training 

initiatives across the industry value chain.
2014 TOC Refrigeration, A/C and Heat Pumps Assessment Report 21

Executive Summaries of all Chapters

Refrigerants

The chapter discusses and provides tabular summaries for identifiers as well as physical, safety, and 

environmental data for refrigerants and includes brief descriptions of refrigerants treated in this report.

Whatever refrigerant is chosen will always have to be a balance between several factors, the 

availability and cost of the refrigerant (and the associated equipment), the system energy efficiency, 

the safety and convenience of applicability, environmental issues and many more. 

The perfect refrigerant does not exist, and is unlikely to come into existence. Choices will therefore 

include existing very low GWP refrigerants (e.g. R-717, R-744 or HCs) and the newly applied or 

developed chemicals. Many new alternatives are proposed which create a challenge of finding the 

right refrigerant for each application. In some cases this may be as simple as changing the refrigerant, 

while in most cases this will require redesign of the system or even change of system topology. The 

search is a trade-off between cost, safety, energy efficiency, and limiting the need for redesign. One of

the important aspects is that refrigerants with low direct impact on climate change are often flammable 

to some extent.

So far 21 refrigerants obtained standardized designations and safety classifications since the 2010 

RTOC assessment report. One new molecule HCFC-1233zd(E) is in this group of new refrigerants and

is an unsaturated HCFC (also referred to as HCFO) with potential to replace HCFC-123. 

Approximately one quarter of the new refrigerants are blends which are replacements for HCFC-22. 

Of the new refrigerants twelve are blends of saturated HFCs and unsaturated HFCs (HFOs) of which 

seven blends are with class 2L flammability.

The new refrigerants address climate concerns, and ozone depletion concerns with replacement 

refrigerants for ozone-depleting substances.

Domestic appliances 

Under the domestic appliance category, the domestic refrigeration sub-sector is the major 

component and comprises appliances that are broadly used domestically, such as refrigerators, 

freezers and combined refrigerator/freezer products. Small beverage dispensing machines are similar 

products and are commonly included in domestic refrigeration, but represent a small fraction of total 

units. 

Globally, new refrigerator production conversion from the use of ODS was essentially completed by 

2008. HC-600a or HFC-134a continue to be the refrigerant options for new production. No other 

new refrigerant has matured to become an energy-efficient and cost-competitive alternative. 

Refrigerant migration from HFC-134a to HC-600a is expected to continue, driven either by local 

regulations on HFCs or by the desire for reduced global warming impact from potential emissions. 

Excluding any influence from regulatory interventions, it is still projected that by 2020 about 75% 

of new refrigerator production will use HC-600a (possibly with a small share by unsaturated HFC 

refrigerants) and the rest will use HFC-134a.

According to some industrial sources, initial developments to assess the use of HFC-1234yf in 

domestic refrigeration have begun, but it is not being pursued with high priority, as in automotive 

applications. Given the cost disadvantage, flammability and investment requirements for product 

development, HFC-1234yf suffers significant disadvantages. With the lack of activity by 

manufacturers, HFC-1234yf is not likely to displace HC-600a or HFC-134a in the foreseeable future.

Alternative refrigeration technologies for domestic refrigeration continue to be pursued for 

applications with unique drivers such as very low noise, portability or no access to the electrical 
2014 TOC Refrigeration, A/C and Heat Pumps Assessment Report 22

energy distribution network. In the absence of unique drivers, no identified technology is cost or 

efficiency competitive with conventional vapour-compression technology for mass-produced domestic 

refrigerators.

The other domestic appliance covered in this chapter is the heat pump clothe (laundry) dryer 

(HPCD). It is included in this chapter for the first time and the title has been accordingly modified as 

“Domestic Appliances” instead of “Domestic Refrigerators” used earlier. The market for HPCD is 

fast growing in the EU with manufacturers from both the EU and Japan. The current market share of 

HPCDs in Article 5 countries is insignificant. These dryers mostly use HFC-134a as a refrigerant and 

refrigerant charge amounts vary from 200 to 400 g. HPCDs using R-407C and HC-290 have also 

been just introduced. Alternative low GWP refrigerant solutions are being explored, including 

R-744, HC-600a and low GWP HFCs.

Non-Article 5 countries completed conversions of new equipment production to non-ozone depleting 

substances (ODSs) more than 15 years ago. Later, a few Article 5 countries also completed their 

conversion, e.g., India by 2003. Therefore, most products containing ozone depleting refrigerants are 

now approaching the end of their life cycle. Field conversion to non-ODS refrigerants has significantly 

lagged original equipment conversion. The distributed and individual proprietor character of the 

service industry is a barrier to co-ordinated efforts to convert from ODS refrigerants. Field service 

procedures typically use originally specified refrigerants. Refrigerant blends developed specifically for 

use as drop-in service alternatives have had limited success. 

Both mandatory and voluntary energy efficiency regulation programs catalysed industry product 

efficiency development efforts. A number of improved energy efficiency design options are fully 

mature, and future improvements of these options are expected to be evolutionary. Extension of 

these to an all-global domestic market would yield significant benefit, but is generally constrained 

by availability of capital funds and related product cost implications.

Commercial refrigeration

Commercial refrigeration can be broadly classified as three different groups of systems: centralised 

systems (refrigerant is field charged) installed in supermarkets, condensing units (refrigerant is field 

charged) installed mainly in small shops and restaurants, and self-contained or stand-alone units 

(refrigerant is factory charged). On a global basis, HCFC-22 continues to represent a large refrigerant 

bank in commercial refrigeration and is used at all temperature levels. The most widely used HFC is 

R-404A and this for all temperature levels. Over the last decade, HCs --for low refrigerant charge 

systems-- and CO2 --for supermarkets-- have taken significant market share, especially in Europe. In 

parallel, progress has been made to improve energy efficiency and leak tightness especially for 

centralized systems. The progressive phase-out of HCFC-22 in developing countries requires making 

informed choices on the best replacement options.

Stand-alone Equipment: Even if they have very different GWPs, HFC-134a and R-404A can be 

expected to be phased-out progressively in developed countries. Lower GWP HFC and HFC blends, 

hydrocarbons and CO2 are replacing R-404A and HFC-134a in new stand-alone equipment. 

Minimum energy standards have been issued or updated in many countries making a new competition 

between manufacturers in order to reach higher energy efficiency in stand-alone systems. 

Condensing Units: Condensing units are designed for several capacities and are standardized 

equipment; their cooling capacities vary from 5 to 20 kW with a refrigerant charge varying from 1 to 5 

kg. HCFC-22 is still the most used refrigerant in all Article 5 countries. For new systems, R-404A is 

still the leading choice, and intermediate blends such as R-407A or R-407F are proposed as immediate 

options to replace R-404A. Global companies are now offering hydrocarbon condensing units for 

smaller capacities.
2014 TOC Refrigeration, A/C and Heat Pumps Assessment Report 23

Supermarket systems: The size of centralised systems can vary from refrigerating capacities of about 

20 kW to more than 1 MW relative to the size of the supermarket. Refrigerant charges range from 40 

up to 3000 kg per installation. In Article 5 countries, HCFC-22 is still the dominant refrigerant used in 

centralised systems. In Europe, new systems have been mainly charged with R-404A; R-744 is now 

taking a significant market share with improved energy efficiency by using two-stage systems, options 

well known from industrial refrigeration. For small and medium size supermarkets, the so-called 

“booster system” has been designed to use CO2 at the low and the medium temperature levels. For 

large supermarkets, the cascade system is preferred with CO2 at the low temperature level and CO2 or 

HFC-134a at the medium temperature level. Distributed systems are also quite common, gaining 

market share with improved energy efficiency, lower charge levels and lower emission rates. Indirect 

systems are also popular in order to limit the refrigerant content by more than 50% and to drastically 

lower refrigerant emission levels. For developing countries, the important issue remains the 

replacement of HCFC-22, either for retrofit or for new installations. Blends such as R-407A or R-407F 

constitute options offering significantly lower GWP than R-404A and R-507A. 

Industrial systems

The majority of large industrial systems use R-717 as the refrigerant. When R-717 is not acceptable in 

direct systems in these countries, options include R-744 or glycol in secondary systems or HCFCs or 

HFCs in direct systems. In countries where R-717 has not been the preferred solution, or in market 

segments with smaller systems, the transition from HCFC-22 is not straightforward. It requires 

acceptance of higher cost fluorocarbons in systems similar to the types used with R-22 or the adoption 

of more expensive systems with the cheaper refrigerants R-717 and R-744. This transition is slow and 

is constrained by a lack of trained personnel and lack of experience of the local end-users. It has been 

facilitated by corporate policy from multinational food and beverage manufacturers. The process of 

moving from HCFCs to zero ODP, low GWP alternatives would be accelerated by a concerted 

education and training programme including operational experience and lessons learned from existing 

systems. This conclusion has been reinforced by several recent fatal accidents in Article 5 countries. 

These accidents appear to be caused by the acceptance of low standards of safety that would not be 

acceptable in more mature markets. Suitable safety standards already exist, for example those 

published by the International Organisation for Standardization (ISO). 

In markets where R-717 is accepted as the preferred refrigerant there is no indication of any likelihood 

of new refrigerants gaining any significant market share. It is self-evident that if the current range of 

HFC fluids that could be used in these applications are being avoided due to concerns about refrigerant 

price and long term availability in bulk quantities then new fluids, which are expected to be even more 

expensive than current HFCs will not be any more successful. There are a few exceptions to this 

general rule. For example, HFC-1234ze(E) has been demonstrated in large district heating systems as 

a possible replacement for HFC-134a, however its performance is not any better than HFC-134a which 

is already limited in application and efficiency compared for example with R-717. HFC-1234ze(E) has 

also been demonstrated in centrifugal chillers which could be used in process cooling or in district 

cooling installations. This may be a key player in addressing the challenge of rapid market growth in 

the Gulf Co-operation Countries over the next twenty years.

The industrial sectors covered by this chapter are too diverse to facilitate the level of development 

expenditure required to bring a new fluid to market. It therefore follows that if any new development 

gains market share in industrial systems, it will be a fluid developed for some other purpose, either as 

a refrigerant in smaller mass-market systems or as a foam-blowing agent, solvent or other specialty

chemical. Apart from absorption systems there is no significant growth of other not-in-kind cooling or 

heating solutions.

Transport refrigeration 

Transport refrigeration is a small segment comprising delivery of chilled or frozen products by means 

of trucks, trailers, vans, intermodal containers and boxes. It also includes the use of refrigeration and 
2014 TOC Refrigeration, A/C and Heat Pumps Assessment Report 24

air conditioning on merchant, naval and fishing vessels above 100 gross tonnes (GT) (over about 24 m 

in length).

Since 2010, most development has taken place in the intermodal container industry. Although many of 

the lessons are applicable to road transport, differences between containers and road vehicles should 

not be neglected, and may lead to different system solutions and (possibly) to different refrigerant 

choices. 

For new systems, hydrocarbons offer high energy efficiency, but the safety risks in transport 

refrigeration applications appear significant and must be mitigated. On the other hand, R-744 has been 

tested in the field since 2011. Its non-flammable characteristics make R-744 attractive, but the gap in 

efficiency in high ambient temperatures and the limited component supply base are limiting its 

penetration into the market. 

Recently there has been an initiative to consider the design and service best practices for flammable 

and high pressure refrigerants which it is hoped will lead to a fast track ISO standard on how these 

refrigerants can be applied to intermodal container refrigeration. The framework of this initiative has 

not yet been set.

In the case of a regulation banning the use of refrigerants above a certain GWP level (as in the EU), 

HFC blends are likely to play a role as a retrofit to R-404A and (possibly) HFC-134a systems: their 

GWP is significantly lower than R-404A and performances are relatively close. Candidates include but 

are not limited to R-407A, R-407F, R-448A, R-449A and R-452A.

One also sees “non-conventional” solutions such as open loop systems or eutectic systems. These 

solutions offer specific advantages in some transport routes, furthermore, the fact that vehicles are 

HFC free and that the supporting installation can be HFC free will continue making them attractive.

New information about vessel type and existing refrigerant charge is provided based on the 2012 IMO 

study. It appears that the differences in type are large and that segmentation will be needed in future. 

The designers must factor in specific safety requirements, space and reliability, but in general, they 

closely follow developments in industrial and air-conditioning systems.

Based on research, the road vehicle fleet size previously estimated at 4 million --in the 2006 and 2010 

RTOC Assessment Reports-- has been downsized to 2 million. This changes the overall picture in that 

the refrigerant banks in vessels almost double the banks in other transport sub-segments.

The bottom line is that while CFCs and HCFCs can still be found in older equipment, virtually all new 

transport refrigeration systems continue to utilize HFCs, with a prevalence of HFC-134a and R-404A. 

Some systems aboard vessels utilize HCFC-22 in both non-Article 5 and Article 5 countries.

Air-to-air air conditioners and heat pumps

On a global basis, air conditioners for cooling and heating (including air-to-air heat pumps) ranging in 

size primarily from 2.0 kW to 35 kW (although in some cases up to over 750 kW) comprise a 

significant segment of the air conditioning market. Nearly all air conditioners and heat pumps 

manufactured prior to 2000 used HCFC-22. Most Article 5 countries continue to utilise HCFC-22 as 

the predominant refrigerant in air conditioning applications, although several major producing 

countries within Asia, Middle East and South America are now initiating HCFC Phase-out 

Management Plans (HPMPs) to introduce non-ODS alternatives.

R-410A is the dominant alternative to HCFC-22 in air-conditioners and is being used in manufacturing 

in most non-Article 5 and several Article 5 countries. This particularly is the case in China, where 

there is a large export market satisfying demand in non-Article 5 countries. However, R-410A units 

are not widely sold in the domestic market because of their higher cost. Whilst the use of R-407C in 

new product designs was common early on because it required minimal design changes, it is currently 
2014 TOC Refrigeration, A/C and Heat Pumps Assessment Report 25

decreasing although it is still preferred in for regions with high ambient temperatures. The other main 

alternatives under consideration are HC-290, HFC-32, R-744, HFC-161 and a number of blends of 

HFCs and unsaturated HFCs such as R-444B, R-446A and R-447A (but also many currently without 

R-number designations). 

Except for R-744, all of the medium and low GWP alternatives are flammable and should be applied 

in accordance with appropriate regulations and/or safety standards (that are continuously under 

development), considering refrigerant charge amount, risk measures and other special construction 

requirements. Some safety standards limit the system charge quantity of any refrigerant within 

occupied spaces; in some countries the application of such guidelines are voluntary although in some 

they are mandatory, whilst flammable gas regulations take precedence. Where national regulations 

place controls on the use of flammable substances, they normally require a risk-based approach and do 

not impose arbitrary charge size limits (e.g., EU Atex directive). Most manufacturers apply the safety 

standards. Some countries are introducing bans on imports of HFC-containing air conditioners.

HC-290 and HC-1270 are mainly considered for systems with smaller charge sizes, whilst the 

operating pressures and capacities are similar to HCFC-22 and the efficiency is higher than HCFC-22. 

Split air conditioning systems using HC-290 have been available in Europe and Australia, are in 

production in India and HCFC-22 equipment production capacity is being converted to HC-290 in 

China (however, with limited output at present). R-744 is considered to have limited applicability for 

air conditioning appliances in Article 5 countries, due to the reduced efficiency when the ambient 

temperature approaches or exceeds about 31°C. There is continuing research on cycle enhancements 

and circuit components, which can help improve the efficiency under such conditions, although they 

can be detrimental to system cost. HFC-161 is currently under evaluation for systems with smaller 

charge sizes due to flammability. The operating pressure and capacity is similar to HCFC-22 and the 

efficiency is at least as high as HCFC-22, although there is concern over its stability. HFC-32 is 

currently on the market for various types of air conditioners and has recently been applied in split units 

in several countries and some OEMs are also considering it for other types of systems. The operating 

pressure and capacity are similar to R-410A and its efficiency is similar or better than that of R-410A. 

There are various proprietary mixtures targeted for air conditioning applications, which comprise, 

amongst others, HFC-32, HFC-125, HFC-134a, HFC-152a, HFC-161, HFC-1234yf, HFC-1234ze, 

HC-600a, HC-600, H-1270 and HC-290. Some mixtures have been assigned R-numbers, such as R444B, R-446A and R-447A, whilst most are still under development. These mixtures tend to have 

operating pressures and capacities similar to HCFC-22 or R-410A, with GWPs ranging from 150 to 

around 1000 and flammability class 1 (for higher GWPs) and class 2L (medium GWPs). Currently, 

most of these mixtures are not commercially available on a broad scale and adequate technical data is 

not yet in the public domain. Other low GWP single component HFCs, such as HFC-1234yf and HFC152a, are unlikely to be used extensively as a replacement for HCFC-22 in air conditioners principally 

because of their low volumetric refrigerating capacity.

A major concern in some regions is the efficacy of the various alternatives to HCFC-22 in high 

ambient conditions (particularly R-410A). Whilst this problem for R-410A can be addressed through 

design and selection, work has fairly recently been carried out on a number of other alternatives, such 

as HC-290 and some of the new blends of HFCs and unsaturated HFCs, that show that performance 

degradation with higher ambient temperatures is similar to or not notably worse than with HCFC-22. 

Another issue is the possible impact on required refrigerant charge, where hotter regions can imply 

greater heat loads, larger system capacity and thus larger refrigerant charge; limits on refrigerant 

charge may be approached at smaller capacities, where additional (safety) measures would then have 

to be applied to the equipment. Systems using low-GWP refrigerants are not currently available for 

large capacity systems in high ambient temperature regions. 

Water heating heat pumps

Within the category of water heating heat pumps there are heat pump water heaters, space heating heat 

pumps and combined space and hot water heat pumps. The required warm water temperature affects 
2014 TOC Refrigeration, A/C and Heat Pumps Assessment Report 26

the selection of refrigerant. Heat pump systems are more efficient at lower sink temperatures, but each 

product must fulfil the required operating temperature. The main use of heat pumps is to replace fossil 

fuel water heating systems. This is done with the purpose of reducing life time cost and/or to reduce 

the impact of greenhouse gas emissions. To compete with fossil fuel water heating systems, cost and 

energy efficiency are the most important factors and have direct impacts on the selection of the 

refrigerant. 

Most heat pumps commercialised today make use of non-ODS refrigerants. Refrigerants used are 

R-410A, HFC-134a, R-407C, HC-290, HC-600a, R-717 and R-744. The majority of new equipment 

uses R-410A. In some Article 5 countries, HCFC-22 is being used due to its favourable 

thermodynamic properties and high efficiency. There are no technical barriers in replacing HCFC-22 

by a non-ODS. The technical and process changes related to pressure, lubrication and contamination 

control are well known. Replacements are commercially available, technically proven and energy 

efficient. All replacements have a similar or lower environmental impact. R-410A has a slightly higher 

GWP but the required charge is less than HCFC-22. The issue of high ambient temperature conditions 

is of minor or no importance for water heating heat pumps. The main parameters to select the 

alternatives and the main issue to switch over from HFCF-22 are efficiency, cost effectiveness, 

economic impact, safe use and easiness of use. Replacements such as HFC-32 and other low-GWP 

HFC blends are under way to become commercially available. 

HFC-134a, R-744 and HFC blends R-407C, R-417A and R-410A are commercially available solutions 

that have the highest grade of safety and easiness to use. R-410A is most cost effective for small and 

medium size systems, while for large systems HFC-134a is most efficient. R-407C and R-417A are 

the easiest alternatives for HCFC-22 from a design point of view, but cannot compete with the other 

HFC-solutions. 

Chillers

Chillers have low emission rates and low direct global warming impact. The issue, then, is to 

determine which of the new refrigerants has high energy efficiency in chillers while being safe to use 

and having acceptable application costs. Though most HFCs in use today are considered to have 

relatively high GWPs, this is not a governing factor for chillers because emissions are minimal. 

The required global phase-out of HCFCs and the need to manage the lifetime operation of HCFCbased equipment, coupled with concerns to reduce global warming, continue to drive the transition 

from ozone depleting substance (ODS) refrigerants. The refrigerants that were used in the transition 

generally were HFCs with global warming potentials (GWPs) that are sufficiently high to cause 

environmental concerns, so a second transition has begun. Major efforts have been launched to 

propose and test new, lower GWP refrigerants to replace higher GWP refrigerants. A number of 

candidates have been proposed and are in the early stages of testing as possible replacements for 

higher-GWP HFCs.

The new candidates generally are unsaturated HFCs or blends which may contain HFCs, HCs, and/or 

unsaturated HFCs. A number of the new candidates have an A2L safety rating which is associated 

with flammability. They have a low flame velocity, distinguishing them from more flammable 

chemicals such as propane (HC-290). It is too early to tell which lower-GWP refrigerants will be 

successful as replacements for the higher GWP HFCs now in use. The parameters to be sorted out 

require balancing energy efficiency, flammability (including application standards and regulations), 

GWP values, cost, worldwide availability, retrofit considerations, and level of system design 

complexity that is required to use the new candidates successfully.

Vehicle air conditioning

In spite of existing regulations in the US (supporting the use of low-GWP refrigerants) and legislation 

in Europe (banning the use of refrigerants with GWP > 150), the overwhelming majority at present 
2014 TOC Refrigeration, A/C and Heat Pumps Assessment Report 27

(year 2014) of the newly sold passenger cars and light trucks worldwide are still equipped with air 

conditioning systems, which use HFC-134a as refrigerant.

At the end of 2014 it looks likely that more than one refrigerant will be used in the coming years for 

car and light truck air conditioning: HFC-134a will remain largely adopted worldwide, HFC-1234yf 

will continue its growth in new models at least in the near future, other new low GWP synthetic 

refrigerants or refrigerant blends (e.g. R-445A) may be implemented and R-744 is expected to be 

implemented by 2017. All options have GWPs below the EU threshold and can achieve fuel 

efficiencies comparable to modern HFC-134a systems. Currently it cannot be forecast whether or not 

all these refrigerants will see parallel use in the market for a long period of time. It is also unclear 

whether the bus and train sector will follow these trends.

The global warming impact is almost identical for the above mentioned refrigerant options when 

considered on a global basis and in comparison to the CO2 tailpipe emissions. Adoption of any of the 

refrigerant choices would therefore be of similar environmental benefit. The decision of which 

refrigerant to choose will have to be made based on other considerations. Here, especially safety, cost, 

and system reliability are important concerns, but also other aspects have to be taken into account, like 

regulatory approval, heat pump capability, suitability for hybrid electric vehicles, servicing, and risk of 

illegal use of high-GWP refrigerants in systems designed for low-GWP refrigerants. In the year 2012, 

HFC-1234yf seemed to be the worldwide accepted alternative to HFC-134a. However, based on new 

findings regarding the on-the-road flammability of HFC-1234yf (classified as A2L) most German 

OEMs abandoned this option and decided to further develop and eventually use R-744 in their future 

air conditioning systems. Further, one Japanese OEM decided to not use HFC-1234yf on the European 

market. Similar to the 2012 acceptance of HFC-1234yf, these decisions are subject to change as the 

OEMs continue their pursuit of alternative refrigerants to meet regulatory requirements and other 

concerns mentioned above.

Owing to safety concerns hydrocarbons and their blends are not considered as viable refrigerant 

options by OEMs. Although HFC-1234yf is also flammable, it has a lower heat of combustion, 

burning velocity and minimum ignition energy compared to hydrocarbons, and has been the subject of 

several safety assessments by OEMs and other research bodies. Today, some OEMs use HFC-1234yf 

as refrigerant in some of their car models.

OEMs and suppliers do also work on future not-in-kind refrigeration concepts. However, the 

development status of such refrigeration technologies, like sorption, thermoelectric or magneto caloric 

systems, are still far away from serial production and presently show very poor price competitiveness 

and poor system performance and efficiency. These concepts are briefly discussed in Annex C of this 

report.

The increasingly rapid evolution of hybrid electric vehicles and electric vehicles with reversible air 

conditioning and heat pump cycles, which use semi hermetic electrically driven compressors 

introduces new challenges for any new alternative refrigerant.

At present, no regulations exists that control the use of fluorinated greenhouse gases as refrigerants for 

MAC systems in buses and trains. It is likely that the choice of refrigerant of passenger car air 

conditioning systems, as well as developments in the stationary heat pump market, will influence the 

choice of refrigerant for air conditioning systems in buses and trains.
2014 TOC Refrigeration, A/C and Heat Pumps Assessment Report 28

Sustainable refrigeration

Refrigeration, air conditioning, and heat pump equipment are vital means for sustainability to 

address the fundamental needs of humans in areas such as food conservation, food security, 

healthcare, water heating, and thermal comfort worldwide. There are, however, a number of 

negative environmental impacts from the use of this equipment that need to be minimized through 

careful consideration of design, operation, and end of life aspects of these equipment and the 

refrigerants they use. 

The most relevant environmental impacts can be minimized by:

a. The use of assessment tools enabling manufacturers to plan for continual improvement of 

the design and operation of their equipment. A number of available assessment tools are 

referenced in this chapter. 

b. The careful choice of refrigerants with lower environmental impact, both direct (due to 

chemical composition) and indirect (such as use of energy and materials). The wide range 

of gases already available in the market, as well as those in the development process, 

stresses the need of conveying updated, unbiased information to both product designers, 

service technicians, and users through initiatives fostered by local governments and 

industry associations.

c. The proper management of the selected refrigerants in response to growing environmental, 

regulatory, and economic concerns associated with refrigerant emissions, through:

 Charge minimization through simple measures such as checking the amount of 

refrigerant being charged, or by innovative technologies such as cascade systems and 

secondary loops; 

 Improved design for leak tightness; 

 Care taken during manufacturing, installation, service, and maintenance; 

 Refrigerant conservation, using commercially available equipment for recovery, 

recycling and recovery, as well as destruction of refrigerants at the end of life.

d. The reduction of CO2 emissions from energy use, achievable through:

 Minimum energy efficiency performance standards applied through national 

regulation;

 The use of renewable energy sources; and

 Better energy management related to smart grid technologies, waste energy analysis, 

heat recovery, and anti-cyclical storage.

e. The adoption and enforcement of responsible national and regional policies, legal 

requirements, and voluntary initiatives aiming to reduce refrigerant emissions through ban 

on venting and other measures.

f. Environmentally sound end-of-life procedures in response to the growing demand of 

national and regional regulations. 
2014 TOC Refrigeration, A/C and Heat Pumps Assessment Report 29

Chapter 1

__________________________________________________________

Introduction

Chapter Lead Authors

Lambert Kuijpers

Roberto de A. Peixoto
30 2014 TOC Refrigeration, A/C and Heat Pumps Assessment Report
2014 TOC Refrigeration, A/C and Heat Pumps Assessment Report 31

1 Introduction

1.1 Montreal Protocol developments

In 1981, the United Nations Environment Programme (UNEP) began negotiations to develop 

multilateral protection of the ozone layer. These negotiations resulted in the Vienna 

Convention for the Protection of the Ozone Layer, adopted in March 1985. In September 

1987, 24 nations, amongst which the United States, Japan, the Soviet Union, certain country 

members of the European Community, the developing countries Egypt, Ghana, Kenya, 

Mexico, Panama, Senegal, Togo and Venezuela, as well as the European Community, signed 

the Montreal Protocol on Substances that Deplete the Ozone Layer. The Montreal Protocol 

entered into force on January 1, 1989. This international environmental agreement originally 

limited production of specified CFCs to 50 percent of the 1986 levels by the year 1998 and 

called for a freeze in production of specified halons at 1986 levels starting in 1992. By April 

1991, 68 nations had already ratified the Protocol: these countries represented over 90 percent 

of the 1991 world production of CFCs and halons.

Shortly after the 1987 Protocol was negotiated, new scientific evidence conclusively linked 

CFCs to the depletion of the ozone layer and indicated that depletion had already occurred. 

Consequently, many countries called for further actions to protect the ozone layer by 

expanding and strengthening the original control provisions of the Montreal Protocol, and 

they decided that a first assessment should be carried out in the year 1989. Numerous 

assessments followed.

The 23rd Meeting of the Parties, held in Montreal in Bali, Indonesia, November 2011, 

considered the 2010 Assessment Reports, next to a large number of other issues. Parties 

decided to request the Assessment Panels to update their 2010 reports in 2014 and submit 

them to the Secretariat by 31 December 2014 for consideration by the Open-ended Working 

Group and by the Twenty-Seventh Meeting of the Parties in 2015 (MOP-27). In the relevant 

Decision (XXIII/11), the Parties also requested the TEAP (and its TOCs) in paragraph 6 to 

consider potential areas of focus:

(a) The impact of the phase-out of ozone-depleting substances on sustainable development, 

particularly in Parties operating under paragraph 1 of Article 5 and countries with 

economies in transition;

(b) Technical progress in all sectors;

(c) Technically and economically feasible choices for the reduction and elimination of 

ozone-depleting substances through the use of alternatives, taking into account their 

impact on climate change and overall environmental performance;

(d) Technical progress on the recovery, reuse and destruction of ozone-depleting 

substances;

(e) Accounting for: the production and use in various applications of ozone-depleting 

substances; ozone-depleting substances in inventories; ozone depleting substances in 

products; and the production and use in various applications of very short-lived 

substances;

(f) Accounting of emissions of all relevant ozone-depleting substances with a view to 

updating continuously use patterns and co-ordinating such data with the Scientific 

Assessment Panel in order periodically to reconcile estimated emissions and 

atmospheric concentrations.

Together with the Science and Environmental Effects Assessment reports, the 2014 TEAP 

Assessment Report --together with the 2014 TOC Assessment Reports-- forms the direct 

response to the above-mentioned decision.
32 2014 TOC Refrigeration, A/C and Heat Pumps Assessment Report

1.2 The UNEP Technology and Economic Assessment Panel

Four Assessment Panels were defined in the original Montreal Protocol as signed 1987, i.e. 

Assessment Panels on (1) Science, and on (2) Environmental Effects, (3) a Technical 

Assessment and (4) an Economics Assessment Panel. The Panels were established in 1988-

89; their Terms of Reference can be found in the Meeting Report of the 1st Meeting of the 

Parties, held in Helsinki in 1989. Under the Technical Assessment Panel five Subsidiary 

Bodies, the so called Technical Options Committees were defined (see Meeting Report of the 

First Meeting of the Parties in Helsinki). The Technical and Economics Assessment Panels 

were merged after the Meeting in London in 1990 to the Technology and Economic 

Assessment Panel. At the Meeting in Copenhagen, it was decided that each Assessment Panel 

should have up to three co-chairs, with at least one from an Article 5 country. After the 

discussions on methyl bromide held at the meeting in Copenhagen, the Methyl Bromide 

Technical Options Committee was founded at The Hague in early 1993. From 1993 until 

2001, the UNEP Technology and Economic Assessment Panel (TEAP) had 7 standing 

Technical Options Committees (TOCs). In 2001, the Economics Options Committee was 

disbanded, which resulted in a number of 6 Committees. In 2005, the Aerosols TOC and the 

Solvents TOC were disbanded, and a new Medical TOC and a Chemicals TOC were formed 

by merging certain parts of the Aerosols and the Solvents TOC, and replenishing the 

membership with additional, new experts. Currently there are the following TOCs: 

1. Chemicals Technical Options Committee

2. Flexible and Rigid Foams Technical Options Committee

3. Halons Technical Options Committee

4. Medical Technical Options Committee 

5. Methyl Bromide Technical Options Committee

6. Refrigeration, A/C and Heat Pumps Technical Options Committee

Where, originally, the Panels were considered as the bodies that should carry out assessments 

pursuant to Article 6 under the Montreal Protocol (at least every four years), it is particularly 

the TEAP that has become a “standing advisory group” to the Parties on a large number of 

Protocol issues. The evolving role of the TEAP -and its Technical Options Committees and 

other temporary Subsidiary Bodies- can be explained by the fact that the focus of the 

Montreal Protocol has shifted from introducing and strengthening control schedules (based 

upon assessment reports) to the control of the use of controlled chemicals and to compliance 

with the Protocol. This implies the study of equipment, of use patterns, of trade, imports and 

exports etc. In the case of the Medical and the Methyl Bromide Technical Options 

Committees, the emphasis of the work has largely shifted to the evaluation and 

recommendation of certain essential (MTOC) and critical (MBTOC) use applications.

At the MOP-19 in Montreal an important Decision was taken on the accelerated phase-out of 

HCFCs in Article 5 countries. In the decision, a reduction schedule for production and 

consumption was defined for the period 2013-2030, with a freeze in 2013 and a servicing tail 

until 2040. Apart from the specific percentages, the decision mentioned:

“....To encourage Parties to promote the selection of alternatives to HCFCs that minimize 

environmental impacts, in particular impacts on climate, as well as meeting other health, 

safety and economic considerations” and 

“....To agree that the Executive Committee, when developing and applying funding criteria 

for projects and programmes, and taking into account paragraph 6, give priority to costeffective projects and programmes which focus on, inter alia: 
2014 TOC Refrigeration, A/C and Heat Pumps Assessment Report 33

“Phasing-out first those HCFCs with higher ozone-depleting potential, taking into account 

national circumstances”, and 

“Substitutes and alternatives that minimize other impacts on the environment, including on 

the climate, taking into account global-warming potential, energy use and other relevant 

factors.”

In this decision it became clear that climate considerations, i.e., a focus on substitutes with an 

overall low climate impact, became very important in the conversion away from HCFCs. 

As a first consequence of Decision XIX/6, the Parties requested the TEAP and its RTOC in 

Decision XIX/8, to report on the status of substitutes and alternatives to HCFCs under high 

ambient conditions. The report was done by a Subcommittee of the RTOC, and submitted to 

Parties in a preliminary form in 2009 and in its final form in 2010. 

In 2008, Parties requested the TEAP and its committees, in Decision XX/8, to look at the 

status of alternatives in the different sectors and subsectors, as covered by the six Technical 

Options Committees. In a report by a Task Force, a large amount of material was 

summarised; this report also contained updated information on banks and emissions from all 

sectors, including refrigeration, AC and heat pumps as well as foams. In 2009, in Decision 

XXI/9, on HCFCs and environmentally sound alternatives, Parties requested the TEAP to 

update the information from the XX/8 report, and to report on the status of low GWP 

alternatives for the replacement of HCFCs, and to report on the comparison of performances 

of high and low GWP alternatives. TEAP established again a Task Force, which reported on 

the definition of the term “low-GWP” and “high-GWP”, and particularly on the 2009/2010 

status of (low GWP) substitutes and alternatives to HCFCs in all sectors and subsectors. In 

2011, 2012, 2013, the Parties requested a number of Task Force reports under Decisions 

XXIII/9, XXIV/7 and XXV/5. It should be noted that the request in Decision XXIII/9 was 

made in parallel with the request for new assessment reports to be submitted by the end of 

2014, requesting information on the costs of alternatives to HCFCs, on alternatives that were 

technically proven, economically viable, environmentally benign, and which could be used in 

high ambient temperature conditions. 

The information requested for these Task Force reports was very much related to the 

information requested on how to deal with a conversion from ODS (particularly HCFCs) to 

environmentally sound alternatives (which definition includes low global warming 

characteristics). For the report under Decision XXIV7, Parties requested to update 

information on alternatives, but also to identify barriers and restrictions to the adoption of 

environmentally sound alternatives, as well as an estimation of the approximate amount of 

alternatives with negative environmental impacts that could be avoided. The Task Force 

XXIV/7 report elaborated on the methodological approach, gave a long description of the 

alternatives that would be environmentally sound, in particular for the RAC, foams, as well as 

the fire protection and solvents sectors. It also determined amounts on alternatives with 

negative environmental impacts that could be avoided (e.g. it was estimated that, integrated 

over the period 2013-2020, 15% could be avoided in the RAC sector).As a result of this 

XXIV/7 reporting, in 2013, the Parties requested a new report under Decision XXV/5. The 

Terms of Reference mentioned that it should report on (1) alternatives that should be 

commercially available, technically proven and environmentally sound, easy and safe to use 

(also in high urban densities), alternatives that would be economically viable and cost 

effective. It also mentioned to again report on the suitability of alternatives under high 

ambient temperature conditions. The decision also requested to assess the economic costs, 

implications and environmental benefits of various scenarios of avoiding high GWP 

alternatives. The decision further asked to expand on the demand issue and to report on 

scenarios for the current and future demand of alternatives. 
34 2014 TOC Refrigeration, A/C and Heat Pumps Assessment Report

The XVV/5 reported in two steps, with a draft report for the OEWG in 2014 and a final report 

for the MOP of the Parties in that same year. The report presented a long list of alternatives 

available and alternatives that would become available, it listed GWPs and costs for 

alternatives as far as information was available and mentioned information related to the 

operation under high ambient conditions -- where available. It reported on alternatives and 

future developments for the refrigeration, AC, foams, fire protection, medical uses and 

solvents sectors.

The XXV/5 report also presented demand scenarios for the period up to 2030 for 

environmentally sound alternatives to ODS for the sectors refrigeration and AC and foams. 

BAU scenarios were defined for non-Article 5 and Article 5 Parties, and it was decided to 

present two mitigation scenarios for the demand, based upon bans for certain refrigerant 

(blowing agent) chemicals in certain years. In these scenarios it was shown that the demand in 

the RAC sector was very much dominant over the demand in other sectors. The assumption of 

two types of mitigation scenarios showed that the growth of high global warming alternatives 

could be curbed. This would be possible with certain plausible (partly already ongoing) 

measures in non-Article 5 countries. Furthermore, stringent (but still plausible) measures as of 

2020-2030 could lead to a real reduction of the demand for non-environmentally benign 

alternatives during the period 2020-2030 in Article 5 countries. 

As an example, the XXV/5 Task Force reported that the first (MIT-1) scenario could 

cumulatively deliver a saving of 3,000 Mtonnes CO2-eq. by 2030 and that the second (MIT-2) 

could deliver 11,000 Mtonnes CO2-eq over that same time period.

As a result of the discussions concerning the information provided in the XXV/5 report, 

Parties requested an update of the report via Decision XXVI/9. This report is expected to be 

delivered by a TEAP Task Force in the course of 2015, that is, after that this 2014 Assessment 

Report has been published. Amongst other information, the XXVI/9 report will use 

information from the XXV/5 Task Force report and from the RTOC 2014 Assessment Report. 

The information collected for the various Task Force reports mentioned above (XXIII/9, 

XXIV/7 and XXV/5) has, of course, been used in the preparation of the 2014 TOC 

Assessment Reports, in particular for the 2014 RTOC Assessment Report. The final versions 

of the Task Force reports are available on the Internet (http://www.unep.org/ozone).

Where Terms of Reference for the TEAP and its TOCs had been drafted in 1996, Parties, in 

Decision XXII/22, requested the TEAP to report on guidelines for nominations, on the 

appropriate expertise when appointing members etc. The report by TEAP resulted in Decision 

XXIII/10 (2011), which requested the Panel to update information on nominations and 

operational procedures of the TEAP and its technical committees, also related to the duration 

of appointments and various other procedures. Delivery of the TEAP XXIII/10 report resulted 

in a new Decision XXIV/8 (2012), which gave –in an 8 page long description- (updated) 

Terms of Reference, a code of conduct and disclosure and conflict of interest guidelines for 

the TEAP and its technical options committees and temporary subsidiary bodies. Decision 

XXV/6 requested information on issues such as the implementation as well as the proposed 

configuration of the TOCs as of 1/1/2015; it also requested to streamline annual progress 

reporting. In its future operations, after delivery of this 2014 Assessment report, the RTOC 

will consider all elements that have been mentioned in these decisions, when deciding on the 

organisation of the Refrigeration, AC and Heat Pumps Technical Options Committee, its size, 

expertise and further operational procedures. 

The 2014 Technical and Economic Assessment has been carried out by the Technology and 

Economic Assessment Panel and its six Technical Options Committees. The six Committees 

consisted of more than 120 experts from a large number of countries (for a list, see the annex 
2014 TOC Refrigeration, A/C and Heat Pumps Assessment Report 35

to the Technology and Economic Assessment Panel Report 2014). The 2014 Refrigeration, 

AC and Heat Pumps Assessment forms an important part of all the 2014 Assessment efforts. 

Most Technical Options Committee reports (including the 2014 Refrigeration, AC and Heat 

Pumps Assessment Report) have been subject to a peer review before final release. The final 

version of the reports will be distributed internationally by UNEP and will also be available 

on the Internet (http://www.unep.org/ozone).

1.3 The Technical Options Committee Refrigeration, A/C and Heat Pumps

This Technical Options Committee Assessment Report on Refrigeration, A/C and Heat 

Pumps (hereafter called “RTOC Assessment Report”) forms part of the UNEP review 

pursuant to Article 6 of the Montreal Protocol.

It is part of the 2014 assessment work of the Technology and Economic Assessment Panel 

(requested by the Parties in Montreal (Decision XXIII/11)). The information collected 

(particularly in the form of the Executive Summaries) will also be part of the Technology and 

Economic Assessment Report 2014, as well as the overall 2014 Synthesis Report composed 

by the three Assessment Panel co-chairs, the beginning of 2015.

The 2014 RTOC Assessment Report has been drafted in the form of a number of chapters. 

There are chapters on refrigerants and their properties, on the different R/AC application areas 

and one chapter on sustainable refrigeration. The structure of the report was chosen more or 

less similar to the structure of the 2010 RTOC Assessment Report.

Table 1-1: "Member countries" of UNEP's Refrigeration, A/C and Heat Pumps Technical 

Options Committee

Belgium 

Brazil 

China

Croatia

Czech Republic

Denmark

Egypt

France

Germany

India

Jamaica

Japan

Lebanon 

Netherlands

Norway 

South Africa

United Kingdom

United States

Each of the chapters was developed by 2-6 experts in the specific sector, and the chapter was 

chaired by a Chapter Lead Author - who did the larger part of the drafting and the coordination. 

The 2014 RTOC included 40 representatives from Asian, European, Middle-East, Latin and 

North American companies, universities and governments, as well as independent experts 

(see Table 1-1). These representatives have been full (reporting) members; as resource 

persons the RTOC also had a small number of reviewing members.

Affiliations of the members are listed in Table 1-2 (40 organisations (including consultancies) 

were involved in the drafting of the report). The names and contact details of all members are 

given as an appendix to this RTOC Assessment Report.

Several drafts of the report were made, reviewed by the separate chapters and discussed in 

five RTOC meetings (outline August 2011, preliminary draft May 2013, a draft December 

2013, a draft May 2014, a draft September 2014, the peer review draft October 2014 and a 

final report December 2014). 

A preliminary committee meeting was held in Prague (during the IIR congress), August 2011. 

Drafting and reviewing meetings were held in France (Paris), May 2013, Canada (Montreal), 

December 2013, Italy (Torino), May 2014, and Germany (Karlsruhe), December 2014.
36 2014 TOC Refrigeration, A/C and Heat Pumps Assessment Report

Table 1-2: Affiliations of the members of UNEP's Technical Options Committee on 

Refrigeration, A/C and Heat Pumps 

1 A/genT Consultancy (Tech. Univ., Eindhoven) Netherlands

2 Alaa Olama Consultancy Egypt

3 Bassam Elassaad, Consultant Lebanon

4 Bitzer Industries Brazil, U.S.A.

5 Braunschweig University Germany

6 Carrier Corporation U.S.A.

7 CRT Cambridge UK

8 Daikin Europe N.V. Belgium

9 Danfoss Denmark

10 Danish Technological Institute Denmark

11 Devotta Consultancy, Chennai India

12 EREIE Consultancy, Palaiseau France

13 Emerson U.S.A.

14 Fiat Ricerche Torino Italy

15 GEA Industries, Consultant South Africa

16 General Electric, Consumer and Industrial U.S.A.

17 Indian Institute of Technology Delhi India

18 Ingersoll Rand Czech Republic

19 James M. Calm, Engineering Consultant U.S.A.

20 Johnson Controls Denmark

21 Johnson Controls U.S.A.

22 JRAIA Japan

23 Karlsruhe University of Applied Sciences Germany

24 Maua Institute of Technology Brazil

25 Nelson Consultancy Jamaica 

26 Panasonic Japan

27 Petra Industries Jordan

28 Ref-tech Engineering Germany

29 Re/genT b.v. Netherlands

30 Re-phridge Consultancy United Kingdom

31 Shanghai JiaoTong University P.R. China

32 SINTEF Energy Research, Trondheim Norway

33 Star Refrigeration United Kingdom

34 Sun Yat-sen University, Guangzhou P.R. China

35 The Trane Company U.S.A.

36 University of Zagreb Croatia

37 U.S. Environmental Protection Agency U.S.A

38 Vodianitskaia Hapy Consultancy Brazil

39 Zhejiang University, Hangzhou P.R. China

The report has been peer reviewed by a number of institutions and associations, plus some 

experts in their personal capacities, each of them reviewing the different chapters sections in a 

co-ordinated effort in a tight timeframe, i.e., between the last week of October and the end of 

November 2014 (see Table 1-3 for the organisations and experts involved, total 20). Peer 

review comments were collected and sorted out, and subsequently sent to all RTOC members. 

All peer review comments were studied and sorted for a study by the Chapter Lead Authors 

before the RTOC Meeting in December 2014. The RTOC members in plenary decided on 
2014 TOC Refrigeration, A/C and Heat Pumps Assessment Report 37

whether or not to amend the text on the basis of the peer review comments during the RTOC 

meeting in Karlsruhe, Germany, December 2014. 

The RTOC greatly acknowledges the voluntary support given by the peer review institutions 

and the experts in their personal capacities. 

Table 1-3: Organisations that participated in the peer review of the UNEP RTOC 

Assessment Report 

AIRAH Australian Institute of Refrigeration, Air Conditioning and Heating

AHRI Air Conditioning, Heating and Refrigeration Institute

AREMA AC and Refr Equipment Manufacturers Association of Australia

CAR Chinese Association of Refrigeration

CHEAA China Household Electric Appliances Association

CRAA Chinese Refrigeration and Air Conditioning Association

DKV German Refrigeration Association

EIA Environmental Investigation Agency

EPEE European Partnership for Environment and Energy

Eurammon European Industry Association for Ammonia etc. 

JRAIA Japanese Refrigeration and Air-conditioning Industry Association

IIR International Institute of Refrigeration

IOR Institute of Refrigeration UK 

Refrigerants Naturally A global not-for-profit initiative of companies to combat climate 

change and ozone depletion (by substituting fluorocarbons)

SAE Society of Automobile Engineers (via members Atkinson, Hill) 

Shecco A Market Development Expert helping companies to bring their climate 

friendly solutions faster to market

WSC World Shipping Council

Lundqvist Personal Review (KTH Stockholm, Sweden)

Polonara Personal Review (Universita delle Marche, Italy) 

Roke Personal Review (Fisher and Paykel, New Zealand)

1.4 Refrigeration, air conditioning and heat pumps

1.4.1 General remarks

Refrigeration, air conditioning and heat pump applications represent more than 70% of the 

ODS and replacement substances used; it is also one of the most important energy using 

sectors in the present day society. Estimates are difficult to give but as an average for the 

developed countries, its share in electricity use is thought to vary between 10 and 30%.

The economic impact of refrigeration technology is much more significant than generally 

believed; 300 million tonnes of goods are continuously refrigerated. While the yearly 

consumption of electricity may be huge, and where the investment in machinery and 

equipment may approach US$100,000 million, the value of the products treated by 

refrigeration either alone will be four times this amount. This is one of the reasons that 

economic impacts of the phase-out of refrigerant chemicals (such as CFCs in the past, and 

HCFCs in Article 5 countries in the foreseeable future) have been and still are difficult to 

estimate.

Refrigeration and air conditioning applications vary enormously in size and temperature level. 

A domestic refrigerator has an electrical input between 50-250 W and contains less than 30-

150 g of refrigerant (dependent on the type of refrigerant), whereas industrial refrigeration 

and cold storage is characterised by temperatures between -10 C and -40 C, with electrical 

inputs up to several MW and refrigerant contents of many hundred kilograms. Air 
38 2014 TOC Refrigeration, A/C and Heat Pumps Assessment Report

conditioning and heat pumps may show evaporation temperatures between 0 C and +10 C, 

significantly different from refrigeration applications, and vary enormously in size and input.

In principle one can therefore discriminate between four main areas which each have 

subsectors: (i) the food chain in all its aspects, from cold storage via transport to domestic 

refrigeration, (ii) process air conditioning and refrigeration, (iii) comfort air conditioning, 

from air cooled equipment to water chillers, including heat pumps, and (iv) mobile air 

conditioning, with very specific, different aspects. This is one of the reasons that all the 

equipment is considered in this report in a large number of separate chapters or sections.

Options and aspects for the refrigeration vapour compression cycle deserve most attention, 

since it is unlikely that during the next 10-20 years other principles will take over a substantial 

part of the market. In all application sectors described in the separate chapters in this report, 

most of the attention is focused on the vapour compression cycle. As stated, this cycle has so 

far provided the simplest (?), economic, efficient and reliable way for refrigeration (this 

includes cycles using ammonia, fluorochemicals and hydrocarbons as refrigerants).

The process of selecting a refrigerant for the vapour compression cycle is rather complex, 

since a large number of parameters need to be investigated concerning their suitability for 

certain designs, including:

- thermodynamic and transport properties;

- temperature ranges

- pressure ratios

- compressor requirements;

- material and oil compatibility;

- health, safety and flammability aspects; 

- environmental parameters such as ODP, GWP and atmospheric lifetime.

These selection criteria were elaborated upon in various chapters of various UNEP RTOC 

Assessment Reports, and these selection criteria have not changed during the last years. Since 

then, it is the emphasis on the emissions of greenhouse gases that has increased; this can be 

directly translated to thermodynamic efficiency and quality of the equipment (leakage of 

refrigerant).

The future of mankind, and his food supply in particular, depends on the availability of 

sufficient energy and on the availability of efficient refrigeration methods. Of course, this 

aspect must be more than balanced by a concern for the conservation of the biosphere, 

including in particular the global warming effect. Energy efficiency, therefore, is one of the 

most important aspects. 

1.4.2 Long term options and energy efficiency

CFC production has been phased out since a decade in the developed countries, and the CFC 

phase-out in the developing countries, which was scheduled for 2010, has been completed. 

Where HCFCs have been largely phased out in the developed countries, the phase-out in the 

Article 5 countries is now asking full attention. In both developed and developing countries, 

HFCs have so far been important substitutes for CFCs and HCFCs. In many applications, 

alternatives to HCFCs have become commercially available, as pure HFCs, as blends of 

HFCs or as non-HFC alternatives. Therefore, HFCs have gained a large share of the 

replacement market. In particular the necessary incentives remain to be provided to Article 5 

countries to transition from HCFCs to non-HCFC refrigerants, which will include both HFCs 

and non-fluorocarbon alternatives.
2014 TOC Refrigeration, A/C and Heat Pumps Assessment Report 39

It should be noted, however, that the changing refrigerant options are only part of the driving 

force for innovations in refrigeration and A/C equipment. Innovation is an ongoing 

independent process, which has to take into account all the environmental issues involved.

In the long term, the role of non-vapour compression methods such as absorption, adsorption, 

Stirling and air cycles etc. may become more important; however, vapour compression cycles 

are thought to remain the most important candidates.

For the long term, there remain, in fact, only five important different refrigerant options for 

the vapour compression cycle in all refrigeration and A/C sectors, listed alphabetically:

 ammonia (R-717);

 carbon dioxide (R-744);

 hydrocarbons and blends (HCs, e.g. HC-290, HC-600a, HC-1270 etc.);

 hydrofluorocarbons (unsaturated HFCs (HFOs) with a four digit number, HFCblends with 400 and 500 number) 

 water (R-718).

The five refrigerant options above are in different stages of development or 

commercialisation. Although high GWP HFCs are (still) widely used in many sectors, low 

GWP HFCs and low GWP HFC blends are now increasingly being applied. Ammonia and 

hydrocarbons enjoy growth in sectors where they can be easily accommodated, and for certain 

applications, CO2 equipment is being further developed and a large number of CO2

demonstration installations have been extensively tested on the market. It may well be that 

CO2 will take a substantial part of the commercial refrigeration equipment market. Water is 

used and may see some increase in use in limited applications. Work is being done by several 

committees in developing standards to permit the application of new refrigerants, and it is the 

intent of companies to reach world-wide accepted limits in those different standards.

Similarly, energy efficiency research is partly spurred by the role of energy production in 

carbon dioxide emissions. Options for energy efficient operation of equipment form an 

important issue in each of the chapters of this 2014 RTOC Assessment report.

1.4.3 Set up of the 2014 RTOC Refrigeration, A/C and Heat Pumps Assessment Report

Chapter 2 presents refrigerants and all their aspects. It elaborates on Ozone Depleting 

Potentials, and on ODP and GWP data for reporting purposes. It also investigates the status 

and research needs for data, i.e., thermophysical, heat transfer, compatibility and safety data.

Chapters 3, 4, 5 and 6 deal with the food chain and investigate the technical feasibility of 

options. They all consider non-ODP options and deal with aspects such as the use of nonfluorochemicals, the reduction of charges, energy efficiency improvements etc. Particularly 

the energy efficiency aspect plays an important role in chapter 3 on domestic refrigeration. 

Chapter 4 discusses the options for the 3 types of commercial refrigeration equipment. 

Chapter 5 deals with industrial refrigeration and cold storage, chapter 6 with transport 

refrigeration. Chapters 7 and 8 deal with air conditioning and heat pumps. Chapter 9 deals 

with the various aspects of chillers, which includes important considerations on energy 

efficiency. Chapter 10 describes the options for mobile air conditioning; in a first instance, it 

deals extensively with HFC-134a, but it also evaluates the potential the options carbon 

dioxide, hydrocarbons, the unsaturated HFCs (i.e., HFC (HFO)-1234yf) and other options will 

have. Chapter 11 deals with sustainability issues in refrigeration.

All chapters have drafted an executive summary; these summaries were put together and are 

presented in the first part of the report. The executive summaries are preceded by a shortened 
40 2014 TOC Refrigeration, A/C and Heat Pumps Assessment Report

(“abstract”) executive summary (e.g. for policy makers) which has been abstracted from the 

separate executive summaries. This is again preceded by key messages derived from the 

abstract executive summaries.
2014 TOC Refrigeration, A/C and Heat Pumps Assessment Report 41

Chapter 2

__________________________________________________________

Refrigerants

From June 2014:

Chapter Lead Author

Asbjørn Vonsild

Co-Authors

Denis Clodic

Daniel Colbourne

Until June 2014:

Chapter Lead Author

James M.Calm

Co-Authors

Glenn Hourahan (non-RTOC)

Asbjørn Vonsild
42 2014 TOC Refrigeration, A/C and Heat Pumps Assessment Report
2014 TOC Refrigeration, A/C and Heat Pumps Assessment Report 43

2 Refrigerants

2.1 Introduction

Since the 2010 assessment report 21 refrigerants obtained standardized designations and 

safety classifications. One new molecule, HCFC-1233zd(E), can be found in this group of 

new refrigerants; it is an unsaturated HCFC (HCFO) with potential to replace HCFC-123. 

Approximately a quarter of the new refrigerants are blends which are replacements for 

HCFC-22. Twelve of the new refrigerants are blends of high global warming potential (GWP)

saturated HFCs and low GWP unsaturated HFCs (HFOs), and seven of these blends are with 

class 2L flammability. 

The search for new refrigerants addresses both climate and ozone concerns, in particular by 

reducing the GWP of the refrigerant and replacing ozone-depleting substances.

The search for new refrigerants addresses both climate concerns and ozone depletion 

concerns, in particular by reducing the GWP of the refrigerants and replacing ozone-depleting 

substances, such as HCFC-22.

2.1.1 Refrigerant progression

The historic progression of refrigerants encompasses four phases based on defining selection 

criteria (Calm, 1997; Calm, 2012):

 1830s-1930s – whatever worked: primarily familiar solvents and other volatile fluids 

including ethers, ammonia (NH3, R-717), carbon dioxide (CO2, R-744), sulphur dioxide 

(SO2, R-764), methyl formate (HCOOCH3, R-611), HCs, water (H2O, R-718), carbon 

tetrachloride (CCl4, R-10), hydrochlorocarbons (HCCs), and others; many of them are 

now regarded as “natural refrigerants” (more exactly non-fluorinated since nearly all 

actually are synthesized, refined, or at least industrially purified).

 1931-1990s – safety and durability: primarily chlorofluorocarbons (CFCs), 

hydrochlorofluorocarbons (HCFCs), ammonia, and water (mostly used in absorption 

cycles).

 1990-2010s – stratospheric ozone protection: primarily HCFCs (for transition use), 

hydrofluorocarbons (HFCs), ammonia, water, hydrocarbons, and carbon dioxide.

 Beyond 2012 – global warming mitigation: to be determined, but likely to include 

refrigerants with very low (< 10-3) or no ozone depletion potential (ODP), low global 

warming potential (GWP), and high efficiency; likely to include, at least initially, 

unsaturated hydrofluorocarbons (hydrofluoroolefins, HFOs discussed below), ammonia, 

carbon dioxide, hydrocarbons and water.

2.1.2 Unsaturated hydrofluorochemicals

Facing regulatory pressures to eliminate refrigerants with high GWPs, the major refrigerant 

manufacturers have pursued unsaturated fluorochemicals. They are chemicals consisting of 

two or more carbon atoms with at least one double bond between two or more of them as well 

as fluorine, hydrogen, and possibly also chlorine or other halogens. Unsaturated fluorocarbons 

also are identified as fluoro-alkenes or fluoro-olefins. Double carbon-carbon bond(s) make(s) 

the compounds more reactive. The result is short atmospheric lifetimes and, thereby, very low 

ODPs and GWPs.
44 2014 TOC Refrigeration, A/C and Heat Pumps Assessment Report

The unsaturated HFC (also identified as hydrofluoro-alkene or hydrofluoro-olefin, HFO) 

family is a focal example with varying extents of halogenation, in part, as a trade-off between 

flammability associated with a lower degree of stability and high GWP associated with a 

higher degree of stability. Chemical producers are pursuing alternatives for the most widely 

used low-, medium-, and high-pressure refrigerants.

In the naming of unsaturated halocarbons the prefix for unsaturated HCFC, and unsaturated 

HFC can alternatively be chosen to be HCFO and HFO respectively, where the O replaces the 

carbon C (ISO 817:2014). In this report the prefix used is the default HCFC and HFC 

respectively.

The extent of long- term acceptability of unsaturated HFCs or more broadly unsaturated 

hydro-halochemicals is uncertain, though a number of initial studies looking at the 

trifluoroacetic acid (TFA) build up resulting from the use of unsaturated HFCs in mobile airconditioning indicate manageable environmental impacts (Kajihara, 2010; Luecken, 2010; 

Papasavva, 2009).

2.1.3 Recent assessment on current and future refrigerants and GWP

There are a number of studies providing assessments of a broad number of alternative 

refrigerants. 

For example, the AHRI Low-GWP Alternative Refrigerants Evaluation Program 

(AHRI/AREP) phase 1 evaluated more than 30 new refrigerants (AHRI, 2013), most of them 

blends and most of them based on unsaturated HFCs mixed with traditional HFCs. The 

refrigerant categories and corresponding 100 year GWP values are given in Table 2-1 

(calculated based on the GWP values of Table 2-7).

Table 2-1: 100 year GWPs for AHRI/AREP alternative refrigerants

Safety Class Range of GWP for Alternatives to

HFC-134a HCFC-22, R-404A, 

R-407C, and R-507A

R-410A

A1 540 – 900 950 – 1600

A2L ≤ 110 200 – 970 280 – 740

A3 14 – 20 1,8 – 5

This table illustrates the relationship between the pressure and the flammability of a fluid, 

although it can be argued that not all the proposed R-410A replacements have high enough 

capacity to be considered replacements for R-410A. There is a clear trend that the higher the 

pressure the higher the minimum GWP that is needed for pure compounds or blends to be 

non-flammable. The above also gives a good estimate of which levels of GWP are to be 

expected for various capacity/pressure levels for a given flammability class. 

Another recent study (McLinden, 2014) started with a database of 100 000 000 chemicals, 

screening the more than 56 000 small molecules and finding non ideal. The conclusion is that 

the perfect cheap, energy efficient, non-toxic, non-flammable, and broadly applicable 

refrigerant with negligible GWP does not exist, and is highly unlikely to come into existence.

2.1.4 Flammable refrigerants and Safety classification

ISO 817 (ISO 817:2014) and ASHRAE 34 (ASHRAE 34-2013) assigns a safety class for each 

refrigerant, for instance “A2L”. The first letter of the safety class describes the toxicity, A for 

lower level of toxicity and B for higher level of toxicity, while the second part is the 
2014 TOC Refrigeration, A/C and Heat Pumps Assessment Report 45

flammability of the refrigerant: 1 (no flame propagation), 2L (lower flammability), 2 

(flammable), and 3 (higher flammability) (Table 2-2; see the annex to this chapter for addition 

details).

Table 2-2: Safety classifications

Flammability Toxicity

A B

1 A1 B1

2L A2L B2L

2 A2 B2

3 A3 B3

As mentioned above, there is a trade-off between GWP and flammability. A low GWP can be 

achieved by having the refrigerant break down quickly in the atmosphere, however this also 

means that the refrigerant breaks down easier when subjected to ignition sources. For many 

applications, flammability is a new aspect to take into account when designing systems.

Although safety standards are not strictly mandatory in most countries, they are one source

where the industry looks for guidance for handling the flammability. For instance, ISO 5149 

(ISO 5149:2014) Part 1 describes limits to charge amount depending on system type, system 

location, and accessibility by people unaccustomed with the safety procedures relating to the 

system. Local legislation will also have an influence, for instance national legislation and 

building codes. The requirements for flammable refrigerants are very similar across the 

different flammability classes, the different flammability properties result in different risks 

(probabilities) and consequences; therefore varying refrigerant charges and thereby system 

designs for each refrigerant. Further discussion is included in the annex to this chapter.

It is still not clear for all applications whether flammability will be accepted for each level of 

cooling or heating capacity needed, and how the various markets will split-up with regard to 

the classes of flammability. The acceptance of flammable refrigerants and the appropriate 

updates of standards and legislation is clearly a contemporary challenge for the refrigeration 

air conditioning, and heat-pump industry.

2.1.5 Climate impact metrics for refrigerants

The most popular metric for indicating the climate impact of refrigerant emissions is 100 year 

GWP, which is the integrated radiative forcing over a 100 year time horizon of 1 kg of 

refrigerant emitted to the atmosphere. Some parties advocate use of GWP values for shorter 

or longer integration time horizons or various instantaneous or sustained metrics such as the 

global temperature potential (GTP) (Shine, 2005; Hodnebrog, 2013; see §8.7 of (IPCC, 2014) 

for detailed discussions of instantaneous GTP and sustained GTP).

In this chapter both 20 year GWP and 100 year GWP values are listed. The advantage of 20 

year GWP over 100 year GWP is that a 20 year time horizon seems more relevant when 

discussing the climate change in the coming decades and it is also better at differentiating 

between substances with short life times. 

The advantage of using 100 year GWP is that it is more commonly used and the popularity of 

a metric is important to the efficiency of communicating the climate impact. Also the 100 

year GWP is better at differentiating between substances with longer lifetimes, although this 

seldom applies to currently used non-ODS refrigerants. An example is PFC-116 and HFC143a; the difference in 20 year GWP is less than 20% while the difference in 100 year GWP 
46 2014 TOC Refrigeration, A/C and Heat Pumps Assessment Report

is more than a factor of 2. As long lived substances can be used in small amounts in blends 

with short lived substances to create lower GWP blends, using 20 year GWP may lead to 

decisions favouring the shorter term at the cost of the longer term.

A classification of 100 year GWP levels which is a slight modification of the proposal in the 

previous RTOC report (UNEP, 2011) is given in Table 2-3. A complication of naming a 

substance as low GWP or high GWP is that the climate impact is the product of the GWP and 

the amount (in kg) emitted, so even though CO2 is classified in Table 2-3 as ultra-low GWP, 

the amount emitted by the human civilization is large enough to give a significant climate 

impact. Table 2-3 categorizes using “less than” or “more than” and this enables a refrigerant 

such as HFC-1234yf to have ultra-low, very low, and Low GWP at the same time. Likewise a 

refrigerant such as HFC-23 has ultra-high, very high, and high GWP. The purpose of this 

feature is to allow simple references to all refrigerants below or above a given limits.

Table 2-3: Classification of 100 year GWP levels

100 Year GWP Classification

< 30 Ultra-low or Negligible

< 100 Very low

< 300 Low

300-1000 Medium

> 1000 High

> 3000 Very high

> 10000 Ultra-high

For gases with lifetimes of a century or more the uncertainties are of the order of ±20% and 

±30% for 20- and 100-year horizons. For shorter lived gases the uncertainties in GWPs will 

be larger (IPCC, 2014). This is one reason why care must be taken when comparing the GWP 

of refrigerants. For substances with very low GWP the picture is further complicated since,

for historical reasons, GWPs for hydrocarbons are indirect GWPs, which include breakdown 

products such as CO2, as opposed to the GWPs for HCFCs, HFCs etc., which do not cover 

breakdown products. 

When comparing carbon emissions associated with the use of refrigerants, care must be 

taken to also include a comparison of energy efficiency of the refrigerant in the given 

application. Emissions from energy production may have a greater climate impact than the 

refrigerant emissions only. For further discussion see chapter 11.

2.1.6 ODP and GWP data for regulatory and reporting purposes

The ODP and GWP data presented in this chapter are based on international scientific 

assessments and reflect the latest consensus determinations on potential impacts. However, 

the reduction requirements and allocations under the Montreal Protocol, emission reductions 

and reporting pursuant to the Kyoto Protocol, and provisions in many national regulations 

pursuant to them use older, adopted values.

Table 2-4 compares the latest consensus ODP data (WMO, 2014) and (WMO, 2011) to the 

“regulatory” ODPs used in the Montreal Protocol (UNEP, 2012). Table 2-5 similarly contrasts 

the latest consensus GWPs, for a 100 year integration, with those used for reporting and 

emission reductions under the Kyoto Protocol from IPCC (1995).
2014 TOC Refrigeration, A/C and Heat Pumps Assessment Report 47

Table 2-4: Scientific and regulatory ODPs for selected BFC, BCFC, CFC, and HCFC 

refrigerants

Refrigerant ODP

(WMO, 2014) (WMO, 2011) Reporting 

(UNEP, 2012)

CFC-11 1,0 1,0 1,0

CFC-12 0,73 0,82 1,0

BCFC-12B1 6,9 7,9 3,0

CFC-13 1,0

BFC-13B1 15,2 15,9 10,0

HCFC-22 0,034 0,04 0,055

CFC-113 0,81 0,85 0,8

CFC-114 0,50 0,58 1,0

CFC-115 0,26 0,57 0,6

HCFC-123 0,01 0,02

HCFC-141b 0,102 0,12 0,11

HCFC-142b 0,057 0,06 0,065

Table 2-5: Scientific and regulatory GWPs for 100 year integration for selected 

refrigerants

Refrigerant GWP

(WMO, 2014) (IPCC, 2014) (WMO, 2011) Reporting 

(IPCC, 1995)

PFC-14 6630 7 390 6 500

HFC-23 12 500 12 400 14 200 11 700

HFC-32 704 677 716 650

PFC-116 11 100 12 200 9 200

HFC-125 3 450 3 170 3 420 2 800

HFC-134a 1 360 1 300 1 370 1 300

HFC-143a 5 080 4 800 4 180 3 800

HFC-152a 148 138 133 140

PFC-218 8 900 8 830 7 000

HFC-227ea 3 140 3 350 3 580 2 900

HFC-236fa 8 060 9 820 6 300

PFC-C318 9 540 10 300 8 700

R-744 (CO2) 1 1 1 1
48 2014 TOC Refrigeration, A/C and Heat Pumps Assessment Report

2.1.7 Selection of refrigerant

There are several factors that should be considered when selecting an alternative refrigerant 

for refrigeration, air conditioning and heat pump systems and applications. These include:

 Zero ODP

 Climate Change impact (reduced direct and indirect emissions)

 Performance (capacity and efficiency)

 Safety, including flammability and toxicity

 Impact on product cost

 Availability and cost of the refrigerant

 Skills and technology required to use

 Recyclability

 Stability

The selection of a refrigerant for a given application will be a compromise of the above 

criteria. Other than zero ODP, the rest of the parameters will to be traded-off against one 

another to arrive at the optimum for each type of system and application. In particular the 

carbon emissions include both the “direct” and “indirect” contribution of the product over its 

life time. A number of approaches have been documented in the literature including: Total 

Equivalent Warming Impact (TEWI), Life Cycle Climate Performance (LCCP), Multilateral 

Fund Climate Impact Indicator (MCII) and other methods.

For new refrigerants for existing systems, there are a number of criteria that should be 

achieved in order for a suitable refrigerant to be selected. In summary, with respect to the 

refrigerant being replaced, these are:

 As close a volumetric refrigerating capacity over the range of normal operating 

evaporator and condenser temperatures;

 Does not lead to lower energy efficiency;

 Does not exceed the condensing pressure at maximum condenser temperature;

 As close a match to the temperature glide, or negligible temperature glide if the original 

was a single component;

 Similar oil solubility and miscibility gap;

 Non-flammable or not higher flammability;

 Lower toxicity or not higher toxicity;

 Commercial availability of refrigerant (with reasonable cost).

There are a number of other parameters that should be considered. However, in practical 

terms it is unlikely that any of the commercially available refrigerants can meet all of the 

above criteria and therefore some compromise should be anticipated.

A refrigerant that is capable of replacing an existing refrigerant without changing any major 

components, including the oil, is sometimes referred to as a drop-in refrigerant. The term 

drop-in is somewhat misleading, as safety standards require the system to be upgraded to the 

latest safety requirements for any change of refrigerant type, and the trade-offs mentioned 

above may affect the performance and durability of the system.
2014 TOC Refrigeration, A/C and Heat Pumps Assessment Report 49

2.1.8 HCFC-22 replacements

The challenge of reducing the use of HCFC-22 has led to the development of refrigerants 

specifically designed to replace HCFC-22 in existing equipment or replace HCFC-22 in new 

systems without the need for significant design changes. 

A main differentiator between the HCFC-22 replacements is whether the refrigerant is 

miscible with the mineral oil often used with HCFC-22. 

The refrigerants which are more miscible with mineral oil typically contain a minute amount 

(< 4%) of hydrocarbon to increase the miscibility and help the oil return to the compressor. 

These refrigerants typically have safety classification A1 and include: R-417A, R-417B, R417C, R-422A, R-422B, R-422C, R-422D, R-422E, R-424A, R-425A, R-428A, R-434A, R438A, and R-442A.

The refrigerants that are designed to fit the thermodynamic properties of HCFC-22 

refrigerants, but not to be used with the mineral oil often used with HCFC-22 includes: R404A, R-407A, R-407B, R-407C, R-407D, R-407E, R-407F, R-421A, R-421B, R-427A, R444B, and R-507A. While they typically have the safety classification A1, some of the more 

recent HCFC-22-like blends (specifically R-444B) have the safety classification A2L.

When changing refrigerant in a system there is always recommended to check gaskets, 

elastomeric seals, and other materials for compatibility with the new refrigerant, and there is a 

risk that exposure to HCFC-22 has changed the properties of polymer materials to the point 

where they will not function correctly or exasperate leakage after a refrigerant change. There 

may also be a need for other system modifications to reach an acceptable energy efficiency 

and capacity. See also the discussion in 2.1.7 on a general discussion about replacing one 

refrigerant with another in existing systems.

For new systems, there are several other options for replacing HCFC-22 with system designs 

adapted to e.g. R-717, R-744, HCs, HFCs, or other newly developed molecules.

2.2 Refrigerant descriptions

The most important refrigerants discussed in this report are described briefly below in Table 

2-6. The list is in numerical order and is meant to serve as a quick reference as it does not 

cover all aspects of the selected refrigerants.

The refrigerants are single component for refrigerant designation numbers below 400 and 

from 600 and up, while designation numbers in the 400’s and 500’s are mixtures of two or 

more components. The 400 series are blends with a temperature glide, known as zeotropes. If 

the glide is large then exchangers need to be designed suitably to take this into account. The 

500 series are blends, which are azeotropic at some condition, thus inferring with negligible 

temperature glide and change in composition between the liquid and vapour phases.

The safety class according to ISO 817 (ISO 817: 2014) of each refrigerant is stated, and 

where ISO 817 does not list the refrigerant, the safety class is taken from ASHRAE 34 

(ASHRAE 34-2013). Where dual classification exists, the higher (i.e. more conservative) 

class is given.

Table 2-6: Description of selected refrigerants

CFC-11 CFC-11 was introduced in 1932 as a replacement to flammable and or toxic 

refrigerants used at the time and gained popularity in Centrifugal chillers 

(Calm, 1997) and was widely used as a solvent and a blowing agent. CFC-11 is 

classed as an A1 refrigerant and is the reference substance for ODP and has a 
50 2014 TOC Refrigeration, A/C and Heat Pumps Assessment Report

defined ODP of 1. It is a low pressure refrigerant, with similar pressure as 

HCFC-123, and has often been replaced with this refrigerant.

CFC-12 CFC-12 was introduced in 1931 as a replacement to flammable and or toxic 

refrigerants used at the time (Calm, 1997) and has been popular in both 

refrigeration applications and chillers for air-conditioning. CFC-12 is classed as 

an A1 refrigerant, and has high ODP, almost as high as CFC-11. The pressure 

is similar to HFC-134a, which replaced it in many applications.

HCFC-22 HCFC-22 was originally used for low temperature refrigeration and later airconditioning, and is today the most popular HCFC refrigerant. It is classed as 

an A1 refrigerant and is the most used refrigerant in the world for commercial 

refrigeration, industrial processes, and mainly air-to-air air conditioning 

systems. The HCFC-22 bank is estimated to be 1,6 million metric tonnes at the 

global level. The energy efficiency of this refrigerant became a reference for 

the validation of its substitutes: R-404A in commercial and industrial 

refrigeration and R-407C and R-410A in air conditioning. HCFC-22 has a 

medium pressure similar to R-404A and R-407C, and as seen in section 2.2.2 

below, alternatives to HCFC-22 has been getting attention in the industry.

HFC-32 HFC-32 was originally used as a component of refrigerant blends such as R407C and R-410A. Pressure and capacity are around 1.5 times higher than 

HCFC-22 and slightly higher than R-410A. It is classed as A2L. The efficiency 

of HFC-32 systems are higher than R-410A but less than HCFC-22. Discharge 

temperatures are higher than R-410A and HCFC-22 and thus some mitigation 

device or controls may be necessary for handling the discharge temperature of 

the compressor especially at high ambient temperatures.

HCFC-123 HCFC-123 is mainly used in centrifugal chillers and is classed as a B1 

refrigerant. HCFC-123 is a low-GWP HCFC refrigerant, but since it is an ODS 

it is being phased-out under the Montreal Protocol.

HFC-125 HFC-125 is used as a component of refrigerant blends such as R-404A and R410A to lower discharge temperature and reduce flammability from other 

components.

HFC-134a HFC-134a is used in a variety of equipment including heat pumps, chillers, 

mobile air conditioning and domestic refrigeration and has a pressure lower 

than HCFC-22 and similar to CFC-12. It is classed as an A1 refrigerant. Energy 

efficiency is good, provided that pipes and heat exchangers are suitably sized.

HFC-152a HFC-152a has performance characteristics similar to HFC-134a as well as 10% 

lower vapour pressure and volumetric refrigeration capacity. It is classed as an 

A2 refrigerant. HFC-152a is used as a component in several new blends.

HFC-161 HFC-161 has with zero ODP and very low GWP of 4 (IPCC, 2014) and it is 

under evaluation to replace HCFC-22 in small air conditioning unit. It is not yet 

classified in ISO 817 (ISO 817: 2014) or ASHRAE 34 (ASHRAE 34-2013) but

is likely to be classified A3. Performance is similar to HCFC-22 and HC-290. 

The lower flammability limit is about 4 times higher than for HC-290 allowing 

for a higher charge to be used and thereby higher cooling capacity to be 

achieved compared with a system using HC-290.

HFC-245fa HFC-245fa has found limited use in centrifugal chillers, high temperature heat 

pumps, and organic Rankine cycle (ORC) power generation cycles and is 
2014 TOC Refrigeration, A/C and Heat Pumps Assessment Report 51

classified as B1. Because the high temperature heat pump and ORC are still 

emerging markets the use may increase. It has operating pressures higher than 

for HCFC-123 but lower than for HFC-134a.

HC-290 HC-290 has thermodynamic properties similar to HCFC-22, although slightly 

lower pressure and capacity. It is classified as A3. Due to its excellent 

thermophysical properties the efficiency is good under most conditions, 

including high ambient, as well as having low discharge temperatures. It is the 

most frequently used hydrocarbon refrigerant in air conditioning applications. It 

is also used as a major component in many HC blends.

R-404A R-404A is used widely in commercial refrigeration systems, and is classified as 

A1. The efficiency is acceptable. A major advantage of R-404A is the low 

discharge temperature, which makes it possible to have a high temperature lift 

in a single stage system, hence it being the primary substitute for R-501. R404A is also used in industrial refrigeration, especially when R-717 is not 

desired for safety or technical reasons. R-404A and R-507A are very similar in 

composition and performance parameters.

R-407A R-407A is a mixture of the same components of other 407 refrigerants but in 

slightly different proportions. It was originally developed to replace HCFC-22 

and is now used as a replacement for R-404A. It is classified as A1. The 

efficiency is acceptable and better than R-404A. However, its moderate

temperature glide and higher discharge temperature needs to be taken into 

account.

R-407C R-407C is a mixture of the same components of other 407 refrigerants but in 

slightly different proportions. It has been used widely in air conditioning, 

chiller and heat pump systems, especially to help the transition from HCFC-22. 

It is classed as A1. The efficiency is acceptable and better than R-404A. 

However, its moderate temperature glide and higher discharge temperature 

needs to be taken into account.

R-407F R-407F is a mixture of the same components of other R-407 refrigerants but in 

slightly different proportions. It is used as a replacement for R-404A. It is 

classified as A1. The efficiency is acceptable and better than R-404A. 

However, its moderate temperature glide and higher discharge temperature 

needs to be taken into account.

R-410A R-410A is used widely in air conditioning, chiller and heat pump systems and 

is classified as A1. The pressure of R-410A is higher than HCFC-22, the R-407 

series and R-404A. Generally the efficiency is equivalent to HCFC-22, 

especially at lower temperatures, although efficiency and capacity deteriorates 

at a greater rate at higher ambient temperatures.

R-417A R-417A is mainly designed to replace HCFC-22 as a “drop-in” in airconditioning systems, but is also utilised in refrigeration and heat pump 

applications in existing systems as well as in new equipment. It is classified A1 

and has a higher GWP than HCFC-22.

R-444A R-444A is a replacement for HFC-134a and is classified as A2L. It has

efficiency, capacity and operating pressures close to HFC-134a.
52 2014 TOC Refrigeration, A/C and Heat Pumps Assessment Report

R-444B R-444B can replace HCFC-22 in new AC equipment without major 

modifications as its pressures are similar. It is classified as A2L. R-444B 

matches the capacity of HCFC-22 with a marginally lower efficiency although 

relative performance can be better in high ambient climates.

R-445A R-445A is a replacement for HFC-134a and is classified as A2L. It has been 

tested in mobile air conditioning systems where its energy efficiency and 

capacity are close to HFC-134a and HFC-1234yf. Its temperature glide is about 

twice that of R-407C, which may influence system design.

R-446A R-446A can replace R-410A in AC equipment and is classified as A2L. 

Efficiency of R-446A systems is comparable to R-410A whilst the capacity is 

lower than R-410A and discharge temperatures are slightly higher. Due to its 

relative higher critical point compared to other refrigerants, R-446A performs 

well at high ambient temperatures.

R-447A R-447A can replace R-410A in AC equipment and is classified as A2L. The 

efficiency of R-447A systems is at the same level as R-410A, the capacity is 

slightly lower and discharge temperatures are slightly higher than R-410A. Due 

to its relative higher critical point compared to other refrigerants, R-447A 

performs well at high ambient temperatures.

R-448A R-448A can replace R-404A in existing and new refrigeration equipment and is 

classified as A1. This refrigerant has capacity and efficiency similar to R-404A. 

However, its notable temperature glide may influence system design.

R-449A R-449A can replace R-404A in new refrigeration equipment and is classified as 

A1. This refrigerant has a capacity marginally higher than R-404A and a 

slightly better efficiency. 

R-450A R-450A can replace HFC-134a in new equipment, where its lower volumetric 

capacity can be addressed in the design of the equipment. It is classified as A1. 

When used in reciprocating or scroll compressors, this refrigerant produces 

efficiency levels comparable to HFC-134a, although the capacity is lower. 

R-507A R-507A is used widely in commercial refrigeration systems, and is classified as 

A1. The efficiency is acceptable. A major advantage of R-507A is the low 

discharge temperature, which makes it possible to have a high temperature lift 

in a single stage system (thus being adopted as a replacement for R-502). It is 

also used in industrial refrigeration, especially when R-717 is not desired for 

safety or technical reasons. R-404A and R-507A are very similar in 

composition and performance parameters.

HC-600a HC-600a is a low pressure hydrocarbon refrigerant classified as A3. The 

operating pressures and capacity is less than half that of HFC-134a, whilst 

efficiency is good. It is used extensively for small refrigeration systems such as 

domestic refrigeration and small commercial systems. It is also used as a 

component in many HC blends.

R-717 R-717 (ammonia, NH3) is classified as B2L. In principle, it has thermophysical properties that lead to excellent efficiency. The vapour pressure and 

refrigerating capacity is similar to HCFC-22. However, R-717 has a very high 

discharge temperature, so for lower temperature applications two-stage-
2014 TOC Refrigeration, A/C and Heat Pumps Assessment Report 53

compression is normally needed. It is not practically compatible with copper

and copper alloys, which limits the system to welded steel or aluminium 

components and piping. The application of R-717 in small to large absorption 

systems is also wide spread.

R-718 R-718 (Water, H2O) is used as refrigerant in vapour compression cycles at very 

low pressures, high compression ratios and high volumetric flow rates, leading 

to larger system sizes and a cost premium. It has also been tested for high 

temperature heat pumps with promising results, especially when it can be 

integrated in direct vapour compression cycles. It is also used in adsorption 

chillers, coupled with widely available adsorbents such as silica gel and zeolite, 

and in absorption systems either with LiBr as absorbent, or as absorbent of 

ammonia.

R-744 R-744 (carbon dioxide, CO2) is classified as A1, and has thermo-physical 

properties that lead to good efficiency for certain levels of temperatures (such 

as for refrigeration range). The vapour pressure is several times greater than 

usual refrigerants and the volumetric refrigerating capacity is correspondingly 

higher for conditions below 25°C. However, with a very low critical 

temperature, the cycle efficiency declines as the temperature before the 

expansion device increases and other features are needed to achieve similar (to 

HCFC-22) efficiency values at higher ambient conditions. Compared to a basic 

cycle, 10–20% energy efficiency improvement can be achieved by applying an 

ejector instead of an ordinary expansion device (Hafner, 2012) although using 

an expander alone can bring the efficiency to within 10% of HCFC-22 

(Subiantoro, 2013). Other features to help improve efficiency in high ambient 

conditions include economiser (parallel compression), liquid-suction heat 

exchange and mechanical subcooling. Also, discharge temperatures are very 

high and therefore, where the high temperature cannot be utilised, technology 

options such as additional compression stages and inter-cooling may be 

adopted in the system design. These additional features add to the complexity 

and cost of the system.

HCFC1233zd(E)HCFC-1233zd(E) is an unsaturated HCFC and has similar pressure to that of 

HCFC-123. It is classified as A1. When used with centrifugal compressors, this 

refrigerant produces efficiency levels similar to HCFC-123, allowing the design 

of systems with very high energy efficiency.

HFC1234yfHFC-1234yf is an unsaturated HFC and can replace HFC-134a in same systems 

since the pressure-temperature characteristics are almost identical, It is 

classified as A2L. In general this refrigerant produces efficiency levels 

comparable to HFC-134a although the theoretical COP is a few percent below 

that of HFC-134a.

HFC1234ze(E)HFC-1234ze(E) is an unsaturated HFC and can replace HFC-134a in new 

equipment where its lower volumetric capacity can be addressed in the design 

of the equipment. It is classified as A2L.

HC-1270 HC-1270 is an unsaturated hydrocarbon with a vapour pressure and capacity 

almost identical to HCFC-22. It is classified as A3 and also has a distinctive 

odour. Due to its excellent thermophysical properties the efficiency is good 

under most conditions, including high ambient, as well as having low discharge 

temperatures.
54 2014 TOC Refrigeration, A/C and Heat Pumps Assessment Report

2.3 Data summary

This section summarizes physical, safety, and environmental data for refrigerants with a 

safety classification in ISO 817 (ISO 817:2014) or ASHRAE 34 (ASHRAE 34-2013).

Table 2-7 covers single component refrigerants; Table 2-8 is the summary for zeotropic 

refrigerant blends, while Table 2-9 covers azeotropic refrigerant blends.

Table 2-7: Data summary for single component refrigerants Designation Refrigerant Chemical Formula Chemical Name Molecular Weight Boiling Point (°C) ATEL/ODL (kg/m

3

)

LFL (kg/m

3

)

Safety Class

Atmospheric 

Lifetime (Years)

Radiative Efficiency 

(W/m/ ppm)

GWP 100 Year

GWP 20 Year

ODP

Methane series 

CFC-11 CCl3F trichlorofluoromethane 137,4 24 0,006 2 NF A1 52 0,26 5 160 7 090 1

CFC-12 CCl2F2 dichlorodifluoromethane 120,9 -30 0,088 NF A1 102 0,32 10 300 10 800 0,73

CFC-13 CClF3 chlorotrifluoromethane 104,5 –81 ND NF A1 640 0,25 13 900 10 900 1

BFC-13B1 CBrF3 bromotrifluoromethane 148,9 –58 ND NF A1 72 0,30 6 670 7 930 15,2

PFC-14 CF4

tetrafluoromethane 

(carbon tetrafluoride) 88,0 -128 0,40 NF A1 50000 0,09 6 630 4 880

HCFC-22 CHClF2 chlorodifluoromethane 86,5 -41 0,21 NF A1 12 0,21 1 780 5 310 0,034

HFC-23 CHF3 trifluoromethane 70,0 -82 0,15 NF A1 228 0,18 12 500 10 800

HCC-30 CH2Cl2

dichloromethane 

(methylene chloride) 84,9 40 ND NF B1 0,4 0,03 9 33

HFC-32 CH2F2

difluoromethane 

(methylene fluoride) 52,0 -52 0,30 0,307 A2L 5,4 0,11 704 2 530

HC-50 CH4 methane 16,0 –161 ND 0,032 A3 12,4 3,63e-4 30 85

Ethane series 

CFC-113 CCl2FCClF2

1,1,2-trichloro-1,2,2-

trifluoroethane 187,4 48 0,02 NF A1 93 0,30 6 080 6 560 0,81

CFC-114 CClF2CClF2

1,2-dichloro-1,1,2,2-

tetrafluoroethane 170,9 4 0,14 NF A1 189 0,31 8 580 7 710 0,5

CFC-115 CClF2CF3 chloropentafluoroethane 154,5 -39 0,76 NF A1 540 0,20 7 310 5 780 0,26

PFC-116 CF3CF3 hexafluoroethane 138,0 -78 0,68 NF A1 10000 0,25 11 100 8 210

HCFC-123 CHCl2CF3

2,2-dichloro-1,1,1-

trifluoroethane 152,9 27 0,057 NF B1 1,3 0,15 79 292 0,01

HCFC-124 CHClFCF3

2-chloro-1,1,1,2-

tetrafluoroethane 136,5 -12 0,056 NF A1 5,9 0,20 527 1 870 0,02

HFC-125 CHF2CF3 pentafluoroethane 120,0 -49 0,37 NF A1 31 0,23 3 450 6 280

HFC-134a CH2FCF3 1,1,1,2-tetrafluoroethane 102,0 -26 0,21 NF A1 14 0,16 1 360 3 810

HCFC-142b CH3CClF2

1-chloro-1,1-

difluoroethane 100,5 -10 0,10 0,329 A2 18 0,19 2 070 5 140 0,057

HFC-143a CH3CF3 1,1,1-trifluoroethane 84,0 -47 0,48 0,282 A2L 51 0,16 5 080 7 050

HFC-152a CH3CHF2 1,1-difluoroethane 66,1 -25 0,14 0,130 A2 1,6 0,10 148 545

HC-170 CH3CH3 ethane 30,1 -89 0,008 6 0,038 A3 5,5 20

Ethers 

HE-E170 CH3OCH3

methoxymethane 

(dimethyl ether) 46,1 -25 0,079 0,064 A3 0,015 0,02 1 1

Propane series

PFC-218 CF3CF2CF3 octafluoropropane 188,0 -37 0,34 NF A1 2600 0,28 8 900 6 640

HFC-227ea CF3CHFCF3

1,1,1,2,3,3,3-

heptafluoropropane 170,0 -16 0,19 NF A1 36 0,26 3 140 5 250

HFC-236fa CF3CH2CF3

1,1,1,3,3,3-

hexafluroropropane 152,0 -1 0,34 NF A1 242 0,24 8 060 6 940

HFC-245fa CHF2CH2CF3

1,1,1,3,3-

pentafluoropropane 134,0 15 0,19 NF B1 7,9 0,24 882 2 980

HC-290 CH3CH2CH3 propane 44,1 -42 0,09 0,038 A3 12,5 

days 5 18
2014 TOC Refrigeration, A/C and Heat Pumps Assessment Report 55

Cyclic organic compounds

PFC-C318 -(CF2)4- octafluorocyclobutane 200,0 -6 0,65 NF A1 3200 0,32 9 540 7 110

Hydrocarbons

HC-600 CH3CH2CH2CH3 butane 58,1 0 0,002 4 0,038 A3 4 15

HC-600a CH(CH3)2CH3

2-methylpropane 

(isobutane) 58,1 -12 0,059 0,043 A3 6,0 days ~20 74

HC-601 CH3CH2CH2-

CH2CH3

Pentane 72,2 36 0,0029 0,035 A3 3,4 

days ~20 74

HC-601a CH(CH3)2CH2-

CH3

2-methylbutane 

(isopentane) 72,2 27 0,0029 0,038 A3 3,4 days ~20 74

Inorganic compounds 

R-702 H2 Hydrogen 2,0 -253 A3

R-704 He Helium 4,0 -269 NF A1

R-717 NH3 Ammonia 17,0 -33 0,000 22 0,116 B2L

R-718 H2O Water 18,0 100 NF A1

R-720 Ne Neon 20,2 -246 NF A1

R-728 N2 Nitrogen 28,0 -196 NF A1

R-740 Ar Argon 39,9 -186 NF A1

R-744 CO2 carbon dioxide 44,0 -78c 0,072 NF A1 1,37e-5 1 1

Unsaturated organic compounds 

HC-1150 CH2=CH2 ethene (ethylene) 28,1 –104 ND 0,036 A3 3,7 14

HCFC1233zd(E) CF3CH=CHCl trans-1-chloro-3,3,3-

trifluoro-1-propene

130,5 18,1 0 NF A1 26,0 

days 0,04 1 5 0,000 34

HFC-1234yf CF3CF=CH2

2,3,3,3-tetrafluoro-1-

propene

114,0 -29,4 0,47 0,289 A2L 10,5 

days 0,02 <1 1

HFC1234ze(E) CF3CH=CHF trans-1,3,3,3-tetrafluoro1-propene

114,0 -19,0 0,28 0,303 A2L 40,4 

days 0,04 <1 4

HC-1270 CH3CH=CH2 propene (propylene) 42,1 -48 0,001 7 0,046 A3 0,35 

days 1,8 6,6

Table 2-8: Data summary for zeotropic refrigerant blends Designation Refrigerant Composition Refrigerant (Mass %) Molecular Weight Dew Point (°C) Bubble Point/ 

ATEL/ODL 

(kg/m3)

LFL (kg/m3)

Safety Class

GWP 100 Year

GWP 20 Year

ODP

R-401A R-22/152a/124 (53,0/13,0/34,0) 94,4 -34,4/-28,8 0,10 NF A1 1 100 3 500 0,02

R-401B R-22/152a/124 (61,0/11,0/28,0) 92,8 -35,7/-30,8 0,11 NF A1 1 200 3 800 0,03

R-401C R-22/152a/124 (33,0/15,0/52,0) 101 -30,5/-23,8 0,083 NF A1 880 2 800 0,02

R-402A R-125/290/22 (60,0/2,0/38,0) 101,5 -49,2/-47,0 0,27 NF A1 2 700 5 800 0,01

R-402B R-125/290/22 (38,0/2,0/60,0) 94,7 -47,2/-44,9 0,24 NF A1 2 400 5 600 0,02

R-403A R-290/22/218 (5,0/75,0/20,0) 92 -44,0/-42,3 0,24 0,480 A2 3 100 5 300 0,03

R-403B R-290/22/218 (5,0/56,0/39,0) 103,3 -43,8/-42,3 0,29 NF A1 4 500 5 600 0,02

R-404A R-125/143a/134a (44,0/52,0/4,0) 97,6 -46,6/-45,8 0,52 NF A1 4 200 6 600

R-406A R-22/600a/142b (55,0/4,0/41,0) 89,9 -32,7/-23,5 0,14 0,302 A2 1 800 5 000 0,04

R-407A R-32/125/134a (20,0/40,0/40,0) 90,1 -45,2/-38,7 0,31 NF A1 2 100 4 500

R-407B R-32/125/134a (10,0/70,0/20,0) 102,9 -46,8/-42,4 0,33 NF A1 2 800 5 400

R-407C R-32/125/134a (23,0/25,0/52,0) 86,2 -43,8/-36,7 0,29 NF A1 1 700 4 100

R-407D R-32/125/134a (15,0/15,0/70,0) 91 -39,4/-32,7 0,25 NF A1 1 600 4 000

R-407E R-32/125/134a (25,0/15,0/60,0) 83,8 -42,8/-35,6 0,27 NF A1 1 500 3 900

R-407F R-32/125/134a (30,0/30,0/40,0) 82,1 -46,1/-39,7 0,32 NF A1 1 800 4 200

R-408A R-125/143a/22 (7,0/46,0/47,0) 87 -45,5/-45,0 0,33 NF A1 3 400 6 200 0,02

R-409A R-22/124/142b (60,0/25,0/15,0) 97,4 -35,4/-27,5 0,12 NF A1 1 500 4 400 0,03

R-409B R-22/124/142b (65,0/25,0/10,0) 96,7 -36,5/-29,7 0,12 NF A1 1 500 4 400 0,03

R-410A R-32/125 (50,0/50,0) 72,6 -51,6/-51,5 0,42 NF A1 2 100 4 400

R-410B R-32/125 (45,0/55,0) 75,6 -51,5/-51,4 0,43 NF A1 2 200 4 600
56 2014 TOC Refrigeration, A/C and Heat Pumps Assessment Report

R-411A R-1270/22/152a) (1,5/87,5/11,0) 82,4 -39,7/-37,2 0,074 0,186 A2 1 600 4 700 0,03

R-411B R-1270/22/152a (3,0/94,0/3,0) 83,1 -41,6/-41,3 0,044 0,239 A2 1 700 5 000 0,03

R-412A R-22/218/143b (70,0/5,0/25,0) 88,2 -36,4/-28,8 0,17 0,329 A2 3 000 5 800 0,02

R-413A R-218/134a/600a (9,0/88,0/3,0) 104 -29,3/-27,6 0,21 0,375 A2 2 000 4 000

R-414A R-22/124/600a/142b 

(51,0/28,5/4,0/16,5) 96,9 -34,0/-25,8 0,10 NF A1 1 400 4 100 0,03

R-414B R-22/124/600a/142b (50,0/39,0/1,5/9,5) 101,6 -34,4/-26,1 0,096 NF A1 1 300 3 900 0,03

R-415A R-22/152a (82,0/18,0) 81,9 -37,5/-34,7 0,19 0,188 A2 1 500 4 500 0,03

R-415B R-22/152a (25,0/75,0) 70,2 -23,4/-21,8 0,15 0,13 A2 560 1 700 0,009

R-416A R-134a/124/600 (59,0/39,5/1,5) 111,9 -23,4/-21,8 0,064 NF A1 1 000 3 000 0,008

R-417A R-125/134a/600 (46,6/50,0/3,4) 106,7 -38,0/-32,9 0,057 NF A1 2 300 4 800

R-417B R-125/134a/600 (79,0/18,3/2,7) 113,1 -44,9/-41.5 0,069 NF A1 3 000 5 700

R-417C R-125/134a/600 (19,5/78,8/1,7) 103,7 –32,7/–29,2 NF A1 1 700 4 200

R-418A R-290/22/152a (1,5/96,0/2,5) 84,6 -41,2/-40,1 0,20 0,31 A2 1 700 5 100 0,03

R-419A R-125/134a/E170 (77,0/19,0/4,0) 109,3 -42,6/-36,0 0,31 0,25 A2 2 900 5 600

R-419B R-125/134a/E170 (48,5/48,0/3,5) 105,2 –37,4/–31,5 A2 2 300 4 900

R-420A R-134a/142b (88,0/12,0) 101,8 -25,0/-24,2 0,18 NF A1 1 400 4 000 0,007

R-421A R-125/134a (58,0/42,0) 111,7 -40,8/-35,5 0,28 NF A1 2 600 5 200

R-421B R-125/134a (85,0/15,0) 116,9 -45,7/-42,6 0,33 NF A1 3 100 5 900

R-422A R-125/134a/600a (85,1/11,5/3,4) 113,6 -46,5/-44,1 0,29 NF A1 3 100 5 800

R-422B R-125/134a/600a (55,0/42,0/3,0) 108,5 -40,5/-35,6 0,25 NF A1 2 500 5 100

R-422C R-125/134a/600a (82,0/15,0/3,0) 113,4 -45,3/-42,3 0,29 NF A1 3 000 5 700

R-422D R-125/134a/600a (65,1/31,5/3,4) 109,9 -43,2/-38,4 0,26 NF A1 2 700 5 300

R-422E R-125/134a/600a (58,0/39,3/2,7) 109,3 –41,8/–36,4 NF A1 2 500 5 100

R-423A 134a/227ea (52,5/47,5) 126 -24,2/-23,5 0,30 NF A1 2 200 4 500

R-424A R-125/134a/600a/600/601a 

(50,5/47,0/0,9/1,0/0,6) 108,4 -39,1/-33,3 0,10 NF A1 2 400 5 000

R-425A R-32/134a/227ea (18,5/69,5/12) 90,3 -38,1/-31,3 0,27 NF A1 1 500 3 700

R-426A R-125/134a/600/601a (5,1/93,0/1,3/0,6) 101,6 -28,5/-26,7 0,083 NF A1 1 400 3 900

R-427A R-32/125/143a/134a 

(15,0/25,0/10,0/50,0) 90,4 -43,0/-36,3 0,29 NF A1 2 200 4 600

R-428A R-125/143a/290/600a 

(77,5/20,0/0,6/1,9) 107,5 -48,3/-47,5 0,37 NF A1 3 700 6 300

R-429A R-E170/152a/600a (60,0/10,0/30,0) 50,8 -26,0/-25.6 0,098 0,052 A3 21 77

R-430A R-152a/600a (76,0/24,0) 64 -27,6/-27,4 0,10 0,084 A3 120 430

R-431A R-290/152a (71,0/29,0) 48,8 -43,1/-43,1 0,10 0,044 A3 46 170

R-432A R-1270/E170 (80,0/20,0) 42,8 -46,6/-45,6 0,002 1 0,039 A3 1,6 5,5

R-433A R-1270/290 (30,0/70,0) 43,5 -44,6/-44,2 0,005 5 0,036 A3 4 15

R-433B R-1270/290 (5,0/95,0) 44 -42,7/-42,5 0,025 0,025 A3 4,8 17

R-433C R-1270/290 (25,0/75,0) 43,6 -44,3/-43,9 0,006 6 0,032 A3 4,2 15

R-434A R-125/143a/134a/600a 

(63,2/18,0/16,0/2,8) 105,7 -45,0/-42,3 0,32 NF A1 3 300 5 800

R-435A R-E170/152a (80,0/20,0) 49 -26,1/-25,9 0,09 0,069 A3 30 110

R-436A R-290/600a (56,0/44,0) 49,3 -34,3/-26,2 0,073 0,032 A3 12 43

R-436B R-290/600a (52,0/48,0) 49,9 -33,4/-25,0 0,071 0,033 A3 12 45

R-437A R-125/134a/600/601 (19,5/78,5/1,4/0,6) 103,7 -32,9/-29,2 0,081 NF A1 1 700 4 200

R-438A R-32/125/134a/600/601a 

(8,5/45,0/44,2/1,7/0,6) 99,1 -43,0/-36,4 0,079 NF A1 2 200 4 700

R-439A R-32/125/600a (50,0/47,0/3,0) 71,2 -52,0/-51,8 0,34 0,304 A2 2 000 4 200

R-440A R-290/134a/152a (0,6/1,6/97,8) 66,2 -25,5/-24,3 0,14 0,124 A2 170 590

R-441A R-170/290/600a/600 (3,1/54,8/6,0/36,1) 48,3 -41,9/-20,4 0,006 3 0,032 A3 5,6 20

R-442A R-32/125/134a/152a/227ea 

(31,0/31,0/30,0/3,0/5,0) 81,8 –46,5/–39,9 0,33 NF A1 1 900 4 200

R-443A R-1270/290/600a (55,0/40,0/5,0) 43,5 –44,8/–41,2 A3 4 15

R-444A R-32/152a/1234ze(E) (12,0/5,0/83,0) 96,7 –34,3/–24,3 A2L 93 330

R-444B R-32/1234ze(E)/152a (41,5/48,5/10) 72,8 –44,6/–34,9 A2L 310 1 100

R-445A R-744/134a/1234ze(E) (6,0/9,0/85,0) 103,1 –50,3/–23,5 A2L 120 350

R-446A R-32/1234ze(E)/600 (68,0/29,0/3,0) 62 –49,4/–44,0 A2L 480 1 700
2014 TOC Refrigeration, A/C and Heat Pumps Assessment Report 57

R-447A R-32/125/1234ze(E) (68,0/3,5/28,5) 63 –49,3/–44,2 A2L 600 1 900

R-448A R-32/125/1234yf/134a /1234ze(E) 

(26/26/20/21/7) 86,4 –45,9/–39,8 A1 1 400 3 100

R-449A R-134a/125/1234yf/32 (26/25/25/24) 87,4 –46,0/–39,9 A1 1 400 3 200

R-450A R-1234ze(E)/134a (58/42) 108,7 –23,4/–22,8 A1 570 1 600

R-451A R-1234yf/134a (89,8/10,2) 112,7 –30,8/–30,5 A2L 140 390

R-451B R-1234yf/134a (88,8/11,2) 112,6 –31,0/–30,6 A2L 150 430

R-452A R-1234yf/32/125 (30/11/59) 103,5 –47,0/–43,2 A1 2 100 4 000

Table 2-9: Data summary for azeotropic refrigerant blends Designation Refrigerant Composition Refrigerant (Mass % ) Molecular Weight Normal Boiling 

Point (°C)

ATEL/ODL 

(kg/m3)

LFL (kg/m3)

Safety Class

GWP 100 Year

G

WP 20 Year

ODP

R-500 R-12/152a (73,8/26,2) 99,3 -33,6/-33,6 0,12 NF A1 7 600 8 100 0,5

R-501 R-22/12 (75,0/25,0) 93,1 -40,5/-40,3 0,21 NF A1 3 900 6 700 0,2

R-502 R-22/115 (48,8/51,2) 111,6 -45,3/-45,0 0,33 NF A1 4 600 5 600 0,1

R-503 R-23/13 (40,1/59,9) 87,2 –88 ND NF A1 13 000 11 000 0,6

R-504 R-32/115 (48,2/51,8) 79,2 –57 0,45 NF A1 4 100 4 200 0,1

R-507A R-125/143a (50,0/50,0) 98,9 -47,1/-47,1 0,53 NF A1 4 300 6 700

R-508A R-23/116 (39,0/61,0) 100,1 -87,4/-87,4 0,23 NF A1 12 000 9 200

R-508B R-23/116 (46,0/54,0) 95,4 -87,4/-87,0 0,2 NF A1 12 000 9 400

R-509A R-22/218 (44,0/56,0) 124 -40,4/-40,4 0,38 NF A1 5 800 6 100 0,01

R-510A R-E170/600a (88,0/12,0) 47,2 -25,2/-25,2 0,087 0,056 A3 3,3 9,8

R-511A R-290/152a (95,0/5,0) 44,8 -42,18/-42,1 0,092 0,038 A3 12 44

R-512A R-134a/152a (5,0/95,0) 67,2 -24,0/-24,0 0,14 0,124 A2 210 710

R-513A R-1234yf/134a (56/44) 108,4 -29,2 A1 600 1 700

2.3.1 Data sources

2.3.1.1 Data sources for Table 2-7

Chemical Formula, Chemical Name, and Boiling Point: ISO 817 (ISO 817:2014) is used 

as first priority, ISO 5149 (ISO 5149:2014) as second priority and ASHRAE 34 (ASHRAE

34-2013) as third priority.

Molecular Weight: Calculated from the sum of atoms making up the molecule (based on the 

chemical formula). The atomic weights are from IUPAC (Wieser, 2013).

ATEL/ODL and LFL: Taken from ISO 5149 (ISO 5149:2014).

Safety Class: ISO 817 (ISO 817:2014) is used as first priority, ISO 5149 (ISO 5149:2014) as 

second priority and ASHRAE 34 (ASHRAE 34-2013) as third priority.

Atmospheric Lifetime: Values are taken from Table 5.1 and Table 5.3 in (WMO, 2014) 

where available, (IPCC, 2014) is used as 2nd priority, (WMO, 2011) is used as 3rd priority, and 

(IPCC, 2007) is used as 4th priority.

Radiative Efficiency: Values are taken from (IPCC, 2014) where available and (IPCC, 2007) 

is used as 2nd priority. (WMO, 2014) and (WMO, 2011) do not give radiative efficiencies.

GWP 100 Year: Values are taken from (WMO, 2014) where available, Table 8.A.1 in 

(IPCC, 2014) is used as 2nd priority, (WMO, 2011) as 3rd priority (HC-290), Table 2-14 and 2-
58 2014 TOC Refrigeration, A/C and Heat Pumps Assessment Report

15 in (IPCC, 2007) as 4th priority (HE-E170 and hydrocarbons), and for the remaining 

refrigerant (HC-600a, HC-601, HC-601a) the approximation of ~20 from (UNEP, 2011) is 

reused. When considering the GWP values for other hydrocarbons, it seems ~20 is likely to be 

a conservative number. GWPs are direct GWPs except for hydrocarbons, which are indirect 

GWPs (e.g., including climate impact of breakdown product). Under UNFCCC accounting, 

only direct GWP is used. 

GWP 20 Year: Values are taken from (WMO, 2014) where available, Table 8.A.1 in (IPCC, 

2014) is used as 2nd priority, (WMO, 2011) does not contain GWP 20 year numbers for the 

remaining refrigerants therefor (IPCC, 2007) is used as 3rd priority. Where values are not 

available from the above sources (HE-E170 and hydrocarbons, all with short atmospheric 

lifetimes) the GWP 20 year will be calculated from GWP 100 year using the approximation 

derived here:

Note that for substance x the GWP of time horizon y is GWPx(y) =aGWPx(y)/aGWPCO2(y), 

and for substances with short atmospheric lifetimes note that a GWP (20 year) is close to a

GWP (100 year), since the substance will be practically removed from the atmosphere within 

the first 20 years and no additional radiative forcing will be added between the 20th and the 

100th year. This makes it possible to estimate GWP (20 year):

(eq. 2.1)

GWP for hydrocarbons includes breakdown products (as opposed to the GWP for HFCs), part 

of the GWP will come from CO2, where the 20 year GWP is 1, so the above formula will give 

GWP 20 values that are slightly too high. This is, however, the approach that has been chosen 

here for these substances.

ODP: Values are taken from (WMO, 2014) where available, (WMO, 2011) is used as 2

nd

priority (for HCFC-123), (WMO, 2007) as 3rd priority (for HCFC-124), and the Montreal 

protocol as 4th priority (for CFC-13).

2.3.1.2 Data sources for Tables 2-8 and 2-9

Molecular weight, GWP 100 Year, GWP 20 Year, ODP: Calculated based on data for 

single components given in Table 2-7. The resulting GWP values are rounded to 2 significant 

digits, since, as mentioned in section 2.1.5, the uncertainty for the GWP values is on the order 

of ±20% for very long lived gases and even larger for shorter lived gases.

Refrigerant Composition, Bubble Point/Dew Point (°C), Safety Class: ISO 817 (ISO 

817:2014) 1st priority, ISO 5149 (ISO 5149:2014) in principle 2nd priority, ASHRAE 34 

(ASHRAE 34-2013) 3rd priority. No information for these tables were simultaneously 

available in ISO 5149 and not in ISO 817, which is why ISO 5149 is in principle only the 

2

nd priority. Where dual safety classes are given in the standards, the higher is used.

ATEL/ODL, LFL: Values are taken from ISO 5149 (ISO 5149:2014).
2014 TOC Refrigeration, A/C and Heat Pumps Assessment Report 59

2.4 Concluding remarks

This chapter discussed and provided tabular summaries for identifiers as well as physical, 

safety, and environmental data for refrigerants including the summary descriptions of 

refrigerants discussed elsewhere in this report.

Whatever refrigerant is chosen will always have to be a balance between several factors, the 

availability and cost of the refrigerant (and the associated equipment), the system energy 

efficiency, the safety and convenience of applicability, environmental issues and many more.

The refrigerants which have emerged since the last assessment report in 2010 address climate 

concerns, with climate impacts considerably lower than most of the currently used substances, 

and ozone depletion concerns with the replacement refrigerants for ozone-depleting 

substances. Among the new refrigerants are several blends based on unsaturated HFCs and a 

new unsaturated HCFC molecule. Most of these are refrigerants with lower flammability

(2L), raising the question of how to handle flammability. 

The perfect refrigerant does not exist, and is unlikely to come into existence. The choice will

therefore be a selection between the existing low GWP refrigerants (e.g. R-717, R-744 or 

HCs) and the newly applied and developed chemicals. Many new alternatives are proposed 

which create a challenge in finding the right refrigerant for each application. One of the 

important aspects is that refrigerants with low direct impact on climate change are often 

flammable to some extent.

There is a complex selection process ahead, where the industry will need to find out which of 

the many proposed new or old refrigerants will be used in each application. In some cases this 

may be as simple as changing the refrigerant, while in other cases this will require redesign of 

the system or even change of system topology. The search is a trade-off between cost, safety, 

energy efficiency, and limiting the need for redesign.

Part of the complexity is that the market is unlikely to be able to support many different 

refrigerants for the same application. This will leave a period in time, likely to last a couple of 

decades, where the industry will have to work with both the currently established refrigerants 

and new refrigerants addressing ozone depletion and/or climate change concerns. In the long 

run the number of candidates is likely to fall, but it is too early to tell which or even how 

many of the refrigerant candidates will survive.

2.5 References

ASHRAE 34-2013 ANSI/ASHRAE, 2014. Standard 34- 2013 with addenda a to n, 

Designation and Safety Classification of Refrigerants American 

Society of Heating, Refrigerating, and Air-Conditioning Engineers 

(ASHRAE), Atlanta, GA, USA

Calm, 2012 Calm, J. M., 2012. Refrigerant Transitions... Again. Moving Towards 

Sustainability. Proc. ASHRAE/NIST Conf., American Society of 

Heating Refrigerating, and Air-Conditioning Engineers (ASHRAE), 

Atlanta, GA, USA

Calm, 1997 Calm, J. M., Didion, D. A. 1997. Trade-Offs in Refrigerant Selections 

— Past, Present, and Future. Proc. ASHRAE/NIST Conf. 

‘Refrigerants for the 21

st Century’, American Society of Heating 

Refrigerating, and Air-Conditioning Engineers (ASHRAE), Atlanta, 

GA, USA

Chen, 2012 Chen, Z. H., 2012. Research on Rotary Compressors Based on R-290 

Technology. Proc. UNEP conference on technologies for high 
60 2014 TOC Refrigeration, A/C and Heat Pumps Assessment Report

ambient conditions, Dubai, UAE

Hafner, 2012 Hafner, A., Försterling, S., Banasiak, K. 2012. “Multi-Ejektoren 

Konzept für R-744 Supermarkt-Kälteanlagen”. Proc. DKV-Tagung, 

AA III.06, Würzburg, Germany

Hodnebrog, 2013 Hodnebrog, Ø., Etminan, M., Fuglestvedt, J. S., Marston, G., Myhre, 

G., Nielsen, C. J., Shine, K. P., Wallington, T. J., 2013. Global 

Warming Potentials and Radiative Efficiencies of Halocarbons and 

Related Compounds: A Comprehensive Review. Rev. Geophys., 51, 

300–378, doi:10.1002/rog.20013

IPCC, 1995 Intergovernmental Panel on Climate Change (IPCC) of the World 

Meteorological Organization (WMO) and the United Nations 

Environment Programme (UNEP), 1996. Climate Change 1995 —

Contribution of Working Group I to the Second Assessment Report of 

the Intergovernmental Panel on Climate Change. Edited by J. T. 

Houghton, L. G. Meira Filho, B. A. Callander, N. Harris, A. 

Kattenberg, and K. Maskell, Cambridge University Press, Cambridge, 

UK

IPCC, 2007 Forster, P., V. Ramaswamy, P. Artaxo, T. Berntsen, R. Betts, D.W. 

Fahey, J. Haywood, J. Lean, D.C. Lowe, G. Myhre, J. Nganga, R. 

Prinn, G. Raga, M. Schulz and R. Van Dorland, 2007. Changes in 

Atmospheric Constituents and in Radiative Forcing. In: Climate 

Change 2007: The Physical Science Basis. Contribution of Working 

Group I to the Fourth Assessment Report of the Intergovernmental 

Panel on Climate Change [Solomon, S., D. Qin, M. Manning, Z. 

Chen, M. Marquis, K.B. Averyt, M.Tignor and H.L. Miller (eds.)]. 

Cambridge University Press, Cambridge, United Kingdom and New 

York, NY, USA

IPCC, 2014 Myhre, G., D. Shindell, F.-M. Bréon, W. Collins, J. Fuglestvedt, J. 

Huang, D. Koch, J.-F. Lamarque, D. Lee, B. Mendoza, T. Nakajima, 

A. Robock, G. Stephens, T. Takemura and H. Zhang, 2013. 

Anthropogenic and Natural Radiative Forcing. In: Climate Change 

2013: The Physical Science Basis. Contribution of Working Group I 

to the Fifth Assessment Report of the Intergovernmental Panel on 

Climate Change [Stocker, T.F., D. Qin, G.-K. Plattner, M. Tignor, 

S.K. Allen, J. Boschung, A. Nauels, Y. Xia, V. Bex and P.M. 

Midgley (eds.)]. Cambridge University Press, Cambridge, United 

Kingdom and New York, NY, USA

ISO 817:2014 ISO 817: 2014. Refrigerants — Designation and safety classification. 

International Organization for Standardization (ISO)

ISO 5149:2014 ISO 5149: 2014. Refrigerating systems and heat pumps — Safety and 

environmental requirements. International Organization for 

Standardization (ISO)

Kajihara, 2010 Kajihara, H., Inoue, K., Yoshida, K., Nagaosa, R., 2010. Estimation 

of environmental concentrations and deposition fluxes of R-1234yf 

and its decomposition products emitted from air conditioning 

equipment to atmosphere. Proc. 2010 Int. Symposium on NextGeneration Air Conditioning and Refrigeration Technology, paper 

noNS24, Tokyo, Japan

Luecken, 2010 Luecken, D. J., Waterland, R. L., Taddonio, N., Hutzell, W. T., Rugh, 

J. P., Andersen, S. O., 2010. Ozone and TFA Impacts in North 
2014 TOC Refrigeration, A/C and Heat Pumps Assessment Report 61

America from Degradation of 2,3,3,3-Tetrafluoropropene (HFO1234yf), A Potential Greenhouse Gas Replacement. Environmental 

Science and Technology, 44(1): 44,343–348

McLinden, 2014 McLinden, M. O., Kazakov, A. F., Brown, J. S., Domanski, P. A. 

2014. A thermodynamic analysis of refrigerants: possibilities and 

tradeoffs for low-GWP refrigerants. J. Refrigeration, Volume 38, pp. 

80-92

Minor, 2014 Minor, B., Sulc, V., Berger, J. Kold, M., Hegar, M., 2014. R-404A 

Alternative with Low Compressor Discharge Temperature. Proc. 15th

International Refrigeration and Air Conditioning Conference at 

Purdue, IN, USA

Papasavva, 2009 Papasavva, S., Luecken, D. J., Waterland, R. L., Taddonio, K. N., 

Andersen, S. O., 2009. Estimated 2017 Refrigerant Emissions of 

2,3,3,3-tetrafluoropropene (HFC-1234yf) in the United States 

Resulting from Automobile Air Conditioning. Environmental Science 

and Technology, 43(24):9252–9259

Rajadhyaksha, 2013 Rajadhyaksha, D., Colbourne, D., Sahu, A., Wadia, B. J., 2013. HC290 as an alternative refrigerant for split air conditioning systems in 

high ambient temperatures. Proc. IIF-IIR Compressors, Papiernička,

Slovakia

Shine, 2005 Shine, K.P., Fuglestvedt, J.S., Hailemariam, K., Stuber, N., 2005. 

Alternatives to the global warming potential for comparing climate 

impacts of emissions of greenhouse gases. Climate Change, 68:281-

302

Subiantoroa, 2013 Subiantoroa, A., Ooi, K. T., 2013. Economic analysis of the 

application of expanders in medium scale air-conditioners with 

conventional refrigerants, R-1234yf and CO2. Int. J. Refrig., Vol. 36, 

No. 5, pp. 1472–1482

Wieser, 2013 Wieser, M.E., Holden, N., Coplen, T.B., Böhlke, J. K., Berglund, M., 

Brand, W. A., De Bièvre, P., Gröning, M., Loss, R. D., Meija, J., 

Hirata, T., Prohaska, T., Schoenberg, R., O’Connor, G., Walczyk, T., 

Yoneda, S., Zhu, X.K., 2013. Atomic weights of the elements 2011 

(IUPAC Technical Report). Pure and Applied Chemistry, Vol. 85, 

Issue 5, pp. 1047-1078

WMO, 2007 National Oceanic and Atmospheric Administration (NOAA), 

National Aeronautics and Space Administration (NASA), United 

Nations Environment Programme (UNDP), World Meteorological 

Organization (WMO), and European Commission, 2007. Report No. 

50, Scientific Assessment of Ozone Depletion: 2006

WMO, 2011 National Oceanic and Atmospheric Administration (NOAA), 

National Aeronautics and Space Administration (NASA), United 

Nations Environment Programme (UNDP), World Meteorological 

Organization (WMO), and European Commission, 2011. Report No. 

52, Scientific Assessment of Ozone Depletion: 2010

WMO, 2014 World Meteorological Organization (WMO), 2014, Scientific 

Assessment of Ozone Depletion: 2014, World Meteorological 

Organization, Global Ozone Research and Monitoring Project—

Report No. 55.

UNEP, 2011 UNEP, 2011. 2010 Report of the Refrigeration, Air-Conditioning and 
62 2014 TOC Refrigeration, A/C and Heat Pumps Assessment Report

Heat Pumps Technical Options Committee, United Nations 

Environment Programme (UNEP), Nairobi, Kenya

UNEP, 2012 UNEP, 2012. Handbook for the Montreal Protocol on Substances that 

Deplete the Ozone Layer (Ninth Edition), United Nations 

Environment Programme (UNEP), Ozone Secretariat, Nairobi, Kenya

Website

AHRI, 2013 Site for Low-GWP AREP Test reports: www.ahrinet.org/

resources/research tab - then AHRI Low-GWP Alternate Refrigerants 

Evaluation Program for list of downloadable test reports
2014 TOC Refrigeration, A/C and Heat Pumps Assessment Report 63
64 2014 TOC Refrigeration, A/C and Heat Pumps Assessment Report

Annex to chapter 2 - safety standards and regulations

With the introduction and potentially wide use of refrigerants that are flammable, have higher 

toxicity and/or operate at notably higher pressures than the conventional ODS refrigerants or 

alternative non-flammable HFC refrigerants, consideration of safety matters has become more 

important. Accordingly, more attention is presently being paid to the requirements of safety 

standards and regulations that directly relate to refrigerants that exhibit these characteristics. 

This section summarises the main implications. 

Safety classification of refrigerants

The most widely used classification of substances under the UN, where so-called dangerous 

goods receive a classification according to their main hazards. 

Within the RAC industry, a different classification scheme is applied, where most refrigerants 

are assigned a safety classification, which is a function of toxicity and flammability. The 

classification scheme is adopted by such standards as, ISO 817 and draft EN 378. An 

overview of this was given in section 2.1.4, see also Table 2-2.

The toxicity classification is based on whether toxicity has or has not been identified at 

concentrations of less than 400 ppm by volume, based on data used to determine the threshold 

limit value – time weighted average (TLV-TWA) or consistent indices. There are two toxicity 

classes:

 Class A: no chronic toxicity effects have been observed below 400 ppm

 Class B: chronic toxicity effects have been observed below 400 ppm

The flammability classification depends upon whether or not the substances can be ignited in 

standardised tests, and if so, what the lower flammability limit (LFL) and the heat of 

combustion are. There are three flammability classes (values according to ISO 817): 

 Class 1: do not show flame propagation when tested in air at 60°C and standard 

atmospheric pressure

 Class 2L: as Class 2 but with a (laminar) burning velocity of less than 0.10 m/s

 Class 2: exhibit flame propagation when tested at 60°C and atmospheric pressure, but 

have a LFL higher than 3.5% by volume, and have a heat of combustion of less than 

19,000 kJ/kg

 Class 3: exhibit flame propagation when tested at 60°C and atmospheric pressure, but 

have an LFL at or less than 3.5% by volume, or have a heat of combustion that is equal to 

or greater than 19,000 kJ/kg

Class 2L is now included in ISO 817, ISO 5149 and proposed for inclusion in EN 378. It is 

primarily intended to differentiate between HFC-152a and the remainder of class 2 

refrigerants (such as R-717, HFC-32 and HFC-1234yf), which tend to be more difficult to 

ignite and is less likely to evolve overpressures that could cause damage.

Typically, a “higher” the classification – that is toxicity Class B instead of Class A, and 

flammability Class 3 instead of Class 1 – means that the refrigerating system has more 

onerous design requirements associated with it, in order to handle the higher risk presented by 

the refrigerant. 

Lower Flammability Limit

The lower flammability limit (LFL) of flammable refrigerants is typically applied as a 

constraint to the amount of refrigerant that can be released into a room or enclosure, as it 
2014 TOC Refrigeration, A/C and Heat Pumps Assessment Report 65

represents the smallest quantity that, when in the presence of an active source of ignition, 

could sustain a flame.

Acute Toxicity Exposure Limit

The acute toxicity exposure limit (ATEL) of any refrigerant may also applied as a constraint 

to the amount of refrigerant that can be released into a room or enclosure, as it represents the 

smallest quantity that could impose adverse toxicological effects onto occupants.

Practical Limit

There is a further safety measure for the application of refrigerants, termed the practical 

concentration limit (PL). This represents the highest concentrations level in an occupied space 

which will not result in any escape impairing (i.e., acute) effects. Thus, it is principally, the 

lowest “dangerous” concentration of a refrigerant, with a safety factor applied. The estimation 

of PL is based on the lowest of the following:

 Acute toxicity exposure limit (ATEL), based on mortality (in terms of LC50) and/or 

cardiac sensitisation, and/or anaesthetic or central nervous system (CNS) effects

 Oxygen deprivation limit (ODL)

 20% of the lower flammability limit (or 25% in ASHRAE 34)

For class A1 (and A2L) and class B refrigerants, the PL is normally based on the ATEL, 

whereas for A2 and A3 refrigerants it is normally dictated by the LFL. For some refrigerants 

the PL is based on historical use experience.

Relevant safety standards

Unlike conventional refrigerants, almost all of the low GWP refrigerants have safety 

characteristics, which demand greater attention, such as flammability, toxicity and higher 

operating pressures. Safety standards (and industry codes of practice) provide guidance to 

offset the additional risks posed by the more hazardous characteristics of the substances. 

Safety standards are generated internationally (e.g., ISO, IEC), regionally (e.g., EN) and 

nationally. Often there are parallels or alignment between standards of similar scope across 

these different levels, although individual countries elect to adopt alternative requirements 

than those at international level. The main international and regional standards that affect 

design and construction of systems as a function of refrigerant selection are listed in Table 

A2-1 and the scope according to the sections in this report is identified.

Table A2-1: Scope of different international and regional safety standards for AC&R 

systems

Chapter/Sector IEC 

60335-

2-24

IEC 

60335-

2-40

IEC 

60335-

2-89

ISO 

5149

ISO 

13043

EN 378

3 / Domestic refrigeration ×

4 / Commercial refrigeration × × ×

5 / Industrial systems × ×

6 / Transport refrigeration [×] ×
66 2014 TOC Refrigeration, A/C and Heat Pumps Assessment Report

7 / Air-to-air air conditioners

 and heat pumps

× × ×

8 / Water heating heat pumps × × ×

9 / Chillers × × ×

10 / Vehicle air conditioning ×

The three important characteristics that differ amongst refrigerants that have a strong 

influence over the design and construction requirements are pressure, flammability and 

toxicity. Typically, the more severe these characteristics (i.e., higher pressure, higher 

flammability, higher toxicity), the more onerous the requirements are. In principle, these more 

onerous requirements are intended to offset the potentially worse consequences arising from 

the more severe characteristics. Table A2-2 provides a summary of the main measures that 

may require attention when adopting such refrigerants

Table A2-2: Main measures to be considered for substances with greater pressure, toxicity 

and/or flammability

Greater pressure Greater toxicity Greater flammability

Thicker materials/higher 

pressure rating for pipes and 

components

Additional use of pressure relief 

devices and/or pressure limiting 

devices

Higher competencies for 

workers involved in construction 

of components and assemblies

Stricter limits on the quantity of 

refrigerant in occupied spaces

Limited use in more densely 

populated areas

Use of gas detection, alarms and 

emergency ventilation

Provision of personal protective 

equipment

Stricter limits on the quantity of 

refrigerant in occupied spaces

Use of gas detection, alarms and 

emergency ventilation

Prohibition of items that could 

act as sources of ignition

Warnings/signage

One critical issue within the various standards, particularly for flammable and higher toxicity 

refrigerants is the allowable and maximum refrigerant charge. Depending upon the type of 

occupancy, different approaches are used to determine such values. Table A2-3 provides 

some indicative charge limits (per refrigerant circuit) based on ISO 5149:2014 for selected 

situations and a number of commonly discussed refrigerants. 

Although these safety standards cover requirements for flammable refrigerants, it is important 

to highlight that in many countries specific standards for equipment using flammable gases 

are available and are generally linked to legislation. For example, in Europe products which 

are placed on the market (except for those that are exempt) and that use flammable gases 

(including refrigerants) must meet the essential health safety requirements (EHSRs) of the 

Atex product directive (94/9/EC). By following the Atex harmonized standards, there is a 

presumption of conformity. Since none of the AC&R safety standards are harmonized to 

Atex, safety standards such as EN 1127-1 can be used for the evaluation of flammability 

safety; provided that AC&R equipment meets the requirements of such standards then 

deviations from the AC&R standards is acceptable if equivalent safety is demonstrated (for 

example, where larger refrigerant charges are needed.) In addition to meeting the EHSRs, the 

general approach prescribed by flammable gas standards and regulations is summarised:
2014 TOC Refrigeration, A/C and Heat Pumps Assessment Report 67

 Identification of explosion hazards and determination of the likelihood of occurrence of a 

hazardous atmosphere;

 Identification of ignition hazards and determination of the likelihood of occurrence of 

potential ignition sources;

 Estimation of the possible effects of an explosion in case of ignition;

 Evaluation of the risk and whether the intended level of protection has been achieved;

 Consideration of and application of measures to reduce of the risks

Table A2-3 provides the result of calculations for determination of allowable and maximum 

charge sizes (per refrigerant circuit) for a selection of commonly discussed refrigerants. 

Table A2-3: Summary of PL and charge size limits for selected refrigerant and occupancies 

according to ISO 5149 Refrigerant 

Class

Example 

Refrigerant

Practical 

Limit (g/m

3

)

Allowable Charge in a 

15 m

2 Occupied Space 

(comfort)

† (kg)

Allowable 

Charge in a 

15 m

2 Occupied 

Space 

(general)* (kg)

Max. Charge in an 

Occupied Space 

(Occupancy A)

Max Charge in Open 

Air or Machinery Room

Max Charge for a 

Ventilated Enclosure

A1

HCFC-22 300 11.3 11.3

PL×RVδ no limit no limit

HFC-134a 250 9.4 9.4

R-404A 520 19.5 19.5

R-407C 310 11.6 11.6

R-410A 440 16.5 16.5

R-744 100 3.8 3.8

A2L

HFC-32 61 1.3 – 4.9 2.3 12 (60‡) no limit 60

HFC-1234yf 58 1.2 – 4.5 2.2 11 (56‡) no limit 56

HFC-1234ze 61 1.3-4.8 2.3 12 (59‡) no limit 59

A2 HFC-152a 27 0.5 – 1.7 1.0 3.4 no limit 17

A3

HC-600a 11 0.1 – 0.4 0.3 1.5 no limit 5.6

HC-290 8 0.1 – 0.4 0.3 1.5 no limit 4.9

HC-1270 8 0.1 – 0.3 0.3 1.5 no limit 6.0

B2L R-717 0.35 0.01 0.01 4.5 no limit 23

δ For systems with multiple indoor heat exchangers a higher charge may be allowed depending on circumstances; 

‡ For systems with multiple indoor heat exchangers; † Depending upon installation conditions; * 2.5 m high room

Note: Allowable and maximum charges are per individual refrigerant circuit

Note: The values provided within this table are indicative and determination of refrigerant charge size limits for 

particular types of systems and installation locations requires the use of the standard and the values within this 

table should not be taken as a substitute.
68 2014 TOC Refrigeration, A/C and Heat Pumps Assessment Report

References

EN 1127-1 EN 1127-1:2011, Explosive atmospheres – Explosion prevention and 

protection. Part 1: Basic concepts and methodology 

EN 378 EN 378-1:2008+A2:2012, EN 378-2:2008+A2:2012, EN 378-

3:2008+A1:2012. EN 378-4:2008+A1:2012, Refrigeration Systems 

and Heat Pumps – Safety and Environmental Requirements

IEC 60335-2-24 IEC 60335-2-24:2010, Specification for safety of household and 

similar electrical appliances. Particular requirements for refrigerating 

appliances, ice-cream appliances and ice-makers

IEC 60335-2-40 IEC 60335-2-40:2003+A13:2012, Specification for safety of 

household and similar electrical appliances. Safety. Particular 

requirements for electrical heat pumps air-conditioners, and 

dehumidifiers

IEC 60335-2-89 IEC 60335-2-89:2010, Specification for safety of household and 

similar electrical appliances. Safety. Particular requirements for 

commercial refrigerating appliances with an incorporated or remote 

refrigerant condensing unit or compressor

ISO 13043 ISO 13043:2011, Road vehicles – Refrigerant systems used in mobile 

air conditioning systems (MAC) – Safety requirements

ISO 817 ISO 817: 2014, Refrigerants — Designation and safety classification. 

International Organization for Standardization (ISO)

ISO 5149 ISO 5149: 2014, Refrigerating systems and heat pumps — Safety and 

environmental requirements. International Organization for 

Standardization (ISO)
2014 TOC Refrigeration, A/C and Heat Pumps Assessment Report 69

Chapter 3

__________________________________________________________

Domestic Appliances

Chapter Lead Author

Sukumar Devotta

Co-Authors

Martien Janssen

Richard DeVos
70 2014 TOC Refrigeration, A/C and Heat Pumps Assessment Report
2014 TOC Refrigeration, A/C and Heat Pumps Assessment Report 71

3 Domestic appliances

3.1 Introduction

Under the domestic appliance category, the domestic refrigeration sub-sector is the major 

component and comprises appliances that are broadly used domestically, such as refrigerators, 

freezers and combined refrigerator/freezer products. Small beverage dispensing machines are 

similar products and are commonly included in domestic refrigeration, but represent a small 

fraction of total units. Domestic dehumidifiers have not been considered in this chapter. For 

domestic wine coolers the same considerations as for domestic refrigerators apply.

Approximately 170 million domestic refrigerators and freezers are produced annually. The 

vast majority are used for food storage in residential dwellings, with a significant minority 

used in offices for domestic purposes and small businesses for commercial purposes. Typical 

storage volumes range from 20 to 850 litres. Various fundamental design approaches and 

consumer convenience features are included within the product offerings. A typical product 

contains a factory-assembled, hermetically sealed, vapour-compression refrigeration system 

employing a 50 to 250 W induction motor and containing 20 to 250 grammes of refrigerant. 

Some topics discussed below have been covered in earlier reports of this committee. They are 

briefly included here to provide a more comprehensive perspective. Niche market products in 

some cases employ alternative technologies to vapour-compression refrigeration. The age 

distribution of the global installed products is extremely broad (Weston, 1997) with median 

age estimates ranging from 9 to 19 years at retirement. Long product life and high volume 

annual production combine for an estimated 2000 to 2300 million unit global installed 

inventory.

The other domestic appliance covered in this chapter is the heat pump clothe (laundry) dryer 

(HPCD), which is emerging in the market as an energy efficient alternative to the electric 

heater dryer. It is included in this chapter for the first time and the title has been accordingly 

modified as “Domestic Appliances” instead of “Domestic Refrigerators” used earlier (UNEP, 

2010). The market for HPCD is fast growing in the EU (while it is very limited in the US and 

other parts of the world). There are manufacturers from EU and Japan. These dryers mostly 

use HFC-134a as a refrigerant and charge amounts vary from 200 to 400 g, though the 

continued use of HFC-134a is under discussion in several global regions. HPCDs using HC290 have been just introduced. The market share of heat pump clothe dryers in Europe was 

about 4% in 2009 or about 200,000 shipments per year (out of 4.9 million total clothe dryer 

sales). The largest market shares in EU are Austria, Germany, Italy and Switzerland. It is 

projected that in EU, HPCDs would continue to gain market share in the next few years. The 

total annual sale of heat pump tumble dryers in 2013 is estimated at 1.5 million. An American 

study has concluded that HPCDs have positive economic benefits only for households with 

high clothe dryer usage or with high electricity prices and moderately high utilization 

(Meyers, 2010). The current market share in Article 5 countries for this product is almost 

negligible.

The ozone depletion potential (ODP) and global warming potential (GWP) values of the 

refrigerants mentioned in this chapter are given in chapter 2 of this report.
72 2014 TOC Refrigeration, A/C and Heat Pumps Assessment Report

3.2 Options for new equipment

Globally, new refrigerator production conversion from use of ODS was essentially completed 

by 2008. HC-600a or HFC-134a continue to be the refrigerant options for new production. No 

other new refrigerant has matured to become an energy-efficient and cost-competitive 

alternative. Refrigerant migration from HFC-134a to HC-600a is expected to continue, driven 

either by local regulations on HFCs or by the desire for reduced global warming impact from 

potential emissions. Excluding any influence from regulatory interventions, it is still projected 

that by 2020 about 75% of new refrigerator production will use HC-600a (possibly with a 

small share by unsaturated HFC refrigerants) and the rest will use HFC-134a. This is further 

discussed in section 3.2.2.

Besides the choice of alternative refrigerants, there are more aspects to consider with respect 

to the environmental impact of the equipment, such as energy efficiency improvements (see 

3.2.5), recycling and end of life issues (see 3.4).

Domestic heat pump clothe dryers have only recently entered the market using mostly HFC134a, R-407C and HC-290 to a small extent. They do not have any significant historical use 

of CFCs or HCFCs. The refrigeration circuit differs from domestic refrigeration by its very 

high evaporation temperature (typical 10 to 30oC) and high condensation temperature (up to 

70oC). Rotary as well as reciprocating compressors are being employed.

3.2.1 Alternatives for domestic refrigerators 

HC-600a: HC-600a is the main energy-efficient and cost-competitive alternative. Concerns with the 

high flammability, which existed at the introduction of the refrigerant in 1994 in Europe have been 

addressed with design features and safety standards, particularly as the charges required for 

domestic refrigeration are below 150 g. When the safety requirements are met (e.g. IEC 60335-2-

24) and adequate risk assessment to address the flammable nature of the refrigerant, HC-600a is the 

ideal refrigerant for domestic refrigeration products, giving roughly 5 % higher efficiency than 

HFC-134a while at the same time reducing noise level of the unit. 

According to a recent study for a review of the European Regulation (EC) on fluorinated gases 

(Schwarz et al., 2013), the investment cost for a manufacturing facility for domestic 

refrigerators using HC-600a is 1.7% higher than for HFC-134a, which represents an incremental 

product costs of around €7/unit, considering European averages. This is basically due to higher 

production costs related to the requirements for safety systems. The report also mentions that 

annual running costs and lifetime cost of HC-600a equipment are lower, resulting in an overall 

negative life cycle cost differential in case of HC-600a. 

In general there are no significant barriers to the use of HC-600a, illustrated by the existence of 

over 500 million domestic fridges in the market to date. However, in the USA the use of HC600a is almost non-existent and this can be attributed to a number of factors. These include 

general concerns regarding public safety (or the perception of), concerns about flammability 

safety and accidents (which are reflected in the restrictive national standards) and the reluctance 

to be one of the early movers in the region. However, during recent years this situation is 

changing which is discussed in section 3.2.2.

HC-600a was the standard refrigerant for European domestic refrigerators and freezers 

originally and proliferated into other regions, including Article 5 countries. Worldwide over 50 

million appliances are produced annually with HC-600a. Increased energy efficiency and the 

low GWP of the HC-600a refrigerant reduce the climate impact of household refrigerators, due 

to mitigation of direct (refrigerant) and indirect (CO2 associated with electricity consumption) 

GHG emissions, compared to HFC-134a.
2014 TOC Refrigeration, A/C and Heat Pumps Assessment Report 73

In the past, where capital resources were constrained, the use of binary hydrocarbon blends 

(HC-600a and HC-290) allowed matching the volumetric capacity of previously used 

refrigerants to avoid investments required to modify compressor manufacturing tools. These 

blends result in a reduction in thermodynamic efficiency versus pure HC-600a and most of 

the productions using blends have migrated to the use of pure HC -600a. The use of HC 

blends has become insignificant and is not further discussed in this chapter. 

HFC-134a: HFC-134a was originally the predominant refrigerant for domestic refrigeration since 

the phase-out of CFC-12. There are no significant safety implications concerning its use. Energy 

efficiency is similar to that of CFC-12, although with continual optimization, the current HFC134a refrigeration units are considerably more efficient than those that used CFC-12. 

HFC-1234yf: It is feasible to use HFC-1234yf in domestic refrigerators and freezers and its 

application can be considered as some way between the use of HFC-134a and HC-600a, since 

the pressure and capacity are slightly lower than for HFC-134a and it has lower flammability 

characteristics than HC-600a. The lower flammability makes application easier for countries 

like USA that have limitations with respect to the allowable refrigerant charge for HC-600a. 

The experience with HC-600a has shown that design changes and investment can abate the 

risk to an acceptable risk level given the lower flammability of HFC-1234yf. 

According to some industrial sources, initial developments to assess the use of HFC-1234yf in 

domestic refrigeration have begun, but it is not being pursued with high priority, as in 

automotive applications (see Chapter 10). The preliminary assessment is that HFC-1234yf has 

the potential for comparable efficiency to HFC-134a, although often slightly worse in 

practice. Long term reliability tests for capillary tube restriction due to chemical degradation 

have not been completed. As such, product costs are estimated to be 1% higher than for HFC134a technology due to the larger surface area of heat exchangers required (to account for 

poorer energy performance) and an additional 1% due to the higher costs of the refrigerant.

Given the cost disadvantage, flammability and investment requirements for product 

development, HFC-1234yf suffers significant disadvantages. With the lack of activity by 

manufacturers, HFC-1234yf is not likely to displace HC-600a or HFC-134a in the foreseeable 

future.

HFC-1234ze: This refrigerant is still in an early exploration phase (Karber, 2012, Leighton, 

2011). The same considerations with respect to flammability as for HFC-1234yf hold. In 

addition, compressor adaptations are required to match the reduced volumetric capacity 

compared to HFC-134a. Therefore, also this refrigerant is not likely to displace HC-600a or 

HFC-134a in the foreseeable future.

R-744: Currently, experience on the use of R-744 is available from a large number of bottle 

coolers, which have been in use since many years, and are similar, low-charged applications. These 

are further discussed in Chapter 4.

R-744 application implies an additional cost, which can be attributed to the greater mass of 

materials necessary to achieve protection against the high pressure level, this in particular for 

the compressor. Further concerns are the extremely small compressor swept volume 

requirements and reduced thermal efficiency (Beek and Janssen, 2008). These concerns and 

the fact that other low GWP alternatives are available make it unlikely that R-744 will 

become commercialized. Moreover, no major domestic refrigerator manufacturer is actively 

developing R-744 systems.
74 2014 TOC Refrigeration, A/C and Heat Pumps Assessment Report

3.2.2 Conversion of HFC-134a domestic refrigerators to low GWP alternatives

Current industry dynamics include increasing migration from HFC-134a to lower GWP 

alternatives. Commercial conversion to date has been restricted to HC-600a. European 

production of No-frost side by side refrigerators began conversion from HFC-134a to HC600a in the early 2000’s. Initial conversions of automatic defrost refrigerators in Japan from 

HFC-134a to HC-600a were discussed in the 2006 report of this committee (UNEP, 2006). 

This conversion, motivated by global warming considerations, has progressed to include more 

than 90 % of refrigerator production in Japan.

The North American appliance market is dominated by HFC-134a while the conversion to 

HC continues in the rest of the world. Several factors are uniquely weighted in the North 

American market that has caused this delay including litigation costs, increased intensity by 

the Consumer Product Safety Commission, local regulations requiring adherence to ASHRAE 

15 and 34 standards, product cost differential for additional safety features, investment costs 

to meet in plant OSHA safety requirements and the investment cost associated with 

serviceability of a refrigerant that must be recovered. In the EU, protection is provided by the 

EU Directive 2001/95/EC on general product safety. North American manufacturers have 

consequently elected to develop additional costly safety requirements in addition to third 

party standards prior to introduction of HC-600a to appliances.

Whilst legal concerns have so far limited the use of HC-600a in USA, a major U.S. 

manufacturer introduced an auto-defrost refrigerators using HC-600a refrigerant to the U.S. 

market in 2010. This introduction was a significant departure from prior North American 

practices for domestic refrigeration. In 2011, US EPA approved HC-600a as acceptable 

alternative under their Significant New Alternatives Policy Program (SNAP) for household and 

small commercial refrigerators and freezers, subject to certain conditions. Conditions included 

a limitation on charge to 57 g (note that substitution will be on an equal-molar basis, i.e. 100 

grams of HFC-134a will be replaced by 57 g of HC-600a) and the requirement that products 

comply with the revised UL 250. Concurrently, the number of HC-based refrigerator models 

offered by manufacturers based in Central and South America are rising as well.

The trend of new production conversion to hydrocarbon refrigerants will continue. Excluding 

any influence from government regulatory intervention, it is still projected that 75% of new 

refrigerator production will use HC-600a or any other alternative low GWP refrigerants and 

25% will use HFC-134a by 2020 (UNEP, 2010). This estimated migration is shown 

schematically in Figure 3-1. Estimated conversion extents are based on the following 

assumptions:

1. All current HC-600a applications will continue.

2. One-half of HFC-134a applications in geographic areas where forced convection, auto 

defrost refrigerators are the typical configuration will convert to either HC-600a or a new 

development alternative refrigerant such a low GWP unsaturated halocarbon refrigerants 

such as HFC-1234yf, e.g. in cases where HC charge limitations are a factor. 

3. Three-fourths of HFC-134a applications in geographic areas where natural convection 

and/or manual defrost refrigerators are the typical configuration will convert to HC-600a 

or to low GWP HFC alternatives. This is driven by the advantages of HC-600a versus 

HFC-134a discussed earlier and production rationalization.

4. Use of low GWP unsaturated HFC refrigerants will require successful addressing of 

numerous application criteria including: thermal stability, hermetic system chemical 

compatibilities, process fluid compatibilities, contamination sensitivities, etc., in addition 

to cost implications. Successful closure of any identified issues will be necessary to 

permit proceeding with confidence for system reliability. Conversions will be influenced 

by regional market or climate change policy choices. Government regulatory influence 

was not considered.
2014 TOC Refrigeration, A/C and Heat Pumps Assessment Report 75

Figure 3-1: New production refrigerant conversion trend

Technologies to accomplish conversions are readily available, though it needs consideration 

that conversion costs of the production facilities are significant. The rate and extent of 

conversion will be influenced by premium product cost to maintain product safety with 

introduction of flammable refrigerants. Premium costs are for modified electrical components, 

increased use of reduced voltage to avoid electrical arcing and any other safety devices. Cost 

pressures are more significant on models with lower profit margins. However, lower-end 

models include fewer components requiring conversions tend to receive priority. 

3.2.3 Alternatives for tumble dryers

These dryers typically use HFC-134a as a refrigerant and charge amounts vary from 200 to 

400 g. Products using R-407C and HC-290 are also being placed on the market and can 

potentially make use of the temperature glide, if heat exchangers are optimised for such 

refrigerants mixtures. Though the continued use of HFCs is under discussion at several global 

regions, it is also recognised that the use of heat pumps in a dryer lead to significant energy 

savings of 50% or more and to a substantial reduction in global warming impact of countries 

using fossil fuel for power generation. Alternative low GWP refrigerant solutions have not yet 

been introduced in the market, but are being explored. This includes R-744, hydrocarbons and 

low GWP HFCs.

Low GWP refrigerants currently explored are:

 R-744 (CO2): The high temperature glide at the gas cooler side can effectively result in an 

efficient drying process and possibly higher air exit temperatures than possible with 

subcritical refrigerants. High costs of some components and the probable need of an 

effective intercooler in order to reduce gas exit temperatures are the challenges currently 

to be faced.

 Hydrocarbons: In principle various hydrocarbons are suitable. Supply of suitable 

compressors is currently very limited. Safety hazards due to the refrigerant flammability 

need careful evaluation as the laundry dryers pose additional risks compared to domestic 

refrigeration due to the high temperatures involved, the presence of dry textile materials, 

mechanically moving objects (drum, motor etc.) and the presence of static charges. 

Further charge minimisation may be needed, considering the relatively high amount of 

refrigerant required
76 2014 TOC Refrigeration, A/C and Heat Pumps Assessment Report

 Low GWP HFCs: Due to the similar characteristics as HFC-134a, this category may offer 

potential candidates. However, their flammability results in similar safety hazards as 

listed for the hydrocarbons, though some of these hazards may be easier to deal with due 

to the reduced flammability characteristic.

3.2.4 Not-in-kind alternative technologies

Alternative refrigeration technologies for domestic refrigeration continue to be pursued for 

applications with unique drivers such as very low noise, portability or no access to the 

electrical energy distribution network. Technologies of interest include Stirling cycle, 

absorption and adsorption cycles, thermoelectric and magnetic. In the absence of unique 

drivers such as the examples cited above, no identified technology is cost or efficiency 

competitive with conventional vapour-compression technology for mass-produced domestic 

refrigerators.

Absorption refrigeration equipment has been used in hotel mini-bar units due to low noise 

levels and for mobile, off-network applications such as campers or mobile homes for many 

years. Thermoelectric or Stirling cycle technologies are used for portable refrigerated chests 

in applications such as medical transport. Thermoelectric is also used for hotel units and wine 

storage units with moderate cooling temperature levels.

Magnetic refrigeration is one of the not-in-kind technologies with possible potential for 

commercialization. Magnetic refrigeration does not use refrigerant and employs an active 

magnetic regenerator, comprising magneto-caloric materials exposed to an intermittent 

magnetic field. At lower cooling power, it possibly presents higher efficiency over 

conventional vapour compression. To decrease the price of the technology, the use of an ironbased alloy to provide the magnetic charge has been considered as an alternative to the rareearth magnets such as gadolinium used originally. 

The remaining specialty niche product areas cited above would each require high capital 

investment to establish mass production capability. These product technologies will not be 

further discussed in this report focused on options for mass produced markets.

Not-in-kind laundry dryer technologies are still in an early exploration stage. 

3.2.5 Product energy efficiency improvement technologies for domestic refrigerators

The energy efficiency of domestic refrigeration products is a topic of active consumer and 

regulatory interest. This topic is discussed at length in Chapter 11 of this report. This section 

contains only a condensed discussion on energy efficiency. A more detailed discussion of 

efficiency improvement options was included in the 2002 report of this committee (UNEP, 

2002). Additional information can be found in various sources, amongst others the reports 

under the Eco-Design Directive studies (Ecocold, 2006). These studies provided capability 

background used for updating European Commission minimum energy efficiency standards 

(EN-643, 2009).

Factors influencing refrigerant selection and product energy efficiency include local, regional 

and national regulation, Eco-labelling, and third party standards. Globally labelling 

requirements and minimum standards are reviewed and upgraded on a regular basis, driving 

the product to reduced power consumption levels with corresponding reductions on global 

warming impact. Such standards for measurement of product sustainability provide 

transparency and credibility in the labelling of product impact on the environment, thus 

driving a more informed decision for the consumer. One example is the recently developed 

AHAM 7001-2012 Sustainability Standard for Household Refrigeration Appliances, 

developed and endorsed by multiple stakeholders including environmental, industry, 

government and consumers. Similar to the EU F-Gas legislation, this standard provides a 
2014 TOC Refrigeration, A/C and Heat Pumps Assessment Report 77

calculation for the net material GWP impact of a product as the mass weighted average GWP 

of the product component materials.

Significant technology options to improve product energy efficiency have already 

demonstrated mass production feasibility and robust, long-term reliability. Both mandatory 

and voluntary energy efficiency regulation programs catalysed industry product efficiency 

development efforts. Efforts to develop a universal energy test protocol are in almost 

completed state (IEC-FDIS 62552-1, 2 and 3, 2014), at present each test procedure is unique 

and the results from one should never be directly compared to results from another. A number 

of improved energy efficiency design options are fully mature, and future improvements of 

these options are expected to be evolutionary. Examples of these options include efficient 

compressors, high efficiency heat exchangers, improved low thermal loss cabinet structures 

and gaskets, and less variable manufacturing processes. Extension of these to all global 

domestic refrigeration would yield significant benefit, but is generally constrained by 

availability of capital funds and related product cost implications. Similarly, retooling 

compressor manufacturing facilities facilitated the recovery of the minor efficiency penalties 

incurred with the use of HC-600a/HC290 blends versus HC-600a. 

Design options with less economic justification are sometimes introduced in premium-cost 

models having incentive subsidies. This provides the opportunity to mature new efficiency 

technologies and progress them through their individual cost/experience curves. This 

increases the likelihood for migration of the efficiency technologies to more cost-sensitive 

model line segments. Options that presently have limited or newly introduced application 

include variable speed compressors; intelligent controls; system reconfigurations, such as dual 

evaporators; advanced insulation systems; and Demand Side Management (DSM) initiatives 

requiring interactive communication with energy providers in order to implement the Smart 

Grid concept. The premium-cost of these options currently restrict their application to highend models and constrain their proliferation for general use. A further constraint is the fact 

that not all energy saving measures results in a reduced energy value during tests according 

the current test standards. The new universal test protocol mentioned earlier attempts to 

improve this situation.

 Variable capacity compressors avoid cycle losses and inertial losses through modulating 

capacity and compressor speed. Use of higher efficiency permanent magnet or linear 

motors is also enabled by electronic commutation controls. 

 Intelligent, adaptive controls allow variable control algorithms that avoid optimising at 

seldom-experienced worst-case conditions (e.g. variable defrost algorithms). 

 Parallel dual evaporators can improve Carnot theoretical efficiency by effectively 

reducing required pressure ratios of the higher temperature evaporator. Cost–effective, 

reliable and stable system controls need to be demonstrated. 

 Advanced vacuum panel insulation concepts have been selectively used for several years 

in Japan, Western Europe and the United States. Their premium cost has constrained 

extension to general use. 

 Power line load management (Smart Grid) features of domestic refrigerators reduce 

energy service provider’s peak load demands. Typically, such a feature on electronic 

models responds to the power company request for reduced energy consumption. 

Consequently, the appliances may postpone heated defrost, delay ice harvests or delay the 

start of a compressor for short periods. The application of such load management features 

to domestic refrigeration market is ramping up very slowly since the consumer benefit is 

marginal.

3.2.6 Product energy efficiency improvement technologies for tumble dryers

For HPCDs the inclusion of a heat pump on itself is a major energy saving technology 

compared to conventional laundry dryers. Current energy saving option is predominantly 
78 2014 TOC Refrigeration, A/C and Heat Pumps Assessment Report

related to optimisation of the refrigeration system in combination with the air circulation 

system.

3.3 Options for existing domestic refrigerators

Non-Article 5 countries completed conversions of new equipment production to non-ozone 

depleting substances (ODSs) more than 15 years ago. Later, a number of Article 5 countries 

also completed their conversion, e.g. India by 2003. Therefore, most products containing 

ozone depleting refrigerants are now approaching the end of their life cycle.

Field conversion to non-ODS refrigerants has significantly lagged original equipment 

conversion. The distributed and individual proprietor character of the service industry is a 

barrier to co-ordinated efforts to convert from ODS refrigerants. Field service procedures 

typically use originally specified refrigerants. Refrigerant blends developed specifically for 

use as drop-in service alternatives have had limited success. The interested reader is referred 

to the 1998 report of this committee for an extended discussion of field repair and conversion 

options (UNEP, 1998). Chapter 2 in this current report contains an updated listing of 

refrigerant blend options.

Limited capital resources also favoured rebuilding service options in Article 5 countries 

versus replacement by new equipment. Rebuilding has the accompanying consequence of 

voiding the opportunity to significantly improve product energy efficiency and reduce stress 

on the power distribution grid.

Field service conversion to non-ODS alternatives e.g. HFC-134a, and HFC and HC blends, is 

not being done significantly. In some countries, the old units are bartered for new appliances 

using non-ODS alternatives. The cost of extensive reconfiguration potentially required to 

properly convert for use of alternative refrigerants is a significant deterrent to this approach. 

In the case of conversion to HC blends, safety considerations require that any flammable fluid 

accumulation within an enclosed volume must avoid the potential within that volume for an 

electrical spark, electrical arc or surface temperature above the auto-ignition temperature of 

the leaked gas in air. The extent of in-service product modification to assure this is dependent 

upon the original product configuration. The original equipment manufacturer is most familiar 

with the product construction and should be consulted for required modifications prior to 

decision to proceed.

 Cold-wall-evaporator constructions require leaking refrigerant to diffuse through the 

refrigerator inner liner or flow by convection through apertures in the liner in order to 

accumulate within the cooled volume. There is a low probability of significant gas 

accumulation. Additionally, electrical components located within the cooled volume are 

limited and consequently there is a low probability of an ignition source within the 

enclosed volume. Economical drop-in conversion of this configuration is alleged to be 

viable as per some reports, but procedure definition by the original manufacturer should 

be sought prior to decision to proceed.

 Thin-wall evaporators positioned within the cooled volume are a common construction 

for automatic-defrost refrigerators. Leakage of refrigerant can accumulate within the 

cooled volume and the risk of ignition is dependent on whether the rate of leakage is 

sufficient to result in a combustible mixture within the cooled volume. Additionally, 

electrical components are commonly located within the cooled volume, such as, 

thermostats, convective fans, defrost heaters, lights, icemakers, etc., increasing the 

probability of an ignition source being present. The viability of a drop-in conversion will 

depend upon the extent of original construction modification required to achieve an 

acceptable configuration. Again, conversion procedure definition by the original 

manufacturer is prudent and should be sought prior to decision to proceed.
2014 TOC Refrigeration, A/C and Heat Pumps Assessment Report 79

3.4 End-of-life disposal

The small unit charge and the geographically dispersed location of these units complicate 

commercial opportunities to promote recovery and recycling initiatives to manage emissions 

from disposed units. Regulations for mandatory end-of-life refrigerant handling have existed 

in many developed countries for several years and are being introduced in Article 5 countries. 

Chapter 11 of this report addresses this and related conservation approaches. Interest in 

conservation programmes is leveraged by the 1 to 2 kg of foam blowing agents typically 

present in a domestic refrigerator.

For HPCDs, similar recovery and recycling technologies apply for refrigerant and lubricant as 

for domestic refrigeration systems, although there is no adequate experience in this emerging 

segment.

3.5 Concluding remarks

Conversion of new equipment production to non-ODS refrigerants in Article 5 countries 

occurred over a span of five to seventeen years ago. Migration to second generation non-ODS 

refrigerant from HFC-134a to HC-600a in new product production is occurring as a result of 

the GWP difference between the two alternatives. This migration began in Japan several years 

ago and is now occurring in Brazil, Mexico and the United States. No new technology is 

required and the trend will likely proliferate. The rate and extent of proliferation will be 

influenced by the relative cost for HFC-134a and HFC-600a products. Current estimates 

indicate that additional cost results from design changes to allow the use of flammable 

refrigerants in automatic defrost refrigerators. 

3.6 References 

Beek, 2008 van Beek, M and Janssen, M., “R-744 compared to R-290 in small freezer 

applications,” 8th IIR Gustav Lorentzen Conference on National Working 

Fluids, Copenhagen, 2008. 

CEP, 2009 Domestic refrigeration refrigerant bank updated data through 2006. 

Authors, CEP, Ecole des Mines, December 2009.

Ecocold, 2006 Eco-design requirements of EuP - Domestic Refrigerator and Freezer 

Directive Studies, July 2006, http://www.ecocold-domestic.org.

Karber, 2012 Karber, K.M., Abdelaziz, O., Vineyard, E.A., Experimental Performance of 

R-1234yf and R-1234ze as Drop-in Replacementsfor R-134a in Domestic 

Refrigerators, International Refrigeration and Air Conditioning Conference 

at Purdue, July 16-19, 2012

Leighton, 2011 Leighton, Investigation of household refrigerator with alternative low 

global warming potential refirgerants, Thesis Faculty of the Graduate 

School of the University of Maryland, College Park, USA, 2011

Meyers, 2010 Meyers, S., Franco, V.H., Lekov, A.B., Thompson, L., and Sturges, A., 

“Do Heat Pump Clothes Dryers Make Sense for the U.S. Market?” 

Presented at 2010 ACEEE Summer Study on Energy Efficiency in 

Buildings, August 2010.

Schwarz, 2012 Schwarz, W., Leisewitz, A., Gschrey, B., Herold, A., Gores, S., Papst, I., 

Usinger, J., Colbourne, D., Kauffeld, M., Pedersen, P.H., and Croiset, I. 

“Preparatory study for a review of Regulation (EC) No 842/2006 on certain 

fluorinated greenhouse gases - Annexes to the Final Report Prepared for the 

European Commission in the context of Service Contract No 

070307/2009/548866/SER/C4”, 2013.

UNEP, 1998 UNEP 1998 Report of the Refrigeration, Air Conditioning and Heat Pumps 
80 2014 TOC Refrigeration, A/C and Heat Pumps Assessment Report

Technical Options Committee, Chapter 3, Domestic Refrigeration (1998 

Assessment).

UNEP, 2002 UNEP 2002 Report of the Refrigeration, Air Conditioning and Heat Pumps 

Technical Options Committee, Chapter 3, Domestic Refrigeration (2002 

Assessment).

UNEP, 2006 UNEP 2006 Report of the Refrigeration, Air Conditioning and Heat Pumps 

Technical Options Committee, Chapter 3, Domestic Refrigeration (2006 

Assessment).

UNEP, 2010 UNEP Technology and Economic Assessment Panel Task Force Decision 

XXI/9 Report, “Assessment of HCFC’s and Environmentally Sound 

Alternatives Paragraph 2C,” (May 2010).

Weston, 1997 Roy W. Weston Inc., Recycling Rate Determinant Study – Phase 1 Report, 

Norcross, Georgia (1997).
2014 TOC Refrigeration, A/C and Heat Pumps Assessment Report 81
82 2014 TOC Refrigeration, A/C and Heat Pumps Assessment Report
2014 TOC Refrigeration, A/C and Heat Pumps Assessment Report 83

Chapter 4

Commercial Refrigeration

Chapter Lead Author

Denis Clodic

Lead Authors or Co-Authors

Martien Janssen

Michael Kauffeld

Petter Neksa

Per-Henrik Pedersen

Alessandro Silva

Rajan Rajandran
84 2014 TOC Refrigeration, A/C and Heat Pumps Assessment Report
2014 TOC Refrigeration, A/C and Heat Pumps Assessment Report 85

4 Commercial refrigeration

4.1 Introduction

Commercial refrigeration is characterised by storing and displaying food and beverages at 

different levels of temperature within commercial stores with sales areas varying in size from 

approximately 10 m2to 20,000 m2. The refrigerating capacities of equipment vary from 

hundreds of Watts to as high as 1.5 MW. Two main levels of temperatures are generated by 

refrigeration systems from around 0 °C to 8 °C for the conservation of fresh food and 

beverages, and around -18 °C for frozen food and ice cream. 

Globally, HCFC-22 continues to represent the largest refrigerant bank in commercial 

refrigeration and is used at all temperature levels. The most used HFC (blend) is R-404A for 

all temperature levels. 

For the past decade, HCs for low refrigerant charge systems, and CO2 for larger supermarket 

applications are increasingly used in many developed nations. 

In parallel, progress has been made to improve energy efficiency and leak tightness, 

especially for centralized systems. The progressive phase-out of HCFC-22 in developing 

countries requires making informed choices on the best replacement options.

AHRI launched a Low GWP Alternative Refrigerant Evaluation Program (AREP) in 2010 

(AHRI, 2013). A number of new blends based on HFC-1234yf and HFC-1234ze(E) as well as 

HFC-32 have been formulated to replace HFC-134a, HCFC-22, and R-404A. So, for the three 

groups of commercial refrigeration equipment, comparisons are now being made in order to 

select amongst the most energy efficient options with the smallest environmental impact due 

to refrigerant emissions.

In commercial refrigeration, as in air-conditioning, high ambient applications require special 

consideration in selecting and designing components and equipment. However, designers of 

commercial refrigeration equipment choose components to design systems based on 

delivering the cooling required at the highest ambient condition. 

For moderate and cold climates it is an important option to recover heat from the refrigeration 

plant for heating purposes in the cold season. Considering the supermarket as an energy 

system for which energy use should be minimized may give considerable energy savings. 

The ozone depleting potential (ODP) and global warming potential (GWP) values of the 

alternates mentioned in this chapter are given in Chapter 2 of this report.

4.2 Applications

Stand-alone equipment are self-contained refrigeration systems and comprise a wide variety 

of applications: ice-cream freezers, ice machines, beverage vending machines, and display 

cases. These systems are found not only in large commercial stores but also restaurants, 

convenience stores, mini supermarkets and gas stations. For developing countries, domestic 

refrigerating equipment, refrigerators, and freezers can be found in small shops and used for 

commercial purposes. Stand-alone equipment are increasingly used in developed countries in 

medium-size supermarkets because of ease of maintenance of the fully-welded circuit. In 

Europe, and lately in other markets, this choice is also often related with the use of 

hydrocarbons or CO2.

Condensing units exhibit refrigerating capacities ranging typically from 1 kW to 20 kW. They 
86 2014 TOC Refrigeration, A/C and Heat Pumps Assessment Report

are composed of one (or two) compressor(s), one condenser, and one receiver assembled into 

a so-called “condensing unit”, which is typically located external to the sales area. The 

cooling equipment consists of one or more display case(s) in the sales area and/or a small cold 

room. Condensing units are typically installed in specialty shops such as bakeries, butcher 

shops, and convenience stores. In a number of supermarkets, one can find a large number of 

condensing units (sometimes up to 20) installed side-by-side in a small machinery room. In 

most of the A5 countries, the use of systems using condensing units is very extensive. 

Condensing units are easily found in all countries through refrigeration equipment 

distributors. The global market of condensing units has a strong consequence in terms of 

refrigerant choices; they are developed based on the most used refrigerants: HCFC-22, R404A, and HFC-134a. 

Centralised and Distributed systems are the preferred options in supermarkets. They operate 

with racks of compressors installed in a machinery room as in the case of a centralized system 

or several smaller racks installed in a machinery room or on the roof as in the case of a 

distributed system. Distributed systems may be thought of as multiple smaller centralized 

systems which lead to lower charge levels. A number of possible designs exist and will be 

addressed in Section 4.3 3. Two main design options are used: direct and indirect systems.

Direct systems are the most widespread. The refrigerant circulates from the machinery room 

to the sales area, where it evaporates in display-case heat exchangers, and then returns in 

vapour phase to the suction headers of the compressor racks. The supermarket cold rooms are 

cooled similarly. In the machinery room, racks of multiple compressors are installed; these 

utilise common discharge lines to the air cooled condenser and common suction and liquid 

lines to the refrigerated fixtures. Specific racks are dedicated to low temperature and others to 

medium temperature. Each refrigerant circuit of each rack is independent. Supermarket 

centralised systems with long piping circuits have led to large refrigerant charges (100 to 

3,000 kg depending on the size of the supermarket) and consequently to large refrigerant 

losses when ruptures occur. Studies have been conducted which show that low leak rates are 

possible to achieve in supermarket applications to less than half the typical values, some as 

low as 3.5% (EPA). Typical emission rates of small supermarkets vary between 15 and 25% 

and those of large supermarkets between 20 and 35%. These figures represent, in general, the 

situation of non-Article 5 countries. The emission rates for most of the Article 5 countries are 

much higher.

Indirect systems are composed of primary heat exchangers where a heat transfer fluid - HTF 

(also called secondary refrigerant) is cooled and pumped to the display cases where it absorbs 

heat, and then returned to the primary heat exchanger. HTFs have been receiving interest 

because indirect systems allow for lower primary refrigerant charge and facilitate the use of 

flammable or toxic refrigerants when isolated from the sales area.

4.3 Options for new equipment

4.3.1 Stand-alone equipment 

Several stand-alone equipment types are described in this section, in order to analyse the 

trends for refrigerant choices depending on the cooling capacity, the refrigerant charge, and 

the refrigerant circuit design. Many of stand-alone equipments are owned and installed by 

global food companies. Those companies develop their own environmental policy and 

choosing low-GWP refrigerants as well as energy-efficient systems are part of the green 

positioning of those companies.

Bottle coolers

Glass-door bottle coolers can be found in nearly every supermarket, gas station, and kiosk. 

The most common type is the one-door 400-liter type, but also bigger (2 or 3 glass doors) and 

smaller types are on the market. 
2014 TOC Refrigeration, A/C and Heat Pumps Assessment Report 87

Hydrocarbon (HC-290) bottle coolers as well as CO2 bottle coolers show good energy 

performances and with R&D developments even better compared to the HFC-134a base line. 

Hydrocarbon bottle coolers showed 28% reduced energy consumption compared to HFC134a bottle coolers, and for CO2 12% energy consumption reduction (Pedersen, 2008). The 

choice of HC-290 is made by several European companies manufacturing those bottle 

coolers, while CO2 is preferred by others, based on a different perception of safety risks.

Within the AHRI / AREP test program, laboratory tests have been performed in order to 

evaluate the two low-GWP HFCs: HFC-1234yf and HFC-1234ze, and HFC-134a based 

blends designed to replace HFC-134a at nearly the same performances. Tests indicate that 

those low-GWP refrigerants are in the same range of performances and that refrigeration 

system optimization is necessary and will be developed in the near future.

Ice-cream cabinets

R-404A and HFC-134a are the refrigerants used in ice-cream cabinets and are progressively 

being replaced with HC-290 by large food companies. In 2014, the number of HC-290 icecream cabinets is expected to be more than one million units as assessed by a leading global 

company (Refrigerants Naturally, 2014). 

Vending machines

Vending machines for soft drinks require a significant cooling capacity to rapidly cool the soft 

drink container. The usual refrigerant charge of HFC-134a varies between 0.5 and 1 kg 

leading to the development of CO2 options to compete with hydrocarbons. High-efficiency 

CO2 cassettes have been developed by a Japanese company and are sold to many OEM 

companies for integration. The CO2 technology is compact and has passed the tests of energy 

efficiency defined by soft drink companies. HC-290 vending machines have also been 

developed to perform satisfactorily from an energy point of view. As for bottle coolers the 

choice between CO2 and hydrocarbons is made based on conclusions drawn from the risk 

analysis and the impact of possible incidents or accidents.

Water coolers

A large number of water coolers for both bottled water and tap water are installed worldwide. 

The refrigeration capacity is small and the refrigeration circuit is fully brazed. Thus this 

equipment looks like a small domestic refrigeration system. Many companies have switched 

from HFC-134a to isobutane (HC-600a). The hydrocarbon charge could be as low as 20 g.

Ice machines

Ice machines are installed in restaurants, bars and hotels, and are dominantly found in North 

America. Many different refrigeration capacities are found depending on the size of the 

machine, as well as different technologies depending on the type of ices: cubes, pellets, flakes 

etc. The usual R-404A charge can vary from 500 g to 2 kg. Within the AHRI/AREP program, 

an ice-machine dispenser has been tested with a new low-GWP HFC-based blend with a 

temperature glide of about 7 K at the evaporator. Report #2 indicates lower refrigeration 

capacity of about 4% without any optimization being done (Schlosser, 2012). In Europe, and 

in other regions, small ice machines now use HC-290 and are sold as a standard option. More 

recently, several equipment manufacturers have started introducing ice machines using CO2

as the refrigerant (Shecco, 2014).

Supermarket plug-in display cases

The use of supermarket cabinets of the plug-in type is increasing in Europe, especially in 

discounter stores. Many small- and medium-size supermarkets install such units instead of the 

cabinet cooled by a remote refrigeration system. The plug-in cabinets have lower installed 

cost, are more flexible and require less system maintenance, because of the fully brazed 

circuit. Plug-in cabinets are significantly less energy efficient compared to display cases 
88 2014 TOC Refrigeration, A/C and Heat Pumps Assessment Report

cooled by condensing units or compressor racks, because small compressors have lower 

energy efficiency than larger ones. 

Moreover, the condenser heat is released into the supermarket sales area where the display 

cases are installed. For high outdoor temperatures, the heat released in the sales area requires 

higher cooling capacity for air conditioning. On the contrary, the heat released is a gain in 

winter in moderate and cold climates. Some installations of stand-alone display cases are 

designed with water cooled condensers allowing the release of heat outdoor, usually using a 

small water chiller; in this specific design, energy efficiency can reach acceptable levels. 

The refrigerant choice used to be R-404A. Since 2007, hydrocarbon display-cases using HC290 have been proposed as a standard option in Europe with an energy efficiency gain 

ranging from 10 to 15% compared to R-404A. CO2 systems for display cases have also been 

introduced by several key suppliers.

The first conclusions that can be drawn for standalone equipment are as follows:

- HFC-134a and R-404A will be phased-out progressively in developed countries. Due 

to multinational companies this phase-out is also beginning in developing countries. 

There are several low-GWP refrigerant options and hydrocarbons, CO2 and new lowGWP HFC-based blends can be used depending on commercial availability. 

- Addition of glass doors and LED lighting to display cases can reduce the refrigeration 

load thus enabling the use of flammable refrigerants for these display cabinets within 

the allowable charge limits.

- Minimum energy standards have been issued or updated in the last years in North 

America, in Europe and in many other countries, making a new competition between 

manufacturers in order to reach higher energy efficiency stand-alone systems; the 

CLASP report (Waide, 2014) estimates the possible gains for the different 

standalone-equipment types between 30 and 40% compared to the current average 

energy consumption.

- Eco-labelling taking into account all impacts during the life cycle of product (see 

Chapter 11) will be soon issued for commercial refrigeration in Europe, energy 

consumption being the main criterion to be addressed in order to lower significantly 

the environmental impact of those equipment. In parallel, the amended F-gas 

regulation will affect refrigerant choices in this equipment.

4.3.2 Condensing unit systems 

Condensing units comprises one or several compressors, an air-cooled condenser (usually), a 

receiver, and a liquid line to be connected to the refrigeration circuit. Condensing units are 

designed for several capacities and are standardized equipment. Condensing units are 

commonly used in commercial refrigeration worldwide and especially in developing 

countries; they are sold by OEMs to installers. The design is as generic as possible and the 

usual refrigerant is HCFC-22 in developing countries, HFC-134a, R-404A and, to a lesser 

extent, R-410A in developed countries. HFC-134a is chosen for small capacities and 

evaporation temperatures > -15°C. R-404A or R-410A are chosen for larger capacities for all 

temperature levels. HFCs form the energy efficiency references for benchmarking all other 

refrigerants. 

Replacement HFC blends

For HCFC-22 replacement, a number of “intermediate” refrigerant blends are proposed, such 

as R-407A, R-407F, R-448A, and R-449A and others have not yet received their ASHRAE 

number. Their GWPs are ranging from about 1000 to 1700. They are designed to replace 

HCFC-22 or R-404A and are used either as retrofit refrigerants or in new equipment. All of 

them present temperature glides from 5 to 7 K which require special attention paid to the 

selection and operation of components. 
2014 TOC Refrigeration, A/C and Heat Pumps Assessment Report 89

A new set of low-GWP R-404A and HCFC-22 replacement refrigerant blends is also being 

introduced with GWPs ranging from less than 150 to 300; they are considered to be 

commercially available before the end of 2016. Some have been tested and results are 

available in (Schultz, 2013) showing a volumetric capacity either identical or in the range of 

±5%, with a COP from 7 to 2% lower compared to HCFC-22. Many low-GWP HFC blends 

contain HFC-32 and HFC-1234yf and/or HFC-1234ze(E), and they are all low-flammable 

refrigerants classified as 2L in ASHRAE 34. For HCFC-22, HFC alternative-blend options 

that are proposed show performances close to the benchmark reference. The results indicate 

that soft optimization could lead to performances on the level of the baseline refrigerants. 

Nevertheless, equipment manufacturers have to take into account in the new equipment 

design that all these refrigerant blends have temperature glides varying from 4 to 7 K.

Ammonia 

R-717 is not used much in these systems for cost and safety issues. However it is used in 

cascade systems with CO2 in the low stage of the equipment.

CO2

New carbon dioxide-based condensing units are sold in Northern Europe and Japan. The 

market penetration is low but increasing. R-744 condensing units require a double-stage 

design if high ambient temperatures occur frequently. Single-stage systems are designed for 

cold climates. The additional cost for a double-stage system is significant compared to usual 

HFC reference condensing units. The cost remains the main barrier for these R-744

condensing units in certain regions, but with increasing production capacities and financial 

incentives this barrier is expected to overcome soon. 

Hydrocarbons 

Several hundred indirect condensing units using HC-290 or HC-1270 are operating in Europe 

with typical refrigerant charges varying from 1 to 20 kg, most of them on the lower charge 

side, with good energy efficiency. 

Direct expansion condensing units from 100 W to 10 kW (up to 1.4 kg charge) are 

commercially available from major manufacturers operating with HC-600a and HC-290, and 

for temperatures ranging from -40°C up to 0°C. Costs for these HC-based systems can be up 

to 15% higher than HFC systems due to safety measures required for flammability mitigation.

4.3.3 Centralized supermarket systems 

Centralized systems are the preferred option in medium to large supermarkets, because they 

usually achieve better energy efficiency than plug-in cabinets and condensing units. This is 

mainly due to compressor efficiencies being higher for larger compressors (in the range of 60-

70%) compared to smaller compressors (in the range of 40-50%) used in plug-in cabinets. 

The sales area of supermarkets with centralized refrigeration systems varies from 400 m2up 

to 20,000 m2for large supermarkets.

Generally, for large supermarkets, the reference design is a direct-expansion centralized 

system with several racks of compressors operating at the two evaporation temperature levels 

(-10 °C ± 4 K and -32 °C ± 4 K for example). Several refrigeration system designs exist for 

medium to large supermarkets; these designs have an impact on refrigerant choices, 

refrigerant inventories, and energy efficiency. Conventionally, they operate with racks of 

parallel piped compressors installed in a machinery room, typically using HCFC or HFC in 

direct expansion refrigeration systems. Typically the compound compressors operate with a 

common condenser which provides a number of different evaporators with liquid refrigerant. 

Places to be cooled by the system include refrigerated counters, refrigerated shelves, freezer 

islands, medium and low temperature storage rooms. Because all cabinets/evaporators are 

connected to all compressors in one compound system, HFC charges can be quite high – up to 

3,000 kg for hypermarkets – with resulting high emissions in the case of component failure 
90 2014 TOC Refrigeration, A/C and Heat Pumps Assessment Report

like pipe rupture, e.g. due to excessive vibration. In addition, the numerous joints of large 

systems are prone to frequent leakage (especially mechanical joints), hence such systems 

often have refrigerant leakage rates in the order of 15 % (Schwarz et al, 2011) or higher, 

typically 25%. In order to limit refrigerant emissions, some commercial companies have put 

significant effort in order to limit their annual emissions; some successes have been reported 

in Germany with reduction of annual emission rates lower than 10% (Kauffeld, 2013).

The different central multi-compressor refrigeration systems offered on the market can be 

categorized according to

 the choice of refrigerant(s),

o HCFC or HFC

o Hydrocarbon (HC)

o Ammonia (R-717)

o Carbon dioxide (R-744)

 the type of refrigerant distribution

o direct expansion or 

o indirect via a heat transfer fluid (HTF) – the HTF can be single phase liquid 

(mainly used for MT), melting ice slurry (only MT) or evaporating carbon 

dioxide (MT and LT), and 

 the kind of cooling of the condenser/gas cooler

o Ambient air cooled; in hot climates sometimes with evaporation of water in 

order to reduce air temperature

o Water cooled; water cooling by ambient air

o Water based heat recovery; i.e. condenser is water cooled heating tap water or 

store

o Air based heat recovery; heating store room air directly.

Most systems have separate MT and LT systems, but especially systems working with R-744 

combine MT and LT in one compound system. Due to safety and technology reasons, not all 

combinations make sense or are acceptable. For example ammonia by reason of its higher 

toxicity is excluded from the costumer area and it will therefore never be used in direct 

expansion systems in the sales area of a supermarket; but ammonia can be used safely as a 

high-efficiency refrigerant in an indirect supermarket refrigeration system, see below.

The evaporator of direct expansion systems is located in the application (i.e., within the cold 

room or cabinet). Condensers can be arranged in air-cooled machine rooms in the building or 

outside of the building. Heat recovered from the condenser can be used for room or tap water 

heating. Direct expansion systems are worldwide the dominating technology for 

supermarkets. The direct expansion centralized system is therefore often used as the reference 

for comparisons of energy performances and refrigerant charges. 

The refrigerants for new systems are R-404A and R-744, especially in Europe. To a smaller 

extent HFC-134a is used for medium temperature applications, as well as R-507A in some 

countries, e.g. Norway. Direct expansion systems will always have refrigerant-carrying pipes 

and components inside of the sales area which the public may enter. Therefore, the refrigerant 

will normally be restricted to lower toxicity, non-flammable safety classification (i.e. class A1 

according to EN-378).

For cost reasons and for technical simplicity, commercial centralized systems have usually 

been designed with a single compression stage even for the low-temperature level (-35°C to -

38°C). Two design options, cascade and boosters systems, which are common in industrial 

refrigeration, have been introduced in commercial refrigeration in order to improve energy 

efficiency, see Figure 4-1 and 4-2. They can be used for all refrigerants, but the development 

has been especially made for R-744. 
2014 TOC Refrigeration, A/C and Heat Pumps Assessment Report 91

Figure 4-1: Cascade system Figure 4-2: Booster system

Cascade systems

The cascade system, as shown in Figure 4-1 connects the low-temperature compressor rack to 

the medium-temperature level, via an evaporator-condenser where the heat released by the 

low-temperature rack is absorbed by the evaporation of the medium-temperature refrigerant. 

The refrigerants at the two levels of temperature can be either different or identical. In any 

case two-stage systems are more efficient than single-stage ones; the energy gain is typically 

of 15 to 20% and is more pronounced for high outdoor temperatures. 

Booster systems

Another design, which is simpler and less costly, is also developed and installed now in 

commercial refrigeration: the booster system presented in Figure 4-2. The low-temperature 

compressor rack discharges its vapour directly in the suction line of the medium-temperature 

rack where it is mixed with the medium-temperature vapour. In this design, the refrigerant is 

the same for the low and medium-temperature levels. The booster system offers several levels 

of pressure by using a flash tank and several expansion valves. A first expansion valve EV1 

expands the refrigerant in the flash tank at a first intermediate pressure; the vapour generated 

by this first expansion is directly sucked by the medium-temperature compressor rack, and the 

pressure of the expanded vapour leaving the flash tank is controlled at the medium 

evaporation pressure by EV2. For CO2 this design presents a great advantage because above 

31°C in the condenser, there is no more condensation and the condenser becomes a gas 

cooler. In the supercritical region, CO2 is in dense gas phase at pressure around 90 bars and 

can be expanded in the flash tank at 40 bars for example, and so a part of the expanded CO2

changes to liquid phase and feeds both the medium-temperature display-cases via the 

expansion valve TXV1 and the low-temperature display case via TXV2. For high outdoor 

temperatures, the booster system offers a efficiency gain for CO2; however, energy loss for 
92 2014 TOC Refrigeration, A/C and Heat Pumps Assessment Report

CO2 systems due to supercritical operation can be overcome with additional design features 

like ejectors, parallel compression or subcoolers.

These two designs are now installed in several thousands of stores; cascade systems – with 

usually HFC-134a at the medium-temperature level – in large supermarkets and full CO2

booster systems in larger to smaller ones. These stores are currently mostly found in Europe, 

but are increasing in adoption in the rest of the world.

Distributed systems

In the USA two designs coexist: the centralized and the distributed system. Distributed 

Systems consist of a number of compact compressor systems / condensing units with –

typically - water-cooled condensers. The compressor systems are located in sound-proof 

boxes, which can be installed in the sales area. Water pipes running through the store remove 

the condenser heat. The design is compact and the refrigerant lines are short, which makes a 

gain in terms of reliability and limits the pressure losses. The refrigerant inventory of a 

distributed system is smaller by about 15% compared to a direct-expansion centralized system 

while the energy efficiency is in the same range.

R-404A is usually used as the refrigerant of choice although HFC-134a is also feasible for 

MT applications and HC-1270 is used in some water cooled condensing units (charge always 

below 1.5 kg). The central chiller can use any kind of refrigerant, many systems use HC-290 

or R-404A.

Indirect Systems

Indirect systems include a secondary cycle which transports the heat by means of a heat 

transfer fluid (HTF) from the refrigerated cabinet to the evaporator of the primary 

refrigeration system which can be located in a secured machine room or in the open air, i.e. 

isolated with no public access, see Figure 4-3. During the last 20 years, indirect systems have 

been developed, mostly for the medium-temperature level, enabling a reduction of the 

refrigerant charge by at least 50%. 

As shown in Figure 4-3, the low-temperature direct expansion system can release the 

condensation heat to the HTF secondary loop, leading to better energy efficiency of the lowtemperature system and allowing also the use of CO2 in subcritical operation at the lowtemperature level. Some other designs are also possible where the condensation heat of the 

low-temperature system is directly released to the atmosphere
2014 TOC Refrigeration, A/C and Heat Pumps Assessment Report 93

.

Figure 4-3: Indirect system at the medium-temperature level and direct expansion at the lowtemperature level

The use of HTF with phase change offers an energy saving potential: ice slurry for medium 

temperature or CO2 for medium and low temperatures (Møller, 2003). Through the selection 

of the correct additive, ice slurry can also outperform a single-phase HTF (Hägg, 2005; 

Lagrabette, 2005).

Indirect systems make the primary refrigeration system design very compact. One can use 

prefabricated units and the assembly of systems can be simplified on site. Indirect systems 

allow also for providing more stable temperatures and increased humidity at the points of 

refrigeration (Rhiemeier et al., 2009). The pumping energy of heat transfer fluid, which can 

be significant, has to be compared with the additional energy consumption due to pressure 

losses of the long suction lines of direct expansion systems. In order to prevent the energy 

consumption increase, it is also important to select the appropriate HTF based on liquid 

viscosity and heat capacity. For indirect systems, the following characteristics have to be 

mentioned: all piping needs to be insulated; HTF leaks are also possible and difficult to 

diagnose. 

Developing country aspects

In developing countries, supermarkets can be of very different sizes but also have a 

centralized machinery room as in developed countries; depending on the leadership of 

companies, one can find CO2 cascade and booster systems in a country such as Brazil. It has 

to be taken into account that for cost reasons and ease of installation many small supermarkets 

and convenience stores in developing countries will be using condensing units.

Refrigerants and systems

HCFCs and HFCs 

The dominant refrigerant for centralized systems in the developing countries is HCFC-22 

while R-404A is common in developed countries. In Japan R-407C is commonly used, and 

some stores using R-404A have switched to R-410A in the last years. Now pure HFC-32 is 

beginning to be used at the medium-temperature level and CO2 or HFC-32 are under 

evaluation for the low-temperature level. The flammability of HFC-32 makes it difficult to be 

used in large direct expansion systems outside of Japan. More recently, lower GWP R-404A 

alternatives like R-448A, R-449A are undergoing field trials and starting production while 
94 2014 TOC Refrigeration, A/C and Heat Pumps Assessment Report

HFC-134a alternative blends like R-450A are also being evaluated. These and other similar 

lower GWP HFC blends are important as replacements for existing systems that use R-404A 

and HFC-134a.

HC-290 and HC-1270

Refrigerant changes have begun since the early 2000 in Europe, and especially in Germany, 

where propylene (HC-1270) has been introduced in supermarkets, using a secondary loop, 

HC-290 is now the preferred option. For all HCs, the machinery room is located outside of the 

store. The number of these HC-systems is limited.

Ammonia

Due to its toxicity, ammonia is confined in a ventilated machinery room and ammonia 

systems are always designed with secondary loops at each temperature level. Several large 

supermarkets operate with ammonia especially in Luxembourg and Switzerland. Ammonia 

can be used at the medium-temperature level, together with CO2 at the low-temperature level. 

CO2 (R-744)

The real breakthroughs using CO2 as refrigerant began around 2005 with two major new

options: CO2 as the only refrigerant in booster systems and CO2 in cascade with HFCs or 

other refrigerants.

For using CO2 as the only refrigerant in small, medium and large size supermarkets, CO2 has 

been introduced in transcritical booster systems (Figure 4-2). The low-temperature rack 

operates at -33°C ± 3°C evaporation temperature. The medium-temperature rack operates at -

9°C ± 3°C evaporation temperature. The heat dissipation occurs up to 30°C depending on the 

outdoor temperature, and above 27°C outdoor temperature, the operational mode becomes 

transcritical. Up to now, more than 3000 transcritical CO2 systems are installed, mainly in 

Europe (95%) (Chasserot, 2014).

CO2 systems operate also at the low-temperature level only. The condensation heat is released 

to the secondary loop, usually at -10°C temperature level as shown in the cascade system 

(Figure 4-1). The interest of keeping this low level of condensation temperature is to use usual 

copper tubing designed for maximum pressure of 3 MPa. The medium-temperature 

compressor rack works with HFC-134a or R-717, those systems are installed in about 2000 

stores (Chasserot, 2013). In Brazil, due to the active policy of a European company, more 

than 50 stores are now operating with CO2 cascade systems. 

The energy efficiency of CO2 systems is better than that of comparable HFC-systems at 

ambient temperatures below 22°C, about equal at temperatures between 22 and 26°C, and 

lower at higher ambient temperatures (Finckh et al, 2011). It should be noted that using 

electronic expansion valves and similar system enhancements used for CO2 systems will also 

have beneficial effects on standard HFC systems. Installation of CO2 systems has also begun 

in Asia, the Americas, and Australia. Shifting from HFCs to CO2 can reduce the carbon 

footprint of supermarkets by 25% (EPA, 2010) but could be higher depending on the 

refrigerant leakage and energy recovery utilization

For moderate and cold climates it is an important option to recover heat from the refrigeration 

plant for heating purposes; e.g. for hot water heating and indoor air heating in the cold season. 

CO2 systems are easily adapted to satisfy such demands. Considering the supermarket as an 

energy system for which energy use should be minimized may give considerable energy 

savings, e.g. 30% has been demonstrated (Hafner et al, 2014a).

With trials of new developments like booster systems, ejector systems, expander systems, 

parallel compression and systems with auxiliary mechanical sub-cooling, the efficiency of 
2014 TOC Refrigeration, A/C and Heat Pumps Assessment Report 95

CO2 systems may, in the future, be improved to the extent that such systems will be more 

energy efficient, even in warmer climates (Huff et al, 2012 and Hafner et al, 2014b).

Low-GWP HFCs and HFC blends for R-404A and HCFC-22 replacement

The AHRI/AREP Report # 21 (Shrestha, 2013) presents several low-GWP HFC blends (from 

220 to 300) proposed to replace R-404A in condensing units that are the same as those 

proposed for centralized systems. The refrigeration capacities of these blends are slightly 

lower, energy efficiency slightly higher and temperature glides of 4 to 7 K are larger 

compared to R-404A. The consequence of the temperature glide is a possible distillation of 

the blend when a leak occurs. Servicing becomes more complex due to the composition 

change of the refrigerant blend due to the different boiling points of the individual 

components of the blend. Some contractors recommend the recovery of all the refrigerant 

remaining in the installation to make a full new charge at the right blend formulation. Such 

practice could add to running costs of systems due to the anticipated higher costs of low GWP 

HFCs and associated destruction costs of the remaining refrigerant.

Some of the low-GWP-HFC blends are designed to replace HCFC-22. For the tested blends, 

the cooling capacity is 2 to 7% lower and the efficiency is from 5 % lower to 10% better. 

Some of the blends formulated to replace R-404A are the same as those formulated to replace 

HCFC-22.

The results of the AHRI / AREP reports show that soft optimization of refrigeration systems 

using those blends may lead to the same level of performances. Three issues are still to be 

addressed: safety rules for low flammability refrigerants, servicing of refrigerant blends with 

possible distillation due to leaks and commercial availability.

A new set of low-GWP R-404A refrigerant blends is also being introduced with GWP less 

than 150.

Summary for centralized systems

In summary, for centralized systems a number of options are available and proven; some of 

them require a higher technical training of contractors especially for two-stage CO2 systems. 

The replacement of R-404A is underway and will lead to several families of technical options 

with either CO2 at all temperature levels or low-GWP HFCs at the medium temperature 

operating in cascade with CO2 at the low temperature. R-404A replacements that are non 

flammable and lower than 2000 GWP will grow in use both in existing and new systems. Low 

GWP and mildly flammable HFCs at all temperature levels will also be considered but 

flammability concerns might limit the types of systems due to the current standards. 

4.4 Options for existing equipment

This section covers the retrofit options for the installed base of equipment. For stand-alone 

equipment, there is no real incentive to change the refrigerant because the refrigeration circuit 

is totally brazed and hermetic, and this type of equipment will be changed based on its current 

lifetime, if no heavy leaks occur. However, a few options for stand-alone equipment are: R448A or R-449A for R-404A and R-450A for HFC-134a. This list can be expected to grow as 

more manufacturers release alternates for existing refrigerants and equipment.

The R-407 series of refrigerants like R-407A, R-407F and R-427A are now used in many 

developed countries as retrofit refrigerants for R-404A depending on individual 

manufacturers’ approvals. These refrigerants, including R-407C, are commercially available 

and are also formulated to replace HCFC-22. Other HFC blends with GWP lower than 2000, 

such as R-448A and R-449A (and others not yet assigned ASHRAE numbers) will be also 

commercially available in 2015 and will be candidates to replace HCFC-22 and R-404A. In 

fact, the most important issue for the replacement of HCFC-22 in developing countries will be 
96 2014 TOC Refrigeration, A/C and Heat Pumps Assessment Report

to find replacement options at acceptable costs; given the fact that developing countries will 

lag the developed nations in adopting these changes, the cost of these changes can be 

expected to be better when Article 5 countries are ready to make the change

Depending on the lifetime of refrigeration systems, the retrofit option is part of the refrigerant 

management plan required to follow the phase-down schedule. Recovery and recycling of 

existing refrigerants represent a strong option in order to smooth the transition from present 

day refrigerants to a series of lower GWP options. 

4.5 References

AHRI, 2013 Low GWP Alternative Refrigerant Evaluation Program 

http://www.ahrinet.org/site/514/Resources/Research/AHRI-LowGWP-Alternative-Refrigerants-Evaluation

Chasserot, 2013 Natural Refrigerants Market Trends; Bangkok Technology conference 

June 30, 2013

Dallinger, 2012 Dallinger, J.; Sheehan, J.: Supermarktkälteanlage mit CO2 als 

Kälteträger – Fallstudie einer Anlage in Australien. DKV Tagung 

2012, Würzburg, Germany

EPA, 2010b US-EPA: Transitioning to low-GWP alternatives in commercial 

refrigeration. Fact sheet, October 2010

EPA, 2014 http://www2.epa.gov/greenchill/reports-guidelines-and-tools

Finckh, 2011 Finckh, O.; Schrey, R.; Wozny, M.: Energy and efficiency 

comparison between standardized HFC and CO2 transcritical systems 

for supermarket applications. IIR Int. Congr. Refr. August 21 – 26, 

2011, Prague, Czech Republic

Hägg, 2005 Hägg, C.: Ice Slurry as secondary fluid in refrigeration systems. KTH 

Stockholm, Schweden, ISBN 91-7178-192-7

Huff, 2012 Huff, H.; Finckh, O.; Verma, P.; Liu H.: Viable solutions to increase 

efficiencies of transcritical CO2 systems for commercial refrigeration. 

IIR Gustav Lorentzen Conference, June 25-27, 2012, Delft, The 

Netherlands

Hafner, 2014a Hafner, A.; Claussen, I.C.; Schmidt, F; Olsson, R.; et al: Efficient and 

integrated energy systems for supermarkets, Proceedings of the 11th 

IIR-Gustav Lorentzen Conference on Natural Refrigerants, GL2014,

International Institute of Refrigeration, ISBN 978-2-36215-004-3.

Hafner, 2014b Hafner, A.; Nekså, P.: System configurations for supermarkets in 

warm climates applying R-744 refrigeration technologies. Case 

studies for selected cities. International Special Issue 2014 - United 

Nations Environment Programme, International Institute of 

Refrigeration, Centro Studi Galileo, Associazione dei Tecnici del 

Freddo, European Energy Centre, Casale M.to, Italy, 2014

Kauffeld, 2013 Trends and perspectives in supermarket refrigeration EC. Europa

Lagrabette, 2005 Lagrabette, O.: Kältetechnik im Einzelhandel – Carrefour setzt auf die 

“grünen” Medien. KKA 1 (2005), S. 20 – 24

Møller, 2003 Møller, J.B. : CO2 is keeping Supermarkets Cool. The NEWS. 8. 12. 

2003

Pedersen, 2008 Pedersen, P.H.; Christensen, B.: Development and test of Bottle 

Coolers with Natural Refrigerants, 8

th IIR Gustav Lorentzen 

Conference on Natural Working Fluids, Copenhagen, 2008
2014 TOC Refrigeration, A/C and Heat Pumps Assessment Report 97

Refrigerants Naturally, 2014

http://www.refrigerantsnaturally.com/statements/unilever.htm

Rhiemeier, 2009 Rhiemeier, J.-M.; Harnisch, J.; Kauffeld, M.; Leisewitz, A.: 

Comparative Assessment of the Climate Relevance of Supermarket 

Refrigeration Systems and Equipment. Environmental Research of the 

Federal Ministry of the Environment, Nature Conservation and 

Nuclear Safety Research Report 206 44 300, UBA-FB 001180/e, 

March 2009

Rivet, 2007 Rivet, P.: Move to HFC 410A in Refrigeration Applications. IIR 22. 

Int. Congr. of Refr., Peking, China, 21. – 26. August 2007

Schlosser, 2012 Schlosser, C.: System drop-in Test of L-40, L-41a and N-40b in Ice 

Machines. AHRI/AREP Test report, 2. Nov. 2012

Schultz, 2013 Schultz, K.; Kujak, S.: System drop-in Tests of R-22 Altermative 

Fluids (ARM-32, DR-7, L-20, LTR4X, LTR6A, and D52Y in a 5-RT 

Air-Cooled Water Chiller (Cooling Mode). AHRI/AREP Test report, 

6. Jan. 2013

Schwarz, 2011 Schwarz, W.; Gschrey, B.; Leisewitz, A.; Herold, A.; Gores, S.; Papst, 

I.; Usinger, J.; Oppelt, D.; Croiset, I.; Pedersen, P.H.; Colbourne, D.; 

Kauffeld, M.; Kaar, K.; Lindborg, A.: Preparatory study for a review 

of Regulation (EC) No 842/2006 on certain fluorinated greenhouse 

gases. Final report, Sept. 2011

Shecco, 2014

http://www.r744.com/news/view/5816?utm_source=mailchimp&utm

_medium=email&utm_campaign=Power%20users

Shrestha, 2013 Shrestha, S.; Sharma, V.; Abdelaziz, O.: Compressor Calorimeter Test 

of R-404A Alternatives ARM-31a, D2Y-65, L-40, and R-32/R-134a 

(50/50). AHRI/AREP Test report #21. Aug. 2013

Waide, 2014 Waide P., Van der Sluis S., Michineau T., CLASP Commercial 

refrigeration equipment: maping and benchmarking.
98 2014 TOC Refrigeration, A/C and Heat Pumps Assessment Report
2014 TOC Refrigeration, A/C and Heat Pumps Assessment Report 99

Chapter 5 

___________________________________________________________

Industrial Systems

Chapter Lead Author

Andy Pearson

Co-Authors

Horace Nelson

Mohamed Alaa Olama

Alexander C. Pachai

Alessandro Silva
100 2014 TOC Refrigeration, A/C and Heat Pumps Assessment Report
2014 TOC Refrigeration, A/C and Heat Pumps Assessment Report 101

5 Industrial systems

5.1 Introduction

The industrial sector has not changed significantly since the publication of the last RTOC 

report (UNEP, 2011). Ammonia continues to be the preferred solution in most markets and 

new development refrigerants have not gained a significant market share in this period. There 

have been several major accidents involving R-717 in article 5 countries since the last report, 

resulting in multiple fatalities. These events have emphasised the need for system design to 

conform to recognised safety standards as these levels of fatality are unprecedented in 

traditional market sectors using ammonia and they have increased the emphasis on the 

education of technicians and engineers. In all cases the accidents would have been avoided if 

current international safety standards had been followed.

The chapter has been expanded to include more information on process cooling, industrial airconditioning and heat pumps. Several examples from different regions including many article 

5 countries have been added. The ozone depletion potential (ODP) and global warming 

potential (GWP) values of the refrigerants mentioned in this chapter are given in chapter 2 of 

this report.

Industrial systems are characterised primarily by the size of the equipment (physical size and 

heat transfer capability) and the temperature range covered by the sector. This chapter 

includes discussion on Industrial Heat Pumps (heating systems similar in scale and 

application to Industrial Refrigeration systems) and Industrial Air-Conditioning (systems for

controlling air temperature in production factories, computer centres and other process areas). 

In addition to size of installation the distinguishing traits of Industrial Air-Conditioning 

systems are that the cooling is not purely for human comfort, the load is not primarily 

seasonal and the operation of the facility would be jeopardised by failure of the cooling 

equipment. Such systems are sometimes called “Mission Critical” and have special design 

requirements, including the need for uninterrupted service, which are not typically provided 

by traditional HVAC practices (ASHRAE, 2009). Large chillers used for air cooling in 

offices, hotels, convention centres and similar installations are not covered by this chapter. 

Detailed information on those systems will be found in chapter 9 on chillers. A brief overview 

of the use of HFCs in Rankine cycle electrical generation is also given.

5.1.1 Background 

Thirty years ago chlorofluorocarbons were widely used in the industrial sector in many 

European countries, particularly blends, such as R-502. The particular advantage of these 

substances was their low index of compression which permitted single stage operation over a 

wider pressure ratio than could be achieved with R-717 or even HCFC-22. Other countries, 

notably the United States and Canada had not moved away from R-717 to the same extent as 

some European countries. In the heat pump sector CFC-12, which has a critical temperature 

of 112°C, was common for systems of all sizes. It is now replaced by HFC-134a for 

temperatures up to about 75°C. R-717 is also used in some large systems up to about 85°C. 

For higher temperatures up to about 120°C, and for ORC's, the market is still limited, but 

HFC-245fa is being used. Industrial Air-Conditioning was less common at that time, and 

tended to use standard chillers with CFC refrigerants. The move away from CFCs in the late 

1980s prompted by the Montreal Protocol presented particular problems in the industrial 

sector because the replacement fluids with lower or no ozone depleting potential were not as 

suitable over the wide operating range required. In some places this resulted in a swift return 

to R-717 technology, for example in the United Kingdom (Brown, 1992). In other countries 

the re-adoption of R-717 was more widely resisted and the adoption of low ODP refrigerants 

was coupled with widespread use of secondary refrigerant systems. For example R-502 had 

been common in Japan. The industrial sector there responded to its removal by the 
102 2014 TOC Refrigeration, A/C and Heat Pumps Assessment Report

development of compact, low charge R-717 systems and the use of secondary systems with a 

limited charge of the more expensive HFC fluids (Kawamura, 2009). In Article 5 countries 

where R-717 was already used for refrigeration these systems were retained and extended 

(Tarlea, 2013) (Gulanikar, 2013), but the designs used tended to be old-fashioned and not as 

efficient or safe as the new Japanese or European innovations. In countries with no history of 

R-717 use, or with no support infrastructure the solution was often to use large numbers of 

smaller light commercial systems to satisfy a large cooling load (Pietrzak, 2011). This is 

expensive to install and maintain, and it is also much less efficient in operation. 

5.1.2 Efficiency and sustainability 

With increased emphasis on climate change in recent years the importance of energy 

efficiency is now far greater than before. This has led to a reappraisal of previous policies, for 

example in the growing trend for central systems with R-717 rather than multiple commercial 

systems with HCFCs. There is also a greater focus on integration of industrial heating and 

cooling systems to make better use of waste heat recovery (Pearson, 2011).

In Europe regulation on the use of fluorinated gases has also encouraged users to consider R717 and other developments such as the use of R-744 in cascade systems, similar to those 

shown in Figure 4-4. The motivation seems to be primarily based on concern about possible 

restrictions on HFCs rather than the immediate effect of the current rules (CGF, 2010), which 

are mainly aimed at commercial and mobile air-conditioning. In the industrial sector it is 

likely that the adoption of R-717 and R-744 by users who previously deployed HCFC-22 and 

HFC blends will reduce the energy-related global warming potential through increased 

efficiency as well as eliminating the direct global warming potential caused by refrigerant 

leakage. Further discussion of sustainable manufacture is provided in chapter 11.

5.1.3 Refrigeration 

Industrial Refrigeration systems are characterised by heat extraction rates in the range 100

kW to 10 MW, typically at evaporating temperatures from –50°C to +20°C. There is some 

overlap at the lower end of the capacity scale with commercial refrigeration for shops, 

restaurants and institutions: industrial systems in this sub-sector are characterised by the 

complexity of the design and the nature of the installation. The size of the industrial 

refrigeration market is difficult to assess because it covers such a broad range of applications. 

Some useful insights can be gained from consideration of the market for evaporative 

condensers, as they are used for heat rejection in the majority of large installations. Data for 

2009 was analysed for three global regions; Europe / Russia, North America and India / 

China. It is assumed that the value of the condenser accounts for 5% of the selling price of the 

refrigeration system – analysis of a wide range of projects showed that the value of the 

condenser was in the range 3% - 7% of the total refrigeration contract value. 

Table 5-1: Estimated market value (2009) for large industrial refrigeration installations

Total Condenser 

Sales (US$m)

Estimated Total 

Market (US$m)

Proportion of R-717 use

Europe/Russia 42 830 90%

North America 77 1,500 95%

India/China 45 900 90%

Evaporative condenser manufacturers also report that 90% of the condensers sold in Europe, 

Russia, India and China are for R-717 systems. In North America the proportion is even 
2014 TOC Refrigeration, A/C and Heat Pumps Assessment Report 103

higher, at 95%. The balance that is used concerns HCFC-22, R-404A, R-507A or occasionally 

HFC-134a. The results are shown in Table 5-1.

Smaller industrial systems more often use air-cooled condensers, and in these cases the 

refrigerant is more likely to be a fluorocarbon, although air-cooled condensers with stainless 

steel tubes are used in smaller R-717 systems. Table 5-2 shows the estimated value of the 

refrigeration market for the same regions with the split between R-717, HCFC-22 and HFCs. 

It should be noted however that there may be significant variations within the regions from 

country to country or state to state due to legislation or tradition. For example the use of R717 in small industrial systems is quite common in Germany, but not in France, and is 

virtually unknown in Canada and some states in the USA, such as New Jersey. Typically if 

HCFC-22 is still permitted, for example in Article 5 countries, it will be used for these smaller 

systems. If ozone depleting substances have already been prohibited then the likely 

refrigerants will be R-404A and R-507A for low temperature systems and HFC-134a for high 

temperature systems. Experience of accelerated ODS phase out in Europe showed that HCFC22 systems continue to be deployed right up to the phase-out deadline. The same pattern of 

behaviour has been observed more recently in the United States which followed the Montreal 

Protocol phase-out schedule. 

Table 5-2: Estimated 2008 market value for small industrial refrigeration installations

Estimated Total 

Market (US$m)

Proportion of R-717 

use

Proportion of 

HCFC-22 use

Proportion 

of HFC use

Europe/Russia 200 25% 10% 65%

North America 300 10% 60% 30%

India/China 500 5% 90% 5%

This table shows that the transition in smaller industrial systems when HCFC-22 is removed 

is mainly to HFC blends. For Article 5 countries it is possible that a different pattern will 

emerge. Concern about a possible “phase-down” of HFCs and associated price increases 

might result in a switch directly from HCFC-22 to R-717 for larger new systems provided 

trained staff are available and the inherent fear of R-717 is overcome. In many ways this is 

simpler than switching to HFCs and then to R-717 at a later date. For example the traditional 

lubricants used with HCFC-22 can also be used with R-717, whereas alternatives (typically 

polyol ester) are required for HFCs and are not compatible with R-717. The use of R-717 as a 

replacement for HCFC-22 for small capacity systems will only be feasible if technician 

training is prioritised and system designs incorporate low refrigerant charge. Uptake of R-717 

in smaller systems would also be helped by the development of reliable semi-hermetic 

compressors suitable for R-717.

In the Middle East, Saudi Arabia and Egypt have a relatively large bank of refrigerants in 

industrial refrigeration applications. Saudi Arabia has an estimated bank of HCFC-22 of about 

2,500 tonnes, in 2008. This constitutes 80% of the total refrigerant bank in Saudi Arabia for 

industrial refrigeration applications. The remaining 20% is distributed between R-717, CFCs, 

R-404A and HFC-134a. The phasing-out of R-502 and the harsh high ambient temperatures in 

the region for a large part of the year coupled with the scarcity of water have resulted in the 

use of small capacity air-cooled condensing units operating on HCFC-22 in many industrial 

systems. R-717 systems are few and are used for large applications such as food processing 

plants, large cold stores and large industrial cooling processes. CFC refrigeration systems are 

still in operation although most are near the end of their operational life and need to be 

replaced.
104 2014 TOC Refrigeration, A/C and Heat Pumps Assessment Report

In Southern Africa almost all large systems use R-717 and although R-744 has been trialled in 

some supermarkets it has not been used in industrial applications. In smaller industrial 

systems HCFC-22 is almost universally used, and the most common alternative is R-404A.

5.1.4 Heat pumps 

The industrial heat pumps sector is growing quickly because it addresses several sustainability 

issues simultaneously: energy savings, reduction of GHG emissions and increased use of 

renewable energy. Industrial heat pump systems have heat delivery rates from 100 kW to over 

100 MW, with the heat source usually at ambient temperature or the waste heat temperature 

of an industrial process. These systems are usually required to deliver higher temperatures 

than domestic or commercial heat pumps used for space or water heating as described in 

chapters 8 and 9. Typical temperatures are in the range 60°C to 90°C, although if the 

recovered heat is to be used for steam raising then it needs to be at least 120°C. Heat 

recovered from large industrial systems is usually transferred to water or a heat transfer fluid 

and used for process heating or for supply to district heating systems. Direct heating of air 

from large systems is unusual because of the large volume of air that would be involved. 

There is no single component of the system that can be identified and tracked to give an 

indication of the overall market size, because the compressors could equally be used in other 

industrial systems and the condenser will be a bespoke design suited to the heating application 

– most probably a fluid heater such as a plate and frame heat exchanger or shell and tube 

pressure vessel. The market is probably around 5% of the industrial refrigeration market in 

Europe, and less in North America, India and China.

5.1.5 Air conditioning

Industrial air-conditioning systems cannot be differentiated from commercial systems on size 

alone, as many commercial office buildings have large cooling loads. An industrial system 

requires a higher level of reliability and is subject to year-round high loads. These systems 

may provide human comfort in highly populated areas with large heat loads, for example in 

trader rooms or dealer floors with a lot of computing equipment. Other industrial airconditioning systems are primarily required to maintain acceptable processing conditions for 

equipment such as computer servers in data centres. In some cases the mission-critical part of 

a total cooling load may be supplied in conjunction with a comfort cooling system, configured 

so that, in the event of partial failure of the system, the mission-critical cooling is maintained 

at the expense of the comfort of the occupants of the rest of the building. Often the chillers 

used for industrial air-conditioning are the same type as described in Chapter 9 – the market 

information and options for future change are described there. However many other industrial 

systems are custom designed for the application.

5.1.6 Rankine cycle

A further use of HFCs not covered elsewhere in this report is in a closed evaporation and 

condensation cycle for the generation of electrical power (or other useful work) from the 

expansion of high pressure gas. The basic system, called the Rankine cycle, is similar to the 

process used for power generation in steam turbines, but operates at lower temperatures 

(dependent on the working fluid properties) and so can make use of heat from geothermal 

sources or rejected from industrial processes. When HFCs are used as the working fluid these 

systems are called Organic Rankine Cycles (ORC) (Zyhowski, 2003). The Rankine cycle uses 

heat to evaporate the working fluid at relatively high pressure. The resultant gas is passed 

through an expansion engine which does useful work, usually driving an alternator to produce 

electrical power. The low pressure gas at the expander outlet is condensed, usually by 

rejecting heat to atmosphere in a cooling tower, and the resultant liquid is pumped up to 

evaporating pressure by a liquid pump. The conversion rate from thermal to electrical power 

varies with the pressure differences and the expansion engine efficiency, but typically is 
2014 TOC Refrigeration, A/C and Heat Pumps Assessment Report 105

between 10% and 15%, including the electrical power required to drive fans and pumps in the 

system (Leslie, 2009).

Some ORC systems use HFC-134a as the working fluid. It has the advantage of being 

relatively cheap and available, but has a low critical temperature and so cannot take full 

advantage of higher temperature heat sources. Other systems use HFC-245fa or HFC-236fa, 

which have significantly higher critical temperatures. The GWP of HFC-245fa is 

approximately 858, whereas for HFC-236fa it is approximately 8060, so it is likely that future 

commercial systems will be based on HFC-245fa (unless severe restrictions are placed on all 

high GWP HFCs). A fluorinated ketone, perfluoro-2-methyl-3-pentanone CF3CF2COCF

(CF3)2, has been used as an alternative (Brasz, 2008). It has zero ODP and near-zero GWP 

(Hodnebrog, 2013) but less favourable thermodynamic properties than HFC-245fa. Other new 

compounds have also recently been proposed, such as R-1336mzz (Z) (Kontomaris, 2014). 

Rankine cycles have also been produced using R-744 (Persichilli, 2012), R-717 and 

ammonia-water mixtures as the working fluid, although strictly speaking these cannot be 

described as “organic”. The R-744 power generation systems either operate with the heat 

input above the critical point (transcritical) or with both heat input and heat output above the 

critical point (supercritical). The relatively high investment cost and relatively low rate of 

return mean that these systems are generally limited to use in large process plants, although a 

few systems have been installed in commercial buildings.

5.2 Applications 

5.2.1 Food processing

Refrigeration is used for chilling and freezing food during processing, in order to prolong 

shelf life, but it can also be used to make handling or processing easier. For example hams are 

temporarily frozen to enable them to be sliced more thinly. Chilling also plays a part in the 

pasteurising process where the product is rapidly cooled after heat treatment to minimise 

spoilage. A wide variety of chilling and freezing techniques are used, including immersion in 

liquid, air blast freezing in batches or in a continuous process and contact freezing on tables 

or in blocks between metal plates. The choice of process depends on the form that the product 

takes, whether it is wrapped or unwrapped, robust or fragile, processed or raw. Some fruits 

and vegetables such as potatoes, apples and most soft fruit are notoriously difficult to freeze 

as the expansion of water destroys the cell walls, leading to mushiness when thawed. Other 

produce, such as peas, corn and beans, can be frozen in very small pieces using a fluidised 

bed of air to allow each individual piece to freeze without agglomerating.

There is a negative public perception of frozen food, which is that thawed food will always be 

inferior quality to fresh. In fact if good quality food is frozen professionally immediately after 

harvest, catch or cooking it should offer increased shelflife and superior quality when thawed. 

Spoilage rates could be substantially reduced if a greater proportion of food were frozen 

before shipment. If the public perception of frozen food is improved then there could be a 

significant increase in this sector of the market. Freezing food requires a lot of heat transfer 

compared to storage, so refrigeration systems are large capacity and require a large power 

input although the freezing chamber may be physically quite small. There is a trade-off

between the time required to complete freezing and the operating efficiency. Running the 

system at very low temperature is less efficient but results in a shorter freezing time

Some food processes require careful control of humidity and temperature to ensure product

quality and in these cases a cooling system is not enough. Examples include bakeries 

producing cakes and bread, fruit and vegetable storage and fruit ripening. The rate of fruit 

ripening is controlled by maintaining low ethylene levels in the atmosphere through the use of 

high rates of ventilation with fresh air. In periods of high ambient temperature the cooling 

load for the incoming air can be substantially higher than the product cooling load. Failure of 

the cooling system would cause the product to ripen too quickly resulting in a large loss of 
106 2014 TOC Refrigeration, A/C and Heat Pumps Assessment Report

product value before it reached the point of sale. In some cases the air-conditioning system is 

connected to a central plant cooling system using R-717 or HFCs but in others a custom 

designed stand alone system in an air-handling unit serves the humidity control requirement.

5.2.2 Cold storage

Cold storage facilities usually operate at two temperature levels, frozen (well below 0oC) and 

chilled (above 0oC). Frozen produce must be stored below -18oC, and it is usual to maintain 

the store between -22oC and -26oC to provide a factor of safety in the event of major 

equipment failure. Some products require lower temperatures, for example ice-cream and 

similar produce is stored between -26oC and -29oC, and some niche market products such as 

some types of sushi must be kept significantly colder, even down to -60oC, in order to retain 

product quality. Chilled produce is typically held between 0oC and 4oC, although fruit, bakery 

products and vegetables are stored between 8oC and 12oC. Some stores offer long term 

storage contracts, in order to stock produce until it is “out of season” and therefore more 

valuable. Stock may be held for months in these warehouses. Other sites provide marshalling 

facilities in order to restock supermarkets on a daily basis; in these plants the product is not 

usually in the building for more than 24 hours. The cooling load on such a building is high 

because of the amount of traffic through the temperature controlled chambers, although 

product load is typically low because the residence time is not long enough for the air 

temperature to have any appreciable effect on the product.

5.2.3 Industrial cooling in buildings, power plant and IT centres 

Some production processes require tight control of the surrounding temperature, for example 

microchip production, paint spraying or injection moulding. These loads are relatively 

constant all year, and production output is affected if the chilling plant is inoperative, so both 

the reliability and the efficiency of the equipment are more important than for office air 

conditioning. This can sometimes lead to the specification of uniquely designed siteconstructed systems to deliver the cooling in order to provide the high level of reliability 

required, or to achieve lower energy use. Where heat loads are too high to be handled by airor water-based cooling systems, for example in some high density data centres and other IT 

cooling applications, other fluids including R-744 have been used in direct systems (Hutchins, 

2005, Solemdal, 2014). Typical loads for these applications may be up to 2 kW per m2in 

comparison to a typical office load of 40 W per m2.

The industrial cooling load is typically almost entirely “sensible” cooling – reducing the air 

temperature without reducing the moisture content, in contrast with a typical commercial air 

conditioning load which is likely to involve more dehumidification, or “latent” cooling. 

Latent cooling requires lower temperatures to bring the air to its dewpoint. If an industrial 

cooling load is 100% sensible cooling, or if the cooling can be split into separate systems for 

sensible and latent cooling, then the operating temperature for the sensible cooling can be 

raised, making the system more efficient. In these cases it may also be possible to use indirect 

evaporative cooling to reject some or all of the process heat load.

There is a significant benefit in pre-cooling the inlet air to gas-fired turbines in higher ambient 

climates. For example reducing the air inlet temperature from 40°C to 8°C will increase 

capacity by 28% (Kohlenberger, 1995). These systems usually use large chillers with R-22, 

R-134a or R-717, cooling glycol.

5.2.4 District cooling

In the Middle East since the 1990’s district cooling applications have become common with 

the rapid rate of economic development in the Gulf area. Those applications serve office 

complexes, shopping malls, airports and call centres (Sarraf, 2012). Because of the high 

ambient temperatures throughout most of the year, the uninterrupted operation of those 
2014 TOC Refrigeration, A/C and Heat Pumps Assessment Report 107

systems is “mission critical”. District cooling providers design multiple redundancies in their 

systems, since stoppage will necessitate vacating those premises incurring heavy fines on the 

operators. 

There is an estimated district cooling installed capacity of about 13.2 GW in the Middle East. 

The UAE have the largest share of this capacity at about 8.8 GW. Qatar is the second with the 

single largest district cooling plant with an installed capacity of 420 MW. Saudi Arabia has 

about 400 MW district cooling capacity and is the fastest growing market. All those systems 

use vapour compression technology and predominantly HCFC and HFC refrigerants. In 

Egypt, with an estimated 350 MW total installed capacity of district cooling, natural gas fired 

absorption chillers are mostly used. Some older district cooling applications in the region still 

use CFC-11 and CFC-12 but the majority of systems are now HCFC-22, HCFC-123 or HFC134a. 

In the Gulf Cooperation Council countries (GCC), the total cooling demand is expected to 

triple between 2010 and 2030 (when HCFC are phased-out) reaching approximately 350 GW. 

This would be the equivalent to 60% additional power generation requirement in the region if 

the same mix of cooling technologies were used. The additional power generation required for 

this mix would consume the equivalent of 1.5 million barrels of oil per day so discussions are 

undergoing to increase the use of district cooling to enable electric power peak shaving and 

therefore reduce oil consumption for generating electricity. The potential for district cooling 

in the GCC counties between 2010 and 2030 is over 100 GW, existing capacity in GCC 

countries is 11.7 GW, and thus an increase of about nine folds of existing capacity is 

expected. This increase between 2012 and 2030 is divided as shown in Table 5-3 (Olama, 

2012)

Table 5-3: Estimated change of district cooling capacity in GCC countries, 2012 - 2030

Kingdom of Saudi Arabia +44.75GW

United Arab Emirates +31.12GW

Qatar +10.18GW

Bahrain +2.63GW

Kuwait +10.95GW

Oman +3.65GW

District cooling systems are not restricted to the extreme tropical climate of the Middle East. 

Similar systems are installed in the United States serving business districts, hospitals and 

university campuses, and such systems are becoming more common in Scandinavia where the 

district heating network makes it easier to incorporate cooling into the existing infrastructure. 

Helsinki for example has a 120 MW district cooling system (Vartiainen, 2011), which is 

projected to grow to 280 MW by 2030. Several large systems have been installed in China, 

including steam-driven absorption. Where absorption chillers are used the district cooling 

system can be integrated with a combined heat and power plant, using the excess heat from 

generators to drive the cooling system. In some coastal sites, for example in Hawaii and 

Mauritius, deep seawater is being considered for district cooling offering a significant 

reduction in demand on an electrical infrastructure which might already be overloaded.

5.2.5 Industrial heat pumps and heat recovery

Many industrial processes including brewing, dairies, food factories and chemical processes 

require large amounts of heat in addition to a cooling load. Even if the primary use of heat, for 

example for cooking food, cannot be achieved by heat pumps or recovery there may be many 

uses for lower grade heat, such as pre-heating boiler feed water or heating wash water for the 

production area. When the application is collecting and redirecting waste heat from a 

refrigerating system it is called heat recovery. When it is performing a non-productive chilling 
108 2014 TOC Refrigeration, A/C and Heat Pumps Assessment Report

process on a source of heat, whether it is at ambient temperature or is the waste heat stream 

from another process such as a cooker flue, it is a heat pump.

Large heat pumps have also been used for heating public buildings, for example in 

Gardermoen Airport, Norway (8100 kW heating capacity) and Akershus hospital, Norway 

(8000 kW heating capacity). These systems are custom-designed, using R-717 as the 

refrigerant (Stene, 2008).

Even larger systems are used for district heating systems, with many examples in 

Scandinavia. The smallest of these systems are about 5 000 kW. Most installations use HFC134a in centrifugal compressors, with some (up to 15 000 kW) using R-717. The largest is in 

Stockholm, with a total capacity of 180 000 kW (180 MW) using HFC-134a in centrifugal 

compressors. This system takes heat from sea water to provide the thermal source; other 

similar installations have used waste water from the sewage system (Bailer, 2006).

Steam-fired absorption systems (as described in section 5.3.6) can be used to raise condenser 

water temperature in power plants to provide heat to district heating networks and some 

industrial processes. Absorption can also be used to boost the temperature of a proportion of a 

medium temperature process stream by cooling the remainder of the stream. In this way a 

small part of a stream at 70°C could be raised to 120°C by cooling the rest of the stream and 

rejecting its heat to atmosphere at, say, 35°C.

5.2.6 Leisure 

The principal use of refrigeration in the leisure market is for ice rinks, extended also to indoor 

ski-slopes, ice climbing walls and other ice features. Many older ice rink systems used direct 

CFC-12 or direct R-717. To change to an indirect system would require replacement of the 

floor slab, which is a considerable capital expenditure. Some CFC-12 systems have been 

converted to HCFC-22 despite the increased pressure. Similarly some R-717 systems in 

Central Europe have been converted to R-744. A few very large systems have been installed 

for bobsled and luge runs, typically associated with winter Olympics. These systems usually 

use pumped R-717. A recently installed cross-country ski track in Finland used R-744 for the 

track cooling, with circuits up to 1 km long.
2014 TOC Refrigeration, A/C and Heat Pumps Assessment Report 109

5.2.7 Process Refrigeration

Cooling is used in a wide variety of process applications (in addition to food industry 

applications covered in section 5.2.1). The cooling can be applied by a direct refrigeration 

system with a coil in the process tank, or a jacket around the outside of a chemical reactor 

vessel or storage tank. Alternatively, a secondary fluid such as water, brine solution or glycol 

may be used. In these cases standard chillers as described in chapter 9 might be used, 

although there may still be other reasons for requiring the chiller to be specially designed for 

the project, for example location of the equipment within a hazardous area.

In refineries refrigeration is used to remove light hydrocarbons from the process stream. Such 

systems can be extremely large and may use HCFC or HFC in centrifugal chillers. It is also 

possible to use the feedstock, particularly ethylene or propylene as the refrigerant, either in a 

closed-loop system or as part of the process flow. In very large systems, the use of HFC-134a 

enables centrifugal compressors to be used whereas ethylene typically requires screw 

compressors, which, at that size, are significantly more expensive.

Some specialist processes including plastic forming, paper milling and precision machining 

require multiple small capacity systems and are typically constructed on site using HCFC or 

HFC. The use of multiple flexible hoses to connect to the moving parts of these machines 

presents a particular challenge due to high refrigerant leak rates.

Where processes produce high grade waste heat, for example flue gases from glass 

production, power stations, steel mills, incinerators or cement factories, the heat can be used 

to drive absorption chillers, either directly or by raising steam which is fed to the chiller. Such 

systems require to be tailored to the application to ensure that the heat production and cooling 

demand are well matched.

The cooling of deep mines presents another challenge because the operating conditions are 

arduous and the available space is severely constrained. Typical systems used centrifugal 

chillers underground. An alternative to the use of CFC-12 or HCFC-123 in centrifugal chillers 

was to produce cooling at the surface, either as cooled ventilation air or as chilled water or 

ice. However the depth to which surface cooling is effective is limited and for mines deeper 

than about 2,000m some form of underground cooling is required to counter the effects of air 

compression and the power required to transport the cooling effect from the surface to the 

workface. There is currently no acceptable alternative to HCFC-123 for underground 

applications to a depth of up to 4,500m (Calm, 2011). Some of the new fluid blends currently 

under development for other applications (see for example chapter 2, chapter 4 and chapter 9) 

may also be suitable for this application but it is unlikely that a fluid will be developed solely 

for this use.

5.3 Options for new equipment

Where its use is still permitted in new systems, particularly in article 5 countries, HCFC-22 is 

still common as an alternative to R-502. It has not been supplanted by HFC blends because it 

is cheaper than any of the blends and usually offers better system efficiencies. The most 

common alternative to HCFC-22 as a replacement for R-502 in new systems is R-404A, 

although it has a significantly higher global warming potential and is less efficient.

5.3.1 R-717 (Ammonia)

The analysis of evaporative condenser use shown in Table 5-1 indicates that R-717 is by far 

the most common refrigerant used in industrial systems. The major hazard presented by R717 is its acute toxicity, although its pungent odour ensures that low, relatively harmless 

concentrations are obvious and provide an early warning of danger.
110 2014 TOC Refrigeration, A/C and Heat Pumps Assessment Report

R-717 is flammable in relatively high concentrations, but it is difficult to ignite and as a result 

R-717 conflagrations are extremely rare. The products of combustion are nitrogen and water, 

so there are no toxic consequences. The lower flammable limit is 16%; about 5,000 times 

higher than the short term exposure limit, and almost 50,000 times higher than the lowest 

level which can be detected by smell.

R-717 systems can be designed for very high efficiency, particularly with higher condensing 

temperatures, so in recent years it has been used more often in smaller systems with air cooled 

condensers, condensing at about 50 °C (IIR, 2008). Compression of R-717 produces relatively 

high compressor discharge temperatures compared with most fluorocarbons, but if oil injected 

screw compressors are used then the heat of compression can be removed by oil cooling. R717 also produces relatively high heat transfer coefficients and requires a low massflow due 

to its high latent heat. The high critical temperature of 133°C makes R-717 very suitable for 

high temperature heat pumps. It is at atmospheric pressure at -33°C, a relatively high 

temperature for industrial freezers. This means that many freezers operate at sub-atmospheric 

pressure, so air and moisture are drawn into the system if it is not pressure-tight on the low 

pressure side. This unfortunate consequence is generally tolerated because the moisture is 

soluble in ammonia liquid so does not immediately cause unreliability and because both air 

and water can be relatively easily removed from the system while it is in operation. However 

excessive water build up will eventually impair operating efficiency and therefore increase 

electrical consumption, so system contamination should not be left uncorrected (Nielsen, 

2000).

5.3.2 Hydrofluorocarbons

When the first HFC refrigerants, particularly HFC-134a, were introduced in the late 1980s to 

replace CFC-12 there was no obvious successor to the most common CFC blend in the 

industrial market, R-502. This had been introduced to enable single stage compression plants 

to be used for low temperature applications without excessive discharge temperatures. When 

it became clear that R-502 could no longer be used, because it contained CFC-115, most 

system designers either used HCFC-22 or R-717, both of which produced higher discharge 

temperatures and therefore required additional cooling or two compression stages for freezer 

applications.

Saturated: Saturated hydrofluorocarbons include fluids such as HFC-134a and HFC-125 and 

blends of fluids, mixed to provide specific advantages for particular applications. HFC-134a 

is used in small high temperature systems; it is at atmospheric pressure at -26oC, and it 

requires larger compressors than R-717. Sub-atmospheric operation is less common with 

HFCs because traces of moisture are liable to freeze and block the expansion valve.

HFC-134a is also widely used in centrifugal compressors, including some very large systems 

used for district heating. A trial system using unsaturated HFC-1234ze(E) as an alternative to 

HFC-134a in district heating has been tested in Norway (Nørstebø, 2013). 

There is no single fluid alternative to HCFC-22 for use in industrial systems. HFC-125 has 

approximately the right pressure temperature relationship, but has an extremely low critical 

temperature of 66oC, and would therefore be extremely inefficient if used in industrial 

systems, unless the condensing temperature was very low. It is used as a component of 

several of the most popular blended refrigerants, where the deficiencies in its physical 

properties can be offset by careful selection of the other components of the blend. The most 

common blends used in the industrial sector are R-404A and R-507A, which are primarily 

mixtures of HFC-125 and HFC-143a; with the latter providing a higher critical temperature 

and hence improved efficiency. Many industrial systems use flooded evaporators, where the 

refrigerant boils in a pool. Zeotropic blends (with a temperature glide during evaporation) are 
2014 TOC Refrigeration, A/C and Heat Pumps Assessment Report 111

not suitable in these systems because the blend components may fractionate, so R-407C and 

service replacement blends such as R-417A have not been much used in the industrial sector.

It is surprising that R-410A has not been more widely used in industrial systems because it 

has a low boiling point at atmospheric pressure (-51.4 oC), very low glide (less than 0.2K at -

40 oC) and the critical temperature is almost the same as R-404A. The compressor swept 

volume required for R-410A is about 30% less than for R-404A, so equipment costs, 

including installed pipework should be less, although operating pressures are higher. The 

main barrier to its use is the high price of the refrigerant, particularly compared to R-717 and 

R-744. When the refrigerant inventory in a system is in tonnes the cost of the charge may be a 

significant part of the total cost of the installation. Typical installations are therefore low 

capacity, low temperature, for example blood freezing and small pharmaceutical systems. The 

introduction of rules and guidance for the use of flammability class 2L refrigerants (those that 

have a burning velocity less than 10 cm s-1and therefore do not explode) might result in an 

increase in the use of HFC-32 as an alternative to R-717 in industrial systems.

Unsaturated: unsaturated hydrofluorocarbons such as HFC-1234yf and HFC-1243ze have not 

to date been used in industrial systems. The low global warming potential may give the 

impression that they could be a suitable alternative to R-717 and R-744, but it is very likely 

that they will be even more expensive than R-410A, with the further disadvantage of being 

flammable. It is therefore likely that none of this family of chemicals will achieve any 

significant market penetration in the industrial sector, even if blended with other compounds 

to reduce price or flammability. An exception may be found with centrifugal compressors for 

industrial chillers and heat pumps where HFC-1234ze(E) might provide an alternative to 

HFC-134a (Nørstebø, 2013). The unsaturated HFC-1336mzz(Z) and the unsaturated HCFC1233zd(E) may also prove to be suitable in heat pumps with centrifugal compressors, 

particularly in very large systems.

5.3.3 Hydrocarbons

Hydrocarbons are not widely used in industrial refrigeration except where additional safety 

measures to ensure that leaking refrigerant cannot be ignited are required anyway, for 

example in a petrochemical plant. They offer excellent efficiency, and compatibility with 

most materials and lubricants. However the precautions required to prevent ignition are 

significantly more expensive than those required for R-717 systems, although the whole 

system cost may be comparable. HC- 290 is generally similar in performance to HCFC-22 

and R-717 in terms of operating temperatures and pressures, and requires similarly sized 

compressors.

5.3.4 R-744 (Carbon dioxide)

R-744 cannot be used in exactly the same way as other industrial refrigerants. It needs to be 

coupled with a higher temperature refrigerant in a cascade system due to the low critical 

temperature of 31oC or else used in a transcritical system. Transcritical systems have been 

used in commercial and small systems, but there are no compressors on the market to provide 

the necessary high operating pressures to run an industrial R-744 system in this way. A 

medium-sized distribution centre with an installed capacity of 1500kW has been operating in 

Denmark since 2008, using multiple commercial-sized compressors (Madsen, 2009).

R-744 is particularly suitable for use in freezer systems because it is liquid at positive 

pressure down to -56oC and the gas is extremely dense, giving very high rates of heat transfer. 

The pressure drop characteristics are also very favourable at low temperatures, so R-744 

freezer systems have been found to be significantly more efficient than any other alternative, 

even R-717 (Pearson, 2009). In slightly higher temperature applications, such as cold storage, 

R-744 cascade systems are likely to be slightly less efficient than two-stage R-717, but still on 

a par with a single stage economised system, and more efficient than any system using a 
112 2014 TOC Refrigeration, A/C and Heat Pumps Assessment Report

secondary fluid due to the much lower pumping cost for R-744 compared to glycol, brine or 

other heat transfer fluids (ASHRAE, 2010).

In Article 5 countries, Saudi Arabia has one cold store application where a cascade system 

utilises R-744/R-717.

In higher temperature applications, for example IT cooling, R-744 is attractive as an 

alternative to chilled water because it is electrically non-conductive, does not cause fabric 

damage in the event of a small leak and enables smaller heat exchangers to be used. The 

major challenge in these systems is that the operating pressure is approximately 50 bar. 

5.3.5 R-718 (Water)

In general R-718 is not suitable for most industrial applications because the triple point is 

very slightly above 0oC, and because, despite the very high latent heat, the swept volume 

required for a typical cooling duty is extremely high. There are a few notable exceptions: R718 has been used for a few deep mine cooling projects where a vacuum system is used to 

create a mix of solid and liquid water (ice slurry) at the triple point. Similar systems have 

been used for large plastics moulding coolers, but these systems have not yet been fully 

commercialised.

5.3.6 Absorption

Absorption systems using aqua-ammonia can be used for low temperature applications, easily 

reaching cold storage temperatures. This is because the ammonia is used as the refrigerant, 

with water as the absorbent. Water-lithium bromide (LiBr) systems can only be used above 

freezing because the water is the refrigerant, and the LiBr is the absorbent. Absorption 

systems are only effective if there is an abundant source of heat at high temperature to drive 

the system. It is not normally economic to burn fossil fuel for the sole purpose of driving the 

regenerator of an absorption system, particularly in low temperature systems, because the heat 

rejection plant is significantly larger than for an equivalent duty, electrically driven vapour 

compression system.

Absorption systems are primarily used for process cooling in food, beverage, chemical and 

pharmaceutical plants where waste heat to drive the system is readily available. Countries 

with a shortage or unreliable electric supply use direct fired chillers in industrial cooling. 

Examples are in India, Pakistan, Bangladesh and China. Those units are generally fuel oil 

fired or gas fired. There is an increase in the food industry, when local on-site power 

generation is used, and provides a source of waste heat. This has been particularly noted in 

developing countries such as India and China, where increased food production is being 

achieved but the electrical infrastructure is still relatively unreliable. In these cases chilling is 

normally achieved with a vapour compression plant, but with some absorption cooling 

available to augment the cooling capacity when the generator is running. In countries where 

natural gas downstream piping infrastructure exist and where gas prices are reasonable 

compared to electricity, direct fired chillers are used to produce chilled water for industrial 

applications. Those are normally double effect units. 

Indirect fired absorption units are used primarily in applications where excess boiler capacity 

is available in summer months and where steam or hot water are generated by a co-generation 

application. Those units are normally single effect and are fired at water or steam 

temperatures of 90 °C to 120 °C. The efficiency of those units is compared to those of vapour 

absorption in chapter 9. The Lithium Bromide-water chillers are all water cooled. 

5.4 Options for existing equipment

Systems using HCFC-22 have been converted to zero ODP refrigerants, but it is difficult to 

replicate the operating conditions of HCFC-22 and so conversions often involve an element of 
2014 TOC Refrigeration, A/C and Heat Pumps Assessment Report 113

equipment replacement. Before committing to any large scale retrofit project consideration 

should be given to the age of the plant, the cost of replacement with a modern, more efficient 

system and the risks to continued operation of retrofit.

5.4.1 Conversion to HFC blends

There are numerous blends for the replacement of HCFC-22 in DX (superheat controlled) 

systems, but there is none that replicates the pressure temperature relationship of HCFC-22 

without significant glide, and so these blends are much less common in flooded systems 

where fractionation of the blend is a concern. Where industrial systems are converted to a 

blend it may also be necessary to change from mineral or alkyl benzene lubricant to a 

synthetic ester. Some blends are formulated with hydrocarbons in the mix so that, although 

still non-flammable, the lubricant is more miscible and less likely to accumulate in the 

evaporator of the system. For a large flooded system it might be appropriate to convert the 

compressors and condensers to an HFC blend, but convert the low pressure side to a 

secondary fluid, or even R-744 as a volatile secondary. Retrofitting of HCFC-22 plant in 

Article 5 countries is very uncommon to date.

5.4.2 Conversion to R-744

The high operating pressure of R-744 systems makes it highly unlikely that an existing 

HCFC-22 system could be converted to operate on R-744. Conversion to a cascade system is 

possible, greatly reducing the inventory of fluorocarbon refrigerant in the system. It may even 

be possible to reuse the low pressure pipework and evaporators in the system if they are 

suitably rated. A cold storage or freezing system operating as a cascade on R-744 could be 

limited to an allowable pressure of 25 bar gauge, however this is a complex retrofit and it may 

well be more economic to replace the whole plant, especially if it is already more than ten 

years old.

5.4.3 Conversion to R-717

In a very few cases a pumped HCFC-22 plant has been converted to R-717 (Jensen, 1996). In 

some cases the compressors and evaporative condensers are suitable for either refrigerant, and 

pipework is probably welded steel in large applications. If the evaporators are copper tube 

then they need to be replaced. It is imperative that the system is carefully cleaned during the 

conversion because any residual traces of HCFC-22, for example in lubricant will react with 

R-717 to produce a solid foam which can block all the internal components. Triple evacuation 

with nitrogen purging is probably necessary – this is time-consuming and expensive and again 

plant replacement should be considered. In the majority of cases, in all countries, equipment 

using HCFC-22 is not suitable for this conversion.

5.4.4 Conversion to hydrocarbon

Unlike R-744 and R-717 it is technically feasible to remove HCFC-22 from existing systems 

and replace it with HC-290, however it is highly likely that the resultant system will not 

comply with safety codes on the use of hydrocarbons because the refrigerant quantity will not 

comply with charge restrictions and the electrical infrastructure will not be suitably protected. 

A conversion of this type is believed to have been responsible for a fatal accident in New 

Zealand in 2008 (NZFS, 2008). A consequence of rapid phase out of HCFCs in Article 5 

countries might be an increase of this type of conversion without adequate controls. There is 

however a case for a controlled conversion from HCFC-22 to HC refrigerant (HC-290 or HC1270) where the system efficiency can be improved. In this case it is essential that suitable 

safety measures are ensured.
114 2014 TOC Refrigeration, A/C and Heat Pumps Assessment Report

5.5 Service requirements

Given the difficulty of converting from HCFC-22 to zero ODP refrigerants, many users with 

multiple systems have planned a replacement strategy to conserve their stock of refrigerant. 

Setting priorities for which system to replace or convert first includes consideration of age of 

the plant, likelihood of leakage and ease of conversion. Refrigerant which is recovered from 

converted systems can be recycled and stored on site to be used in the remaining plants. In 

Europe, where service with “virgin” HCFC-22 was prohibited from the beginning of 2010, 

some users have banked additional refrigerant by overcharging their plants with new HCFC22 prior to the end of 2009 and then recovering the excess refrigerant, which is then classed as 

recycled. This practice is not strictly outside the law, but it is not in the spirit of the 

regulation. It probably accounted for some additional sales of HCFC in the two years leading 

up to the prohibition, keeping sales artificially high at a time when many plants were being 

converted or decommissioned. If other regions implement similar regulations for the phase 

out of HCFCs they should consider ways to plug this loophole, for example by limiting the 

time that recovered HCFC can be stored before it is used, and requiring it to be sent for 

destruction or reprocessing if it is not used within the timeframe. This was done in Ireland, 

and greatly improved the effectiveness of the restriction on virgin HCFC-22.

5.6 Concluding remarks

The majority of large industrial systems in some parts of the world use R-717 as the 

refrigerant. When R-717 is not acceptable in direct systems in these countries, options include 

R-744 or glycol in secondary systems or HCFCs or HFCs in direct systems. In countries 

where R-717 has not been the preferred solution, or in market segments with smaller systems, 

the transition from HCFC-22 is not straightforward. It requires acceptance of higher cost 

fluorocarbons in systems similar to the types used with HCFC-22 or the adoption of more 

expensive systems with the cheaper refrigerants R-717 and R-744. This transition is slow and 

is constrained by a lack of trained personnel and lack of experience of the local end-users. It 

has been facilitated by corporate policy from multinational food and beverage manufacturers 

exemplified by the policy statement from the Consumer Goods Forum (CGF, 2010).

The industrial sectors covered by this chapter are too diverse to facilitate the level of 

development expenditure required to bring a new fluid to market. It therefore follows that if 

any new development gains market share in industrial systems it will be a fluid developed for 

some other purpose, either as a refrigerant in smaller mass-market systems or as a foamblowing agent, solvent or other specialty chemical. Apart from absorption systems there is no 

significant growth of other not-in-kind cooling or heating solutions.

5.7 References

ASHRAE, 2009 ASHRAE, 2009. Design Considerations for Datacom Equipment 

Centers, Second Edition, ASHRAE TC9.9, Atlanta

ASHRAE, 2010 ASHRAE, 2010. “Refrigeration Handbook, chapter 3”, Atlanta

Bailer, 2006 Bailer, P. and Pietrucha, U., 2006. “Design and Application of 

Ammonia Heat Pump Systems for Heating and Cooling of NonResidential Buildings” 10th International Symposium on District 

Heating and Cooling, Hannover

Brasz, 2008 Brasz, J., 2008. “Assessment of C6F as a working fluid for Organic 

Rankine Cycle Applications”, Int. Conf. on Refrigeration and AirConditioning, Purdue University

Brown, 1991 Brown, A. H., 1991. “Return to Ammonia?” Institute of 

Refrigeration, London
2014 TOC Refrigeration, A/C and Heat Pumps Assessment Report 115

Calm, 2011 Calm, J.M., 2011. “Refrigerants for deep mine refrigeration”, Proc. 

IIR Congress, Prague

CGF, 2010 Anonymous, 2010. “Resolution on Sustainable Refrigeration”, The 

Consumer Goods Forum, Paris

CRAA, 2012 CRAA, 2012. Survey of Refrigerant consumption for Industrial 

Refrigeration in China, CRAA, Beijing

Gulanikar, 2013 Gulanikar, A.D., 2013. “Energy Conservation in Ammonia 

Refrigeration System Installed for Meat Processing Unit in India” 

Proc 5th Ammonia Refrigeration Technology Conf., IIR, Ohrid

Hodnebrog, 2013 Hodnebrog, Ø., Etminan, M., Fuglestvedt, J. S., Marston, G., Myhre, 

G., Nielsen, C. J., Shine, K. P., Wallington, T. J., 2013. “Global 

Warming Potentials and Radiative Efficiencies of Halocarbons and 

Related Compounds: A Comprehensive Review”, Rev. Geophys., 51, 

300-378, Washington DC

Hutchins, 2005 Hutchins, G., 2005. “Mission Critical Cooling” Institute of 

Refrigeration Annual Conference, London

IIR, 2008 International Institute of Refrigeration, 2008. “Ammonia as a 

Refrigerant, 3rd Edition”, IIR, Paris

Jensen, 1996 Jensen, S.S., 1996. “Conversion from R22 to R717, Practical 

Experiences from three Industrial Plants” Proc IIR Conf Applications 

for Refrigerants, Aarhus

Kawamura, 2009 Kawamura, K., 2009. “Global Solutions for Ammonia Industrial 

Refrigeration” ATMOSphere, Brussels

Kontomaris, 2014 Kontomaris, K., 2014. “HFO-1336mzz-Z: High Temperature 

Chemical Stability and Use as a Working Fluid in Organic Rankine 

Cycles”, 15th Int. Conf. on Refrigeration and Air-Conditioning, 

Purdue University

Kohlenberger, 1995 Kohlenberger, C., 1995. “Gas Turbine Inlet Air Cooling and the 

Effect on a Westinghouse 501D5 CT”, Proceedings of the 

International Gas Turbine and Aeroengine Congress & Exposition, 

Paper No. 95-GT-284, ASME, New York

Leslie, 2009 Leslie, N., Sweetser, R., Zimron, O. and Stovall, T., 2009. 

“Recovered Energy Generation Using an Organic Rankine Cycle 

System” ASHRAE Transactions Vol. 115 Part 1, Atlanta

Madsen, 2009 Madsen, K., 2009. “Living without HFCs: the Danish Experience”, 

Institute of Refrigeration, London

Nielsen, 2000 Nielsen, P.S., 2000. “Effects of Water Contamination in Ammonia 

Refrigeration Systems, Danfoss, Nordberg

Nørstebø, 2013 Nørstebø, A., 2013. “District Heating and Cooling based on large 

Heat Pumps”, Proc. HPP Workshop, Oslo

NZFS, 2008 New Zealand Fire Service, 2008. Report No F128045 “Inquiry into 

the Explosion and Fire at Icepak Coolstores, Tamahere, on 5 April 

2008”, Wellington

Olama, 2011 Olama, M. A., 2011. “The National Survey for HCFC based 

refrigerants for Refrigeration Systems in the Kingdom of Saudi 

Arabia”, UNIDO 
116 2014 TOC Refrigeration, A/C and Heat Pumps Assessment Report

Pearson, 2009 Pearson, A.B., 2009. “Calculating Freezing Times in Blast and Plate 

Freezers”, Proc Int. Institute of Ammonia Refrigeration Annual 

Meeting, Dallas

Pearson, 2011 Pearson, A.B., 2011. “Opportunities for Combined Heating and 

Cooling”, Proc 4th Ammonia Refrigeration Technology Conf., IIR, 

Ohrid

Persichilli, 2012 Persichilli, M., Kacludis, A., Zdankiewicz, E and Held, T., 2012. 

“Supercritical CO2 Power Cycle Developments and 

Commercialization: Why sCO2 can Displace Steam”, Power-gen 

India and Central Asia, New Delhi

Pietrzak, 2011 Pietrzak, J., 2011. “Economic Optimisation of Refrigeration Systems 

at the Design Phase”, Proc 4th Ammonia Refrigeration Technology 

Conf., IIR, Ohrid

Sarraf, 2012 Sarraf, G., Fayad, W., El Sayed, T., Monette, S-P., 2012. “Unlocking 

the Potential of District Cooling – The Need for GCC Governments 

to Take Action”, Booz and Co, Chicago

Solemdal, 2014 Solemdal, Y., Eikevik, T., Tolstorebrov, I. and Veiby, O., 2014.

“CO2 as a refrigerant for cooling of data-center: a case study”, Proc 

GL2014, IIR, Hangzhou

Stene, 2008 Stene, J., 2008. Design and Application of Ammonia Heat Pump 

Systems for Heating and Cooling of Non-Residential Buildings” Proc 

GL2008, IIR, Copenhagen

Tarlea, 2013 Tarlea, G.M., 2013. “Romania – Ammonia Traditional User” Proc 5th

Ammonia Refrigeration Technology Conf., IIR, Ohrid

UNEP, 2011 UNEP, 2011. Report of the Refrigeration, Air Conditioning and Heat 

Pumps Technical Options Committee (RTOC) 2010 Assessment.

Vartiainen, 2011 Vartiainen, J. and Salmi, J., 2011. “District Cooling in Helsinki”, 

Helsingin Energia, Helsinki

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IIR Congress, Washington DC
2014 TOC Refrigeration, A/C and Heat Pumps Assessment Report 117

Chapter 6

Transport Refrigeration

Chapter Lead Author

Radim Čermák

Co-Authors

Michael Kauffeld

Holger König

Richard Lawton

Alexander C. Pachai 

Giorgio Rusignuolo
118 2014 TOC Refrigeration, A/C and Heat Pumps Assessment Report
2014 TOC Refrigeration, A/C and Heat Pumps Assessment Report 119

6 Transport refrigeration

6.1 Introduction 

Transport refrigeration is a small but vital segment comprising delivery of chilled or frozen 

products by means of trucks, trailers, vans, intermodal containers and boxes. It also includes 

the use of refrigeration and air conditioning on merchant, naval and fishing vessels above 100 

gross tonnes (GT) (over about 24 m in length). 

Most development has taken place in the intermodal container industry since 2010. Although 

many of the lessons are applicable to road transport, differences between containers and road 

vehicles should not be neglected, and may lead to different system solutions and (possibly) to

different refrigerant choices. The three top candidates in the container industry are R-744, 

hydrocarbons and low-GWP HFCs. 

In contrast to the 2010 report, more insight is provided on eutectic and cryogenic systems 

which may be attractive for some types of transport routes. Porthole container ships, which do 

not exist any longer, are omitted, as are dedicated railway systems where trailer units or 

intermodal containers units are now utilized. The niche segment of airfreight containers is 

added. 

New information about vessels in terms of type and refrigerant charge is provided based on 

the 2012 IMO study. It appears that the differences in type are large and segmentation is 

needed in the future. Analyses on refrigerant options are limited in this chapter, and the reader 

is advised to consult the chapters dealing with industrial and air-conditioning systems. 

Based on research, the road vehicle fleet size previously estimated at 4 million in the 2006 

and 2010 RTOC Reports has been downsized to 2 million. This changes the overall picture in 

that the refrigerant banks in vessels almost double the banks in other transport sub-segments.

While CFCs and HCFCs can be found in older equipment, virtually all new transport 

refrigeration systems continue to utilize HFCs, with a prevalence of HFC-134a and R-404A. 

Some systems aboard vessels utilize HCFC-22 in both non-Article 5 and Article 5 countries. 

R-717 and R-744 systems are being installed on fishing vessels.

Appendix A contains a general overview and technical progress information, further, the 

ozone depletion potential (ODP) and global warming potential (GWP) values of the 

refrigerants discussed in this chapter are given in chapter 2 of this report.

6.2 Options for new equipment

6.2.1 Intermodal containers and road vehicles

6.2.1.1 Hydrocarbons

While hydrocarbons offer superior thermodynamic properties which lead to high energy 

efficiencies, the possible leakage of the refrigerant inside the box and other failure scenarios 

present a safety challenge, since these refrigerants are flammable. 

Due to the lack of specific safety standards applicable to transport refrigeration, the design 

usually relies on safety standards for adjacent applications, such as ISO 5149 (ISO, 2014a) or 

EN 378 (2008). For example, according to the scope, ISO 5149 (ISO, 2014a) covers transport 

refrigeration but the detailed safe design and operation for all the mentioned applications are 

not described (König, 2013a). Most standards rely on the concept of “lower flammability 

limit” combined with a maximum charge and safety factor. In a traditional concept of a 

transport refrigeration unit, even assuming a significant charge reduction compared to today’s 
120 2014 TOC Refrigeration, A/C and Heat Pumps Assessment Report

typical charge levels, leakage inside the box would inevitably lead to concentrations above the 

flammability limit. 

The use of higher amounts of refrigerant charge over the thresholds established by the 

existing standards would require the adoption of provisions covering safe system design and 

safe operations. These higher amounts can be permitted only when special measures are taken 

to limit the refrigerant concentrations in case of leakage and the presence of sources of 

ignition. To justify such special measures, a risk analysis shall be performed to include all 

foreseeable uses (König, 2013a). All this may increase complexity and may introduce an 

additional risk that manufacturers must consider.

Measures can include ventilation and shut-off valves, combined with refrigerant detectors and 

alarm systems. Ventilation may be realized using explosion-proof fans, sensors, etc. Or, as 

alternative, the flammable refrigerant maybe isolated in a separate circuit and placed outside 

of the cargo box. A secondary fluid can be used to provide cooling inside the cargo box. The 

above measures either do not eliminate completely the flammability risk, or make the system 

very complex, or increase power consumption.

Refrigeration units with direct expansion using HC-290 and HC-1270 have been tested to date 

in a small number of trucks in the UK and Germany. One European manufacturer has 

developed a road vehicle system operating on HC-1270, the safety issues being addressed by 

having a jointless evaporator and installing a detection system. However, this unit is not 

commercially available. One intermodal container manufacturer (MCI, 2014) announced a 

possible market introduction of a refrigeration system with HC’s in 2018-19 subject to the 

boundaries of future legislation.

In summary, specific research on the use of flammable refrigerants in transport refrigeration 

should continue but (as it is the case today) their use would most likely require the 

implementation of safety measures that could increase the complexity of the system and/or, in 

case of indirect system, could penalize their efficiency.

6.2.1.2 R-744

R-744 is a promising alternative to HFC refrigerants and its widespread use in transport 

refrigeration will only come when systems using R-744 can exhibit efficiencies comparable to 

the efficiencies that are obtained at present from systems using HFC refrigerants. 

R-744 is undergoing a renaissance and the technology and learning curve in transport 

refrigeration is at an early stage. All major manufacturers have displayed concepts of units 

with R-744 at trade shows or have demonstrated an interest in R-744 solutions through 

research publications. One manufacturer has been testing an intermodal container unit with 

customers across the globe, and is now offering the unit. Since 2013, a supermarket chain in 

the UK has been conducting a trial with an urban distribution trailer fitted with a modified 

version of the intermodal container system. 

The annual energy consumption and the efficiency depends on the ambient air temperature 

and the cargo box air temperature (refer to appendix A 4.1 for details). Systems using R-744 

are more efficient than systems using HFC refrigerants under low-medium ambient 

temperature conditions. At the same ambient temperature, systems using R-744 are more 

efficient for chilled cargo and less efficient for frozen cargo than systems using HFC 

refrigerants. 

Literature mainly published for commercial refrigeration and mobile air conditioning 

application (see Table 6-1) show “crossover temperatures” (= ambient temperatures below 

which R-744 is more efficient) ranging between 21C and 40C. Data for transport 

refrigeration is limited.
2014 TOC Refrigeration, A/C and Heat Pumps Assessment Report 121

Table 6-1: Crossover temperature with regard to energy consumption/efficiency 

Source Segment Baseline 

Refrigerant

Tevap, °C Tcrossover, °C

Shimada, 

2011

Commercial refrigeration R-404A 5 32

-25 38 to 40

Finckh, 

2011

Commercial refrigeration R-404A -5 to -7 21 to 26

Hrnjak, 

2013

Mobile air conditioning 

(Summary of SAE MAC 

program)

HFC-134a about 5 25 (on the road)

35 (idling)

Möhlenka

mp, 2014

Transport refrigeration R-410A -20 25 to 40 

comparable 

Figure 6-1 shows a comparison between the R-744 reefer container unit and the incumbent 

HFC-134a unit (with comparable technology level) in terms of efficiency. Data was provided 

from a large manufacturer. Based on typical total cost of ownership of models used in the 

industry, approx. 15% of the time is estimated to be spent in full load conditions, moderate -

high ambient (an ambient temperature of 38 C is normally used to represent this condition), 

while an estimate 85% of the time is spent at medium-low ambient, part load (an ambient 

temperature of 25 C). The results show a disadvantage of R-744 at the 38 C full load point, 

but an advantage at the 25 C ambient point, with chilled cargo and in part load conditions. 

Figure 6-1: Container refrigeration, comparison between HFC-134a and R-744 for typical 

test conditions. 

Note 1: The two systems have different optimization logic (the R-744 system is mostly optimized for part load 

conditions, not full load conditions). 

Note 2: At -18C box temperature, the R-744 system has tighter air temperature control than the HFC-134a one.

R-744 in general requires dual stage compression. R-744 open shaft compressors have 

technological challenges in the transport refrigeration pressure range, and are not available 

today. On the other hand, semi-hermetic reciprocating compressors are available today, and 

scroll compressors may become available in the future. This may, for the time being, 

adversely impact the application of R-744 in sub-segments where open shaft compressor and 

scroll technologies are being utilized (for example vehicle powered truck refrigeration 

systems).
122 2014 TOC Refrigeration, A/C and Heat Pumps Assessment Report

6.2.1.3 HFC refrigerants

Refrigerant manufacturers are developing low-GWP HFC alternatives of which several have 

the potential to match the cooling capacity, power consumption and pull-down expected from 

today’s standard R-404A or HFC-134a systems. The flammability of these refrigerants is one 

of the major concerns for their use in transport refrigeration and the same principals of safety 

have to be fulfilled in transport refrigeration as described above for use of hydrocarbons 

(UNC, 2011). At the moment, there are no non-flammable very low-GWP HFC candidates 

(below GWP 150). 

Changes to refrigerant classification have been proposed to mitigate the flammability concern 

of the medium and low-GWP HFC refrigerants. For example, ASHRAE Standard 34 (2013) 

(since 2010 edition) and ISO 817 (ISO, 2014b) recognize subclass 2L (= 2 low) refrigerants 

that are defined as class 2 refrigerants with a maximum burning velocity of =10 cm/s. The 

most recent revision of standard ISO 5149 (ISO, 2014a) recognizes the fact that A2L and A3 

refrigerants need to be treated differently, and proposes more relaxed charge limits for A2L 

refrigerant when compared with A3. Still, even the more relaxed A2L limits appear not to be 

compatible with the charge levels / volumes typical of transport refrigeration applications. In 

addition, for transport refrigeration applications, due to the flammable nature of refrigerants 

classified as A2L, A2 and A3, a risk assessment should be carried out to ensure compliance 

with occupational health and safety requirements and other regional standards and 

requirements.

A calculation assuming a release of 4 kg HFC-1234yf in a 25 m3trailer box (80% loaded by 

cargo) yields concentrations that are at best comparable to the refrigerant concentration limit 

(RCL) of the ASHRAE Standard 34 (2013), and above the lower flammability limit, using the 

recommended safety factor of 4. The opening of the box and the consequent leakage of oil or 

other contaminants in presence of a source of ignition or self-ignition conditions could create 

an ignition risk. On the other hand, in personal cars, a sudden leakage in case of collision is 

usually associated with the collapse of the cabin and the consequent ventilation through the 

broken windows; therefore it is considered a lower and acceptable safety risk for mobile air 

conditioning systems. 

A side-by-side “drop in” comparison of three state-of-the-art low-GWP 2L flammable fluids 

(GWP ranging from 200 to 400) was conducted as part of AHRI Alternate Refrigerant 

Evaluation Program (Kopecka, 2013). The evaluation showed that although these 2L 

flammable fluids were not suitable for retrofit in the field (drop in), they did show potential 

for increased efficiency and capacity with respect to R-404A. 

System manufacturers are also testing low-GWP HFCs to assess the impact of other concerns 

such as stability, risk of clogging valves and expansion devices and other aspects.

Recent studies identified various non-flammable blends that offer different combination of 

GWP (ranging between 1300 and 2200), ease of retrofit, properties, performance and 

consistency with R-404A. These blends have important benefits: they are non-flammable

(A1), and in some cases they can be retrofitted in the field. The main limitation is the GWP: 

significantly lower than R-404A, but still higher than so-called natural or unsaturated HFC 

(HFO) refrigerants. 

The list includes and is not limited to R-407A, R-407F, R-448A, R-449A and R-452A (MotaBabiloni, 2014, Minor, 2014).

In this group of non-flammable blends, R-448A and R-449A stand out as lower GWP (both 

approx. 1400) alternatives to R-404A, but have higher discharge temperatures, requiring 

system changes such as liquid injection in order to achieve comparable capacity, efficiency 

and reliability. This makes them especially suitable for new systems using liquid injection 
2014 TOC Refrigeration, A/C and Heat Pumps Assessment Report 123

devices. On the other hand, R-452A has the GWP of approx. 2100 and it stands out as easiest 

direct drop, allowing it to achieve equivalent performance as R-404A without additional 

system changes. 

Overall, it is likely that each of these blends will have a role to play in the general move 

towards more environmentally friendly alternatives. 

While in transport refrigeration the majority of the attention is currently focused on R-404A 

due to the higher GWP level, several non-flammable, lower GWP blends have also been 

developed as alternative / retrofit to HFC-134a. Their GWP is in the 600-700 range, 

approximately 50% lower than HFC-134a.

6.2.1.4 Cryogenic systems

Liquid nitrogen or carbon dioxide open cooling systems entail low noise levels and low 

emissions of air pollutant due to the elimination of diesel powered refrigeration. This can 

bring benefits at the local scale, in addition to lower greenhouse gas (GHG) emissions in the 

use phase, and therefore of benefit for heavily populated areas. However, the energy required 

to produce the liquefied gases is substantial and therefore, if fossil fuels are employed during 

production, GHG emission would rise proportionally. Other options for reducing GHG 

emissions might be using alternative energy sources in production of liquefied gases such as 

off-peak nuclear or wind power or, in the case of nitrogen, ensuring that it is a by-product of 

oxygen production. 

Technologies currently under development include systems for recovering mechanical energy 

from the expansion of liquid nitrogen, leading to a potentially low-GWP nitrogen economy.

Use of cryogenics systems will continue to be determined by the availability of liquefied gas 

charging stations (see a parallel with liquefied natural gas, or LNG, in some regions). Where 

available, cryogenic systems can provide an alternative to traditional diesel powered trucks 

and trailers on a case by case basis. 

6.2.1.5 Eutectic systems

There are a limited but important number of applications where eutectic systems represent, 

and will continue representing, an option for the future: small vans, dedicated to a specific 

cargo, and with a predictable and repetitive duty cycle. Also, eutectics will continue to be an 

important solution in some applications in developing countries, where precision of 

temperature control is less relevant compared to the overall fuel and system cost. 

Eutectic systems generally require the use of a refrigerant to “freeze” the eutectic. Some 

applications use an external system to freeze the eutectic, and the vehicle can be regarded as 

“refrigerant free”. The external system has a different safety, space, etc. requirement and 

allows for deployment of R-744 or flammable refrigerants that may otherwise have 

constraints for application in vehicles.

Technology in eutectics is also moving ahead, and some manufacturers are developing new 

“phase change” materials that offer high capacity/weight ratio. 

6.2.2 Vessels

HFC-134a has been the most often used alternative to HCFC-22 in new vessels for provision 

refrigeration. New ships may also use R-407C or R-407F for air-conditioning going forward, 

as it is becoming widespread in other sectors. R-744 in cascade with R-717 is used for 

freezing down to -50 °C (mainly with fish as the cargo). 

Some shipyards utilize HCFC-22 for small fishing vessels in Article 5 countries, but not for 
124 2014 TOC Refrigeration, A/C and Heat Pumps Assessment Report

international commercial vessels.

Large industrial systems can use R-717 or R-744 where it makes sense. R-717 systems are 

limited to ships that do not carry passengers but professional crew only (due to toxicity 

consideration), and ships with a relatively high refrigeration capacity. This makes it suitable 

for large fishing vessels.

R-744 has been used as a refrigerant with own compressors (second stage in a cascade) or a 

secondary coolant being circulated by pumps. When used in the second stage, it can cover the 

temperature range between -10 and -50 °C. HFCs or R-717 is used in the first stage. Further, 

R-744 Refrigerated Sea Water (RSW) systems have been developed and may be used for 

replacing HCFC-22 systems to be taken out of operation. Again, these systems are limited to 

the fishing industry.

Cruise ships use chillers mostly with HFC-134a and it is foreseen that they will continue with 

this as long as possible due to the safety of the refrigerant hence the passengers. In 2014, a 

large manufacturer launched a 50 Hz water-cooled centrifugal chiller that utilizes HCFC1233zd(E) as an alternate technology to HFC-134a.

For commercial vessels and for the off-shore business there is a potential for HC-290 to be a 

substitute for HCFCs and HFCs as most of the fleet already have Zone 1 or 2 onboard. HC290 can be used for air conditioning as well as for provision plants, but most systems will be 

indirect secondary systems using a heat transfer fluid. 

The classification companies have to approve a given refrigerant before it can be used 

onboard ships. The procedure of approval takes time and costs money and therefore only 

refrigerants requested by the owners are approved. This comes on top of the normal 

procedures on land. This also slows down the process of changing from one refrigerant to 

another.

6.3 Options for existing equipment 

6.3.1 Road equipment and intermodal containers

The lifetime of road equipment and intermodal containers usually does not exceed 12 to 18 

years, respectively. It is determined by their heavy duty and in Europe by the ATP scheme, 

which has a 3-year recertification period after the first 6-year in operation. HCFC refrigerants, 

if any are still in use, are being fast replaced by HFCs. Eutectic and cryogenics systems on 

vehicles are not limited by safety, space and other requirements of transport application, and 

so can use a variety of refrigerants in their stationary systems.

Of the HCFC and CFC containing fluids, R-502 was widely used in the road transport 

industry after 1960, to overcome issues with HCFC-22. The retrofit options include R-408A, 

R-402A (both contain HCFC-22), R-404A or R-507A which, however, require a component 

change. 

Testing of low-GWP alternatives (below GWP 150, usually containing unsaturated HFCs) to 

the most widely used R-404A is in progress elsewhere. An AHRI AREP participant 

conducted side-by-side “drop in” comparisons of three state-of-the-art low-GWP 2L 

flammable fluids (Kopecka, 2013). The evaluation showed that these 2L flammable fluids 

were not suitable for R-404A retrofit in the field.

Recent studies identified various non-flammable blends that offer different combination of 

GWP (ranging between 1300 and 2200), ease of retrofit, properties, performance and 

consistency with R-404A. These blends are safe, they have GWP significantly lower than R-
2014 TOC Refrigeration, A/C and Heat Pumps Assessment Report 125

404A, and in some cases they can be directly dropped into existing units. This makes them a 

likely solution for the R-404A installed population as well as new systems. 

The list includes and is not limited to R-407A, R-407F, R-448A, R-449A and R-452A (MotaBabiloni, 2014, Minor, 2014).3

In this group of non-flammable blends, R-452A stands out as easy and direct drop in, able to 

achieve equivalent performance as R-404A without additional system changes. The GWP is 

at approx.2100. On the other hand, R-448A and R-449A stand out as lower GWP (approx. 

1400) options, requiring system changes with various degree of complexity (typically addition 

of liquid injection to limit discharge temperatures). 

At present between 3.5 and 6% of the refrigerated ISO container fleet has been found to 

contain counterfeit refrigerants, many containing chlorine with an ODP (Lawton, 2012). It is 

assumed that refrigerant cost and limited availability put a pressure to adopt inexpensive 

counterfeit refrigerants with the subsequent environmental damage. Taxing of existing HFCs 

(for instance based on GWP) will likely increase the use of counterfeit refrigerants.

6.3.2 Vessels

The lifetime of vessels is considerably longer than that of the road equipment and intermodal 

containers. Vessels are in operation for 30 years on average. Merchant and cruise ships are 

among the newer equipment. The average age of a merchant vessel has been decreasing from 

18.9 years in 2008 to 16.7 years in 2012 (ISL, 2012). The number of cruise ships and their 

size has about doubled in the last decade (ISL, 2011).

HCFC-22 has been the dominant refrigerant in many marine applications. Now it is being 

phased out gradually and many plants are retrofitted. R-417A, R-422D and R-427A have 

mainly been used to retrofit HCFC-22 which remains the most common refrigerant in the 

existing fleet. As discussed in previous chapters, retrofit with the zeotropic refrigerant may 

not be possible where flooded evaporators are used.

In large passenger ships/cruise liners, large chillers are being used. The most used refrigerant 

in new ships used to be HFC-134a but also R-410A has been used frequently. For retrofit of 

existing AC systems other HFC alternatives such as R-407C and R-427A require 

modifications to the equipment to reach a reasonable efficiency. HCFC-123 never became a 

real option aboard ships, possibly because of higher toxicity.

It is anticipated that marine AC systems will follow the development of new solutions seen in 

on-shore systems, perhaps with a small delay of some years due to the long expected life of 

the systems onboard ships.
126 2014 TOC Refrigeration, A/C and Heat Pumps Assessment Report

6.4 Concluding remarks 

It is clear that, in the transport refrigeration application, a unique, low-GWP or natural 

solution which would be ideal for new and field retrofit applications does not exist.

In the case of a regulation banning the use of refrigerant above a certain GWP level as in the 

EU, HFC blends will likely play a role as a retrofit to R-404A and (possibly) HFC-134a 

systems in the installed base: their GWP is significantly lower than R-404A and performances 

are relatively close. The level of system change in the field depends on the refrigerant choice.

For new systems, hydrocarbons offer high energy efficiency, but the safety risks in transport 

refrigeration application appear significant, with possible exceptions. On the other hand, R744 has been tested in the field since the 2010 RTOC report. The non-flammable 

characteristics make R-744 attractive, but the gap in efficiency in high ambient temperatures 

and the limited component supply base are limiting its penetration into the market. 

Recently there has been an initiative to consider the design and service best practices for 

flammable and high pressure refrigerants which it is hoped will lead to a fast track ISO 

standard on how these refrigerants can be applied to intermodal container refrigeration. The 

framework of this initiative has not yet been set.

We are also seeing “non-conventional” systems such as cryogenic systems or eutectic 

systems. These technologies offer specific advantages in specific applications, and the fact 

that they are HFC free will continue making them attractive.

6.5 References

AHRI, 2013 AHRI Standard 1110, 2013, Performance rating of mechanical 

transport refrigeration units, AHRI, Arlington, VA, USA

ATP, 2013 Agreement on the international carriage of perishable foodstuffs and 

on the special equipment to be used for such carriage, 2013, United 

Nations, ISBN 978-92-1-139147-3

ASHRAE, 2013 ASHRAE Standard 34, 2013, Safety Standard for Refrigeration 

Systems and Designation and Classification of Refrigerants, Atlanta, 

GA, USA

Cavalier, 2013 Cavalier and Devin, 2013, F-Gazes in transport refrigeration: 

situation and perspectives, 15. European Conference, Latest 

technologies in refrigeration and air conditioning, Milano, June 7-8

EN, 2008 EN 378, 2008, Refrigerating systems and heat pumps. Safety and 

environmental requirements, CEN, Brussels, Belgium

Finckh, 2011 Finckh, O., Schrey, R., Wozny, M., 2011, Energy and efficiency 

comparison between standardized HFC and CO2 transcritical system 

for supermarket applications, 23rd IIR Int. Congress of Refrigeration, 

August 21-26, Prague

Hrnjak, 2013 Hrnjak, P., 2013, Current and alternative refrigerants, 2nd IIR Int. 

Conference on Sustainability and the Cold Chain, April 2-4, Paris

IHS, 2013 http://www.ihs.com/products/maritime-information/ships/seaweb.aspx, retrieved on 2013-10-19

IMO, 2012 Lloyd’s Register, 2012, Study on the treatment of Ozone Depleting 

Substances used to service ships commissioned, report number 

LDSO/ENG/Q12-02RMS/07/02 – REV 4
2014 TOC Refrigeration, A/C and Heat Pumps Assessment Report 127

ISL, 2011 Shipping Statistics and Market Review, Volume 55, No 8 – 2011, 

Institute of Shipping Economics and Logistics

ISL, 2012 Shipping Statistics and Market Review, Volume 56, No 1/2 – 2012, 

Institute of Shipping Economics and Logistics

ISO, 2014a ISO 5149, 2014, Refrigerating systems and heat pumps -- Safety and 

environmental requirements, ISO, Geneva, Switzerland

ISO, 2014b ISO 817, 2014, Refrigerants -- Designation and safety classification, 

ISO, Geneva, Switzerland

Kopecka, 2013 Kopecka M., Hegar M., Sulc V. and J. Berge, 2013, System Drop-In 

Tests of Refrigerant Blends L-40, DR-7 and ARM-30a in a Trailer 

Refrigeration Unit Designed for R-404A, AHRI Low-GWP 

Alternative Refrigerants Evaluation Program

König, 2013a König, H., Enkemann, T., 2013, Risk assessment and standards 

aurvey for use of flammable refrigerants in transport refrigeration 

applications, 2nd IIR Int. Conference on Sustainability and the Cold 

Chain, Paris, France, April 2-4

König, 2013b König, H., Enkemann, T., 2013, Einsatz von brennbaren Kältemitteln 

in der Containerkühlung, Stand der Normung und Risikobewertung, 

DKV Jahrestagung November, Hannover

Lawton, 2012 Lawton and Cavalier, 2012, Risk Inherent in the Use of Counterfeit 

Refrigerants, 23rd Informatory Note on Refrigeration Technologies, 

IIR, November 2012.

MCI, 2014 Maersk Container Industry, EPA-HQ-OAR-2014-0198-0089, 

http://www.regulations.gov, retrieved on 2014-12-15

Minor, 2014 Minor, B., Sulc, V., Berge, J., Kolda, M. and Hegar M., 2014, R404A Alternative with Low Compressor Discharge Temperature, 15th 

Int. Refrigeration and Air Conditioning Conference at Purdue, July 

14-17, paper #2175

Mota-Babiloni, 2014 Mota-Babiloni, A., Navarro-Esbrí, J, Barragán, Á., Molés, F., Peris, 

B., 2014, Theoretical comparison of low GWP alternatives for 

different refrigeration configurations taking R404A as baseline, Int. 

Journal of Refrigeration, Vol. 44, August, pp. 81-90.

Möhlenkamp, 2014 Möhlenkamp, A., Lemke, N., Köhler, J., 2014, Comparison of 

different refrigerants for a two-stage transport refrigeration system, 

3rd IIR Int. Conf. on Sustainability and the Cold Chain, June 23-25, 

London

Shimada, 2011 Shimada G., 2011, High Ambient Energy Efficient CO2 refrigeration 

unit for supermarket and CVS, ATMOsphere Europe, October 11-12, 

Brussels

TEAP, 2012 TEAP 2012 Progress Report, in response to Decision XXIII-7
128 2014 TOC Refrigeration, A/C and Heat Pumps Assessment Report
2014 TOC Refrigeration, A/C and Heat Pumps Assessment Report 129

Annex to Chapter 6

The following sections describe technical progress and general characteristics of the transport 

refrigeration sector. Differences from other sectors are discussed. Fleet size and refrigerant 

charge estimates are provided in order to assess the relative importance and contribution of 

the various sub-sectors to the refrigerant banks and emissions. 

A6.1 Requirements

Technical requirements for transport refrigeration systems are extremely complex. The 

equipment has to operate over a wide range of ambient temperatures and weather conditions 

(wind, solar radiation, rain, sea water spray, etc.). The equipment has to be able to carry any 

one of a wide range of cargoes with different temperature needs and even different 

temperatures simultaneously in different compartments.

All transport refrigeration systems have to be very robust and reliable to withstand vibrations 

and shocks. At the same time, the systems must be compact to maximise cargo space, and 

lightweight to reduce the energy required to move the vehicle.

It is imperative that spare parts (including refrigerant) are available along transport routes 

world-wide. Returning to a port can be a major issue for marine vessels in case of a 

refrigeration plant breakdown. This must be considered when design changes and 

improvements are made and introduced. Rigorous testing must be carried out so that only 

proven reliable systems are commissioned for field use.

Despite these efforts, refrigerant leaks inevitably occur within the refrigeration systems 

because of vibrations and shocks, and sometimes because of collisions with other objects. In 

addition, the harsh environmental conditions tend to accelerate the equipment aging. The 

equipment lifetime is usually between 10 and 15 years for road vehicles, railcars and 

intermodal containers, or less than 10 years in case of intensive use, and 20 to 25 years for 

merchant, naval and fishing vessels.

Safety is a number one priority in all transport refrigeration systems, because trained and 

certified service personnel may not be available along transport routes. Safe operation is 

particularly essential in the case of marine vessels, where evacuation is difficult or 

impossible. Safety must be either inherent in the fluids, or must be ensured through a number 

of technical measures.

A6.2 Vessels

It is assumed that nearly all vessels above 100 GT have refrigeration systems for their 

provision rooms and air conditioning for the occupied cabin space. IHS Fairplay, the sole 

global issuing body of the IMO Ship, Company and Registered Owner numbering system, 

claims to register nearly 180,000 ships of 100 GT and above (IHS, 2013). Of those, 

refrigeration is used more extensively for process or cargo cooling in several vessel types, 

namely cruise ships, refrigerated cargo ships and fishing vessels. Refrigerated cargo ships 

consist of specialized refrigerated ships (reefers), LPG carriers, nuclear fuel carriers and juice 

carriers. According to Lloyds Register porthole ships no longer exist and they have removed 

the survey requirements from their notation.

HCFC-22 has been the dominant refrigerant used aboard ships (estimated 80% of present 

fleet). HFC-134a has been the most often used alternative to HCFC-22 in new vessels for both 

air conditioning and refrigeration. R-404A and R-407C have been used mainly to retrofit 

HCFC-22. New ships may also use R-410A going forward, as it is becoming widespread in 

other sectors. HFC-23 is used for freezing at -60 °C and below (mainly fish as cargo). Natural 

refrigerants have been used in a relatively few vessels; primarily larger fish trawlers.
130 2014 TOC Refrigeration, A/C and Heat Pumps Assessment Report

The typical charge size for different types of vessels is provided in Table A6-1 reprinted from 

the 2012 Lloyd’s report (IMO, 2012). Although the refrigerant charge of cruise ships can be 

as high as 4,000 kg or more, their fleet is small. In 2011, the total passenger and 

passenger/roll-on roll-off cargo fleet for ships of 300 GT and over was composed of 4,131 

ships, including only 426 and 35 large cruise ships and liners, respectively (ISL, 2011). The 

number of reefers, LPG and LNG carriers, porthole container ships, nuclear fuel carriers and 

juice carriers is also very low. The only growing sector may be the LPG carriers, while cargo 

containerization has increased, this has removed cargo from reefer ships and which have 

therefore declined, porthole containers and their ships have disappeared.

Table A6-1: Average refrigerant charge size in kg (IMO, 2012)

Cruise Ship Refrigerated 

Cargo

Fishing 

Vessel

Other

Air Conditioning 1800 110 60 90

Provision Room 300 15 10 15

Cargo Cooling 0 825 1500 0

Engine Control Room 12 6 5 7

Wheel House 0 8 8 8

Spare Refrigerant 700 317 785 35

Total 2812 1281 2368 155

The ODS inventory is difficult to estimate. The 2012 Lloyd’s report quantified the inventory 

of ozone depleting refrigerant for 41 flag administrations, which estimated stock was greater 

than 100 t, at 17,696 t. Provided that these 41 countries made up over 82% of the estimated 

ozone depleting potential refrigerants used in the marine sector as stated in the report, the total 

inventory could be 21,580 t. Using a much less sophisticated approach, the 2012 TEAP 

Progress Report (TEAP, 2012) arrived at the total inventory estimate of 27,650 t. 

The 2012 Lloyd’s report provided also a type-specific estimate of refrigerant leakage rates. 

The percentages were lower (5 to 15%) for cruise and refrigerated cargo ships, and higher (on 

average 50%) for the fish factory and trawlers. Regardless of type, the 2012 Progress Report 

provided an estimated leakage rate of 30% for HCFC-22. Based on the refrigerant charge size 

and the fleet size, the annual usage quantity (leakage) was estimated at 4.858 t in the Lloyd’s 

report and 8,420 t in the 2012 TEAP Progress Report.

The pieces of information collected so far on the estimated refrigerant charges, leakage rates 

and fleet sizes suggest that the fishing sector shall be consulted for more details. 

Refrigeration systems have to comply with legislation of the state whose flag they are entitled 

to fly. In the case of servicing, refrigerant sales to vessels operating under a foreign flag are 

generally considered national exports and imports, and hence restrictions may apply.

A6.3 Trucks, trailers and rail cars

The road refrigeration market comprises several vehicle segments: small trucks and vans with 

a cargo volume below roughly 19 m3, large trucks with a volume between 20 and 59 m3, and 

trailers and semi-trailers with a box volume up to more than 100 m3. Small trucks and vans 

are used predominantly for distribution in urban and sub-urban areas, while long haul 

transport favors large trucks and trailers.

It is common to state the maximum refrigeration capacity at two or three operating conditions 

that represent frozen cargo and chilled (perishable) cargo. The exact rating conditions vary 

slightly for different markets and countries: the North American market prefers to rate at box 

temperatures of –17.8 oC and 1.7 oC at an ambient temperature of 37.8 oC (AHRI, 2013), 

while the countries committed to the ATP Agreement (ATP, 2013) prefer the box 

temperatures of –20 oC and 0 oC at an ambient temperature of 30 oC.
2014 TOC Refrigeration, A/C and Heat Pumps Assessment Report 131

The flexibility required by the carriers of perishable food has brought up the need for multi 

temperature compartment box in all categories of vehicles, from small vans to the largest 

trailer. Multi-temperature equipment has been developed for nearly two decades to optimize 

different logistic scenarios. They allow the same vehicle with only one refrigeration unit to 

carry products at different temperatures in 2 or 3 compartments. They represent 25% of the 

French market (Cavalier, 2013) (25% is a weighted average of 9% vans, 44% trucks and 41% 

trailers). Some operators purchase only the multi-temperature equipment even if they often 

operate in mono-temperature mode.

If the exact rating conditions and the vehicle type are neglected, the maximum refrigeration 

capacity ranges from less than 500 W up to 10 kW at the frozen cargo temperatures and from 

less than 1 kW up to 20 kW at the chilled cargo temperatures. The refrigeration capacity 

during transportation varies with the actual heat load. Most units are able to provide heating in 

the cargo box, usually by means of hot gas (compressor discharge), electricity, or independent 

gas heating equipment.

Majority of road and rail equipment utilizes the vapour compression cycle. The systems for 

small trucks and vans are typically vehicle powered (direct drive). Large trucks and trailers 

are self-powered; they contain a power source independent of the vehicle, usually a diesel 

engine. So called multi temperature units can serve up to 3 compartments at different 

temperature levels in one vehicle. Single temperature units are traditional and more frequent.

The total world fleet size is difficult to estimate. The new published data suggest that the total 

fleet size is 2,000,000 vehicles and so is considerably smaller than anticipated previously in 

RTOC reports. Cavalier and Devin (Cavalier, 2013) analyzed UNECE, IIR, EU and expert’s 

figures and estimated the European Union fleet at some 1,100,000 vehicles. In China and 

India, the fleet size was estimated at 100,000 and 6,000 vehicles, respectively.

Of the road transport equipment, about 25% are trailers, 25% are large trucks and 50% are 

small trucks and vans (Cavalier, 2013). These data represent a shift if compared to the 

estimates presented in the RTOC 2010 report, where it was assumed that trailers and trucks 

represent, each, 30% of the fleet, and vans covered the remaining 40%. The portion may vary 

from region to region. 

The refrigerant charges ranged typically between several hundred grams and 10 kg, usually 

less than 6 kg for small and large trucks. Micro-channel condenser technologies have become 

available because of technical progress in the last few years. Innovation reduced the 

refrigerant charge by approx. 30%: for example, in new trailer units, the charge has been 

reduced from around 7.5 kg to 5 kg. 

Refrigerants typically used are R-404A and HFC-134a, in some cases R-410A. Cavalier and 

Devin reported that R-404A is present in more than 95% of equipment and HFC-134a in 

about 4% of equipment in the European Union.

There is an ongoing effort in the industry to reduce the greenhouse gas emissions. 

Technologies and designs applied today in vapour compression systems include: microchannel condensers to reduce refrigerant charge, hermetic solutions to reduce leak rates, 

reduced number of joints and better process controls and leak testing for joint integrity. In 

addition to the above, many solutions are being tested in a limited volume base such as 

alternative propulsion systems (hybrid, electric, etc.) instead of diesel engines.

There are two systems other than the vapour compression cycle and diesel engine system that 

are available in the market and used in road transport today. Their fleet size is currently, 

however, small.
132 2014 TOC Refrigeration, A/C and Heat Pumps Assessment Report

Eutectic systems rely on the concept of latent heat. When the unit is plugged in, the eutectic 

solution is frozen; in operation and delivery, the system is unplugged and the eutectic solution 

changes state, absorbing heat and cooling the cargo. Eutectic systems have a fundamental 

advantage: they do not require a diesel engine, so they are noiseless, produce no emissions 

during operation, and need low maintenance. At the same time, some key limitations apply: 

they operate at a single temperature (they are not thermostatically controlled), and they have 

limited pull down, capacity and autonomy. 

Cryogenic systems carry liquid nitrogen R-728 or carbon dioxide R-744 in an insulated tank. 

When needed, the liquid is expanded in a heat exchanger, absorbing heat and cooling the 

cargo, and then released to the atmosphere. Earlier technologies, where R-728 was supplied 

directly to the cargo box are not used any longer. Cryogenic systems are noiseless, reliable 

and offer fast pull down and high capacity regardless of the vehicle speed. On the other hand, 

they require periodic refilling and infrastructure for liquefied gases. The carbon emissions 

from liquefying the gas need be considered. 

The principles of the cryogenic and eutectic systems are illustrated in Figure A6-1.

Figure A6-1: Schematic of a cryogenic system (left) and an eutectic system (right)

Refrigerated railcars have become very rare. There is a clear and definite trend to replace 

them with intermodal refrigerated containers that can be placed on a flat car. There is a small 

market of refrigeration systems built to handle severe rail and intermodal duty.

A6.4 Intermodal containers

The intermodal containers category includes refrigerated ISO containers (reefers), air freight 

containers, and small containers and insulated boxes. 

Refrigerated ISO containers generally come in 20 ft and 40 ft lengths. Non-standard sizes 

exist as do swapbodies. The fleet size numbers are fairly accurate. It is estimated that, in 

2013, there were approximately 100,000 units of 20 ft containers and 1,000,000 units of 40 ft 

containers in use. There are about 100,000 new refrigerated containers built annually.

The vapour compression cycle has been the only technology used in refrigerated ISO 

containers. Because the equipment lifetime is around 12-15 years (up to 18 years in new 

equipment), and the last HCFC units were produced in 2000, only a few HCFC units may be 

still in use in ocean traffic today. Current systems utilize HFC-134a or R-404A. 

Approximately 60% of new units are fitted with hermetic scroll compressors, about 40% of 

the units are equipped with reciprocating, single or 2-stage compressors. The current 

technology features have resulted in reduced refrigerant charges and reduced emissions. The 

typical charge is approximately 4.5 kg, some manufacturers reporting charge of 2.8 kg HFC134a. 

All container units are electricity driven due to availability of electric grid on ships. When 

used on land (trailers, flat railcars, etc.), electricity is supplied from the electric grid or from a 

diesel engine generator set (gen-set) that is mounted on the unit front or the trailer.
2014 TOC Refrigeration, A/C and Heat Pumps Assessment Report 133

The refrigeration performances can be tested according to ISO 1496-2:2008. The maximum 

refrigeration capacity is commonly stated at three operating conditions that represent frozen 

cargo and chilled (perishable) cargo. The maximum refrigeration capacity is around 4 kW at a 

box temperatures of –29 oC, around 6 kW at a box temperatures of –18 oC, and it is around 12 

kW at a box temperatures of 2 oC, all rated at the ambient temperature of 38 oC. All units are 

able to transport any type of cargo in any climates. This means that both refrigeration and 

heating must be supplied.

Reducing energy consumption has been a continuing effort in reefer container industry. 

Manufacturers have focused on compression technology, technologies to part load operation 

of compressor (such as digital or variable speed by frequency inverters), and improving the 

control logic, mainly looking for an optimized balance between air temperature control range 

and energy consumption. 

The safety requirements are most complex for intermodal equipment because of the various 

modes of transport (ship, terminal, road, rail, public events), including air freight. Therefore 

the reefer industry and operators have established a full operation control technology 

reporting and documenting the different states of reefer container positions, locations, 

forwarding information, as well as refrigeration system related information such as cargo 

temperature. 

Dry ice (solid carbon dioxide) and gel packs are the most common types of coolants used for 

air freight transport. Dry ice is classified as “dangerous goods” and subject to IATA 

regulations – mass is declared. A small number of air freight containers use HFC-134a in a 

battery-powered vapour compression cycle. The cooling capacity as well as the refrigerant 

charge is low.

Small containers and insulated boxes are usually used in road transport. They are refrigerated 

mainly with dry ice, but also with eutectic plates, ice slurry or small vapour compression 

units. Boxes are generally not reusable and refrigerated with eutectic sticks or solid carbon 

dioxide. They are widely used for transport of pharmaceutical products and samples of food 

products.

A6.5 Temperature profiles

Both ambient temperature and cargo temperature vary during the operation of a refrigerated 

ISO container. Figure A6-2 presents the average annual ambient temperature profile collected 

by Maersk Container Industry (König, 2013b). It covers random container operations in a 

representative container fleet during a period of three years. The data include operations on 

vessel (including systems using both water-cooled and air-cooled condensers), rail and road, 

as well as operations in terminals. Temperatures between 17 and 33 C represent 73% of the 

time. 

Although ambient temperature profiles may vary from shipping line to shipping line, they 

peak most frequently between 21 and 33 C. Temperatures around 29 C are the most 

frequent and close to the ATP rating temperature of 30 C (ATP, 2013).

Most frequent cargo temperatures are as follows: -18 C (41%, frozen), 0 C (28%, chilled) 

and 15 C (17%, banana). The other temperatures represent 14% of the refrigerated ISO 

container fleet operation (König, 2013b).
134 2014 TOC Refrigeration, A/C and Heat Pumps Assessment Report

Figure A6-2: Average annual ambient temperature of reefer container fleet (König, 2013b)
2014 TOC Refrigeration, A/C and Heat Pumps Assessment Report 135

Chapter 7

_________________________________________________________________

Air-to-air air conditioners and heat pumps

Chapter Lead Author

Daniel Colbourne

Co-Authors

Sukumar Devotta

Samir Hamed

Fred Keller

Makoto Kaibara

Ting Xun Li

Rajan Rajandran

Tetsuji Okada
136 2014 TOC Refrigeration, A/C and Heat Pumps Assessment Report
2014 TOC Refrigeration, A/C and Heat Pumps Assessment Report 137

7 Air-to-air air conditioners and heat pumps

7.1 Introduction

On a global basis, air conditioners (ACs), including reversible air heating heat pumps 

(generally defined as “reversible heat pumps”) ranging in size from 1 kW to 750 kW 

comprise a vast majority of the air conditioning market (the majority are less than 70 kW). In 

the remainder of this chapter the term air conditioning will be used to apply to both air 

conditioners and air-to-air heat pumps that directly heat air. This broad category is sometimes 

referred to as air-cooled or unitary equipment. These systems cool and/or heat enclosed 

spaces ranging from single rooms to large exhibition halls. Essentially, most are electrically 

driven vapour-compression systems using hermetic rotary, reciprocating or scroll compressors 

for units with capacities up to about 100 kW, and single or multiple semi-hermetic 

reciprocating, scroll or screw compressors for units with capacities up to 750 kW. Air in the 

space is drawn over a coil containing evaporating refrigerant. Heat transfer occurs between 

the air and the circulating refrigerant. With systems that provide heating and cooling, the role 

of the evaporator and condenser can be reversed to provide either heating or cooling. In the 

heating mode, air from the conditioned space passes over the same coil that contains 

refrigerant undergoing condensation thereby transferring heat to the air.

Nearly all air conditioners manufactured prior to 2000 used HCFC-22. The transition away 

from HCFC-22 is nearly complete in non-Article 5 countries. The phase-out of HCFC-22 in 

the manufacturing and import of new products in the EU and Japan was completed between 

2004 and 2010, whilst North America and Australia and New Zealand are now also 

completing the process. However, it is important to note that technical options available at the 

time of the phase-out in these countries were environmentally focused on the protection of the 

ozone layer and not on the reduction of global warming potential (GWP). Some Non-Article 5 

countries began the transition to non-ODP alternatives ahead of the Montreal Protocol 

commitment dates (primarily within Europe and Japan). In addition, certain Article 5 

countries such as South Korea also pursued an accelerated phase-out similar to non-Article 5 

countries. 

Globally, in 2014, the majority of the installed unit population currently uses HCFC-22 and 

approximately around one half of the units produced globally use non-ODP refrigerants. An 

estimated two-thirds of a billion HCFC-22 air conditioners were operating worldwide, 

representing approximately one million metric-tonnes of HCFC-22.

The scope of this Chapter includes an overview of the common types of air conditioning 

equipment, their characteristics and where they are normally applied. Sections also highlight 

the alternatives refrigerants currently being used and anticipated for use, examining factors 

such as safety, climate impact, performance, cost implications and lubricants and commercial 

availability. In addition, issues related to refrigerant charge reduction and not-in-kind 

technologies applied to air conditioners are also covered. Alternative refrigerants for existing 

equipment, options for refrigerant replacement (only) and retrofit are summarised and 

implication of refrigerant choice for new systems used in high ambient temperatures is also 

addressed. The ozone depletion potential (ODP) and GWP values of the refrigerants 

mentioned in this chapter are given in Chapter 2 of this report.

The main developments compared to the last assessment report is related the increased 

substitution of HCFC-22 and the greater consideration of use of medium and low GWP 

alternatives. Regarding the use of HCFC-22, in 2010 many non-Article 5 countries were 

approaching the final phase-out of HCFC-22 in new systems; this has now been completed 

and most major Article 5 countries have initiated their transition from HCFC-22. Previously, 

medium and low GWP alternatives were not being given major consideration (except 
138 2014 TOC Refrigeration, A/C and Heat Pumps Assessment Report

hydrocarbons (HCs) such as HC-290) whereas now additional manufacturers are adopting 

HCs and there is also uptake of HFC-32, whilst others are also considering the variety of new 

HFC/unsaturated HFC blends. China has made a decision to convert some production lines to 

HC-290 as part of their HPMP, whilst in India there is at least one plant where HC-290 air 

conditioners are being produced. There are also new additions to information relating to 

different alternatives performance under high ambient conditions.

7.2 Equipment types 

Air conditioners generally fall into four distinct categories, based primarily on capacity or 

application: small self-contained air conditioners (window-mounted and through-the-wall air 

conditioners); non-ducted split residential and commercial air conditioners; ducted, split 

residential air conditioners; and ducted commercial split, multi-split (including variable 

refrigerant flow, VRF) and packaged air conditioners (commercial air cooled). In each of 

these categories, the term “air conditioner” includes systems that directly cool or heat the 

conditioned air. 

Table 7-1 summarises the typical physical and installation characteristics of each type of air 

conditioner.

Table 7-1: Typical configurations of air conditioner type

Type Primary configuration System layout Capacity range(kW)

HCFC-22 

charge 

range (kg)

 Small selfcontained

Window Small self-contained Self-contained 1 – 10 0.3 – 3

Portable Small self-contained Self-contained 1 – 10 0.3 – 3

Through-thewall Small self-contained Self-contained 1 – 10 0.3 – 3

Packaged 

terminal Small self-contained Self-contained 1 – 10 0.3 – 3

Split (non-ducted) Non-ducted split Remote 2 – 15 0.5 – 5

Multi-split Non-ducted and ducted split Remote 4 – 300 2 – 240

Split (ducted) Ducted split Remote 4 – 17.5 1 – 7

Packaged rooftop Ducted commercial Self-contained 7 – 750 5 – 200

Ducted commercial split Ducted commercial Remote 10 – 750 5 – 250

7.2.1 Small self-contained air conditioners

Small Self-Contained (SSC) air conditioners are small capacity units in which all of the 

refrigeration system components are contained within a single package. These products have 

cooling capacities typically ranging from 1.0 kW to 10 kW (having an average size of 2.7 

kW). This category of products includes the following common configurations: 

 Window Mounted Room Air Conditioner, 

 Through-the-Wall Air Conditioner

 Portable Air Conditioner 1

 Packaged Terminal Air Conditioner (PTAC).

Small self-contained air conditioners are designed to heat or cool single spaces, such as bed-

 

1

Portable air conditioners are a special class of room air conditioners that can be rolled from room to 

room. They exhaust their condenser air through a small flexible conduit, which can be placed in an 

open window. Some portable air conditioners use a separate outdoor condenser, which connects, to the 

indoor section with flexible refrigerant piping.
2014 TOC Refrigeration, A/C and Heat Pumps Assessment Report 139

rooms, small shops, restaurants and offices. Small self-contained air conditioners, because of 

their size and relatively low cost, have often been the first individual comfort electrically 

driven vapour-compression systems to appear in emerging air conditioning markets. 

However, duct-free, split type room air conditioners are being selected more frequently as the 

first comfort air conditioning option in most countries resulting in a global decline in the 

demand for window mounted and through-the-wall air conditioners.

These systems have average refrigerant charge levels of approximately 0.25 kg per kW of 

cooling capacity, for example, 0.75 kg of HCFC-22. The majority use hermetic rotary 

compressors, with the remainder employing reciprocating or scroll compressors.

Most small self-contained air conditioners historically used HCFC-22. As non-ODP 

refrigerants have been applied to these products-the majority have used HFC blends, R-407C 

and R-410A. A small proportion of units are using HC-290.

Globally there are about 17 million SSC air conditioners currently produced (Gloёl, 2014).

With service lives over 10 years, it is estimated that more than 170 million SSC air 

conditioners remain in operation globally.

7.2.2 Split (non-ducted) residential and commercial air conditioners

In many parts of the world, residential and light commercial air-conditioning is done with 

non-ducted split air conditioners. Non-ducted split air conditioners are widely applied in 

commercial buildings, schools, apartments and freestanding residences and range in capacity 

from 2.0 kW to 20 kW (average size of 3.8 kW). 

They comprise a compressor/heat exchanger unit (condensing unit) installed outside the space 

to be cooled or heated. The outdoor unit is connected via refrigerant piping to a fan-coil unit 

located inside the conditioned space, generally on the wall but also can be ceiling or floor 

mounted designs. Single splits often position the expansion device also within the 

condensing/outdoor unit. Compressors are typically hermetic rotary, scroll or reciprocating 

type; high energy saving potential comes from introducing inverter technology and 

technology is currently used in about half of new units. 

Reversible air conditioners (heat pumps) are gaining market acceptance in cool and cold 

climates where they are used primarily for heating but also provide cooling during summer 

operation. These units are designed to provide high efficiency and capacity at low ambient 

temperatures; typically down to -30°C. Reversible air conditioners can reduce indirect CO2

emissions by providing an efficient and cost effective alternative to electric resistance and 

fossil fuel heating. Heat pumps designed for cold climates utilize one or more technologies to 

improve their low ambient performance. These technologies include, multi-stage or variable 

speed compression, larger heat exchangers and enhanced control strategies. 

The vast majority of mini-split residential and commercial air conditioners manufactured 

prior to 2000 used HCFC-22 refrigerant. Mini-split air conditioners have average HCFC-22 

charge levels of approximately 0.25 to 0.30 kg per kW of cooling capacity. The majority of 

non-ODP refrigerants that have been applied to these products are HFC blends such as R410A and R-407C, whilst HFC-134a has been more dominant in regions that experience high 

ambient conditions. 

The current global market for these types of split systems is around 80 million units per year 

(Gloёl et al, 2014). 
140 2014 TOC Refrigeration, A/C and Heat Pumps Assessment Report

7.2.3 Multi-split air conditioners for commercial and residential 

A second type of products are multi-split; essentially the same as a single split (as described 

above) but a single condensing unit may feed two or more indoor units, although 50 indoor 

units can be used with 1 km of piping. Whilst dual indoor unit models may be used for 

residential applications, this category of split systems is more often used in commercial 

buildings. Specific refrigerant charges tend from around 0.3 kg/kW upwards, depending upon 

the installation characteristics. As with single splits, non-ducted and ducted multi-splits also 

offer reversible (heating) options. 

Variable Refrigerant Flow (VRF) systems are a sub-category of the multi-split air 

conditioning systems and are distinguished from regular multi-split systems by their ability to 

modulate the refrigerant flow in response to the system demand. The outdoor air conditioning 

unit can adjust the refrigerant flow in response to the demand from each indoor unit. In some 

configurations, these systems can have independent cooling or heating functionality for each 

indoor unit thus simultaneously heat and cool separate indoor spaces. The outdoor unit 

modulates the total refrigerant flow using various compressor capacity control methodologies, 

with compressor types generally being rotary or scroll type. VRF systems have capacities

ranging from 10 kW to over 150 kW. Although systems produced before 2000 tended to use 

HCFC-22, there has since been a growing increase in the use of R-407C and R-410A even in 

Article 5 countries, with typical charge levels of 0.30 – 0.70 kg/kW of cooling. 

Cooling capacities range from about 4 kW to about 150 kW, with an average (module) 

capacity of 20 kW (noting that modules are often multiplexed to provide greater capacities). 

Approximately 1 million systems are produced each year (Gloёl et al, 2014). 

7.2.4 Split ducted air conditioners (residential and commercial)

Ducted, split residential air conditioners are typically used where central forced-air heating 

systems necessitate the installation of a duct system that supplies air to each room of a 

residence or small zones within commercial or institutional buildings. A condensing unit 

(compressor/heat exchanger), outside the conditioned space, supplies refrigerant to one or 

more indoor coils (heat exchangers) installed within the duct system or air handler. Air in the 

conditioned space is cooled or heated by passing over the coil and is distributed to the 

conditioned spaces by the duct system. Systems can in principle be designed as reversible 

types, although for this category of ducted air conditioners it is done less frequently. 

Compressor types typically include hermetic rotary, reciprocating and scrolls. The most 

common refrigerant in these systems was HCFC-22 until the period 2005 – 2010, although 

over the past few years the majority has transferred to R-410A and R-407C. For residential 

systems, capacities range from 5 kW to 17.5 kW (average size around 10 kW) and each has 

an average HCFC-22 charge of 0.26 to 0.35 kg per kW of capacity. For commercial systems, 

capacities range from 7 to 750 kW with a current annual output of about 10 million units 

(Gloёl et al, 2014). 

7.2.5 Ducted commercial packaged (self-contained) air conditioners

Ducted commercial packaged air conditioners and heat pumps are single self-contained units 

which comprise an integral fan and heat exchanger assembly which is connected by means of 

ducting to the air distribution system of the commercial structure. The other part of the 

package is the condensing unit, normally with an air cooled condenser and compressors, which 

are often hermetic scrolls, although hermetic and semi-hermetic reciprocating and screw 

machines are sometimes employed.
2014 TOC Refrigeration, A/C and Heat Pumps Assessment Report 141

The majority of ducted commercial packaged air conditioners and heat pumps are mounted on 

the roof or outside on the ground of offices, shops, restaurants or institutional facilities. 

Multiple units containing one or more compressors are often used to condition the enclosed 

space of low-rise shopping centres, shops, schools or other moderate size commercial 

structures.

They are offered in a wide range of capacities from around 7 kW to over 700 kW and have 

specific refrigerant charges of around 0.3 to 0.5 kg per kW of cooling capacity. Most ducted 

systems historically used HCFC-22, whilst in non-Article 5 countries R-410A is mainly used 

and to a lesser extent R-407C, which is used more frequently in regions with higher ambient 

conditions. Annual market is currently about 1 million units (Gloёl et al, 2014).

7.3 Options for new equipment

As discussed in Chapter 2, there are several factors that should be considered when selecting 

an alternative refrigerant. Accordingly, this section provides a summary of the most viable 

HCFC-22 replacement candidates for new air-conditioners, based on the current information 

available to the RTOC. 

Several single component HFC refrigerants have been investigated as replacements for 

HCFC-22, although previously, HFC-134a was the only single component HFC that has been 

commercially used in air conditioning systems to a limited extent. Recently air conditioners 

have become available with HC-290 and HFC-32 as single component refrigerants. A number 

of HFC blends have emerged as replacements for HCFC-22 in air conditioning systems. 

Various compositions of HFC-32, HFC-125, and HFC-134a are being offered as non-ODS 

replacements for HCFC-22. The two most widely used HFC blends are R-407C and R-410A. 

Both R-407C and R-410A have GWP values close to that of HCFC-22 (Table 2-7 and 2-8).

More recently, new low- and medium-GWP blends are being proposed, which comprise 

unsaturated HFCs (such as HFC-1234yf, HFC-1234ze(E), HFC-1243zf, etc.) with other nonODP refrigerants such as HFC-32, HFC-134a and R-744. These blends are mixed in order to 

more closely match the performance of the refrigerants currently being used in these products 

such as HCFC-22 and R-410A (Minor, 2008, Spatz et al., 2010). Due to their compositions, 

most of these blends exhibit various levels of temperature glide (being the difference in dewand bubble-point temperature at a given saturation pressure) and in most cases are flammable. 

There are a large number of such blends proposed by manufacturers, but to date few have 

been assigned an R-number (although this is expected to change in the next two to three 

years).

Whenever an alternative refrigerant is selected, there must be a corresponding choice of 

lubricant (i.e., the base oil and appropriate additives) and this choice is also affected by the 

compressor technology and the anticipated range of operating conditions of the system. The 

selection of the lubricant to be used with a particular HFC is generally made by the 

compressor manufacturer which makes the selection after extensive material compatibility 

and reliability testing. 

Considering the various alternatives with medium and lower GWP, the majority of these are 

flammable to some extent. If flammable refrigerants are selected they present hazards not 

historically associated with safety concerns with air conditioners. In the event of ignition of a 

refrigerant leak, possible consequences can result in overpressure and thermal radiation, 

leading to further secondary consequence (secondary fire, fragments, high toxicity 

decomposition products, etc.). Furthermore, the societal tolerance of consequences from 

flammables tends to be lower than with other hazards. Therefore appropriate measures have to 

be applied in order to mitigate the risk, for example, minimising the amount of refrigerant that 

can leak into occupied spaces or removing the refrigerant from the occupied space entirely, 
142 2014 TOC Refrigeration, A/C and Heat Pumps Assessment Report

ensure that probability of ignition is greatly reduced through risk assessment and at a 

minimum, meet the requirements of national regulations and/or appropriate safety standards

(where they exist); such rules are continuously under development.

7.3.1 HFC-134a 

Whilst HFC-134a is a potential HCFC-22 replacement in air-cooled systems, it has not seen 

broad use because manufacturers have been able to develop substantially lower cost aircooled air conditioning systems using HFC blends such as R-407C and R-410A. 

To achieve the same capacity as an HCFC-22 system, the compressor displacement must be 

increased approximately 40% to compensate for the lower volumetric refrigeration capacity 

of HFC-134a. Similarly, significant equipment redesign is necessary to achieve efficiency and 

capacity equivalent to HCFC-22 systems. These design changes include larger heat 

exchangers, larger diameter interconnecting refrigerant tubing, larger compressors and resized compressor motors.

Although it is seldom a cost-effective alternative, it has been used widely in regions that 

experience high ambient temperatures for a variety of different types of air-to-air systems. 

7.3.2 R-407C

Since R-407C requires only modest modifications to existing HCFC-22 systems, it has been 

used as a transitional refrigerant in equipment originally designed for HCFC-22. However, 

since around 2004 many of the R-407C systems have been redesigned for R-410A to achieve 

size and cost reductions. An exception is when the target market’s standard conditions are 

high ambient temperatures, such as above 40-55°C. 

There are currently R-407C air conditioning products available in Europe, Japan and other 

parts of Asia. Because of its low saturated pressure, R-407C is chosen as an alternative to 

HCFC-22 by some manufactures in the Middle East where ambient temperatures can be high.

R-407C has also seen some limited use in the North America, primarily in commercial 

applications. Generally, R-407C has little chance to replace widely HCFC-22 in the air 

conditioning sector in future, at least where standard temperatures apply. 

Performance tests with R-407C indicate that in properly designed air conditioners, this 

refrigerant will have capacities and efficiencies within ± 5% of equivalent HCFC-22 systems 

(Li and Rajewski, 2000). Linton et al (2000) found that for a fixed capacity, R-407C resulted 

in a 5-11% lower cooling COP. 

As R-407C is a zeotropic blend, temperature glide is significant but has been manageable 

through many years of use and experience. Counter flow design of heat exchangers can 

mitigate the negative impact of refrigerant glide. However, with reversible heat pumps it is 

difficult to employ counter flow heat exchanger designs because the refrigerant has opposite 

flow directions in the heating and cooling modes unless complex reversible refrigerant heat 

exchanger circuiting is employed.

Polyolester (POE) or polyvinylether (PVE) lubricants can be selected for R-407C. Of these, 

POE is the most widely used lubricant in HFC refrigerant applications. A recent tendency is 

for compressor manufacturers to use POE oils in compressors so the system manufacturers 

can use the same compressor for both HCFC-22 and R-407C systems.
2014 TOC Refrigeration, A/C and Heat Pumps Assessment Report 143

7.3.3 R-410A

R-410A can replace HCFC-22 in new equipment production, since the operating pressures are 

around 50-60% higher than HCFC-22. Due to its thermophysical properties, the design of R410A units can be more compact than the HCFC-22 units they replace. In addition, R-410A 

can have better performance in inverter type air conditioner than HCFC-22.

R-410A air conditioners are currently commercially available in the US, Asia and Europe. A 

significant portion of the duct-free split products sold in Japan and Europe now use R-410A 

as the preferred refrigerant. 

System designers have addressed the higher operating pressures of R-410A through design 

changes such as thicker walls in compressor shells, pressure vessels (accumulators, receivers, 

filter driers etc.). In addition, the considerations for lubricant requirements are as described 

for R-407C; POE or PVE have to be used. 

As concerns over GWP have increased, with it high value, R-410A is becoming seen as a less 

viable alternative for HCFC-22 in the longer term, although it currently remains the first 

choice for new air conditioning equipment. Another concern is its low critical temperature 

that can result in degradation of performance at high condensing temperatures (see Section 

7.5.1).

7.3.4 HFC-32

HFC-32 is seen as a replacement for R-410A due to its medium GWP and slightly higher 

capacity and similar efficiency. Due to lower density the specific refrigerant charge (per kW 

of cooling capacity) is around 10-20% less (Piao et al, 2012, Yajima et al., 2000). R-410A 

systems can be redesigned for HFC-32 with modifications and with additional safety 

considerations given its class 2L flammability (see Annex to Chapter 2); appropriate design, 

application and service changes will be required for it to be safely applied. Another factor that 

must be considered with flammable refrigerants is refrigerant reclaim and recovery requirements 

during servicing and at the end of the product’s life to protect those servicing or recycling the 

product. The current POE and PVE lubricants used with R-410A have insufficient miscibility 

with HFC-32 (Ota and Araki, 2010) and therefore modified oils are selected.

HFC-32 has comparable efficiency to that of R-410A and HCFC-22 in many mini-split ACs, 

as shown recently by a number of performance evaluations. Barve and Cremaschi (2012) 

tested HFC-32 in an R-410A reversible AC, with various optimization modes. In cooling 

mode, the COP varied by 0% to -2%, but with up to +8% higher capacity. Pham and 

Rajendran (2012) reported on tests with HFC-32 in an R-410A system gave about +3% higher 

cooling capacity with -1% lower COP and in heating mode capacity was about 4% higher 

with negligible change in COP. Three different R-410A units were tested with HFC-32 by 

Guo et al. (2012). The capacity increased by about +5 to +6% whilst COP was -3% to 0% 

lower. As part of the AHRI “low GWP AREP” programme, HFC-32 was tested against R410A in two reversible heat pump air conditioners (Crawford and Uselton, 2012). Depending 

upon the conditions, the cooling capacity ranged from -1% to +3% of R-410A with cooling 

COP and heating COP varying by -1% to +2% and -6% to +4%, respectively. In a subsequent 

report (Li and By, 2012), HFC-32 was shown to have an increased cooling capacity ranging 

from +2% to +4% and a COP of 1% to 2% higher. Piao et al (2012) showed in a split air 

conditioner a 4% higher cooling COP and 1% higher heating COP compared to an R-410A 

system. Yajima et al. (2000) reported 10% higher cooling COP and 7% higher heating COP in 

a commercial split system.

In 2014, HFC-32 systems have been presented to the market in Japan, Europe, India and 

Australia, amongst others. One Japanese manufacturer reported that although there are some 

million split-type units installed there have been no incidents reported so far. 
144 2014 TOC Refrigeration, A/C and Heat Pumps Assessment Report

7.3.5 HFC-152a 

HFC-152a has performance characteristics similar to HFC-134a as well as 10% lower vapour 

pressure and volumetric refrigeration capacity. As such, significant redesign of existing 

HCFC-22 systems would be required, similar to that described for HFC-134a. Application of 

HFC-152a demands that systems must be designed, constructed and installed with due 

consideration of its class 2 flammability (see Annex to Chapter 2), as well as due 

consideration to reclaim and recovery requirements during servicing and at end of life. 

It is unlikely that HFC-152a will be commercialised in air conditioning systems primarily 

because its low volumetric refrigerating capacity implies increased costs relative to an HCFC22 system, added to the considerations required to handle flammability.

7.3.6 HFC-161

HFC-161 is also being evaluated as a replacement for HCFC-22 in air conditioning systems. 

It has similar thermodynamic properties to HCFC-22 and is flammable and therefore systems 

have to be designed, constructed and installed accordingly (see Annex to Chapter 2), as well 

as due consideration to reclaim and recovery requirements during servicing and at end of life. 

One potential obstacle exists in that the toxicity classification has still not been assigned under 

the relevant standards (see Annex to Chapter 2).

In terms of performance, the volumetric refrigerating capacity is close, around 5% lower, to 

that of HCFC. Tests comparing the efficiency have found that the COP of HFC-161 is about 

10% higher than HCFC-22 (Padalkar et al., 2011). Furthermore the refrigerant mass can be 

decreased to about half of the HCFC-22 charge. Wu et al. (2012b) reported on tests in split air 

conditioners, showing that both cooling and heating capacity was about 5% lower than 

HCFC-22, whilst cooling and heating COP was between 5 – 10% higher. As the ambient 

temperature increases (towards 48°C), the difference in cooling capacity reduced and the 

improvement in COP increased. Discharge temperature was consistently about 5 K lower than 

with HCFC-22. Han et al (2012) measured efficiencies of about 10 – 15% higher than R5410A and HFC-32. 

Either mineral oil or POE can be used for HFC-161. There have also been some questions 

raised regarding the thermal stability of HFC-161; one recent study has shown it can degrade 

under elevated temperature and pressure conditions, forming acids and thus corrosion (Leck 

and Hydutsky, 2013).

7.3.7 HFC-1234yf 

Since the thermodynamic characteristics of HFC-1234yf are very similar to HFC-134a, the 

same general observations about its applicability in air-to-air systems are as stated previously, 

i.e., it has a much lower volumetric refrigerating capacity and cannot be used as a direct 

replacement. Compressors would need a significantly larger displacement and experimental 

studies indicate is should be 40% larger than HCFC-22 systems (Fujitaka et al., 2010; Hara et 

al., 2010). Additional design changes include increased heat exchanger areas and larger 

diameter interconnecting tubing. As with HFC-134a, HFC-1234yf is therefore likely to suffer 

from cost issues, although possibly more so given the anticipated higher fluid costs. Although 

it is unlikely that unitary air-conditioners using pure HFC-1234yf will be commercially viable 

in most cases, there may be interest in some cases, such as for regions that experience high 

ambient temperatures. However, HFC-1234yf is being successfully demonstrated as a 

beneficial ingredient in refrigerant blends for use in air conditioning and refrigeration 

applications.

Given the class 2L flammability classification, systems should be designed, constructed and 

installed with due consideration of its flammability (see Annex to Chapter 2), as well as due 
2014 TOC Refrigeration, A/C and Heat Pumps Assessment Report 145

consideration to reclaim and recovery requirements during servicing and at end of life. 

7.3.8 HC-290

HC systems are commercially available in low charge air conditioning applications, such as 

small split, window and portable air conditioners. HC-290 is the most frequently used HC

refrigerant in air conditioning applications. When used to replace HCFC-22, HC-290 has 

performance characteristics which tend to yield higher energy efficiency and slightly lower 

cooling and heating capacity. In terms of improvements in system COP in split type and 

window air conditioners with HC-290, values range from around -4% to +20%, such as: 4-7% 

(Chinnaraj et al, 2010); up to 8% (Devotta et al, 2005b); 4-12% (Jin et al, 2012); 10-15% (Li 

et al, 2010); 10-20% (Liu, 2007); up to 14% (Padalkar et al, 2010); up to 11% (Park et al, 

2008); up to 2% (Park et al, 2007); 1-4% (Teng et al., 2012);12-19% (Wang et al, 2004); up to 

12% (Xiao et al, 2006); up to 10% (Xiao et al, 2009); around 7% (Xu et al, 2011); up to 10% 

(Yan, 1999); up to 12% (Zhang et al, 2002); up to 9% (Zhou and Zhang, 2010). Amongst 

these studies, capacity varies within -10% to +10%. 

Since HC-290 has lower density and higher specific heat, the charge quantity is about 45% of 

HCFC-22; typically around 0.05 – 0.15 kg/kW of rated cooling capacity. In addition, HC-290 

has reduced compressor discharge temperatures and improved heat transfer due to favourable 

thermo-physical properties. Compressor manufacturers indicate that both mineral oil-based 

and POE lubricants are being used in HC compressors (Chen and Gao, 2011, Suess, 2004, 

Bitzer, 2012), however they should be optimised, for example with certain additives. 

The main difficulty with HC-290 is its class 3 flammability, which creates safety concerns in 

application, installation and field service. European and international standards limit the 

charge of HC-290 (see Annex to Chapter 2). Such charge size limitations can constrain the 

use of HC-290 to smaller capacity systems that need to achieve a certain efficiency level,

depending upon the specific heat load (i.e., kW/m2) of the application; in order to extend the 

capacity range, charge reduction techniques can be applied. Charge reduction technologies 

and correct oil selection can be used to minimise the amount of refrigerant, which can 

increase the capacity range. Similarly, control strategies can be applied to restrict the amount 

of refrigerant that can leak into the occupied space can be applied, which may prevent up to 

80% of the charge being released (Colbourne et al., 2013). Furthermore, systems (such as 

centralised/packaged) can use two or more independent refrigerant circuits or reboiler loop, 

although this implies a cost increase.

Leak, ignition and fire tests demonstrated that even with catastrophic refrigerant leaks, only 

sources of ignition present in the immediate vicinity of the indoor unit have the possibility to 

ignite a leak of refrigerant and consequences are insufficient to damage doors or windows 

(Zhang et al., 2013). Similar findings for developed concentrations were reported by Li 

(2014a). Risk analyses on the use of HCs in air conditioners suggest that when the 

requirements of safety standards are met, the probability of ignition during normal operation 

is extremely low (Colbourne and Suen, 2004). A recent study demonstrated that the 

flammability risk associated with split air conditioners is around 100 times lower than with 

HC-600a domestic refrigerators (Colbourne, 2014). The situation leading to highest risk is 

sudden leaks, refrigerant handling, and servicing activities, thus, installation and service 

practices must be modified to avoid exposing occupants and field technicians to the additional 

risks associated with flammable refrigerants. 

Another factor that must be considered with flammable refrigerants is refrigerant reclaim and 

recovery requirements during servicing and at the end of the product’s life to protect those 

servicing or recycling the product. Current recovery and recycling practices depend largely upon 

national or regional regulations. For example, in Europe waste legislation implies that HCs must 

be recovered, whereas in many Article 5 countries, venting of HCs may be considered an 
146 2014 TOC Refrigeration, A/C and Heat Pumps Assessment Report

acceptable option, but should only be done subject to a risk assessment.

Some major Chinese and Indian manufacturers have had commercially available HC-290 

products since 2012 and have been available in Europe and Australia for several years. To date, 

whilst output is limited, conversion of production capacity from HCFC-22 to HC-290 of 

approximately four million units per year has been completed in China (Zhou, 2014). 

7.3.9 HC-1270 

HC-1270 has favourable characteristics from the point of view of both thermodynamic and 

transport properties, but is a class 3 flammable refrigerant. It has a similar cooling capacity to 

HCFC-22 but higher (about 4%) efficiency (Lin et al., 2010). Wu et al. (2012a) measured the 

performance of a split type air conditioner with HC-1270 and HC-290 whilst exchanging the 

compressor to match the original HCFC-22 capacity. For both refrigerants, improvements of 

1-5% in COP were observed. Chen et al. (2012) and Chen et al. (2011) compared HC-290 and 

HC-1270 in a split air conditioner and found that despite a drop in cooling capacity of 8% and 

4% respectively, COP was always higher than HCFC-22. Park et al. (2010) measured the 

performance of a split type air conditioner in heating mode and results showed that the 

capacity of HC-1270 was 3-10% higher than that of HCFC-22 and the COP was 3% higher. 

HC-1270 also has a lower discharge temperature than HCFC-22.

The charge mass is about 40% of HCFC-22 and compared with HC-290, HC-1270 has a 

larger capacity which is useful to reduce the specific charge. Similarly, the obstacles and 

flammability risk for use of HC-1270 in air conditioners are similar to those of HC-290 (see 

Annex to Chapter 2).

Some manufacturers of room air conditioners are developing products using HC-1270.

7.3.10 R-744

R-744 has a low critical temperature, which results in significant efficiency losses when it is 

applied at the typical indoor and outdoor air temperatures of air-to-air air conditioning 

applications. This is particularly the case in high ambient climates, which could result in 

higher system costs (Elbel and Hrnjak, 2008; Hafner et al., 2008; Johansen, 2008). R-744 air

conditioning systems typically operate above the critical temperature of R-744 during heat 

rejection. 

R-744 air conditioners operating in warmer climates (design temperatures greater than 30C) 

could have efficiencies approaching best in class HFC based designs (Neksa et al, 2010); 

tested prototypes at 36°C ambient had COPs between 6% and 21% lower than the best R-410A 

models. However, a number of design enhancements can be made to improve their efficiency. 

The efficiency of R-744 systems can be improved through multi-stage compression, addition 

of oil separators, use of refrigerant ejectors and expanders, various inter-cycle heat 

exchangers, and cross-counter-flow heat exchangers, which take advantage of the favourable 

thermophysical properties of R-744 (Xie et al., 2008; Wang et al., 2008; Koyama et al., 2008; 

Li and Groll, 2008; Peuker and Hrnjak, 2008; Kasayer et al., 2008). The addition of efficiency 

enhancing components can improve the efficiency of R-744 systems, but will also increase 

the cost of R-744 systems. 

Gas cooler operating pressures for R-744 systems are high; typically up 50 140 bar, with a 

mean system pressure near 50 bar (Ibrahim and Fleming, 2003). The required hydrostatic 

burst strength of systems operating at these high pressures would have to be approximately 

300 (Bosco and Weber, 2008) to 400 bar (see Annex to Chapter 2). The higher operating 

pressures contribute to high specific cooling capacity, thus allowing the reduction of inner 

diameters of tubes and lower compressor displacement or swept volume. The smaller 

component diameters result in comparable wall thickness to address the high operating 
2014 TOC Refrigeration, A/C and Heat Pumps Assessment Report 147

pressures of R-744. Design changes required to address the burst pressure requirements of R744 systems may also result in manufacturing cost increases. The high cost of R-744 systems, 

unless resolved, is expected to substantially hinder the adoption of R-744 technology in air-toair air conditioning applications.

Air-cooled R-744 air conditioners are available in capacities from about 3 to 300 kW.

Experimental results show that R-744 systems may compete in energy efficiency with high 

efficiency R-410A systems for moderate climates in both cooling and heating mode; however, 

improvements are needed to significantly increase the capacity, efficiency and reduce the 

peak electrical power requirements during the cooling mode in high ambient conditions 

(Jakobsen et al., 2007).

The solubility of R-744 in lubricant is relatively high at the crankcase operating pressures of 

R-744 compressors (Dorin, 2001). The knowledge base of information on lubricant 

compatibility in R-744 refrigeration systems is expanding as more researchers conduct studies 

of R-744 compressors (Hubacher, 2002; Li et al., 2000; Youbi-Idrissi, 2003; Muller and 

Eggers, 2008). Some of the lubricants being considered for R-744 systems are POEs, PAO, 

and naphthenic mineral oil or alkyl benzene lubricants (Youbi-Idrissi, 2003; Seeton, 2006). It 

is very likely that an oil separator will be needed in R-744 systems because of the large 

detrimental impact oil circulation has on the heat transfer performance of R-744 (Muller and 

Eggers, 2008).

7.3.11 R-446A and R-447A

The blends R-446A and R-447A have similar pressure and capacity characteristics to R-410A 

and are feasible for use in most types of air conditioning. Since they have class 2L

flammability, the maximum charge is constrained for larger capacity systems (see Annex to 

Chapter 2). As with other flammable refrigerants, systems should be designed, constructed 

and installed with due consideration of its flammability, as well as due consideration to 

reclaim and recovery requirements during servicing and at end of life.

The efficiency is comparable to that of R-410A for moderate ambient temperatures. Both R446A and R-447A have higher critical temperature of around 84C and 83°C, respectively, 

compared to 71C for R-410A. This higher critical temperature enables them to have a higher 

efficiency at high ambient temperature (Sethi, 2013).

The cost implications should be comparable to those of R-410A, although marginally greater 

due to the higher refrigerant price at present. 

Currently there is testing and trials on going and manufacturers in Japan, Korea, China and 

New Zealand are developing prototypes.

7.3.12 R-444B

Use of the R-444B is feasible in split ACs, for example, where HCFC-22 or R-407C is 

already used. Since it has class 2L flammability, the appropriate safety standards should be 

followed (see Annex to Chapter 2). As with other flammable refrigerants, systems should be 

designed, constructed and installed with due consideration of its flammability, as well as due 

consideration to reclaim and recovery requirements during servicing and at end of life.

The efficiency is comparable to that of HCFC-22 and the liquid density indicates that the 

charge should be about 10-15% lower than HCFC-22. R-444B has a critical temperature 

similar to HCFC-22 and thus substantially higher than R-410A, which implies that it should 

show performance at high ambient temperatures similar to HCFC-22. Preliminary test results 

indicate that R-444B shows similar capacity and efficiency to HCFC-22 (Sethi et al, 2014).
148 2014 TOC Refrigeration, A/C and Heat Pumps Assessment Report

The cost implications should be comparable to that of HCFC-22 although probably greater 

due to the higher refrigerant price at present. 

Currently there is testing and trials on going and manufacturers in Japan, Korea and China are 

developing prototypes.

Table 7-2: Refrigerant options for existing HCFC-22 and new equipment 

Type Options for new 

equipment

Options for existing equipment

Refrigerant replacement 

(only) Retrofit

Window

R-410A, R-407C, HC-290, 

HC-1270, HFC-32, R444B, R-446A, R-447A 

R-417A

R-417B

R-422A

R-422B

R-422C

R-422D

R-424A

R-425A

R-428A

R-434A

R-438A

R-442A

R-407A

R-407B

R-407C

R-407D

R-407E

R-421A

R-421B

R-427A

Portable

Through-the-wall

Packaged terminal

Split (non-ducted) smaller

Split (ducted)

Split (non-ducted) larger

R-410A, R-407C, HFC-32, 

R-444B, R-446A, R-447A 

Multi-split

Packaged rooftop

Ducted commercial split

NOTE: All the options are not universally applicable in the listed equipment types and this list is not exhaustive.

7.3.13 Charge reduction

In general, there is a tendency for an increase in specific refrigerant charge due to increasing 

efficiency implications. When the design of a system remains principally the same (such as 

heat exchanger configuration), an increase in system efficiency is typically coupled with a 

greater specific charge due to the need of larger heat exchanger surfaces to reduce approach 

temperature differences, thus larger internal volumes and refrigerant amount (ICF, 2006). As 

an example, in the United States, the minimum efficiency of residential air conditioners that 

can be manufactured was increased in 2006 from “10 SEER” (2.93 kWh/kWh) to “13 SEER” 

(3.81 kWh/kWh), by approximately 30%. Products meeting the new minimum efficiency 

levels have specific charges some 20 to 40% greater than the products meeting the prior 

minimum efficiency levels (ICF, 2006). 

Contrarily, the object of refrigerant charge reduction is becoming an increasingly important 

consideration in the design of air conditioning systems. There are several reasons for this and 

these mostly depend upon refrigerant types. 

 Cost reduction. A smaller refrigerant charge means less expenditure on refrigerant, 

which is likely to be of greater importance as newer substances are likely to demand 

much higher costs. Furthermore, since a lower charge often corresponds to smaller 

component volumes, less expenditure of materials is implied. 

 Reduction in environmental impact. A smaller charge corresponds to a smaller 

potential contained impact (in terms of mass × ODP or mass × GWP). Moreover, the 

degradation of system performance arising from a loss of refrigerant is likely to be 

observed sooner and remedial action can be taken to minimise further leakage. 

 Risk mitigation. For all refrigerants, but moreover for flammable substances, a 

smaller quantity of refrigerant equates to a smaller risk (assuming no other 

differences in conditions). So in situations where it is desirable to reduce the risk 

associated with a particular refrigerant, a reduction in charge can bring the 

interpretation of risk to a more acceptable level. Furthermore, certain safety standards 
2014 TOC Refrigeration, A/C and Heat Pumps Assessment Report 149

impose charge size limits for refrigerants in different situations (see Annex to Chapter 

2) and through a process of charge reduction, the extent of use of a given refrigerant 

in a particular situation can be extended.

A reduced refrigerant charge can have both positive and negative effects on system efficiency 

(for a given capacity) (Poggia et al., 2008). In addition, a disadvantage of reducing the charge 

size is that the performance of systems tends to be more sensitive to leakage, i.e., greater 

degradation of efficiency and capacity can occur for the same amount of refrigerant lost. It is 

important to carry out charge reduction commensurate with system performance optimisation, 

also considering the impact on reverse mode operation and defrosting (if relevant).

Considerable research has and continues to be conducted into reducing refrigerant charge 

levels (Fernado and Lundquist, 2005). Most large system manufacturers actively pursue 

developments in charge reduction and there are regular IIR conferences on the topic. 

In carrying out charge reduction, consideration of the typical refrigerant quantities within 

different components can be useful to help identify target areas; for most air conditioners, 

condenser, compressor, evaporator and liquid line should be approached. Techniques include 

use of mini- or micro-channel heat exchangers, evaporative condensers, flat tube heat 

exchangers and/or pipework, smaller tube diameters, oil selection for low solubility, small 

internal volume compressors and avoidance or careful selection of liquid receivers and 

accumulators (GIZ, 2010). Further discussion on this topic is in Chapter 11.

7.3.14 Not-in-kind alternative technologies 

In past assessment reports, a number of potential new technologies were presented as options 

that could have a positive impact on the phase-out of ODS refrigerants. Some of the 

technologies presented in prior assessments were: absorption, desiccant cooling systems, 

Stirling systems, thermoelectric and number of other thermodynamic cycles. However, a 

search of the literature published since the previous assessment has continued to confirm that 

most of these technologies have not progressed much closer to widespread commercial 

viability for air-cooled air conditioning applications than they were at the time of the 1990 

and the four subsequent assessment reports and will therefore not be discussed further.

7.4 Options for existing equipment

As the HCFC phase-out proceeds in non-Article 5 or Article 5 countries, there remains a need 

to service the installed population of products until the end of their useful lives. When 

servicing these products the treatment of refrigerant can fall into the following categories:

 Use existing refrigerant

 Refrigerant replacement only2

 Retrofit (refrigerant change and system components)

 Conversion (to flammable refrigerant)

Most of these categories are likely to be important for Article 5 countries because systems are 

often repaired several times in order to extend their useful lives. There are a large number of 

Low Volume Consuming (LVC) countries, which import rather than manufacture airconditioners where most of the HCFC consumption is used to service the installed base of airconditioners. In these countries, HCFC consumption can be reduced by the use of service 

refrigerants or by retrofitting existing equipment to non-ODP refrigerants. An additional less 

desirable option because of cost would be to replace the existing equipment before the end of 

its useful life. In non-Article 5 countries, unit replacement is more common because the costs 

 

2 Usually the term “drop-in” is used for this type of replacement. However, since there are no alternatives with 

identical thermophysical, safety and chemical properties as the existing refrigerant (e.g., HCFC-22) then the phrase 

“refrigerant replacement only” is used to substitute the term “drop-in”.
150 2014 TOC Refrigeration, A/C and Heat Pumps Assessment Report

associated with performing a major repair or retrofit can often be greater than the cost to 

replace the product. The need for retrofit and replacement refrigerants will largely be 

determined by the size of the installed population of HCFC-22 products, HCFC phase-out 

schedule, allowed “service tail”3, the availability of HCFC-22 and the recovery and reclaim 

practices in place leading up to the phase-out. The installed population of air conditioners and 

heat pumps has an average service life in non-Article 5 countries of 15 to 20 years and may be 

longer in Article 5 countries. Therefore, implementing recovery and reclaim programmes 

coupled with the availability of replacement and retrofit refrigerants could help reduce the 

demand for HCFC-22. 

Using the existing refrigerant following a repair, one can follow normal practices using 

virgin, recycled or reclaimed refrigerant (i.e., typically HCFC-22). 

For refrigerant replacement only, HCFC is replaced with a blend, but without changing the 

lubricant used in the original equipment or any other system component. Refrigerants used for 

this activity are sometimes referred to as “service blends” or “drop-ins”. Such a change in

refrigerant in most cases results in a lower capacity and/or efficiency, different operating 

pressures, temperatures and compressor power compared to HCFC.

Retrofit refers to not only changing the refrigerant, but also system components such as 

lubricant (although not always necessary), filter dryer (if required) and more extensive 

modifications which could include the replacement of the compressor, refrigerant, lubricant, 

dryer, expansion device, and purging and flushing the system to remove all residual lubricant 

from the system. Retrofitting can be substantially more costly than using existing refrigerant, 

replacing the refrigerant without additional changes or even unit replacement; it is probably 

not cost effective if either the compressor or heat exchangers have to be replaced. 

Conversion is where the existing refrigerant is replaced with another without necessarily 

having to address the refrigeration circuit components and lubricant in the same way as

retrofit, but because the replacement refrigerant is flammable, the external aspects of the 

equipment, such as potential sources of ignition, have to be addressed. However, since this is 

a complex process and can lead to unforeseen safety risks, it is not normally recommended. 

Again, such a change in refrigerant can affect capacity and/or efficiency, operating pressures, 

temperatures, lubricity, etc., to HCFC.

In the case of refrigerant replacement and retrofit in HCFC systems, the GWP of the new

should also be given consideration as many blends have a GWP higher than HCFC. 

In all cases, before changing the refrigerant it is recommended that the system manufacturer 

be consulted. 

7.4.1 Replacement refrigerants only

There are several refrigerants currently introduced to replace HCFC-22 for servicing. They 

generally combine two or more HFC refrigerants with a small amount of HC (or certain HFC 

refrigerants, such a HFC-227ea), which are added to the blend to enable the refrigerant to 

work with the naphthenic mineral-oil-based and alkyl benzene lubricants used in nearly all 

HCFC-22 air conditioning systems. Thus these refrigerants attempt to mimic the performance 

of HCFC-22. However, they seldom perform as well as HCFC-22; having either lower 

capacity, efficiency or both. For example, in a split air conditioner Spatz and Richard (2002) 

showed that R-417A exhibited a 10% drop in both capacity and COP at standard test 

conditions, compared to HCFC-22. Calorimeter tests of Allgood et al. (2010) showed that R438A has a capacity and COP around 7% and 2% lower than HCFC-22, respectively. A study 

 

3 The term ”service tail” is used to describe the time between when a refrigerant has been phased out for use in 

new equipment and the date at which the refrigerant may no longer be produced.
2014 TOC Refrigeration, A/C and Heat Pumps Assessment Report 151

by Messineo et al. (2012) found that none of the HFC blends, R-417A, R-407C and R-404A 

performed better than HCFC-22 when measured in field trails in an air conditioning system. 

Although not conventionally used for air conditioners, Bolaji (2011) compared R-404A and 

R-507A against HCFC-22 in a window air conditioner. The average refrigeration capacities of 

R-507A and R-404A were 4.7% higher and 8.4% lower than that of HCFC-22, respectively, 

while the average COP were increased by 10.6% and reduced by 16.0%.

In addition to the performance and efficiency impacts the blends may not perform the same 

for oil return. HCs are added to allow for the oil return, but it may not be as effective and 

problems could result at lower loads and extreme operating point seen during high ambient 

temperatures and heat pump operation.

A selection of the many commercially available HCFC-22 replacement blends is listed in 

Table 7-2. Compressor and system manufacturers often carry out evaluations of such 

refrigerant options and provide recommendations as to which they believe are suitable for use 

in their equipment. Information on the application of these blends can be obtained from 

manufacturers. It may also be recognised that since some HCFC-22 compressors are now 

supplied with POE oils, R-407C or similar HFCs could in principle be used as a direct 

replacement.

There are a number of criteria that should be achieved in order for a replacement only 

refrigerant to be selected and these are discussed in Chapter 2.

7.4.2 Retrofit refrigerants

A number of the HFC blends proposed for alternatives to HCFC-22 in air conditioners, are 

also deemed as suitable retrofit refrigerants for HCFC-22 systems; examples of such HFC 

blends are listed in Table 7-2. 

Whilst many of the proposed blends are seldom used, R-407C has been demonstrated to be an 

acceptable retrofit refrigerant and has seen widespread use in some regions. This is especially 

the case in regions with high ambient temperatures as the capacity drop at elevated 

temperatures is relatively lower than that of R-410A, although there is some loss in capacity 

and efficiency compared to HCFC 22. Devotta et al. (2005a) found a 2-8% drop in capacity 

and 8-14% increase in COP when a window type HCFC-22 air conditioner was retrofitted 

with R-407C. Conversely, a drop of about 7% in COP was observed by Raghavan and Pss 

(2010). Gopalnarayanan and Rolotti (2000) tested a reversible split system in both cooling 

and heating mode and found that in cooling mode R-407C capacity matched that of HCFC-22 

and there was a marginal increase in COP when the oil was changed from a mineral to a POE

oil. However, in heating mode, there was a capacity and COP drop of less than 5%. Fathouh 

et al. (2010) found that the cooling capacity and COP was around 8% and 6% lower, 

respectively for R-407C. Judge et al (1995) tested two different units and showed that in one, 

the cooling capacity was marginally lower than HCFC-22 with 10% loss in COP, whereas in 

another unit there was a marginal increase in capacity and a 5% drop in COP.

As indicated, provided that the compressor already uses a mineral oil, a change from HCFC22 to R-407C requires that the existing naphthenic mineral oil or alkyl benzene synthetic oil 

lubricant be replaced and filter driers that are able to absorb breakdown products from 

synthetic lubricants should also be installed. The disadvantage of using high glide blends is 

the need to remove and replace the entire charge during servicing to avoid substantial 

composition shift. However, because R-407C has a moderate glide, laboratory and field 

experience indicates R-407C can be serviced without replacing the entire refrigerant charge 

with minimal impact on performance. The other HFC blends will tend to have similar 

practical implications as R-407C. 
152 2014 TOC Refrigeration, A/C and Heat Pumps Assessment Report

The criteria for selecting a suitable retrofit refrigerant are discussed in section Chapter 2.

7.4.3 Conversion to flammable refrigerants

HC refrigerants such as HC-290, HC-1270 and blends including these as well as HC-170 and 

R-E170 (e.g., R-433A, R-433B, R-433C, R-441A and R-443A) are being used as conversion

replacements for HCFC-22 in some regions, typically in small systems (such as window and 

single splits). Some countries are including this approach in their HCFC phase-out strategies, 

whilst the practice is not legal in other countries (such as in USA). While these refrigerants 

may provide capacity and efficiency close to HCFC-22 (see examples in section 7.3), this 

practice can create a significant safety hazard because of the flammability of these 

refrigerants. In general, HCs are not recommended for use in systems that have not been 

specifically designed appropriately. If HCs are being considered then the applicable safety 

standards and codes of practice should be strictly followed. The GIZ Handbook for 

Hydrocarbon Safety (GIZ, 2010) is one source of information on the utilisation of these

refrigerants.

In addition to the above, there are also some other mixtures with class 3 flammability being 

marketed, which in addition to HCs also comprise R-E170 (dimethyl ether) and HFC-152a. 

For example, Park et al. (2009a) measured performance of R-431A and HCFC-22 under airconditioning and heat pumping conditions. Results showed that the COP of R-431A is 4% 

higher than that of HCFC-22 while the capacity of R-431A is similar under both conditions. 

Comparing the performance of R-432A and HCFC-22, Park et al. (2009b) showed that the 

COP and capacity of R-432A are 9% and 2 – 6% higher for both conditions.

7.5 High ambient considerations

The objective of this section is to summarise the performance of the various HCFC-22 options 

for high ambient air conditioning applications; “high ambient” is considered to be between 

40°C and 55°C (which represents the maximum rating conditions for the Middle East region). 

The governing thermodynamic properties and principles result in a declining capacity and 

efficiency for all refrigerants as the heat-rejection (refrigerant condensing) temperature 

increases, including HCFC-22. However, some of the HCFC-22 replacements exhibit greater 

degradation in capacity and efficiency than HCFC-22 under high ambient conditions. Another 

consideration is with regards to the possible impact on required refrigerant charge, where 

hotter regions can imply greater head loads, larger system capacity and thus larger refrigerant 

charge. Therefore where limits on refrigerant charge apply, those limits may be approached at 

smaller capacities; in these cases additional (safety) measures may need to be applied to the 

equipment. 

Currently, the most widely applied replacements for HCFC-22 in these air conditioning 

applications are HFC blends, primarily R-410A and R-407C. HCs are also being used in some 

low refrigerant-charge applications. R-410A and R-407C both have lower critical 

temperatures than HCFC-22 (refer to Chapter 2 for values) because HFC-125 (a component 

of both R-407C and R-410A) has a comparatively low critical point temperature; this is an 

important parameter since such refrigerants will exhibit a steeper decline in capacity with 

increased ambient (outdoor) temperatures than refrigerants having higher critical 

temperatures. This steeper decline in capacity is of particular importance in geographic 

regions, which have condensing design temperatures approaching the critical temperature of 

the refrigerant. 

As well as the use of high efficiency components, the optimum selection of compressor, 

airflow, condenser design (i.e., tube diameter, fin design, coil circuitry, etc.) and expansion 

device can reduce the performance losses at high ambient temperatures (Bitzer, 2012). If the 

curve is steep something must be done about the starting point. i.e., the reference efficiency 
2014 TOC Refrigeration, A/C and Heat Pumps Assessment Report 153

should be set at a higher level in order to compensate for the possibility of lower efficiency at 

high ambient conditions. Thus for most refrigerants, by taking measures to appropriately 

optimise the system, similar efficiencies to HCFC-22 can be achieved at higher ambient 

temperatures.

Systems using low-GWP refrigerants are not currently available for large capacity systems in 

most regions with high ambient temperatures.

7.5.1 Performance of alternatives under high ambient temperatures

Table 7-3A: Comparative theoretical cycle volumetric refrigerating capacity of selected 

alternatives relative to HCFC-22

Condensing temperature

40°C 50°C 60°C 70°C

HCFC-22 100% 100% 100% 100%

HFC-32 100% 99% 99% 98%

HFC-134a 100% 98% 96% 94%

HFC-152a 100% 100% 101% 102%

HFC-161 100% 100% 101% 103%

HC-290 100% 98% 96% 93%

HFC-1234yf 100% 96% 91% 85%

HC-1270 100% 99% 97% 94%

R-407C 100% 98% (97%) 96% (94%) 92% (90%)

R-410A 100% 97% 93% 86%

R-444B 100% 99% 98% (97%) 96% (94%)

R-446A 100% 99% 97% 95% (94%)

R-447A 100% 99% (98%) 97% (96%) 94% (93%)

NOTE: Condenser subcooling = 5 K; evaporating temperature = +10°C; evaporator exit superheat = 5 

K; suction line superheat = 0 K; volumetric efficiency = 100%; properties from Refprop9; reference 

condition for blends: dew point and mid-point (in parentheses, if different)

Table 7-3B: Comparative theoretical cycle COP of selected alternatives relative to HCFC22

Condensing temperature

40°C 50°C 60°C 70°C

HCFC-22 100% 100% 100% 100%

HFC-32 100% 99% 97% 95%

HFC-134a 100% 99% 99% 97%

HFC-152a 100% 101% 102% 104%

HFC-161 100% 101% 102% 103%

HC-290 100% 99% 98% 95%

HFC-1234yf 100% 98% 94% 90%

HC-1270 100% 99% 98% 95%

R-407C 100% 99% 97% 94% (93%)

R-410A 100% 97% 93% 86%

R-444B 100% 100% (99%) 99% (98%) 97%

R-446A 100% 99% 97% 95% (94%)

R-447A 100% 99% 97% 94%

NOTE: Condenser subcooling = 5 K; evaporating temperature = +10°C; evaporator exit superheat = 5 

K; suction line superheat = 0 K; global compressor efficiency = 100%; properties from Refprop9; 

reference condition for blends: dew-point and mid-point (in parentheses, if different)

As an initial reference point, Table 7-3A and 7-3B provide the results of theoretical 

refrigerant performance calculations for various alternative refrigerants at elevated 
154 2014 TOC Refrigeration, A/C and Heat Pumps Assessment Report

condensing temperatures, when compared against HCFC-22 at a reference condition of 40°C.4

Performance in real systems and measures to design and optimise systems for high ambient 

conditions are discussed in the following sections. 

R-410A

R-410A systems have been demonstrated to operate acceptably at ambient temperatures up to 

52C. The performance (capacity and efficiency) of R-410A air-conditioners falls off more 

rapidly than HCFC-22 systems at high ambient temperatures (above 40C). At a condensing 

temperature of 70°C, both capacity and COP of R-410A degrades by around 14% relative to 

HCFC-22, as shown in Table 7.3. Very few studies are available in the literature to illustrate 

the extent of performance depredation in real systems. In one, Domanski and Payne (2002) 

report on measurements of an air conditioner comparing HCFC-22 and R-410A but with two 

different compressors. With one compressor, R-410A indicated a 7-8% reduction in capacity 

at 52°C and around 14 – 20% drop in COP.

Even with optimised designs, systems that will operate a significant number of hours at high 

ambient temperatures, the system designer should take into consideration the reduced high 

ambient capacity when sizing the equipment. For cases where the base capacity of the unit 

would need to be increased to meet the building load at extreme ambient temperatures the 

cost impact can be approximated as proportional to the respective capacity degradation. 

A few studies where made to enhance the performance of the R-410A refrigerant in high 

ambient conditions. Chin and Spatz (1999) also conducted simulations comparing HCFC-22 

against R-410A, showing a 6% and 7% drop in capacity and COP, respectively, at 52°C 

ambient. Another study by Wang et al. (2009) for a two-stage heat pump system with special 

vapour-injected scroll compressor showed an enhancement on the cooling capacity of R-410A 

at high ambient conditions as high as 15% and an enhancement of the COP between 2 – 4%. 

R-407C

R-407C systems will typically perform in nearly the same way as HCFC-22 systems at typical 

ambient temperatures. At ambient temperatures above 40C, R-407C systems show less 

degradation of capacity and efficiency than R-410A systems. However, an R-407C system 

will still exhibit a capacity approximately 8% less than an HCFC-22 system at a condensing 

temperature of 70C and 6% reduction in COP (Table 7-3). 

Even though the R-407C is in most cases more preferable to be used in air conditioning 

systems than HFC-32 and R-410A because the thermodynamic characteristic are much closer 

to HCFC-22, the effect of the high temperature glide of R-407C only has a minor effect in the 

new systems. As such R-407C can be considered better option than R-410A for high ambient 

regions.

HFC-134a 

HFC-134a has a relatively high critical temperature. However, theoretical cycle calculations 

show that the performance degradation relative to HCFC-22 at high ambient temperature 

shows 6% lower capacity and 3 % lower COP.

HC-290

 

4

(To put these values into context, it must be noted that the capacity of HCFC-22 falls by 25% and its 

COP reduces by 60% as the condensing temperature rises from 40°C to 70°C. Thus, degradation of (for 

example) 10% of one alternative relative to HCFC-22 represents only 21⁄2% and 6% further absolute 

reduction, respectively.)
2014 TOC Refrigeration, A/C and Heat Pumps Assessment Report 155

HC-290 has performance characteristics similar to HCFC-22 and the characteristics are close 

enough that the current products that employ HCFC-22 could be re-engineered to employ 

HC-290. HC-290 has successfully been demonstrated as an HCFC-22 replacement in low 

charge, room and portable air-conditioners applications (Devotta et al., 2005; Padalkar et al, 

2014) for regions that experience high ambient conditions. 

HC-290 shows a 4% reduction in capacity at 70C based on theoretical calculations (Table 7-

3). Some recent studies at ambient temperatures up to 54°C (Chen, 2012; Rajadhyaksha et al, 

2013; Li, 2014b) showed the degradation of capacity and COP of HC-290 relative to HCFC22 at high ambient temperature to be within 3%. An intensive study by Wu et al. (2012a) 

showed results at high ambient temperatures as similar to HCFC-22. The use of special design 

heat exchangers like micro channel aluminium type showed favourable results and the 

refrigerant charge can be reduced as low as 0.07 kg/kW or even less (Rajadhyaksha et al, 

2014). 

HC-1270 

HC-1270 has performance characteristics similar to HCFC-22 and the characteristics are close 

enough that the current products that employ HCFC-22 could be re-engineered to employ 

HC-1270. Based on theoretical cycle calculations, HC-1270 shows a 7% reduction in capacity 

at 70C and a 3% reduction in COP relative to HCFC-22 (Table 7-3). 

HFC-32

HFC-32 is being considered as an alternative to R-410A with a higher efficiency and capacity 

at high ambient temperatures, although worse than HCFC-22, where the capacity is 

approximately 2% less and COP 5% in theoretical cycle calculations (Table 7-3). Discharge 

temperature can be from 5 K to 30 K higher than R-410A and HCFC-22. However, this can 

be managed by injection technology or wet suction control, although this implies at a cost 

and/or performance penalty to the AC. It can also be tackled by adjusting the viscosity of oil 

(Piao et al., 2012), although this impacts reliability. 

A performance comparison of R-410A and HFC-32 in vapour injection cycles (Xu et al., 

2012) shows HFC-32 is slightly better than R-410A at higher ambient conditions. In Piao et 

al. (2012), HFC-32 achieves the same COP as HCFC-22 at 52°C if the COP of HFC-32 at 

rating conditions is 9.4% higher than HCFC-22. Consistent with this, Chen (2012) showed 

that HFC-32 has a small relative drop in capacity compared to HCFC-22, yet at 52°C it 

exhibits a 10% relative reduction in COP. Again, as with other alternatives, this loss in 

performance can be managed through system and/or compressor technology, which may or 

may not incur cost implications. The use of an injection circuit (to reduce excessively high 

discharge temperature, in excess of 137°C), whilst not affecting COP results in a 5% drop in 

capacity relative to HCFC-22. The injection yields the benefit of reducing discharge 

temperature to 115°C, although this is still about 5 K above both HCFC-22 and R-410A.

R-744

The desirable characteristics of R-744 are offset by the fact that it has a very low critical 

temperature (31C) and will operate above the critical point conditions in most airconditioning applications. Operation at these conditions results in a significant degradation in 

both capacity and COP at high ambient temperatures. These losses can be partially offset by 

the addition of internal cycle heat exchangers and expanders or ejectors. However, R-744 

systems are not expected to provide a cost effective alternative to HCFC-22 or HFC 

refrigerants when being applied in high temperature regions (> 40C). 

HFC-161 
156 2014 TOC Refrigeration, A/C and Heat Pumps Assessment Report

At a 70C condensing temperature HFC-161 has a theoretical capacity and COP 

approximately 3% greater than HCFC-22 (Table 7-3) and exhibits a considerably better high 

ambient performance than R-410A. Practical measurements by Wu et al. (2012b) support 

these theoretical characteristics, where the relative COP and capacity of HFC-161 improve 

relative to HCFC-22 as the ambient temperature increases. As such, this implies interesting 

possibilities for countries, which experience hot climates. 

HFC-152a 

HFC-152a has performance characteristics similar to HFC-134a. Although activities within 

industry indicate little interest in this substance currently, HFC-152a has performance better 

than that of HCFC-22, showing a 3% increase in capacity at 70C and a 4% increase in COP 

relative to HCFC-22 (Table 7-3). 

HFC-1234yf 

HFC-1234yf ordinarily has performance characteristics similar to HFC-134a. However, 

considering behaviour at high ambient conditions, the degradation of performance is closer to 

R-410A, where there is a 15% reduction in capacity at 70C and a 10% reduction in COP 

relative to HCFC-22 (Table 7-3) based on theoretical cycle calculations. 

R-444B 

R-444B systems are expected to perform similar to HCFC-22 systems at high ambient 

temperatures; theoretical cycle performance indicates that the capacity and COP are about 5% 

and 3% lower, respectively, relative to HCFC-22 (Table 7-3). Tests on a split air conditioner 

(with modified capillary tube and evaporator circuitry to account for the temperature glide) 

achieved identical capacity and COP as HCFC-22 at both 46°C and 52°C ambient (Sethi et al, 

2014). The discharge temperature is also the same as with HCFC-22.

R-446A and R-447A

R-446A and R-447A systems are expected to perform slightly worse compared to HCFC-22 

high ambient temperatures; theoretical cycle performance indicates that the performance is 

around 5-7% lower relative to HCFC-22 (Table 7-3). Tests on a split air conditioner, showed 

a degradation of both capacity and COP about 5% worse than R-410A at 46°C ambient from a 

baseline of 35°C (Alabdulkarem et al, 2013).

7.5.2 Measures to design and optimise air-conditioners for high ambient conditions 

There are several aspects that can be considered important when adapting equipment for use 

in high ambient conditions. 

The evaporator coil design should be reselected to adopt the new pressure and pressure drop 

characteristics at high ambient conditions for the replacement refrigerants. Also the tube 

diameter can be reduced to enhance the heat transfer for the evaporator coils; typically using 

1⁄4 inch OD tube diameters will enhance the performance and can bear higher pressures for 

high pressure refrigerants like R-410A and HFC-32.

The condenser coil design should also be reselected to accommodate the new pressure drop 

characteristics for the replacement refrigerants. Micro channel aluminium coils can be used in 

order to enhance the heat transfer and to reduce the condensing temperature at high ambient 

conditions, whilst larger condenser coils and special condenser fans also can be used to 

reduce the condensing temperature at high ambient conditions. Controlling the subcooling by 

using condensers with dedicated subcooling circuits is vital in high ambient conditions to 

enhance the efficiency (Qureshi et al., 2012). 
2014 TOC Refrigeration, A/C and Heat Pumps Assessment Report 157

Special types of compressors are needed for the high pressure refrigerants such R-744. While 

normally the same compressor design can be used for R-407C and HC-290, larger 

displacement compressors (~10%) can be used to compensate for the lower capacity resulting 

from using these refrigerants. It should also be considered to add vapour and/or liquid 

injection to an intermediate pressure area in the compressor to enhance the performance at 

high ambient conditions. Additionally techniques can be applied to the compressor, such as 

oil flooding or vapour injection, which can yield significant benefits (Bahman et al, 2014).

Another consideration is the use of a thermostatic expansion valve instead of a capillary tube. 

In fact the use of capillary tubes for small air conditioners is not recommended, especially at 

high ambient conditions (Chinnaraj et al, 2011; Zhou and Zhang, 2010). The wide range of 

temperatures make the use of capillary tubes impossible for sufficiently accurate control of 

superheat where subsequently compressor discharge temperatures will affect the performance 

of the whole system (Chen et al, 2009) and is also useful to accurately control both suction 

gas superheat, discharge temperature and subcooling in the circuit.

7.6 Concluding remarks

HCFC-22 remains the dominant refrigerant in use, where the refrigerant bank for unitary air 

conditioners is estimated to be in excess of 1 million tonnes. In new systems, HCFC-22 is 

only being used in Article 5 countries. The HFC blend R-410A is the most common 

alternative and to a limited extent R-407C along with HFC-134a are used in regions with high 

ambient temperatures. HC-290 is being used in split systems, window and portable air 

conditioners. HFC-32 is being used in split systems and is being proposed for larger ducted 

and multi-split systems. These various alternatives highlighted have also been found to 

achieve performance approaching, as good as or better than HCFC-22.

In general there is still a significant proportion of the sector throughout almost all Article 5 

countries that remains to be shifted from HCFC-22 to a zero ODP alternative. R-410A is 

increasingly becoming considered unacceptable because its high GWP and so investigations 

into medium and low GWP alternatives is continuing. In cooler climates, R-744 is available 

for commercial sized systems and the technology is further being explored. There are a large 

number of new mixtures being considered for air conditioning systems primarily consisting of 

HFCs and unsaturated HFCs, such as R-444B, R-446A and R-447A. Although there is 

concern over the use of R-410A in high ambient temperatures, appropriate design measures 

can be used to help remedy the relatively greater degradation in performance; nevertheless, 

work is underway to investigate this refrigerant and others further.

The forthcoming direction remains unclear in terms of which alternatives this sector, subsectors and regions will settle upon. It is likely that different manufacturers and countries will 

opt for a variety of alternatives before any single option is chosen (if at all). In the meantime, 

investigations will continue into medium GWP flammable HFCs, HFC/unsaturated HFC 

blends and HCs for normal operating conditions as well as high ambient.

7.7 References

Alabdulkarem et al, 2013 Alabdulkarem, A., Hwang, Y., Radermacher, R., 2013. Test 

Report #20 System Drop-In Tests of Refrigerants R-32, D2Y-60, 

and L-41a in Air Source Heat Pump. Air-Conditioning, Heating, 

and Refrigeration Institute (AHRI) Low-GWP Alternative 

Refrigerants Evaluation Programme (Low-GWP AREP), 

Arlington, USA.

Allgood and Lawson, 2010 Allgood, C. C., Lawson, C. C., 2010. Performance of R-438A in 

R-22 Refrigeration and Air Conditioning Systems". Proc. Int. 
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Refrig. and Air Condition. Conf. at Purdue, West Lafayette, IN, 

USA.

Bahman et al, 2014 Bahman, A., Groll, E., Horton, T, Braun, J., 2014. Technologies 

to Improve the Performance of A/C Systems in Hot Climate 

Regions. Proc. Int. Refrig. And Air Condition. Conf. at Purdue, 

West Lafayette, IN, USA. 

Barve and Cremaschi, 2012 Barve, A., Cremaschi, L., 2012. Drop-in Performance of Low 

GWP Refrigerants in a Heat Pump System for Residential 

Applications. Proc. Int. Refrig. and Air Condition. Conf. at 

Purdue, West Lafayette, IN, USA.

Biswas and Cremaschi,2012 Biswas, A., Cremaschi, L., 2012. Performance and Capacity 

Comparison of Two New LGWP Refrigerants Alternative to R410A in Residential Air Conditioning Applications. Proc. Int. 

Refrig. and Air Condition. Conf. at Purdue, West Lafayette, IN, 

USA.

Bitzer, 2012 Bitzer, 2012. Refrigerant Report 17, A-501-17, BITZER 

Kühlmaschinenbau GmbH, Eschenbrünnlestraße 15, 71065 

Sindelfingen, Germany.

Bolaji, 2011 Bolaji, B.O., 2011. Performance investigation of ozone-friendly 

R404A and R507 refrigerants as alternatives to R22 in a window 

air-conditioner. Energy and Buildings 43 (11), pp. 3139-3143. 

Bosco and Weber, 2008 Bosco, R., Weber, G., 2008. Challenges on the Development of 

A CO2 Compressor Focusing on Structural Strength and 

Reliability. Proc. 8th IIR Gustav Lorentzen Conference on 

Natural Working Fluids, Copenhagen, Denmark.

Chen et al, 2011 Chen, J., Li, H., Ji, C., Xi, L., 2011. Performance of a split-type 

air conditioner with natural refrigerant R1270 to replace R22. 

Advanced Materials Research 243-249, 4979-4982.

Chen et al, 2012 Chen, J., Li, H., Xi, L., 2012. Performance of air cooled heat 

pump Air Conditioner with Natural Refrigerant R1270 and R290 

to Replace R22. Advanced Materials Research 374-377, 484-

487.

Chen et al, 2009 Chen, L., Chen, J., Liu, J., Chen, Z., 2009. Experimental 

investigation on mass flow characteristics of electronic 

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Chapter 8 

__________________________________________________________

Water Heating Heat Pumps

Chapter Lead Author

Martin Dieryckx

Co-Authors

Guangming Chen

Marino Grozdek

Makoto Kaibara

Petter Nekså

Tetsuji Okada
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2014 TOC Refrigeration, A/C and Heat Pumps Assessment Report 169

8 Water heating heat pumps

8.1 Introduction

Heat pumps are able to upgrade (“pump”) heat from a lower temperature to a useful higher 

temperature level. The heat is used for space heating, service (including domestic) water 

heating, and manufacturing process heating. The heat sources are generally ambient air, water 

or ground-source heat. The heat sink can be air, water or a process fluid. This chapter covers 

only systems where water is the sink (grey zone indicated in Table 8-1). The products for 

industrial process heating, large capacity systems, typically MW capacity, are covered in 

chapter 5 “Industrial systems”. Air-to-air heat pumps are the most widely used heat pumps. 

Their construction and refrigerant use are similar to air conditioners; therefore they are 

covered in chapter 7 “Air-to-air air conditioners and heat pumps”.

The temperature difference between the source and sink has a direct impact on the pressure 

difference the compressor must meet for a specific refrigerant. In general, heat pump systems 

will be less efficient under higher temperature difference condition. The required compressor 

power input is a fraction of the total useful energy delivered. The required input power to the 

heat pump is mainly dictated by the heating capacity required from the heat pump, the 

temperature difference between the source and sink, the effectiveness of heat exchangers and 

compressor/driver efficiency. Required power input to water pumps and fans must be 

included to determine the power consumption of the total heat pump system. The heat pump 

overall coefficient of performance (COP) is defined as the useful heat delivered divided by 

the total power input. Recent standards and regulations are referring to a seasonal coefficient 

of performance (SCOP) defined as the useful heat delivered during the heating season divided 

by the corresponding power input.

Heat pumps are in most applications an alternative to fossil fuel gas or oil combustion boilers, 

often resulting in a significant reduction in CO2 emission and primary energy consumption. 

The cost of the equipment and efficiency are most important to compete with fossil fuel 

solutions.

In 2012 the global air to water heat pump market increased by around 5.4 % to 1,37 million 

units. Both Europe and China had an increase of respectively 7% and 11%, while Japan had a 

drop of 12.8% (JARN, 2013/08). 

The Ozone Depleting Potential (ODP) and Global Warming Potential (GWP) values of the 

refrigerants mentioned in this chapter are given in chapter 2 of this report.

8.2 Heat pump types, implications and trends

8.2.1 Heat pump types

Heat pumps are classified by heat source (air, water, and ground) and heat sink (air, water), 

resulting in the following naming of heat pumps used in this chapter as given in Table 8.1. 

Table 8-1: Heat pump classification

Heat source (direct expansion or indirect expansion system)

Air Water Ground

Heat 

sink

Air Air to air Water to air Ground to air

Water Water heater Air to water Water to water Ground to water

Space heating

Combined
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Air-source heat pumps are equipped with air-to-refrigerant evaporator coils and fans to obtain 

heat from the ambient air. Water-source heat pumps are equipped with water-to-refrigerant 

evaporators and a water circulation pump to obtain the heat from a water source. Ground 

source heat pumps are generally equipped with a brine-to-refrigerant evaporator and brine to 

ground tubes combined with a circulation pump or, refrigerant-to-ground evaporator tubes to 

obtain heat from the ground. The tubes in the ground are installed horizontally one to a few 

meters below ground level or installed in a vertical drilled hole, typically 50-150 m deep.

Most heat pumps are driven by electric motors, but gas engine drives are also used to a small 

extent. Heat pumps may also be thermally driven, using a sorption or ejector concept.

It is also possible to classify heat pumps by types depending on the usage:

1) Heat pump water heaters (HPWH)

2) Space heating heat pumps

3) Combined water and space heating heat pumps

Heat Pump Water Heaters (HPWH)

Heat pump water heaters (HPWH) are a category of heat pumps designed to heat domestic 

and other service hot water to temperatures between 50 and 90 °C. These operating 

temperatures must be considered when selecting the refrigerant.

A HPWH basically consists of a water storage tank and a heat pump water heating unit and in 

some designs an additional heat exchanger. In the heat pump unit, water supplied from the 

storage tank or directly from the city water supply is heated by the condenser or, for transcritical cycles using R-744 the gas cooler of the refrigerant circuit or, for absorption cycles by 

both condenser and absorber, and then returned to the storage tank or used directly for service. 

Stored hot water is supplied to each tapping point, in response to the demand.

The basic components of the heat pump unit are: a compressor driven by an electric motor or 

gas engine, a condenser or a gas cooler for heating water, an evaporator to absorb heat from 

the heat source, refrigerant, a refrigerant expansion device, and a control unit. Heat pump 

units that use R-744 as a refrigerant typically use an additional internal heat exchanger, and in 

some cases, an ejector or expander to improve energy efficiency. Different from mechanical 

compression type heat pumps, there is not any mechanical compressor for absorption types. 

Instead one or two generators, one or two solution heat exchangers, one or two solution 

valves and a solution pump are used.

Space Heating Heat Pumps

A space heating heat pump is optimised for comfort heating. Comfort heating heats the room 

by heating water for distribution to an air handling unit, radiator or under floor panel. The 

required water temperature depends on the types of emitter, low temperature application 

ranging from 25 to 35°C for under floor heating, for moderate temperature application such as 

air handling units around 45 °C, for high temperature application such as radiant heating 55 to 

60 °C, and for very high temperature application, as high as 65 to 80 °C, such as for the fossil 

fuel boiler replacement market. The required water temperature affects the selection of 

refrigerant. Heat pump systems are more efficient at lower sink temperatures, but each 

product must fulfil the required operating temperature.

A space heating heat pump using water for distribution generally consists of a heat pump unit 

and often an additional heat exchanger unit and a water storage tank. Several different 

configurations are used. The basic components of a heat pump space heating unit are similar 

to those of heat pump water heaters.
2014 TOC Refrigeration, A/C and Heat Pumps Assessment Report 171

In most cases air source heat pumps are used for space heating. Ground and water source heat 

pumps are also used, especially in colder regions, but they represent a smaller segment of the 

total heat pump market.

Combined Space and Hot Water Heat Pumps

Combined water heating and space heating heat pumps have two functions, supplying hot tap 

water and providing space heating. Several configurations of combined space and water 

heating heat pumps exist in order to optimise the seasonal energy efficiency for a specific 

application. In most configurations a water storage tank is used to store the domestic hot 

water and also to act as a small heat buffer for the space heating function.

In order to obtain high water temperatures at low outdoor ambient temperatures, air to water 

heat pump systems can utilise a multistage compression system or a cascade refrigerating 

system with different refrigerants for each stage in the cascade.

Capacity Ranges of Water and Space Heating Heat Pumps 

Table 8-2 lists the most common heating capacity range offered by single units of each type 

of heat pumps.

Table 8-2: Heat pump capacity ranges

Heat pump type Capacity Range (kW)

Heat pump water heater 1.5 – 50

Space heating heat pump 4 – 400

Combined water and space heating heat pump 6 – 45

8.2.2 Heat pump implications and trends

Most of the space heating and water heating systems globally use fossil fuels. Since fossil fuel 

burning systems generate CO2 during combustion, they contribute to global warming. Heat 

pumps also contribute to global warming, but in a different way. The contribution to global 

warming is only related to CO2 emissions in the generation of the electricity to drive the 

compressor and possible direct contributions due to refrigerant emissions. Therefore, the heat 

pumps energy efficiency is the primary environmental consideration. Efficient heat pumps 

can reduce global warming impact compared with fossil fuel burning systems significantly, 

typically in the range of 50-80% whilst inefficient heat pumps can lead to a significant 

increase in global warming impact. The reduction depends on the efficiency level of the heat 

pump and the carbon emission per kWh of the electricity generation.

The tendency of decarbonisation of electricity strengthens this positive effect. Also the 

efficiency levels of heat pumps are being improved year by year. However, the investment in 

a heat pump is in most cases more expensive than a fossil fuel system because they employ 

complicated refrigerant circuits, compressors, larger heat exchangers and other special 

features. The majority of purchasers have not yet accepted the significantly higher first costs 

of heat pumps as a means to reduce running costs, compared to lower first cost fossil fuel 

based space and water heating systems, especially in colder regions.

In 2013 the EU commission decided upon a common energy label (commission delegated 

regulation No 811/2013) for hydronic heating systems comparing the primary energy 

efficiency of all major heat generators. This may have a positive impact on the heat pump 

applications in Europe. Minimum efficiency requirements are set separate for heat pumps. 

Both the energy label and minimum efficiency requirements will have a major impact on the 

refrigerant choice. Air source heat pumps have become the most popular heat pump type in 
172 2014 TOC Refrigeration, A/C and Heat Pumps Assessment Report

Europe. They have experienced strong growth over the last several years because of their 

economic benefits and recognition as renewable energy source. The positive environmental 

aspects and potential market growth of heat pumps must be taken into account when 

refrigerant options and limitations are considered 

In Japan, heat pump water heaters using the refrigerant R-744 have become very popular in 

recent years under the trade name “Eco-cute” and are also introduced in Europe. These heat 

pump water heaters were launched in 2001. Between 2008 and 2011, there were annual sales 

of around 500,000 units (JARN, 2013/08). An evaluation method for defining the annual 

performance factor of heat pump water heaters has been established in Japan. This method 

considers the typical Japanese life style usage of hot tap water. 

In the USA, commercial interest for combined water and space heating heat pumps resumed 

in late 2009 and 2010. Three major and several additional manufacturers began marketing 

newer, more efficient integral designs in 2010. These new products use either HFC-134a or 

R-410A as the refrigerant, but the split between them is uncertain. Predicated on the new 

efficiency standards and analyses used in development of national requirements, estimated 

HPWH shipments in the USA are 10,000 units per year in 2010, 260,000 units per year by 

2015, and - though somewhat speculative - 270,000 or more units per year by 2020.

The general trend when taking new building standards into account is that the relative 

importance of tap water heating will increase compared to space heating. It is expected that 

this will be reflected in future systems.

8.3 Options for new equipment

In most non-article 5 countries the transfer to non-ODS refrigerants was completed several 

years ago. But, based on its favourable thermodynamic properties and high efficiency in heat 

pump applications, HCFC-22 is still in use for high and moderate temperature water and 

space heating heat pumps in the A5 countries.

When selecting refrigerants, both the direct and indirect climate impacts must be considered 

(see chapter 2 and chapter 11). For heat pumps, the reduction in emission resulting from 

replacing fossil fuel burning may be the most important factor regarding greenhouse gas 

emissions.

Options for new heat pumps include HFC-32, HFC-134a, R-407C, R-410A, R-417A, HFC1234yf, new HFC blends, HC-290, HC-600a, R-744 and R-717.

Studies of new low-GWP fluorochemicals (notably unsaturated HFCs – see Chapter 2 

“Refrigerants”) in heat pumps are ongoing, notably in several European countries, Japan and 

the USA. Similar studies are underway to evaluate use or broader use of R-744 and 

hydrocarbons as refrigerants in several types of heat pumps, though actual product 

development and commercialization are limited to Europe and Japan at present.

8.3.1 HFC-134a and HFC blends R-407C, R-417A and R-410A

HFC-134a, R-407C and R-410A are used widely in heat pump systems and are well 

commercialised globally. R-417A is used in heat pump application in existing systems as well 

as in new equipment. 

These refrigerants are being used in high to low temperature water and space heating heat 

pumps, in countries where HCFC-22 consumption reduction started in advance of the 

Montreal Protocol. These refrigerants are used mainly in Europe. In Japan R-410A is used 

and HFC-134a and R-410A are used in Canada and USA and to a lesser extent in Mexico and 

the Caribbean countries. R-407C has been used to mainly replace HCFC-22 in existing 
2014 TOC Refrigeration, A/C and Heat Pumps Assessment Report 173

product designs because minimal design changes are required. However, the use of R-407C is 

declining in favour of the higher efficiency of R-410A and lower system cost. To use R-410A 

design changes are necessary to address its higher operating pressures and to optimise the 

system to its properties and thereby achieve a higher performance. Cascade heat pumps using 

HFC-134a and R-410A are commercialised in high temperature combined space and hot 

water heating heat pumps in Europe. These heat pumps have a relatively good performance 

and can operate without auxiliary electrical heaters. The heat pump can supply water at 

temperatures approaching 80 oC.

Most new heat pump products are using refrigerant R-410A because it results in more 

compact and efficient systems when they are optimised.

Air to water split cascade systems are put on the market using R-410A for the low 

temperature and HFC-134a for the high temperature circuit. They guarantee high seasonal 

COP for colder climates even at high water sink temperatures, while keeping the required 

heating capacity without auxiliary electrical heaters. They are most used for combined space 

and hot water heating to replace existing boiler systems.

Energy efficiency of R-407C systems is typically poorer than HCFC-22, although similar 

COPs can be achieved if the system is carefully designed. R-407C shows a pronounced 

temperature glide in practice, which can lead to operational difficulties. 

R-417A has been used by some manufactures for heat pump water heaters. R-417A provides 

lower capacity than HCFC-22 but has demonstrated its effectiveness at higher temperatures.

As the cost of the refrigerant itself is minor in the total system cost, limited differences in 

refrigerant cost have a minor effect. The cost of components has a major impact. A more 

compact design results in general in a lower cost. For larger systems the design pressure has a 

larger impact on the cost than for small systems. For small and medium size systems R-410A 

is the most cost effective, while for large systems HFC-134a is most effective.

There are no significant barriers to their use at the moment, but the high GWP of the 

refrigerants may put them under pressure to changes for lower GWP fluids.

8.3.2 HFC-32

The use of HFC-32 in water heating heat pumps is not commercialized yet on a larger scale. 

HFC-32 has a higher operating efficiency than HCFC-22 and R-410A (Shigehara, 2001). It

has saturation pressures slightly higher than R-410A which is approximately 60% higher than 

HCFC-22. The system refrigerant charge can be up to 43% less than for HCFC-22 while the 

energy efficiency is the same or higher (Yajima, 2000). It has better heat transfer and 

transport properties than R-410A due to lower molar mass. Since it has higher discharge 

temperatures than R-410A more accurate control of temperature is necessary especially for 

high temperature water heating heat pumps and low temperature heat source.

The direct cost of the pure HFC-32 substance is lower than R-410A, but this has limited effect 

on the system cost. Based on the refrigerant properties, the equipment is more compact and 

consequently potentially cheaper, while mitigation devices for high discharge temperature 

may add some cost.

The main barriers are related to the safe use of the lower flammable refrigerants (class 2L by 

ISO 817); see chapter 2. Standard ISO-5149 is updated in 2014 and IEC-60335-2-40 is in 

process of update to accommodate this new class. In general safety aspects during the 

lifecycle of the equipment are limited. However, some building codes do not allow the use of 

flammable refrigerants in certain type of buildings. If the refrigerant water heat exchanger is 
174 2014 TOC Refrigeration, A/C and Heat Pumps Assessment Report

located in outside occupancy, the safety issue is easier to solve but frost prevention becomes 

an issue. 

8.3.3 HFC-1234yf and other low-GWP HFC blends

HFC-1234yf is similar in thermophysical properties to HFC-134a.

A number of other unsaturated chemicals are being identified in the patent literature as 

possible low-GWP refrigerants for heat pumps. Blends with HFC-32 or HFC-125 may make 

it possible to approach the properties of HCFC-22 or R-410A, but it results in a higher GWP 

than pure HFC-1234yf. As sample supply of these refrigerants is very limited, it is too early to 

judge whether any of these chemicals will be commercialised and will show acceptable 

performance and competitiveness in heat pump systems. Due to the price competitiveness 

pure HFC-1234yf is not considered as a future solution.

For water heating and space heating heat pumps using HCFC-22, R-410A, R-407C, 

significant design changes would be required to optimise for HFC-1234yf. Some of the 

required changes include larger displacement compressors, larger diameter interconnecting 

and heat exchanger tubing and additional heat exchanger surface to offset lower heat transfer 

and higher flow resistance.

The heat transfer is expected to be lower than for R-410A systems because of its lower 

saturation pressure. The relatively higher pressure drop in the refrigerant pipes and heat 

exchanger will result in poor efficiency at high temperatures typical for heat pump water 

heaters. 

As a new molecule due to a different manufacturing process, the HFC-1234yf and other LowGWP HFC blend refrigerants has significant higher cost than that of HFC-134a. Components 

cost will be similar to HFC-134a, but the flammability will have effect for larger systems due 

to the pressure vessel codes. 

The same restrictions as for HFC-32 apply (see Annex to Chapter 2). 

8.3.4 R-744 (carbon dioxide)

In the past, R-744 was not used in water and space heating heat pumps because of its high 

pressure characteristics (Fernandez, 2008). 

Development of R-744 heat pumps started around 1990 (Nekså, 1998). R-744 heat pump 

water heaters were introduced to the Japanese market in 2001, with heat pumps for heating of 

bath or sanitary water as the main application. Space heating heat pumps that operate at lower 

water temperatures in combination with hot water heating have also been developed, but the 

numbers sold are less. R-744 operates at very high pressures; approximately 5 times higher 

than HCFC-22 and 3.5 times higher than R-410A. This is an advantage enabling more 

compact system designs. The low critical temperature of R-744 results in trans-critical 

operation. R-744 refrigerant has been used primarily in storage type heat pump water heater 

applications.

Continued growth of market for domestic hot water heat pumps is expected in Japan, Asia and 

to some extent in Europe. Recently, R-744 heat pumps for domestic space heating application 

have been developed in Europe for use in cold climates if combined with very high 

temperature radiator type space heating. For commercial buildings with combined radiator 

and air heating systems, R-744 is a very promising refrigerant (Nekså, 2002). This also holds 

for new low energy buildings where the domestic hot water demand is large compared to the 

space heating requirement. It is not known what level of market penetration R-744 space 

heating heat pumps will experience. The ultimate market acceptance will be determined by 

the system economics, energy labelling and minimum energy efficiency requirements. 
2014 TOC Refrigeration, A/C and Heat Pumps Assessment Report 175

R-744 as refrigerant enables domestic water heating up to temperatures as high as 90 oC 

without use of an auxiliary electrical heater. R-744 may give a high performance when it is 

used with low temperature sources and high temperature sinks with a certain temperature 

difference between inlet and outlet water temperature (Steene, 2008). This makes it well 

suited for use in storage type heat pump water heaters in which low temperature inlet water is 

heated to a high temperature for thermal storage of domestic hot water.

Compared to HFC refrigerants design modifications are required to get equivalent 

performance with R-744 for space heating alone (Nekså, 2010). To obtain high efficiency for 

domestic space heating application is challenging if the difference between the high and low 

water temperature of the heat sink is low. System designs enabling a low water return 

temperature are then required (Nekså, 2010) or introduction of work recovery components, 

e.g. ejectors or expanders may overcome the energy efficiency barrier, but the cost for it may 

make the product less competitive. 

The cost of the working fluid is low. However, because of the high pressure, certain types of 

systems require more robust designs for pressure safety which adds cost, while specific tube 

dimensions are much smaller compared to current technology which gives the advantage of 

compact tubing and insulation material.

The main barrier is cost of the system and energy efficiency in some applications.

8.3.5 Hydrocarbons

Hydrocarbons (HCs) include three main refrigerants, HC-290 (propane), HC-1270 (propene) 

and HC-600a (iso-butane).

At present HC-290 systems are sold in a limited number of low charge level heat pump water 

heater installations in Europe. While, for hydronic systems, with ventilated enclosures 

configuration, larger refrigerant charges are allowed. Use in Europe has declined due to 

introduction of the Pressure Equipment Directive (Palm, 2008) but some compressor 

manufacturers are now offering compressors for HC-290 applications.

The efficiency of HC-290 and HC-1270 in heat pumps is known to be good (Palm, 2008).

The direct cost of the substance is favourable. Based on the refrigerant properties the 

equipment cost is similar to HCFC-22 while mitigation devices for safety add some cost.

The main barriers are related to the safety. For systems with parts, which are located in 

occupied spaces, the allowable charge quantity is limited, whereas for systems located 

outside, there are no major restrictions. The necessity to ensure that technicians are 

appropriately trained to handle the flammability of hydrocarbons is a main barrier. For 

equipment manufacturers the liability aspects combined with the costs for safety measures are 

the main barriers to extend the use of hydrocarbons.

8.3.6 R-717 (ammonia)

R-717 is used mainly for large capacity systems. It has also been used in a small number of 

reversible heat pumps and sorption ones. It is not expected to be used in small capacity water 

and space heating heat pumps. 

The energy efficiency of R-717 heat pumps is known to be very good. Crucial problems in 

commercial ammonia direct expansion system is oil return so as to achieve good heat transfer 

in the evaporator. These problems can be solved by use of oil which is soluble in ammonia 

(Palm, 2008). 
176 2014 TOC Refrigeration, A/C and Heat Pumps Assessment Report

The cost effectiveness is unfavourable for non-industrial process use due to equipment and/or 

installations costs. 

The main barriers are related to safety aspects (see Annex to Chapter 2) during the life cycle 

of the equipment and the minimal capacity required for cost-effectiveness and certain national 

regulations controlling installation, even though it has been shown that small capacity heat 

pump systems can be designed to operate with very low charge of ammonia (100 g of 

ammonia for 9 kW heating capacity (Palm, 2008).

The main obstacle for the commercialization of small capacity heat pump systems is the 

limited supply of components. Particularly, there are no hermetic or semi-hermetic 

compressors for ammonia available and ammonia is incompatible with copper.

8.4 Refrigerant charge Levels

Table 8-3 shows approximate charge levels for HPWHs and space heating heat pumps for 

several typical refrigerants.

Charge levels may vary over a range of values for each refrigerant and type of heat pump 

depending on capacity levels, target energy efficiency levels, types of heat exchangers used in 

the system, etc.

Table 8-3: HPWH and space heating HP refrigerants; average charge levels given

Refrigerant kg/kW

HCFC-22 0.30

HFC-134a 0.40

HFC blends R-410A and R-407C 0.30

Hydrocarbons 0.15

R-744 0.15

8.5 Options for existing systems

Replacing an ODS refrigerant, mostly HCFC-22, by a non-ODS refrigerant has similar 

considerations as described in Chapter 7. As for most water heating heat pumps there is no 

refrigerant field piping involved the option to replace the total unit is in many cases the better 

economical solution. For larger units located in places where the replacement of the total unit 

may be difficult, sometimes the option is taken to replace components such as the compressor, 

expansion device, gaskets, safety devices and oil. For that purpose manufacturers of the 

equipment sometimes provide special retrofit packages. 

8.6 Concluding remarks

Most heat pumps commercialised today make use of non-ODS refrigerants. Refrigerants used 

are R-410A, HFC-134a, R-407C, HC-290, HC-600a, R-717 and R-744. The majority of new 

equipment use R-410A. In some Article 5 countries, HCFC-22 is being used as it has 

favourable thermodynamic properties and high efficiency. To replace HCFC-22 by a nonODS there are no technical barriers. The technical and process changes related to pressure, 

lubrication and contamination control are well known. Replacements are commercially 

available, technically proven and energy efficient. All replacements have a similar or lower 

environmental impact. R-410A has a slightly higher GWP but the required charge is less than 

HCFC-22. The issue in high ambient is of less or no importance for water heating heat pumps. 

The main parameters to select the alternatives and the main issue to switch over from HFCF22 are the efficiency, cost effectiveness, economic impact, safe use and easiness of use. 
2014 TOC Refrigeration, A/C and Heat Pumps Assessment Report 177

Replacements such as HFC-32 and other low-GWP HFC blends are under way to become 

commercial available. 

HFC-134a, R-744 and HFC blends R-407C, R-417A and R-410A are commercial available 

solutions that have the highest grade of safety and easiness to use. R-410A is most cost 

effective for small and medium size systems, while for large systems HFC-134a is most 

efficient. R-407C and R-417A are from design point of view the easiest alternatives for 

HCFC-22, but cannot compete with the other HFC-solutions. 

8.7 References

Fernandez N., 2008 N. Fernandez, Y. Hwang*, R. Radermacher, Center for 

Environmental Energy Engineering, Department of Mechanical 

Engineering, University of Maryland, PERFORMANCE OF CO2 

HEAT PUMP WATER HEATERS ,8th IIR Gustav Lorentzen 

Conference on Natural Working Fluids September 7-10, 2008

IPCC/TEAP, 2005 IPCC and TEAP, Special Report on Safeguarding the Ozone Layer 

and the Global Climate System, Issues Related to 

Hydrofluorocarbons and Perfluorocarbons, Intergovernmental Panel 

on Climate Change Technology and Economic Assessment Panel, 

2005.

JARN, 2013/08 The Japan Refrigeration and Air Conditioning Industry Association; 

Heat Pumps overview, August, 2013

Neskå, 1998 Nekså, P., Rekstad, H., Zakeri, G.R. and Schiefloe, P.A.: CO2 – heat 

pump water heater: characteristics, system design and experimental 

results, Int. J. Refrig. Vol. 21, No. 3, pp.172-179, 1998

Neskå, 2002 Nekså, P: CO2 Heat Pumps, International Journal of Refrigeration, 

Vol 25, Issue 4, June 2002, p 421-427, 2002

Neskå, 2010 Nekså, P., Walnum, H. and Hafner A.: CO2 - A refrigerant from the 

past with prospects of being one of the main refrigerants in the future, 

9th IIR Gustav Lorentzen Conference 2010, Sydney, April 12-14, 

ISBN 978-2-913149-74-8, ISSN 0151-1637, 2010

Palm, 2008 Palm, B. (2008) Hydrocarbons as refrigerants in small heat pump 

and refrigeration systems-a review, Int. J. of Refrigeration 31, 2008

Shigehara, 2001 T Shigeharu, Y Ryuzaburo, K Shigeru, (2001) The Performance 

Evaluation of Room Air Conditioner using R32 In the Case of 

Cooling and Heating Mode, Trans JSRAE, Vol.18; No.3.

Stene, 2008 J. Stene, SINTEF Energy Research, Department of Energy Processes, 

Norway, CO2 Heat Pump System for Space Heating and Hot Water 

Heating in Low-Energy Houses and Passive Houses, 8th IIR Gustav 

Lorentzen Conference on Natural Working Fluids September 7-10, 

2008

Yajima, 2000 R. Yajima, K. Kita, S. Taira, N. Domyo R32 as a solution for energy 

conservation and low emission , IIR 2000 Purdue
178 2014 TOC Refrigeration, A/C and Heat Pumps Assessment Report
2014 TOC Refrigeration, A/C and Heat Pumps Assessment Report 179

Chapter 9

__________________________________________________________

Chillers

Chapter Lead Author

Kenneth E. Hickman

Co-Authors

James M. Calm

Martin Dieryckx

Dennis Dorman

Mohamed Alaa Olama

Andy Pearson
180 2014 TOC Refrigeration, A/C and Heat Pumps Assessment Report
2014 TOC Refrigeration, A/C and Heat Pumps Assessment Report 181

9 Chillers

9.1 Introduction 

Comfort air conditioning in large commercial buildings and building complexes is commonly 

provided by chillers. The chillers that serve these systems cool water or other heat transfer 

fluid that is pumped through heat exchangers in air handlers or fan-coil units for cooling and 

dehumidifying the air. Chillers also are used for process cooling in commercial and industrial 

facilities such as data processing and communication centers, electronics fabrication, 

precision machining, molding, and mining (particularly in deep mines with high thermal 

gradients). District cooling is another application that provides air conditioning to multiple 

buildings through a large chilled water distribution system. Chapter 5 provides additional 

information on chillers used in these applications.

Chillers commonly employ a vapour compression cycle using reciprocating, scroll, screw, or 

turbo (centrifugal or mixed axial/centrifugal flow) compressors. Heat typically is rejected 

through air-cooled or water-cooled heat exchangers. Evaporatively-cooled condensers and dry 

coolers also can be used for heat rejection. Though less common, an absorption refrigeration 

cycle is used in absorption chillers, especially where a low-cost source of hot water or steam 

is available. 

Chillers tend to stay in service for long periods in the range from 20 to 40 years. Even though 

CFCs were phased out for new equipment in 2010, a significant number of CFC-11, CFC-12,

and HCFC-22 chillers are still operating. HCFC-123 also is used, but will be phased out in 

2020. Article 5 countries may still use all these refrigerants. The change-over to zero ODP 

refrigerants required a very high investment and was a lengthy process. However, the current 

generation of chillers has proven to be highly reliable and has resulted in higher performance, 

no small feat. 

The zero ODP refrigerants used today generally have GWPs greater than 1000. Climate 

change concerns are driving efforts to seek lower-GWP refrigerants to replace the refrigerants

currently in use, mainly HFC-134a and R-410a. Also, Article 5 countries are expressing 

interest in “leap-frogging” to the next generation of refrigerants in order to avoid investing in 

technology that may become obsolete. 

While manufacturers, consumers, and regulators alike have an interest in low GWP 

refrigerants, a number of things stand in the way. This chapter presents refrigerants under 

consideration and factors affecting their success. In the end, the time and expense to change to 

another generation of refrigerants likely will be required again.

All other considerations aside, to be acceptable, new refrigerants should result in products 

with energy efficiencies that are equal to or better than the refrigerants replaced. This is 

because the global warming effects from chillers are dominated by the energy-related 

component from their power usage. Life Cycle Climate Performance (LCCP) models 

typically show that more than 95% of the climate effect is due to energy consumption. The 

direct global warming effects from refrigerant emissions are significantly smaller. Emissions 

have been significantly reduced in recent years through lower charge systems, low-leak 

designs, manufacturing and testing improvements, and improved service practices. At the 

same time, chiller energy efficiency has been enhanced in today’s systems by adding features 

such as variable speed drives, economizers, suction line heat exchangers, and increased 

subcooling. The use of higher performing chillers is more important to climate change than

prematurely changing to another intermediate refrigerant solution.
182 2014 TOC Refrigeration, A/C and Heat Pumps Assessment Report

Fortunately, the consumer can make intelligent choices when alternatives are explored. The 

annual energy consumption can be calculated with computer simulation programs using the 

chiller(s) load profile, building loads, and weather data. For large and complex chiller 

systems, extensive modeling can provide systems and chiller solutions that minimize total 

energy consumption. However, smaller machines are commonly sold on the basis of full 

and/or part load rating, a simplified representation of energy consumption. Rating standards 

and rating certification programs exist in most countries. AHRI Standard 550/590 (AHRI 

2011) and EN 14825 are among the rating standards in use. 

Other methods used to describe the environmental effects of chiller operation are Total 

Equivalent Warming Impact (TEWI) or Life Cycle Climate Performance (LCCP). These 

methods are defined in Chapter 2, Refrigerants, and further discussed in Chapter 11, 

Sustainable Refrigeration. The ozone depletion potential (ODP) and global warming potential 

(GWP) of the refrigerants mentioned in this chapter are given in Chapter 2. Chapter 2 

includes other refrigerant properties and a description of the issues associated with changing 

refrigerants, including safety aspects. 

9.2 Types of equipment and applications

9.2.1 Mechanical vapour compression chillers

Vapour-compression chillers use either centrifugal or positive displacement compressors. The 

positive displacement category includes reciprocating piston, rotary, screw, and scroll 

compressors. Not all refrigerants can be used in all compressor types because compressors 

generally are designed for specific refrigerants and applications.

Water-cooled positive-displacement chillers below 700 kW commonly employ directexpansion (DX) shell-and-tube evaporators with chilled water on the shell side, or brazed 

plate evaporators. Chillers above 700 kW typically use flooded/pool-boiler type, falling film, 

or spray evaporators with the refrigerant on the shell side of the tubes. Similar to compressor 

technology, heat exchangers are designed for particular refrigerants and applications.

For flooded evaporators or falling film evaporators there is a limit on refrigerant selection. 

Zeotropic refrigerants such as R-407C with high temperature glide can fractionate during 

evaporation and during condensation in shell-side condensers, creating significant 

performance issues (see Section 9.3.1).

9.2.2 Absorption chillers 

Absorption chillers utilize heat provided by a fuel-fired burner, steam, or hot water as the 

main energy source. Electricity still is required for internal solution pumps and controls. 

Large absorption systems commonly use water and lithium bromide. Small absorption chillers 

may use an alternative fluid pair, R-717 and water where water is the absorbent. Other 

working pairs are proposed and see very limited use. Chillers with lithium bromide and water 

all are water-cooled. Chillers using R-717 and water can be water-cooled or air-cooled.

Absorption chillers are identified by the number of heat input levels they employ (e.g., singleeffect or double-effect), and whether they are direct-fired with a burning fuel, or use steam or 

hot water as the heat source. 

Single-effect absorption applications, with lower efficiency, typically are limited to sites that 

can utilize waste heat in the form of recovered hot water or steam as the energy source, or 

where boilers must be run year-round such as in hospitals. Other sites include co-generation 

systems where waste engine heat or steam is available. 
2014 TOC Refrigeration, A/C and Heat Pumps Assessment Report 183

Double-effect machines have an additional heat recovery heat exchanger and can be driven by 

hot water or steam, or can be direct-fired. Double-effect absorption chillers can have primaryenergy-based efficiencies that are 35 – 45% of those of vapour-compression systems. For 

example, double-effect absorption chillers can have a cooling coefficient of performance 

(COP) of 0.9 to 1.2 on a seasonal basis based on source energy input. Electrical vapourcompression systems can have a COP as high as 7.8, which must, in the case of thermal 

power plants, be multiplied by the heat-source-to-electricity delivery efficiency of the power 

plant and distribution system - around 35% for heat-driven generators that are predominant. 

Triple-effect machines have been commercialized but are not used widely. A fluid pair other 

than water/lithium bromide must be used in the high stage generator.

9.2.3 Chiller capacity ranges

Table 9-1 lists the cooling capacity range offered by single units of each type of chiller. (Most 

applications, particularly in larger capacities, use multiple chillers)

Table 9-1: Chiller capacity ranges

Chiller Type Approximate Capacity Range 

(kW)

Typical Refrigerants

Scroll, rotary, and reciprocating watercooled10 - 1,200 R-410A,

HCFC-22, R-407C

Less commonly, HC-290

Screw water-cooled 100 – 7,000 HFC-134a, HCFC-22 

R-717

Screw, scroll, rotary, and reciprocating aircooled 10 – 1,800 HFC-134a, R-410A, 

HCFC-22, R-407C

Centrifugal water-cooled 200 - 21,000 HFC-134a,

HCFC-123

Centrifugal air-cooled 200 – 7,000 HFC-134a

Absorption (R-717-water, air or water 

cooled)

17 – 85 R-717

Absorption (R-717-water, water cooled) 700 – 3500 R-717

Absorption (water-lithium bromide – shell 

and tube)

140 -18,000 R-718

Absorption (water-lithium bromide – shell 

and coil)

17 – 120 R-718

9.3 Options for new equipment 

9.3.1 Evaluation of experimental refrigerants for vapour compression chillers.

Many of the refrigerants in Table 9-1 have GWPs greater than 1000, which is considered to be 

undesirably high. Lower-GWP refrigerants have been tested and evaluated for several years. 

With interest growing to find replacements for existing refrigerants, refrigerant manufacturers 

are proposing new chemicals and blends with lower GWP. As stated in Chapter 2, the perfect, 

inexpensive, energy efficient, non-toxic, non-flammable, and broadly applicable refrigerant 

does not exist and is highly unlikely to come into existence. There is a complex selection 

process ahead where the industry will need to find out which of the many proposed new 

refrigerants are appropriate for each chiller system. The selection process is a trade-off among

GWP, energy efficiency, safety, applied cost, and limiting the need for redesign.
184 2014 TOC Refrigeration, A/C and Heat Pumps Assessment Report

In 2011 the U.S. Air-Conditioning, Heating, and Refrigeration Institute (AHRI) launched an 

industry-wide cooperative research program to identify and evaluate promising alternative 

refrigerants for major product categories including chillers (Johnson 2012). The program, 

referred to as the Low-GWP Alternative Refrigerants Evaluation Program or Low-GWP 

AREP, was desired by the industry to assess the research needs, accelerate industry's response 

to environmental challenges raised by the use of high GWP refrigerants, and avoid duplicative 

work. Many refrigerant blends as well as single-component refrigerants were candidates for 

chiller applications. A number of the proposed alternatives have vapour compression cycle 

characteristics that are close to those of the chiller refrigerant being replaced, namely HFC134a, R-410A, HCFC-22 (and R-407C), and HCFC-123. 

Test results from the Low-GWP AREP program are available from an AHRI website (AHRI,

2013). Tests of alternative lower-GWP refrigerants also have been conducted in Japan under 

the auspices of the Ministry of Economy, Trade and Industry (METI), and in China. Industry 

has not yet selected any preferred candidates for commercialization from this work.

Additional information on non-fluorinated and low-GWP refrigerants for chillers is given in 

Section 4 of the TEAP XXIV/7 Task Force Report (TEAP, 2013). The energy efficiency, 

efficacy, costs, cost effectiveness, and extent of commercialization are presented for a number 

of selected ODS refrigerant alternatives. 

When evaluating a new refrigerant there are many characteristics to consider beyond 

operating pressure levels, cooling capacities, and energy efficiencies. Chapter 2.1.7 presents 

these characteristics. The Annex to Chapter 2 includes application and safety standards for 

refrigerants and systems employing them. Flammable refrigerants, Class 2L, 2, and 3, are part 

of the mix of potential choices, Class 2L is a new classification that was defined in 2010. 

Timelines for introduction of A2L refrigerants will vary by country, and their application in 

large chillers where system charges are unlimited likely will not come until experience is 

gained in smaller limited-charge systems.

Several limitations for refrigerant selection, unique to chillers, are important to note. A 

limitation on the application of blended non-azeotropic refrigerants exists in large chillers 

with flooded evaporators and shell and tube condensers. “Glide” in heat exchangers is a 

change in refrigerant temperature at constant pressure during evaporation. Flooded 

evaporators used in larger chillers are essentially isothermal and isobaric, so the "glide" 

tendency is exhibited as a composition change between the liquid and vapour phases in the 

evaporator. Glide also occurs during condensation. Glide can be at least partially 

accommodated in the traditional cross-flow air-side condenser heat exchangers of air-cooled 

chillers. Refrigerants with little or no temperature glide (1 K or less) are required for use in 

shell and tube heat exchangers with refrigerant on the shell side. Refrigerants with 

temperature glides up to around 5.6 K can be used in DX systems, but designs must be 

modified to account for glide which otherwise may handicap chiller efficiency and tends to 

increase heat exchanger size. Zeotropic refrigerants with glide also require special

consideration of service practices that avoid composition changes resulting from separation 

and differential leakage of blend components

Other unique refrigerant parameters that chiller designers must take into account in choosing a 

refrigerant include heat transfer coefficients in large pool boiling evaporators and compressor 

discharge temperatures, particularly at low suction temperature or high ambient conditions. 

Heat recovery and heat pumping applications for chillers are increasing. A refrigerant’s 

performance in these higher-temperature conditions will be important for these applications.

Another consideration is operating pressure level and the related need for pressure vessel code 

redesign
2014 TOC Refrigeration, A/C and Heat Pumps Assessment Report 185

Unlike small systems that predominately use coils, refrigerant cost is an additional important 

factor. Centrifugal chillers of an average size (e.g., 1400 kW) hold a refrigerant charge of the 

order of 500 kg. Refrigerant cost may be affected favorably by increased production volumes 

if a new low-GWP refrigerant can be used as a retrofit in existing chillers or if there are highvolume applications for a refrigerant such as use as a foaming agent.

9.3.2 Options for new vapour compression chillers

9.3.2.1 Fluorinated refrigerants

Options to replace HFC-134a in new chillers 

HFC-134a is used in positive displacement chillers and centrifugal chillers. Heat exchangers 

with refrigerants on the shell side vs. inside the tubes and plate heat exchangers with 

refrigerant inside differ in their sensitivity to temperature glide which can occur with 

zeotropic refrigerant blends (see section 9.3.1). 

Zeotropic mixtures offer the greatest flexibility in blending refrigerants to approximate the 

physical and thermodynamic properties of HFC-134a - particularly the general trend of the 

pressure/temperature relationships. There are a number of A1 refrigerant candidates with low 

glide and capacities close to HFC-134a with GWPs around 600. Candidates with low GWP 

(150 or less) all are in safety classes A2L or A3.

Earlier studies based on thermodynamic properties suggest that the COP of chillers using one 

candidate, unsaturated HFC-1234yf refrigerant, is not as good as for HFC-134a (Kontomaris, 

2009) and (Leck, 2010). However, a recent study based on chiller measurements indicates that 

the performance of R-513A, an azeotropic blend, is equivalent to HFC-134a (Kontomaris, 

2013). Other evaluations of unsaturated HFCs for chillers have been done (Kontomaris, 

2010a), (Kontomaris, 2010b), (Kontomaris, 2010c), and (Spatz, 2008). 

In Europe chillers are on the market using unsaturated HFC-1234 ze(E) as the refrigerant. The 

efficiency is found to be better than HFC-1234yf and equivalent to HFC-134a. Testing has 

shown that HFC-1234ze(E) has a capacity reduction of approximately 25% compared to 

HFC-134a (Schultz, 2012). The choice of refrigerant in Europe will be influenced by the Fgas regulation and the pressure equipment directive, amongst many other parameters such as 

end user specifications.

It is not possible at this time to know which particular low-GWP refrigerants or blends will 

find significant acceptance for use in chillers.

Options to replace R-410A in new chillers 

R-410A is used primarily in positive-displacement water-cooled and air-cooled chillers. 

Although it operates at higher pressure levels and lower volume flow rates, R-410A became 

the successor to HCFC-22 in the capacity ranges where hermetic reciprocating and scroll 

compressors commonly are used. Chillers with R-410A generally employ DX heat 

exchangers, microchannel heat exchangers, or plate heat exchangers. 

One of the alternatives tested as a possible successor to R-410A is HFC-32. This refrigerant is 

used as a component in blends including R-410A. HFC-32 can be used in positive 

displacement chillers by itself and as a component in blends with HC-600 (n-butane), HC600a (isobutane), and other low GWP components because it has a moderate GWP, good 

energy efficiency, and high capacity in the vapour-compression cycle. Disadvantages include 

flammability and operating pressure levels higher than for HCFC-22. HFC-32 is classed as an 

A2L refrigerant. Chillers using HFC-32 (other than as a blend component) have not been 

widely commercialized yet and will require changes to meet still-to be-developed safety codes 

and building standards.
186 2014 TOC Refrigeration, A/C and Heat Pumps Assessment Report

Other alternatives identified during the Low-GWP AREP program are blends that have 

similar or lower cooling capacities than R-410A. Several of the blends have temperature 

glides of 5.6 K or less. All of the alternatives have higher estimated COPs than R-410A. None 

of the alternatives have a GWP <150. All of the alternatives are in the A2L safety class. 

Options to replace HCFC-22 in new chillers

HCFC-22 was favored for many years as a refrigerant for positive displacement chillers. 

HCFC-22 also was used in some centrifugal chillers produced before 2000. It was phased out 

in 2012 for use in new equipment in developed countries. HCFC-22 still is offered for chillers 

in some Article 5 countries. 

The zeotropic mixture R-407C served as a transition refrigerant. It allowed manufacturers to 

offer chillers with a zero ODP refrigerant by making modest changes in their HCFC-22 

products. R-407C has an appreciable temperature glide (5 K) so is not suitable for use in 

flooded evaporators that predominate in larger chillers. R-407C still is used in Europe, on a

more limited basis in Japan as a replacement for HCFC-22, and elsewhere as one of a number 

of zero-ODP aftermarket drop-in options for retrofits. The retrofit list includes R-421A, R422D, R-427A, R-438A, and others.

The low-GWP AREP program alternatives for HCFC-22 include five A1 refrigerants. Three 

others are A2L refrigerants. The remaining candidates are A3, or in the case of R-717, B2L 

A1 and A2L refrigerants have temperature glides so system designs optimized to use R-407C 

are more appropriate than systems designed for HCFC-22. The COPs of the A1 and A2L 

refrigerants are estimated to be lower than for equivalent HCFC-22 systems. Only one A2L 

alternative has a GWP <150. The selection of a preferred candidate for further development in 

chillers has not been made.

Refrigerant options for new centrifugal chillers

Centrifugal compressors are the most efficient technology in large units, those exceeding 

1700 kW capacity. Water chillers employing these compressors are designed for specific 

refrigerants. 

HFC-134a is a popular choice for large centrifugal chillers. Two other refrigerants are also 

used. These refrigerants have particularly high thermodynamic efficiency and operate at lower 

pressure levels and higher volumetric flow rates than HFC-134a. They are HCFC-123 and 

HFC-245fa. HCFC-123 is a low-GWP HCFC refrigerant which is subject to phase-out under 

the Montreal Protocol in 2020. Large chillers using HCFC-123 likely will continue to be 

produced in North America and China until the phase out occurs. HFC-245fa is an HFC 

which has found limited use in centrifugal chillers, heat pumps, and organic Rankine cycle 

(ORC) power generation cycles. HFC-245fa has operating pressures higher than for HCFC123 but lower than for HFC-134a. Chillers employing HCFC-1233zd(E) have recently been 

introduced on the European market.
2014 TOC Refrigeration, A/C and Heat Pumps Assessment Report 187

9.3.2.2 Non-fluorinated refrigerants

R-717 

Chillers employing R-717 as a refrigerant have been available for many years and are widely 

used in industrial and central chiller plant systems (see Chapter 5). There are a number of 

installations in Europe, the Middle East, China, and the U.S.A. R-717 chillers are available 

with open drive screw compressors in the capacity range 100-7000 kW. Chillers with open 

drive reciprocating compressors are available in the capacity range 20-1600 kW. 

R-717 chillers are manufactured in small quantities compared to HFC chillers of similar 

capacity. Different materials of construction are used because R-717 causes rapid corrosion of 

copper, the most widely used heat exchange surface in HFC chillers. Plate-and-frame steel 

heat exchangers are common in R-717 systems. 

R-717 is better suited to water-cooled chillers because of higher costs of air-cooled R-717 

condenser coils. Information on R-717 chiller applications in building air conditioning is

given in (Pearson, 2008a), (Pearson, 2008b), and (Pearson, 2012). 

R-717 is not a suitable refrigerant for centrifugal chillers because it requires four or more 

compressor stages to produce the pressure rise (“lift” or “head”) required. 

If the use of R-717 refrigerant in chillers is to expand in the capacity range served by positive 

displacement compressors, particularly outside Europe, several impediments must be 

addressed:

 Chiller costs typically are higher than for HCFC and HFC chillers. 

 Safety concerns with R-717 in comfort cooling applications can increase 

installation costs. Building codes in some countries heavily restrict applications. 

None-the-less, the market for R-717 chillers is growing in regions where concerns about the 

control of high-GWP refrigerants are strong. 

Hydrocarbons

Hydrocarbon refrigerants all are flammable and are classified A3. A discussion of safety 

aspects is given in the Annex to Chapter 2. Chillers employing hydrocarbons as a refrigerant 

have been available for many years, though typically only in small capacities (up to 200 kW) 

per refrigerant circuit and for outdoor applications. HC-290 s used in chillers in air 

conditioning and industrial applications. HC-290 and another hydrocarbon, HC-1270, are 

used in a limited number of small (<1200 kW) air-cooled chiller installations in Denmark, 

Norway, the United Kingdom, Germany, Ireland, the U.S.A., and New Zealand. Some Article 

5 countries such as Indonesia, Malaysia, and the Philippines are applying hydrocarbon chillers 

to large space cooling needs. The current market for hydrocarbon chillers is larger than for R717 chillers on a global basis but still very small compared to the market for HCFC-22 and 

HFC chillers. 

Apart from safety considerations, HC-290 and HC-1270 have properties similar to those of 

HCFC-22. This allows their use in new equipment of current design after appropriate 

adjustments for safety aspects and different lubricants. Chillers employing hydrocarbon 

refrigerants are somewhat higher in cost than HFC chillers though modification of equipment 

originally designed for HCFC-22 is fairly straightforward. 

All safety codes impose strict requirements on hydrocarbons in large refrigerant charges in 

chillers, particularly for indoor chiller installations in machinery rooms. Accordingly, 

hydrocarbon chillers have not been adopted in all regions. In regions supporting hydrocarbon 
188 2014 TOC Refrigeration, A/C and Heat Pumps Assessment Report

solutions the safety concerns have been addressed by engineering design, technician training, 

and changes in building codes and safety standards. If experience is successful, the use of 

hydrocarbon chillers may grow in the future. However, in countries such as the U.S.A.,

regulations, building codes, and legal environments make it unlikely that hydrocarbons will 

be used in commercial chillers in the foreseeable future.

Hydrocarbon refrigerants are in limited use in centrifugal chillers in petrochemical plants 

where a variety of very hazardous materials are routinely used and the staff is highly trained 

in safety measures and emergency response (see Chapter 5). Hydrocarbon refrigerants have 

not been used in centrifugal chillers for air conditioning due to safety code restrictions, 

concerns with large charges of flammable refrigerants, liability, and insurance issues. 

R-744 

R-744 air-cooled chillers have been introduced in the northern European market. Both airand water-cooled gas cooler versions are available. Models with cooling capacities from 40 to 

500 kW are offered. In climates where the dominant cooling requirement is at an average 

ambient temperature of 150C or less, these systems can be equivalent in energy efficiency and 

LCCP with systems employing HFCs, R-717, or HCs. R-744 chillers are less attractive at 

higher ambient temperatures due to decreasing efficiency with increasing ambient 

temperature. 

There heat recovery to generate hot water at temperatures of 60oC or higher can be employed 

in a total energy strategy for a building, R-744 chillers offer the advantage of being able to 

use waste heat to raise water to higher temperatures with higher efficiency than other 

refrigerants. Chilled water can be used to sub-cool the refrigerant before expansion. For this 

application, R-744 heat recovery chillers provide good efficiency.

R-718

The very low pressures, high compression ratios, and high volumetric flow rates required in 

water vapour compression systems require high volumetric flow axial compressor designs 

that are uncommon in the chiller field. However, several research projects are active and 

developmental companies have attempted their commercialization. A product was announced 

in 2014 using water as the refrigerant. Applications for water as a refrigerant can chill water 

or produce an ice slurry by direct evaporation from a pool of water. R-718 systems carry a 

cost premium above conventional systems. The higher costs are inherent and are associated 

with the large physical size of water vapour chillers and the complexity of the compressor 

technology. Several developmental chillers and commercial vacuum ice makers have been 

demonstrated in Europe, the Middle East, and South Africa including deep mine refrigeration 

(Jahn, 1996), (Ophir, 2008), (Sheer, 2001), (Calm, 2011).

9.3.2.3 Alternatives to mechanical compression systems (absorption and adsorption 

chillers) 

Absorption water chillers are a viable alternative to the vapour-compression cycle for some 

installations. Absorption chillers have been described in Section 9.2.2. 

Adsorption chillers using water and zeolite also are an alternative (Boone, 2011).

9.4 Options for existing chiller equipment 

When CFC and HCFC refrigerants are phased out (and in several countries that phased out 

HFCs), the functions performed by chillers employing those refrigerants have to be supported 

in one of the following ways:
2014 TOC Refrigeration, A/C and Heat Pumps Assessment Report 189

Retain/Contain: continued operation with stocked and/or reclaimed inventories in 

conjunction with containment procedures and equipment modifications to reduce emissions.

Retrofit: modification to allow operation with alternative refrigerants (HFCs where 

permitted) depending on applicable regulations.

Replace: early retirement/replacement with new chillers (preferably having higher efficiency 

which reduces energy-related climate impact) using allowed refrigerants or not-in-kind 

alternatives, 

The retrofit options depend on the specific refrigerant for which the chiller was originally 

designed. When any retrofit is performed, it is recommended that the machinery room be 

upgraded to the requirements of the latest edition of safety standards such as ASHRAE 15 

(ASHRAE, 2013), and EN 378 (EN, 2008) or international standards such as ISO 5149 (ISO,

2014). It is also recommended that the manufacturers of the equipment be consulted in any 

retrofit program.

9.4.1 Positive displacement chillers

A positive displacement compressor inherently can be applied to handle a number of different 

refrigerants and pressure ratios in a chiller if its motor has adequate power, the compressor, 

tubing, heat exchangers, and other components can meet pressure codes and regulations with 

the refrigerants, and the system materials and lubricant are compatible with the refrigerants. 

Despite this flexibility, there remain a number of issues in retrofitting positive displacement 

chillers to operate with new refrigerants. These issues were discussed in the 2010 RTOC 

report.

9.4.2 Centrifugal chillers

Centrifugal compressors by nature must be designed specifically for a particular refrigerant 

and a particular set of operating conditions for the refrigerant cycle in which they are used. 

Direct refrigerant substitution in centrifugal chillers can be made only in cases where the 

properties of the substitute refrigerant are nearly the same as those of the refrigerant for which 

the equipment was designed, or when the impeller speed and/or impeller geometry can be 

changed easily. In the past this has been accomplished by gear changes in open drive chillers 

and with variable speed drives in both open and hermetic compressor chillers. The 

compressor surge margin must be checked using the properties of the substitute refrigerant.

9.4.3 Non-vapor compression chiller replacements – absorption 

The most common absorption chiller is the water-lithium bromide solution type, both direct 

and indirect fired versions. When comparing the size of a mechanical vapour compression 

chiller with an absorption chiller of similar capacity, the absorption chiller is about 25 to 50 % 

bulkier. This factor may be crucial when retrofitting existing systems because of the size of 

access ways and corridors. Another important factor is the cooling tower requirement of an 

absorption chiller. Because absorption chillers require cooling for their condenser as well as 

their absorbers where the mixing of the refrigerant and absorbent occurs, resulting in the 

emission of heat of mixing and heat of solution that need to be removed, the cooling tower of 

an absorption system can be 30 to 60 % larger than that of a mechanical vapour compression 

system of a similar capacity. 

On the other hand, the replacement of a mechanical vapour compression system with an 

absorption system saves a portion of the electric consumption of the building. This reduces 

the capacity requirements for the transformer, electric switchboards, and electric conduits. 

Provision has to be made for suitable gas piping and train when a natural gas fired system is 

used. Absorption systems do not require anti-vibration mounting since they have few moving

parts.
190 2014 TOC Refrigeration, A/C and Heat Pumps Assessment Report

9.5 Alternatives for high ambient conditions

Chiller rating points commonly involve ambient air temperatures of 35oC (95oF). However, in 

very warm climates there is interest in knowing how chillers will perform when air 

temperatures reach 47oC or even 52oC, and also, how the design of chillers can be modified to 

improve high ambient operation.

This section focuses on air cooled chillers. The design of water cooled chillers for high 

ambient conditions involves the same approaches as for air cooled chillers but is less 

challenging because condensing temperatures are lower for a given ambient temperature.

Air-cooled chillers with positive displacement compressors (rotary, reciprocating, scroll, 

screw) designed for an ambient of 35oC will operate at high ambient conditions but with 

reductions in capacity and COP. An illustrative example is given for actual 3 ton residential 

air conditioners in the May 2010 TEAP XX/8 Task Force Report. For HCFC-22, capacity was 

reduced by 15% and COP was reduced by 35% when the ambient temperature increased from 

35oC to 52oC. For R-410A the reductions were 18% and 40 % respectively. Design changes 

that can improve chiller performance at high ambient temperatures include applying a 

compressor with proper capacity and compression ratio for the ambient condition, adjusting 

the compressor built-in volume ratio for scroll and screw compressors, increasing condenser 

size, and providing a properly-sized expansion device. Features such as economizers are more 

effective in high ambient conditions than for lower condensing temperatures. HFC-134a has 

less performance degradation than R-410A, and HFC-32 (an A2L refrigerant) has even less 

performance degradation. These refrigerants are not interchangeable because of their differing 

capacities, pressure levels, and lubricant requirements. Chiller design must be tailored for the 

specific refrigerant selected.

Chillers with centrifugal compressors require a different approach. Typically, additional 

compressor stages may be required. If condensers cannot be water-cooled because water is 

scarce or expensive, dry coolers are used. Air-cooled condensers with tubes and fins or 

microchannel heat exchangers are not commonly used with centrifugal compressors because 

they are sensitive to the increased pressure drop on the refrigerant side of these types of 

condensers as compared to dry coolers. The refrigerants used in centrifugal chillers for high 

ambient conditions typically are HFC-134a and HCFC-123. 

HFC-32, an A2L refrigerant, is being considered as a lower-GWP alternative to R-410A or 

HFC-134a for high ambient applications. R-444B has been shown to perform well at high 

ambient conditions (Schultz 2014). It is too early to know whether or when other lower GWP 

refrigerants will be available as alternatives to R-410A, HFC-134a, and HCFC-123 for 

chillers operating in high ambient conditions.

9.6 Concluding remarks

 This chapter shows that no “ideal” low-GWP replacements for HFC-134a, R-410A, and 

HCFC-22 have been identified for chiller applications. An “ideal” refrigerant would 

have nearly-zero ODP, a zero or low GWP, an A1 ASHRAE/ISO safety classification, 

near-zero temperature glide, energy efficiency equivalent to or better than the 

refrigerant being replaced, and acceptable cost for the quantity used in typical chillers. 

Additionally, the cost of conversion of compressors and heat exchangers should not be 

prohibitive to manufacturers. 

 Global warming effects from chillers are dominated by their energy use. There 

continues to be consumer and regulatory pressure to improve full and part load or 

seasonal energy consumption which will have a positive climate impact.

 Direct global warming effects from refrigerant emissions from chillers are significantly 

smaller than the climate effect from the energy consumed during the lifetime of 
2014 TOC Refrigeration, A/C and Heat Pumps Assessment Report 191

operation. Emissions have been significantly reduced in recent years through lower 

charge systems, low-leak designs, manufacturing and testing improvements, and 

improved service practices.

 Thus, chemical producers and chiller manufacturers will continue to focus their efforts 

on refrigerant candidates that provide energy efficiencies that are equal to or better than 

the refrigerants being replaced. 

 A1 refrigerants with GWPs up to 675 offer performance and safety benefits for some 

applications.

 The ultimate goal is to choose alternative solutions that are the most energy efficient 

while remaining viable to chiller manufacturers, regulators, and users.

9.7 References 

AHRI, 2011 Standard 550/590-2011 with Addendum 1: Performance Rating of 

Water-Chilling and Heat Pump Water-Heating Packages Using the 

Vapor Compression Cycle, 2011. Air-Conditioning, Heating, and 

Refrigeration Institute, Arlington VA, USA

ASHRAE, 2013 ANSI/ASHRAE Standard 15-2013, Safety Standard for Refrigeration 

Systems, 2013. American Society of Heating, Refrigeration, and AirConditioning Engineers (ASHRAE), Atlanta, GA, USA

Boone, 2011 Boone, J., Adsorption Chiller, UNEP/IIR 14th European Conference 

on Renewable Energy Applications in Heating and Cooling, 

Edinburgh, 2011

Calm, 2011 Calm, J.M., Refrigerants for Deep Mine Refrigeration, Refrigerants 

for Sustainable Development, Proceedings of the 23rdInternational 

Congress of Refrigeration, Prague, Czech Republic, August 21-26, 

2011; International Institute for Refrigeration, Paris, France, Paper 

914

EN, 2008 EN378: 2008. Refrigerating Systems and Heat Pumps – Safety and 

Environmental Requirements, 2008, A1 2012 Parts 1-4, Comite 

Europeen de Normalisation, Brussels

ISO, 2014 ISO Standard 5149:2014. Mechanical Refrigeration Systems Used 

for Heating and Cooling – Safety Requirements, International 

Organization for Standardization, Geneva, Switzerland

Jahn, 1996 Jahn, E., Lausen, D., and Paul, J., 1996. Cooling of Mines with 

Vacuum Ice, Proceedings of the FRIGA’96 Conference, 

Johannesburg, South Africa

Johnson, 2012 Johnson, P.A., Wang, X., and Amrane, K., AHRI Low-GWP 

Alternative Refrigerant Evaluation Program, ASHRAE/NIST 

Refrigerants Conference, NIST, Gaithersburg, MD USA, American 

Society of Heating, Refrigeration, and Air-Conditioning Engineers 

(ASHRAE), Atlanta, GA, USA , October 29-30

Leck, 2010 Leck, T.J., Kontomaris, K., and Rinne, F., 2010. Development and 

Evaluation of High Performance, Low GWP Refrigerants for AC and 

Refrigeration, Conference on Sustainable Refrigeration and Heat 

Pump Technology, Royal Institute of Technology (KTH), Stockholm, 

Sweden, June 13-16

Kontomaris, 2009 Kontomaris, K., Leck, T.J., 2009. Low GWP Refrigerants for 

Centrifugal Chillers, American Society of Heating, Refrigeration, 
192 2014 TOC Refrigeration, A/C and Heat Pumps Assessment Report

and Air-Conditioning Engineers (ASHRAE), 2009 Annual 

Conference, Louisville, KY, USA, June 24

Kontomaris, 2010a Kontomaris, K., and Leck, T.J., 2010. Low GWP Refrigerants for Air 

Conditioning of Large Buildings, 10th REHVA World Congress, 

Sustainable Energy Use in Buildings, Antalya, Turkey, May 9-12

Kontomaris, 2010b Kontomaris, K., Leck, T.J., and Hughes, J., 2010. A NonFlammable, Reduced GWP, HFC-134a Replacement in Centrifugal 

Chillers: DR-11, 13th International Refrigeration and AirConditioning Conference, Purdue University, Lafayette, IN, USA, 

July 12-15

Kontomaris, 2010c Kontomaris, K., 2010. A Low GWP Replacement for HCFC-123 in 

Centrifugal Chillers: DR-2, American Society of Heating, 

Refrigeration, and Air-Conditioning Engineers (ASHRAE) and 

United Nations Environmental Programme (UNEP) Conference, 

Road to Climate Friendly Chillers – Moving Beyond CFCs and 

HCFCs, Cairo, Egypt, September 30-October 1

Kontomaris, 2013 Kontomaris, K., Kulankara, S., and Kauffman, J.P., A Reduced 

Global Warming Potential Replacement for HFC-134a in Centrifugal 

Chillers: XP-10 Measured Performance and Projected Climate 

Impact, HVAC&R Research, 19(7) p. 857-864

Ophir, 2008 Ophir, A., 2008. Mechanical Heat Pumps Using Water as Refrigerant 

for Ice Production and Air Conditioning, presentation, International 

District Energy Association (IDEA), 99th Annual Convention in 

Orlando, FL, Westborough, MA, USA

Pearson, 2008a Pearson, A., 2008. Ammonia’s Future, ASHRAE Journal, American 

Society of Heating, Refrigerating, and Air Conditioning Engineers 

(ASHRAE), Atlanta, GA, USA, 50(2): 30-36

Pearson, 2008b Pearson, A., 2008. Water Chillers with Ammonia for Building 

Services, Natural Refrigerants – Sustainable Ozone and Climate 

Friendly Alternatives to HCFCs, published by German Technical 

Cooperation Programme Proklima, German Federal Ministry for 

Economic Cooperation and Development, Bonn, Germany, July 

Pearson, 2012 Pearson, A., 2012. Opportunities for Ammonia, ASHRAE/NIST 

Refrigerants Conference, NIST, Gaithersburg, MD USA, American 

Society of Heating, Refrigeration, and Air-Conditioning Engineers 

(ASHRAE), Atlanta, GA, USA, October 29-30

Schuiltz, 2012 Schultz, K., Kujak, S., System Drop-In Tests of R-134a Alternative 

Refrigerants (ARM-42a, N-13a, N-13b, R-1234ze(E), and Opteon 

TM (XP10) in a 230-RT Water Cooled Water Chiller, AHRI LowGWP AREP Test Report #7, Nov. 19, 2012 (See website below for 

access)

Schultz, 2014 Schultz, K., 2014. Performance of R-410A and R-22 Low GWP 

Alternative Refrigerants at Elevated Temperatures, 15th International 

Refrigeration and Air-Conditioning Conference, Purdue University, 

Lafayette, IN, USA, July 14-17

Sheer, 2001 Sheer, T.J., Butterworth, M.D., and Ramsden, R., 2001. Ice as a 

Coolant for Deep Mines, Chapter 52, Proceedings of the 7th

International Mine Ventilation Congress, Research and Development 

Center for Electrical Engineering and Automation in Mining, 
2014 TOC Refrigeration, A/C and Heat Pumps Assessment Report 193

Krakow, Poland, June 

Spatz, 2008 Spatz, M.W., 2008. Latest Developments in Refrigerants for A/C&R 

Applications, The International Symposium on New Refrigerants and 

Environmental Technology 2008. Kobe, Japan, November 20-21

TEAP, 2013 Decision XXIV/7 Task Force Report, Additional Information on 

Alternatives to ODS, 2013. Report of the UNEP Technology and 

Economic Assessment Panel, UNEP Ozone Secretariat, Nairobi, 

Kenya, September 2013

Website

AHRI 2013 Site for Low-GWP AREP Test reports: 

www.ahrinet.org/resources/research tab - then AHRI Low-GWP 

Alternate Refrigerants Evaluation Program for list of downloadable 

test reports
194 2014 TOC Refrigeration, A/C and Heat Pumps Assessment Report
2014 TOC Refrigeration, A/C and Heat Pumps Assessment Report 195

Chapter 10

__________________________________________________________

Vehicle Air Conditioning

Chapter Lead Author

Jürgen Köhler

Co-Authors

Radhey Agarwal

Radim Čermák

Jiangping Chen

Dave Godwin

Carloandrea Malvicino
196 2014 TOC Refrigeration, A/C and Heat Pumps Assessment Report
2014 TOC Refrigeration, A/C and Heat Pumps Assessment Report 197

10 Vehicle air conditioning

10.1 Introduction

Vehicles (cars, trucks, buses and trains – this chapter does not cover ship air conditioning) 

built before the mid-1990’s used mostly CFC-12 as the refrigerant with some HCFC-22 use in 

trains. Since then, in response to the Montreal Protocol, new vehicles with air conditioning 

(AC) have been equipped with systems using HFC-134a. By the year 2000, the transition 

from CFC-12 to HFC-134a as an Original Equipment Manufacturer (OEM) refrigerant, for 

factory installed AC systems, was complete in all developed countries. The transition to HFC134a in developing countries was completed by approximately 2007. In addition, since the 

mid-1990’s, development of alternatives to HFC-134a has been underway due to the high 

Global Warming Potential [GWP] of HFC-134a.

In this chapter, mobile air conditioning systems are those used in passenger cars, light duty 

trucks, buses and rail vehicles that are generally based on vapour compression cycles. This 

chapter also addresses the heat pump mode of the air conditioning cycle, for example systems 

used for heating battery-driven electric vehicles (BEVs). Annex C (Not-In-Kind Alternatives) 

provides a brief overview of other refrigeration techniques which might become important for 

vehicle air conditioning systems in the future (beyond 2020).

Chapter 10 covers the new developments in the field of mobile air conditioning systems since 

the RTOC 2010 Report. For more details on the system design and the history of refrigerant 

system development for these vehicles prior to 2010, see that and all preceding RTOC reports.

It should be mentioned that the development in this field is strongly driven by legal guidelines 

and regulations (probably much stronger than in other fields). So, Annex B provides a partial 

overview of the legal situation worldwide.

The ozone depletion potential (ODP) and global warming potential (GWP) values of the 

refrigerants mentioned in this chapter are given in chapter 2 of this report.

10.2 Description of systems and current and future applications of mobile air 

conditioning systems

Detailed descriptions of direct and indirect (secondary loop) systems can be found in the 

2002, 2006, and 2010 RTOC Reports. As noted above, due to the transition from CFC to 

HFC's in the mid-1990's, HFC-134a quickly became the refrigerant of choice for new 

equipment as well as retrofits of CFC-12 designs. Most non-Article 5 countries phased in 

HFC-134a in new vehicles similarly to the U.S., starting in the early 1990s and completing 

this transition by the mid-1990s. Article 5 countries followed with some models offered 

during the 1990s and full transition by the following decade.

HFC-134a systems have become increasingly more leak tight taking benefit in part from the 

technology developed in the study of R-744 (carbon dioxide) and in part from regional leak 

reduction programs, e.g., US light-duty vehicle regulations, the Improved Mobile Air 

Conditioning (I-MAC) program, etc. Correspondingly, hose materials and coupling designs 

for hoses have also been improved in a relevant way. In addition to that, compared to earlier 

designs, HFC-134a systems today show improved energy efficiency and lower fuel 

consumption to meet new regulatory requirements in the USA (USEPA, 2011b) and driven by 

increased awareness of fuel consumption of mobile air conditioners (MACs) in the EU. 
198 2014 TOC Refrigeration, A/C and Heat Pumps Assessment Report

10.2.1 Refrigerant cost and recharge

Passenger cars and light duty trucks have refrigerant charge amounts from 0.3 kg to 1.4 kg. 

Bus and rail vehicles can have refrigerant charge amounts from 2 kg to 15 kg and some even 

higher amounts.

The rise in counterfeiting is probably due to production and use restrictions on some 

refrigerants in accordance with the 1987 Montreal Protocol and the 1997 Kyoto Protocol and 

to the higher cost associated with more environmentally friendly refrigerants than what they 

are replacing (Velders, 2009). Hence, counterfeited HFC-134a is infiltrating the refrigerant 

bank in Asia, and affecting also other countries.

Today, even if the relative cost of HFC-134a is low, i.e. 5 US$/lb or 11 US$/kg (or even less),

counterfeit HFC-134a is still appearing in the automotive market. Counterfeit HFC-134a

containing multiple CFC, toxic, or corrosive components is a serious threat destroying 

equipment and injuring end-users. It also has an increasing opportunity to enter the supply 

chain. The issue is even more relevant in non-European countries (Coll, 2012).

So, in case that a drop-in or nearly drop-in but more expensive refrigerant will be chosen to 

replace HFC-134a worldwide, the counterfeit risk will become even more relevant and this, 

beside all the other impacts, could strongly reduce the expected environmental benefit.

The commercial expected price of HFC-1234yf (Weissler, 2013) is estimated at US$ 40-45/lb 

or US$ 88-99/kg (retail prices could be 2 to 3 times higher). The expected price of R-445A 

probably will be lower but there exist questions that have been raised on patent issues. Cost 

and availability are crucial issues that have to be considered in identifying replacement(s) for 

HFC-134a, currently widely adopted in car air conditioning systems. 

10.2.2 Future Trends

The European Union and the United States already have in place regulations that influence 

mobile air conditioning designs while the other countries with a high density of road vehicles 

are rapidly moving in the same direction (for example Brazil, Inovar Auto, 2012).

This drives to more efficient on-board systems including MACs and to the replacement of 

high GWP fluid with lower GWP substances.

Meanwhile the same regulations are leading to a progressive diffusion of hybrid vehicles in 

the short-medium term (3 - 10 years) that in the medium-long term (5 - 15 years) will be 

further integrated with fully electric vehicles. These vehicles require highly efficient mobile 

air conditioning to minimise the impact on the pure electric range and, as additional evolution, 

to be able to operate also as a heat pump. These challenges will be met by developing and 

adopting technical solutions that will have to represent the best trade-off among economic and 

environmental sustainability issues.

In this framework the thermal systems and especially the MAC systems have a relevant role 

and will likely undergo a deep change where the system integration will represent a relevant 

evolution guideline.

It is expected that the passenger cars and light duty vehicle domain will rapidly move toward 

downsized turbocharged engines often coupled with different levels of hybridization to make 

the overall powertrain more efficient and to reduce CO2 emissions, with effects on MACs as 

described below. Increased levels of transmission gears are also occurring, moving vehicles 

from 4/5/6 levels to 7/8/9 levels leading to a reduction of average compressor speeds so 

implying AC capacity concerns at low speeds in some cases or to the increase of the 

compressor displacement or finally to the adoption of electrically driven systems.
2014 TOC Refrigeration, A/C and Heat Pumps Assessment Report 199

To answer to the increased demand of capacity and reduction of GHG emission, the car air 

conditioning systems using HFC-134a have to become increasingly more leak tight and 

efficient.

The adoption of improved components (compressor and heat exchangers) and the introduction 

of internal heat exchangers as well as improved control strategies allowed a significant 

increase of system efficiencies.

New sealing concepts and improved hose materials have also been developed to reduce 

refrigerant direct emissions and to reduce the frequency of required maintenance or service. 

The trend in the MACS service profiles over the last 10 years (2003-2013) indicates that with 

reduced refrigerant emissions, the system is being serviced later in the vehicle’s life,

indicating more years of useful life from the system. With this extended lifetime, service is 

more likely to be purchased by the vehicle’s second owner as compared to previous surveys

of earlier vehicles (Atkinson, 2014).

Stop & Start and Hybrid Vehicles

The diffusion of vehicles able to carry out part of their mission with the combustion engine 

off (e.g. Stop & Start, extended Stop & Start, and hybrids) asks for new solutions for the air 

conditioning system to guarantee the summer and winter thermal comfort in all the 

operational conditions. 

The majority of these vehicles will have 12 V to 48 V electric energy sources and only part of 

them will have higher voltage network (e.g. up to 350 V), while all will have an additional onboard electric energy storage unit with a capacity ranging from 0.2 kWh (low voltage) up to 5 

kWh (high voltage).

This implies that only a small portion of the future vehicles will have an electric compressor 

while a large part will be equipped with mechanically driven compressors as today due to 

energy balance and cost, so measures will be adopted to maintain the required comfort and 

guarantee the safety performance (i.e. de-fogging), as for example:

 cooling energy storage unit based on phase change materials

 secondary loop system taking benefit from its thermal inertia to store cooling power 

 additional electric compressor, downsizing the belt-driven compressor

The increase of on-board electric power and the diffusion of turbocharged engines together 

with the need to at least maintain the aerodynamic drag will presumably lead to a low 

temperature cooling loop integrating the charge air cooler, air conditioning condenser, power 

electronics and generator in the case of hybrid powertrain. 

In synthesis, the evolution will produce a deeper integration of the on-board thermal systems 

and the air conditioning will become part of it.

Plug-in Hybrids and Battery-driven Electric Vehicles

For Plug-in Hybrids (PHEV) and Battery-driven electric vehicles (BEV), vehicle air 

conditioning systems for cooling as well as heat pump systems for heating need to have very 

high energy efficiency to minimize the impact on the vehicle driving range.

MAC systems, when operating as a heat pump with HFC-refrigerants currently used can take 

benefit of the on-board outdoor heat sources (battery, power electronics, etc.) to enhance their 
200 2014 TOC Refrigeration, A/C and Heat Pumps Assessment Report

effectiveness in case of very low ambient temperatures partially compensating for their low 

efficiency and capacity. This can be achieved adopting a secondary loop that by collecting the 

heat from the on-board electronics can raise the temperature of the heat source. In this 

framework, dual loop systems (with liquid cooled condensers and liquid heated evaporators) 

offer the highest flexibility level and at the same time allow the OEM to minimize the 

refrigerant charge, the leak rate, and the risk of dispersion in case of an accident. However, 

these secondary loop systems do increase the vehicle mass due to the additional coolant and 

components which might adversely affect vehicle fuel economy at all times of vehicle usage.

For some applications the MAC system will be also used for battery thermal control as well as 

power electronics (i.e. cooling and heating).

New Refrigeration Systems

The need to progressively increase the energy efficiency requires the exploitation of all 

available waste energies, heat included. The application of heat driven refrigeration systems 

(e.g. adsorption, absorption, etc.) can be foreseen for the heavy duty vehicle domain (e.g. 

trucks and coaches) which often operate at near constant speed (highway) and where the 

weight and packaging constraints are less severe than in the passenger cars field.

Waste Heat Recovery

The adoption of a Rankine Cycle to convert part of the combustion waste heat of a thermal 

engine into mechanical or electric energy could allow manufacturers to increase dramatically 

the vehicle energy efficiency (see section 5.1.6 of this report, and for example Horst et al. 

2014 or Hartmann 2014).

These systems are under investigation for diesel heavy duty truck applications in Europe and 

the US and for gasoline light trucks in the US.

As a working fluid, the Rankine cycle can use water, ethanol or a mixture of both, or an 

organic fluid like HFC-245fa, hydrocarbons, or carbon dioxide. 

The fluid HFC-245fa has good properties for the application but has a GWP of 1050, higher 

than the threshold of the MAC Directive in Europe.

Studies are ongoing to evaluate the application of fluids with similar properties but with a 

lower GWP, as for example HCFC-1233zd(E) and HFC-1336mzz(Z) (Kontomaris, 2014).

10.3 Options for New and Future Mobile Air Conditioning Systems

10.3.1 Passenger Car and Light Truck Air Conditioning\

As already mentioned in the introduction, this report concentrates on vapour compression 

refrigeration cycle technology for vehicle air conditioning. 

Improved HFC-134a Systems

With the introduction of the credit system in the USA, and also upcoming legislation in 

Europe, more vehicle OEMs are introducing technologies to reduce energy consumption with 

HFC-134a refrigerants. Many efficiency-improving technologies are now being used in 

current production HFC-134a systems, for example, internal heat exchangers, oil separators in 

compressors, increased use of externally controlled compressors, etc.
2014 TOC Refrigeration, A/C and Heat Pumps Assessment Report 201

HFC-1234yf Systems

HFC-1234yf systems are able to reach the same system performance and fuel efficiency as 

HFC-134a system if they use either an internal heat exchanger (IHX) or a condenser in which 

the subcooling area is enlarged by about 10% while keeping the same total exchange area 

(Zilio, 2009). In the latter case, HFC-1234yf charge amounts could increase by a maximum of 

10% depending on the system layout. The addition of an IHX also generally increases charge 

amount but some suppliers are reducing the liquid-side volume to minimize this and in some 

cases there are issues with pressure drop on the liquid side of the IHX. Thus, manufacturers 

are working now on ways to compensate for this and to reduce refrigerant charge further due 

to the higher (i.e., more than 10 times expected) cost of HFC-1234yf as compared to HFC134a. Due to increased density of HFC-1234yf versus HFC-134a, it might be possible to 

reduce the charge amount depending on the system layout.

HFC-1234yf is designated as an A2L refrigerant, meaning that it is flammable under 

prescribed testing conditions but exhibits a lower burning velocity than other flammable 

refrigerants designated as class 2 or 3 flammability refrigerants (ASHRAE, 2013). The 

flammability potential has led to high scrutiny surrounding the safe use of the refrigerant and 

possible ways to mitigate any risks. 

The US EPA has studied the potential use of HFC-1234yf as a MAC refrigerant under the US 

Clean Air Act’s Significant New Alternatives Policy (SNAP) Program and has SNAP-listed 

HFC-1234yf as an acceptable refrigerant with the following additional use conditions 

(USEPA, 2011a):

 HFC-1234yf MAC systems must meet the requirements of the 2011 SAE J639 

standard version („Safety Standards for Motor Vehicle Refrigerant Vapor 

Compression Systems“), describing the safety requirements for the use of R-1234yf 

in MAC systems.

 Manufacturer for MAC systems and vehicles have to conduct and keep records of a 

risk assessment and Failure Mode and Effects Analysis according to the SAE J1739 

standard („Potential Failure Mode and Effects Analysis in Design (Design FMEA) 

and Potential Failure Mode and Effects Analysis in Manufacturing and Assembly 

Processes (Process FMEA) and Effects Analysis for Machinery (Machinery FMEA)“) 

for at least three years from the date of creation

Further requirements outside the US are based on ISO 13043:2011.

Some car manufacturers currently have new vehicles equipped with the HFC-1234yf on the 

European market (Mandrile, 2013) and in the United States (McAvoy, 2014 and 

Moultanovsky, 2014). Atkinson, 2014 provides a list of 9 car types which use HFC-1234yf in 

the US market.

A SAE Cooperative Research Project (CRP) set up to assess the HFC-1234yf systems safety 

concluded that HFC-1234yf is acceptable for market without concentration limits. Even the 

German VDA stated in a 2012 publication (Hammer, 2012) that flammability and toxicity of 

the refrigerant or possible decomposition products do not lead to higher level of risks for 

vehicle occupants or helpers at accidents, e.g. fire fighters, and cars using HFC-1234yf are as 

safe as those using HFC-134a. SAE standards have been developed to cover service best 

practices, safety practices, technician training, and refrigerant purity of HFC-1234yf (SAE 

J2845, 2013).

Further analyses, however, have disputed these earlier findings that the flammability and 

toxicity of HFC-1234yf do not lead to higher level of risks. A German car manufacturer 
202 2014 TOC Refrigeration, A/C and Heat Pumps Assessment Report

carried out a series of additional tests on HFC-1234yf as part of a new test scenario developed 

in-house which goes above and beyond the legally prescribed requirements. Under these 

conditions, described by the manufacturer as real-life, the reproducible test results 

demonstrate that HFC-1234yf, which is otherwise difficult to ignite under laboratory 

conditions, mixed with lubricant can indeed prove to be flammable in a hot engine 

compartment. Similar tests of the current HFC-134a refrigerant and lubricant did not result in 

ignition. Based on these new findings, the German car manufacturer concluded that HFC1234yf will not be used in its products (Daimler, 2012).

Some EU countries are starting to ask for additional safety evaluation and preventive safety 

measures to assure the higher safety standards. Nevertheless, the EU, in agreement with the 

Regulation that does not indicate any specific substance, decided to not change the regulation 

or allow any delay or derogation. 

In response and to address the safety concerns of the German car manufacturer, a new SAE 

CRP (1234-4: SAE press rel., 2013) was formed and continued its process of carefully 

reviewing the use of HFC-1234yf by using universally accepted engineering methods, 

including analysis of recent OEM testing from actual vehicle crash data, on-vehicle 

simulations, laboratory simulations, bench tests, and over 100 engine compartment refrigerant 

releases. Based on this testing the CRP has found that the refrigerant is highly unlikely to 

ignite and that ignition requires extremely idealized conditions, even when mixed with the 

lubricant as normally happens in real world conditions. The SAE CRP team has also 

identified that the refrigerant release testing completed by the German car manufacturer was 

unrealistic by creating the extremely idealized conditions for ignition while ignoring actual 

real world collision scenarios. These conditions include specific combinations of temperature, 

amount and distribution of refrigerant, along with velocity, turbulence, and atomization, 

which are highly improbable to simultaneously occur in real-world collisions. The SAE CRP 

team included European (but no German), North American, and Asian OEMs (SAE, 2013).

According to a report (Reuters, 2013), the accuracy of which has been disputed, five German 

OEMs and (only for the European market) one Japanese OEM made the decision 

(temporarily) not to use HFC-1234yf in their cars but to use old type approval schemes for 

extending the use of HFC-134a. This development is slowing down the introduction of HFC1234yf globally.

To review and address the safety concerns of the German car manufacturer, Germany's 

Federal Motor Transport Authority (Kraftfahrt-Bundesamt, KBA) commissioned tests based 

on a variation of the R94 crash test with standard cars equipped with HFC-134a and HFC1234yf air conditioning systems. The German Technischer Überwachungsverein (TÜV)

tested four cars on behalf of KBA. The general test condition employed were the following: 

40 km/h, 40% vehicle off-set simulated crash, hot engine test, refrigerant leakage varied in the 

various test stages:

 Stage 1: simulated 40% off-set, vehicle crash where components were checked for 

refrigerant leakage

 Stage 2: non-leaking A/C parts that were damaged in simulated crash, were manually 

made to leak refrigerant

 Stage 3: further changes made to A/C parts to change direction of refrigerant leakage 

flow by turning lines and adding plate or fish mouth aperture. 

Two realistic scenarios have been evaluated (stage 1 and 2). The second stage intended to 

evaluate the dispersion of the refrigerant in the engine bay because of breaches that have not 

been created during the crash test but that could be possible. In all of the situations no ignition 
2014 TOC Refrigeration, A/C and Heat Pumps Assessment Report 203

and no hydrogene fluoride (HF) production have been observed. A third scenario (stage 3) has 

been considered where the components have been manually modified in order to simulate 

further breaks and underhood situations that could be possible. For HFC-1234yf, Stage 3 

showed higher hydrogene fluoride values. At that level a fire occurred in one of the four cars. 

The test was repeated twice more; a fire occurred in one of those two tests. In the test where 

the refrigerant ignited, peak HF concentrations of more than 3000 ppm were measured briefly 

(a few seconds) in the engine compartment. No HF concentration was found at the 

measurement point in the vehicle interior (at the sun visor near the driver’s head). In a 

comparative test with HFC-134a under those same conditions (level 3 test of this one model) 

no fire occurred. .

Based on these tests KBA found that compared to cars with HFC-134a air conditioning 

systems the safety level of a car is decreasing if the car is equipped with a HFC-1234yf air 

conditioning system. Based on this, KBA recommends further investigation and asks for a 

specific legislation that defines tests for the type approval (KBA, 2013).

The Joint Research Centre (JRC) of the EU was holding discussions with relevant 

stakeholders during the review of the safety of HFC-1234yf. This consultation process was 

essential to provide for transparency and confidence in the process, but did not entail the 

approval by the stakeholders of the JRC report. Therefore, on behalf of the European 

Commission, DG ENTR and the JRC requested industry stakeholders and institutions which 

have conducted relevant test procedures and risk assessments and could provide further 

information useful for the process, to participate in this process and communicate the relevant 

information available.

Following this consultation process, in March 2014 the JRC completed its final report with 

the following conclusions (EU, 2014a and EU, 2014b):

1. Regarding the general approach to the testing by KBA, the report acknowledges that 

there is no "Standard" or "Regulatory" testing procedure available for the purpose. 

Therefore the KBA has legitimately used the experts' judgments and engineering 

judgments for selecting the test conditions.

2. Regarding the pre-tests that the KBA carried out to determine the desired test 

temperature for the refrigerant release tests, the testing of the vehicles followed the 

objective to reach the highest possible temperatures. The derived scenarios were 

extreme, but justifiable and reasonable ones, covering urban, extra-urban and 

highway driving conditions, and fully justified within the scope of the vehicle 

testing for the purpose of product safety investigations.

3. Regarding the crash tests, the JRC considered that the approach taken by the KBA 

was justified.

4. Regarding the Level 1 and Level 2 tests, the KBA concluded that "results do not 

provide sufficient supporting evidence of a serious risk within the meaning of the 

Product Safety Act (ProdSG) with the vehicle types tested hereto warrant the taking 

of any immediate measures by the KBA pursuant to that Act". The JRC underlined 

that these tests showed no ignition of refrigerants and very low hydrogen fluoride 

(HF) release despite the very high temperatures in the engine compartment. 

Consequently the results as such with the vehicles tested under the conditions as 

described provided no evidence of a serious risk. The JRC hence supports the 

evaluation of the KBA that there were no grounds for the authorities to take 

measures under the European general product safety legislation. Therefore, 

according to this legislation, the products tested have to be considered safe products.
204 2014 TOC Refrigeration, A/C and Heat Pumps Assessment Report

5. Finally, regarding the refrigerant release tests under Level 3, these were not taken 

into account by KBA as relevant input "for the assessment of a possible risk within 

the scope of the statutory tasks as product safety authority". This approach is 

supported by the JRC. One driving force behind the tests carried out under Level 3 

is exploring what could happen under assumed extreme conditions not yet covered 

in Level 1 and Level 2 testing. The research character is also confirmed by going 

beyond the boundaries and limitations set for Level 1 and Level 2 tests, to verify if 

the worst case was chosen in the test setup, and considering in Level 3 also the 

"development of engines which can be expected for the future". Whilst Level 1 and 

Level 2 tests were realistic and were considered by KBA for their conclusions on 

risks with respect to the product safety regulations, the Level 3 tests could not be 

associated with the necessary concrete probability of occurrence, but serve as a 

general appraisal of the risk. Compared to the scenarios for the realistic Level 1 and 

Level 2 testing, the probability of Level 3 scenarios must be assumed to be far 

lower, and not reflecting "normal or reasonably foreseeable conditions of use" under 

which the General Product Safety Directive 2001/95/EC applies. 

6. Although not being part of the working group's mandate, during the meetings some 

measures to further improve MAC safety were presented. Examples such as release 

valves in MAC circuits, fire extinguisher, reduction of hot surfaces (thermal 

insulation) and additional ventilation were discussed in different occasions during 

the working group meetings.

As other methods to mitigate the flammability risks of HFC-1234yf MACs, studies are ongoing in industry on flame arrestors (Koban, 2013) and on the adoption of a liquid cooled 

condenser.

Carbon Dioxide (R-744) Systems

R-744 refrigerant charge amounts are typically reduced by 20-30% as compared to HFC-134a 

systems. The US EPA has studied the potential use of R-744 as a refrigerant under the US 

Clean Air Act’s Significant New Alternatives Policy (SNAP) Program and has SNAP-listed 

R-744 as an acceptable refrigerant with the following additional use conditions (USEPA, 

2012a):

 Engineering strategies and/or mitigation devices shall be incorporated such that in the 

event of refrigerant leaks the resulting R-744 concentrations do not exceed the short 

term exposure level. Vehicle manufacturers must keep records of the tests performed 

for a minimum period of three years demonstrating that R-744 refrigerant levels do 

not exceed the STEL (short-term exposure limit) of 3% averaged over 15 minutes in 

the passenger free space, and the ceiling limit of 4% at any time in the breathing zone.

 The use of R-744 in MAC systems must adhere to the standard conditions identified 

in SAE J639 Standard.

Outside of the US, ISO Standard 13043:2011 may be employed which provides additional 

exposure limits which deviate from the SNAP values listed in the first bullet: an acute toxicity 

exposure limit (ATEL) of 4% averaged over 30 minutes, an acute toxicity exposure limit of 

5.5% averaged over 5 minutes, and a peak limit of 9%.

SAE standards are being developed to cover service best practices, safety practices, and 

refrigerant purity of R-744 (SAE J2845, 2013). However, many of the R-744 standards were 

not completed and published due to the interest by the industry in HFC-1234yf. With the 

renewed interest in R-744 the SAE ICCC is currently reviewing standards for its use.
2014 TOC Refrigeration, A/C and Heat Pumps Assessment Report 205

R-744, with appropriate system design and control, has been shown to be comparable to HFC134a systems with respect to cooling performance and total equivalent CO2 emissions due to 

MAC systems, and qualifies for use in the EU under the current regulation (Directive 

2006/40/EC). In a generic study which does not depend on an actual state of development, 

Strupp (2011) compared the required energy input (which is proportional to the CO2

emission) of typical R-744 air conditioning systems with low, medium and high energy 

efficiencies to a typical HFC air conditioning system. With a high resolution, his comparison 

takes into account the climatic region, the local population density, and the user behavior 

(how many cars are at a particular time on a particular road). He did this comparison for the 

typical climatic regions China, Europe, India, and USA, with the result that the differences 

between the required annual energy inputs to drive the different air conditioning systems in a 

particular climatic region are in a margin of plus/minus seven percent.

R-744 heat pumps are available from one German supplier as compact cooling and heating 

systems for the particular application in hybrid and battery driven electric vehicles (Hinrichs,

2011). In comparison to electric resistance heaters (positive temperature coefficient (PTC) 

heaters), which reduce significantly the vehicle fuel efficiency and hence driving range, R744 heat pumps operate at a substantial higher level of efficiency and offer the advantage of 

reducing only moderately the vehicle fuel efficiency and hence driving range (Steiner, 2014).

Currently, technical hurdles (noise, vibration, harshness (NVH) reliability, and leakage) and 

commercial challenges (infrastructure development, handling, aftermarket servicing,

additional costs, etc.) exist that will require resolution prior to the implementation of R-744 as 

a general refrigerant for car air conditioning. As a consequence of the safety concerns of one 

German OEM regarding HFC-1234yf, in March 2013, four additional German car 

manufacturers proclaimed that they will also develop R-744 (see for example Volkswagen, 

2013). 

Together with suppliers the German OEMs are working seriously (several working groups, 

standardization, etc.) to achieve the aim of serial-produced R-744-systems in the year 2017 

(see for example Geyer, 2013; Pelsemaker 2013; and Leisenheimer, 2013).

Carbon dioxide has also the potential to be used as working fluid in future car Organic 

Rankine Cycles (ORC) which could help improve the overall fuel efficiency of vehicles (see, 

for example, Chen, 2010 as well as Mitri, 2013).

HFC-152a Systems

Because of its flammability, HFC-152a would require additional safety systems. Most 

development activity has been focused on using this refrigerant in a secondary loop system 

but more probably in a double secondary loop system as a means of assuring safe use. 

Refrigerant charge amounts in a direct expansion system could be reduced by 25-30% in mass 

as compared to HFC-134a and with a secondary loop system, typically 50%. Industry experts 

have discussed using HFC-152a, but only in a secondary loop type system. A secondary loop 

system uses glycol and water as the direct coolant in the passenger compartment with this 

coolant being cooled under-hood by the refrigerant. A double secondary loop system uses 

glycol and water as the direct coolant passenger compartment and another glycol and water 

loop being used with the condenser. The use of two loops prevents refrigerant leaking into 

passenger compartment or leaking during breach of condenser during an accident. Prototype 

HFC-152a MACs and prototype vehicles using them have been demonstrated in the past years 

(for example, Craig, T, 2007 or Lemke, 2014). The obstacles to the implementation due to the 

additional cost, weight increases and size constraints are in part compensated by the 

advantages in case of Stop & Start thanks to the additional inertia of the system and the 

possibility to store cooling power.
206 2014 TOC Refrigeration, A/C and Heat Pumps Assessment Report

The US EPA has studied the potential use of HFC-152a as a refrigerant under the US Clean 

Air Act’s Significant New Alternatives Policy (SNAP) Program and has SNAP-listed HFC152a as an acceptable refrigerant with the following additional use condition (USEPA, 2008): 

 Engineering strategies and/or devices shall be incorporated into the system such that 

foreseeable leaks into the passenger compartment do not result in HFC-152a 

concentrations of 3.7% v/v or above in any part of the free space inside the passenger 

compartment for more than 15 seconds when the car ignition is on. 

As already mentioned in the RTOC 2010 Report, HFC-152a in a secondary loop system has 

been shown to be comparable to HFC-134a with respect to cooling performance and 

equivalent CO2 emissions due to MAC systems and qualifies for use in the EU under the 

aforementioned regulations. 

At present, only one car manufacturer has expressed a certain interest in adoption HFC-152a 

as the refrigerant for MAC serial production, due to NVH and cost (for dual evaporator 

systems) advantages related to the secondary loop system (Andersen, 2013). 

With many new vehicle designs, using a secondary loop system may have advantages for idle 

stop, cooling batteries or on-board electronics cooling. It also reduces the amount of 

refrigerant and leak rate for multi-evaporator installations since chilled coolant is circulated 

throughout the vehicle not refrigerant.

An Italian and a German OEM jointly completed an EU financed project with a double loop 

(liquid cooled condenser and chiller) whose concept has been presented on a light duty 

commercial demo vehicle (Malvicino, 2012); the same concept has been proposed also for 

hybrid and electric vehicles (Leighton, 2014).

In China, some of the vehicle companies are using R-415B as refrigerant, which was 

developed as alternative refrigerant for CFC-12 and HFC-134a. It consists of 75% by mass 

HFC-152a and 25% HCFC-22.

Unsaturated Fluorinated Hydrocarbons and Blends containing Unsaturated Fluorinated 

Hydrocarbons

In addition to HFC-1234yf, some zeotropic blends are still considered as possible candidates 

in vehicle air conditioning systems by many researchers. Two mildly flammable blends were 

introduced by a large chemical company, which has a history that traces its roots to HFC-134a 

and other fluorochemical production in England. This chemical company registered the lesser 

flammable of the two blends at the January 2013 ASHRAE meeting with a nominal mass 

composition of 6% (±1%) R-744, 9% (±1%) HFC-134a and 85% (±2%) HFC-1234ze(E). It is 

designated R-445A. The other blend, designated R-444A, is 12% HFC-32, 5% HFC-152a and 

83% HFC-1234ze(E) by mass and is also registered with ASHRAE. Presentations regarding 

these two blends were made at the annual SAE symposiums in Scottsdale, AZ and Troy, MI 

(see for example Peral-Antunez, 2011; Atkinson and Hope, 2012; Peral-Antunez, 2012; and 

Peral-Antunez, 2013).

Both blends are below the European Community regulated global warming limit of 150. Both 

blends exhibit some flammability, with a designated A2L safety rating under ASHRAE 

Standard 34-2013. The blends are being evaluated by a Cooperative Research Program (CRP) 

under SAE rules. The more flammable blend (R-444A) matches the LCCP (life cycle climate 

performance, a measure of environmental impact) of HFC-1234yf, whereas the lesser

flammable blend (R-445A) needs some improvement in efficiency to reach LCCP equality. 

However, engineering approaches to reach this point are believed to have been identified, and 
2014 TOC Refrigeration, A/C and Heat Pumps Assessment Report 207

if the significant temperature glide (20K and more) also proves to be manageable, R-445A 

would be the preferred blend because of its lower potential flammability than HFC-1234yf.

The CRP reports said that the more flammable blend R-444A has a pressure-temperature 

curve and cooling efficiency close to both HFC-134a and HFC-1234yf, that its flammability 

is similar to HFC-1234yf, and that the glide is similar to zeotropic blends in stationary 

cooling. 

Atkinson and Hope (2012) as well as Peral-Antunez (2012, 2013) report of significant 

different leakage rates of the three components which could lead to a concentration shift after 

some operating time or due to servicing. However, the team around Peral-Antunez (2014) 

encountered no significant leakage problems during a four month/50,000 km on-the-road test 

of two new cars equipped with R-445A MAC systems. Compared to HFC-134a, R-445A has 

a higher high-side pressure (about 2bar) and a higher compressor discharge temperature 

(about 10K). Due to the high temperature glide it has the risk of ice formation in the 

evaporator (Koehler et al. 2013, and Li 2013). Owing to the high temperature glide R-445A 

has the potential to be used as a heat pump fluid. Overall toxicity was described in promising 

terms for both blends and a preliminary toxicology estimate for the Occupational Exposure 

Limit, assigned by the CRP, shows that both are higher than the 500 ppm of HFC-1234yf and 

close to the 1000 ppm for HFC-134a.

Hydrocarbons and Blends containing Hydrocarbons

In Australia and the USA, hydrocarbon blends, sold under various trade names, have been 

used as refrigerants to replace CFC-12 and to a lesser extent for HFC-134a. The retrofits with 

HCs are legal in some Australian states and illegal in others and in the USA. US EPA has 

forbidden the uses of HCs for retrofit but has considered the possible use of HCs for new 

systems, but is awaiting proof that safety issues have been mitigated.

HCs or HC-blends, when correctly chosen, present suitable thermodynamic properties for the 

vapour compression cycle and permit high energy efficiency to be achieved with welldesigned indirect systems (same systems as the secondary loop system presented above for 

HFC-152a). Nevertheless, even with indirect systems, HCs are so far not seen by the largest 

part of vehicle manufacturers as replacement fluids for mass-produced AC systems due to 

safety concerns.

The combined needs of advanced thermal systems and air conditioning for hybrid and electric 

vehicles and lower GHG emissions makes promising the introduction of a compact 

refrigeration unit incorporating an electric compressor and fully sealed and pre-charged 

design. The compact refrigeration unit being constituted by two liquid cooled exchangers 

(chiller and condenser and where requested of an internal heat exchanger) is able to produce 

hot or cold coolant, normally a water-glycol mixture, and to minimize the refrigerant charge 

and leak.

With this perspective, the use of hydrocarbons or blends of them becomes once again 

interesting, being such fluids are worldwide available, cheap and with a very low 

environmental impact. 

The use of a compact refrigeration unit with a double loop enables the opportunity to mitigate 

the issue related to refrigerant leak allowing very low charge (-50%). Furthermore it enables 

also the use of the air conditioner as heat pump without the need of a 4 way valve, making 

easier the thermal management of the batteries and electronics. This approach is under 

development in Italy and Germany and the components are already available from different 

leading suppliers in Italy, France, as well as in Germany and US.
208 2014 TOC Refrigeration, A/C and Heat Pumps Assessment Report

Hydrocarbons have also the potential to be used as working fluid in future car Organic 

Rankine Cycles which could help improve the overall fuel efficiency of cars (Preißinger, 2012 

and Mitri, 2013).

10.3.2 Bus and Rail Air Conditioning

Mass transit vehicles involve buses, coaches and rail cars, which can further be segmented to 

conventional trains, high speed trains, trams, subways, etc. As compared to passenger cars, 

their air conditioning systems are larger in size, have a higher cooling capacity, and in general 

use modified commercial components. They are usually packaged specifically for each 

application.

The mass transit vehicle fleet is smaller than that of passenger cars. The latest statistical data 

for the 27 European countries show that per 1000 inhabitants, there are approx. 1.6 buses and 

coaches, 0.1 locomotives and rail cars, and 477 passenger cars (Statistical Handbook, 2012). 

The number is assumed to be different elsewhere (in the North America and Japan, more 

passenger cars than mass transit vehicles; in developing countries, the reverse). It may be 

assumed that, on average, at least 50% of the current EU mass transit vehicle fleet is airconditioned. Both climate and economic conditions would determine the likelihood of air 

conditioning in transit vehicles in other regions.

Today, most buses and coaches have the entire air-conditioning system mounted in the roof, 

except for the compressor, which is driven from the vehicle engine. The air conditioning units 

for rails cars can have a similar concept, especially if powered by diesel engines. But more 

often, in about 75% of cases, the air conditioning systems in rail cars are self-contained and 

electrically powered. The self-contained concept reduces both the charge and the leakage rate. 

The predominant refrigerant used in new buses and coaches is HFC-134a. While several years 

ago the refrigerant charge used to be in the excess of 10 kg per unit (Schwarz, 2007), the 

introduction of microchannel condensers as well as component downsizing reduced the 

current refrigerant charge below 5 kg in the new systems. The air conditioning units for rail 

cars use HFC-134a and R-407C in about equal share. A small fraction of rail cars use R410A. The refrigerant charge is about 10 kg. 

In China, heat pump systems are used for thousands of electric buses, which utilize the 

refrigerant blends R-407C and R-410A. As train air conditioning units usually are hermetic 

systems with hermetic or semi-hermetic compressors, their system design is based more on 

stationary air conditioning than on mobile air conditioning. Here R-410A is preferred.

Older systems in developing countries still utilize HCFC-22. According to the European 

statistics, the average age of a European bus or coach is 16.5 years. Although the rail car units

are designed to last for more than 30 years, technological progress and fleet upgrades 

determine their lifetime to about 20 years. Even before a rail car reaches its end-of-life, a 

major overhaul is often performed wherein the air conditioner is replaced.

Although limited by its volume, the mass transit vehicle industry follows closely the 

developments in passenger cars and other fields. A large German manufacturer has on-going 

fleet tests of R-744 systems in buses since 2003 (see for example Eberwein, 2011; Schirra, 

2011; and Sonnekalb, 2012). In the year 2012 a Polish bus manufacturer started selling 

battery-driven electric busses with reversible R-744 heat pump systems for heating and 

cooling (Solaris, 2012). The significant potentials of energy efficiency improvements of R744 bus air conditioning systems, due to measures like cylinder bank shut-off controls, 

ejectors, and two-speed planetary gearbox compressor drives, were investigated by Kossel

(2011) and Kaiser (2012).
2014 TOC Refrigeration, A/C and Heat Pumps Assessment Report 209

The Low-GWP Alternative Refrigerants Evaluation Program of AHRI investigated the use of 

drop-in alternative refrigerant blends in bus air conditioning (N-13a [R-450A] and AC5 [R444A] as alternatives for HFC-134a, and L-20 [by mass 45% HFC-32/20% HFC-152a/35% 

HFC-1234ze(E)] and D52Y [by mass 15% HFC-32/25% HFC-125/60% HFC-1234yf]as 

alternatives for R-407C). They found mostly comparable or lower energy efficiencies for bus 

air conditioning systems which used the alternative blends (Kopecka, 2013a and 2013b).

Environmental and fuel price concerns lead bus and coach manufacturers to pursue 

development of hybrid and battery driven electric vehicles. The concept makes traditional 

engine-driven compressors obsolete and favors self-contained hermetic systems, where the 

refrigerant charge and leakage rate are lower. The electric power is supplied either from the 

on-board sources, or engine-driven generators. These systems are not limited to electric 

vehicles, but can be applied also in traditional buses and coaches. Installations can be found in 

trolleybuses.

10.4 Options for existing Systems

10.4.1 Retrofit of CFC-12 systems

There are 12 blend refrigerants that are approved by the USEPA under the SNAP regulation 

for retrofit of CFC-12 systems (USEPA, 2013); however, many of these have seen only 

minimal use and some were never fully commercialized. Retrofit to HFC-134a was approved 

by the OEMs and was more commonly used if a retrofit was deemed appropriate. In a 2013 

MAC survey about 6% of all cars were still operating with CFC-12 and about 10% of all cars

had been retrofitted to HFC-134a (Atkinson, 2014). However, retrofitting of CFC-12 vehicles 

has declined significantly primarily due to the declining fleet of vehicles with CFC-12 MACs 

and in part due to the continued availability of reclaimed CFC-12. In the USA, the sale of 

CFC-12 is restricted only to certified technicians.

10.4.2 Hydrocarbon retrofits

Retrofit of HFC-134a and CFC-12 systems to hydrocarbons is still occurring in various 

regions, particularly in Australia and to some extent in North America even though vehicle 

OEMs and some regulatory bodies do not approve of this process due to inadequate safety 

mitigation

10.5 Concluding Remarks

Currently, more than one refrigerant are being used for car and light truck air conditioning: 

HFC-134a will remain largely adopted worldwide, while HFC-1234yf is currently 

implemented in some models and likely will be used in more models in the near future. 

Development of R-744 continues and will also likely be used. Possibly some new low GWP 

synthetic refrigerant or refrigerant blend (e.g. R-445A) will also be used. In existing systems 

(designed for CFC-12 or HFC-134a), even hydrocarbons (e.g. HC-290) are used in some 

regions (e.g. Australia). 

At the moment, it cannot be foreseen whether or not all these refrigerants will remain for a 

long period of time parallel in the market. If the bus and train sector will follow these trends is 

also unclear.
210 2014 TOC Refrigeration, A/C and Heat Pumps Assessment Report

10.6 References

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2014 TOC Refrigeration, A/C and Heat Pumps Assessment Report 211

EU Directive, 2007 EU Directive, 2007. DIRECTIVE 2007/37/EC of 21 June 2007 

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Motor Vehicle Air Conditioning Sector Under the Significant New 

Alternatives Policy (SNAP) Program. FR Doc. 2012–13657, Filed 6–

5–12, Final rule published June 6, 2012 (77 FR 33315).

USEPA, 2012b USEPA, NHTSA (National Highway Traffic Safety Administration) 

Joint Technical Support Document: Final Rulemaking for 2017-2025. 

Light-Duty Vehicle Greenhouse Gas Emission Standards and 

Corporate Average Fuel Economy Standards, EPA-420-R-12-901, 

Washington, DC, USA, August 2012. 

http://www.epa.gov/otaq/climate/documents/420r12901.pdf.

USEPA, 2013 USEPA 2013. Substitutes in Motor Vehicle Air Conditioners. 

http://www.epa.gov/ozone/snap/refrigerants/lists/mvacs.html, last 

updated June 24, 2013.

USEPA, 2014 USEPA 2014. Protection of Stratospheric Ozone: Change of Listing 

Status for Certain Substitutes Under the Significant New Alternatives 

Policy Program; Proposed Rule. http://www.gpo.gov/fdsys/pkg/FR2014-08-06/pdf/2014-18494.pdf, August 6, 2014 (79 FR 46126).

US President, 2013 US Executive Office of the President, 2013. The President’s Climate 

Action Plan., June 2013. 

http://www.whitehouse.gov/sites/default/files/image/president27sclim

ateactionplan.pdf

Vasile, 2005 Vasile, C., Muller, C., 2005. A new system for a 

magnetocaloricrefrigerator. Proceedings of First International 

Conference on Magnetic Refrigeration at Room Temperature, 

Montreux, Switzerland, September27-30, 2005, International Institute 

of Refrigeration, Paris, France, Conference Proceedings pp. 357-366

Vasta, 2012 Vasta S., Freni, A., Sapienza, A., Costa, F., Restuccia, G., 2012. 

Development and lab-test of a mobile adsorption air-conditioner. 

International Journal of Refrigeration, 35(3), 701–708. 

doi:10.1016/j.ijrefrig.2011.03.013.

Velders, 2009 Velders, G., J., M., Fehey, D.,W., Daniel, J., S., McFarland, M., 

Andersen, S., O, 2009. Proceedings of the National Academy of 

Sciences, 106, June 2009.VW press rel., 2013 Volkswagen press 

release, 2013. Volkswagen to use CO2 as future refrigerant for air 

conditioning systems. Wolfsburg, Germany, 

https://www.volkswagen-mediaservices.com/medias_publish/ms/content/en/pressemitteilungen/2013/

03/08/volkswagen_to_use.standard.gid-oeffentlichkeit.html, March 8, 

2013

Weissler, 2013 Weissler, P., 2013. A/C industry faces challenges from Daimler R1234yf issue, explores other options. SAE Vehicle Engineering 

Online, SAE, February 25, 2013.
216 2014 TOC Refrigeration, A/C and Heat Pumps Assessment Report

Yu, 2010 Yu, B., Liu, M., Egolf, P. W., Kitanovski, A., 2010. A review of 

magnetic refrigerator and heat pump prototypes built before the year 

2010. International Journal of Refrigeration, 33, 2010, pp.1029-1060

Zilio, 2009 Zilio, C., 2009. A small vehicle MAC system exploited w/ R-1234yf: 

bench results. 3rd MAC Workshop, Turin, Italy, 2009.

Zink, 2010 Zink, F., Vipperman, J. S., Schaefer, L. A., 2010. Environmental 

motivation to switch to thermoacoustic refrigeration. Applied 

Thermal Engineering, 30, 2010, pp. 119-126.

Zoontjens, 2005 Zoontjens, L., Howard, C., Zander, A., and Cazzolato, B., 2005. 

Feasibility Study of an Automotive Thermoacoustic Refrigerator. 

Proceedings of ACOUSTIC, November 9-11, 2005, Busselton, 

Western Australia. 
2014 TOC Refrigeration, A/C and Heat Pumps Assessment Report 217

Annex to Chapter 10

Annex B: Regulatory actions affecting vehicle air conditioning and refrigerants

This annex summarizes for several, but not all, different regions the legal situation for vehicle 

air conditioning systems.

Light-Duty Cars and Trucks

Brazil and Latin America: No specific regulations are in place in Brazil regarding mobile air 

conditioning. The current most important regulation (Resolução 267_00 CONAMA) states 

that the current gas refrigerant has to comply with the Montreal Protocol and to have low 

ozone depletion potential (ODP). 

The refrigerant currently used not only in Brazil but in whole Latin America is HFC-134a.

China: In China, the refrigerant in Mobile Air Conditioning (MAC) systems had been 

completely changed to HFC-134a since June 30, 2007. The consumption of HFC-134a in 

MAC in 2012 can be estimated to be about 20,000 tons. The Chinese government also 

realizes the importance of reducing the emission of greenhouse gas (GHG) since HFC-134a 

has a high GWP value. For the refrigerant in the vehicle, the work of Chinese government is 

mainly focused on refrigerant recovery and reducing the refrigerant charge amount since the 

substitute of HFC-134a is still not so clear.

Europe: European Union (EU) regulations, which control MAC system direct emissions, fall 

into two groups:

 controlling leaks 

 phasing out high-GWP fluorinated GHG's. 

Directive 2006/40/EC (EU Directive, 2006) applies to passenger cars and light commercial 

(categories M1 and N1) and covers both the emissions from air-conditioning systems in motor 

vehicles and the ban on use of refrigerants with a GWP greater than 150 in new type vehicles 

from January 1, 2011 and all new vehicles from January 1, 2017. 

Due to the shortage of the low-GWP refrigerant R-1234yf, which had apparently been chosen 

by most if not all OEMs, the European Commission decided not to enforce the Directive until 

the end of 2012. Although the MAC systems of new types of vehicles to be type approved had 

to be compatible with MAC directive 2006/40/ EC requirements, manufacturers were allowed 

to fill new type approved production vehicles with R-134a until 31 December 2012. The 

European Commission (EC) has confirmed several times that this situation of refrigerant 

shortage has been resolved to its satisfaction and therefore the MAC Directive has been in full 

effect since 1 January 2013.

The type-approval authorities of the Member States are responsible for the monitoring of the 

implementation of the measures above and for verifying the conformity of production after 31 

December 2012. 

EU Commission Regulation (EC) No 706/2007 (EU Regulation, 2007) includes a harmonized 

test for measuring leakages from mobile air conditioning systems. 

EU Commission Directive 2007/37/EC (EU Directive 2007) limits refrigerant emissions from 

mobile air conditioning, using refrigerants with GWP>150, to 40 g/y for single evaporator 
218 2014 TOC Refrigeration, A/C and Heat Pumps Assessment Report

systems and 60 g/y for dual evaporator systems beginning with new type vehicles in June 

2008 and all vehicles in June 2009.

The European Regulation (EC) No 443/2009 (EU Regulation 2009) sets emission 

performance standards for new passenger cars as part of the Community’s integrated 

approach to reduce CO2 emissions from light-duty vehicle. The Regulation limits CO2

emissions per kilometer to 130 gCO2/km from 2012 to 2019 and 95 gCO2/km from 2020 

onwards. The regulation includes off-cycle credit for innovative technologies reducing the 

fuel consumption, so-called eco-innovations (chapter 12 of the Regulation), but for mobile air 

conditioning systems that will be regulated by a specific procedure. The EU is currently 

cooperating with the stakeholders to develop this procedure.

It is possible that the Regulation will be extended to all the other motor vehicle categories 

once the application transient on passenger cars and light commercial vehicles is completed

India: India has comprehensive Ozone Depleting Substances (Regulation and Control) Rules, 

2000 which were put in place from July 19, 2000 under the Environment (Protection) Act 

1986. These rules set the deadlines for phasing-out the ozone depleting substances. There is a 

mandatory requirement of registration for ozone depleting substances producers, consumers, 

importers, reclamation centers, destruction facilities, etc. with a designated authority. The 

unique feature of these rules is banning of use of CFCs in manufacturing of new products and 

equipment including refrigeration and air-conditioning equipment for cars, busses and trains 

as early as January 1, 2003. This not only achieved the phase-out of CFCs earlier than the 

Montreal Protocol schedule but also reduced the inventory of CFC based equipment which 

resulted in the lowering of servicing requirements of CFCs. As a consequence of ozone 

depleting substances rules in India all light-duty vehicle Mobile Air Conditioning 

manufacturing was converted to HFC-134a from January 1, 2003 and all new manufacturing 

capacities were put up with HFC-134a and same is continuing. The busses and trains use 

either HFC-134a or HCFC-22. Most of the old MAC and train air-conditioning CFC based 

systems were retrofitted to HFC-134a. The Ozone Depleting Substances (Regulation and 

Control) Rules, 2000 have been amended from time to time to align with the Montreal 

Protocol phase-out schedule and internal policies of the country. These rules have been 

amended in 2014 to align with accelerated phase-out of HCFCs and amendment has been 

notified as Ozone Depleting Substances (Regulation and Control) Amendment Rules, 2014.

Japan: In August 2009, Japanese government allowed the import of HFC-1234yf into Japan 

without the limitation of usage amount, aspects and any special monitoring. This decision was 

made after HFC-1234yf was examined by Japan’s Ministry of Health, Labor, and Welfare, 

Japan's Ministry of Economics Trade and Japanese Ministry of the Environment based on 

“Toxic Chemicals Control Law”.

USA: Motor Vehicle Air Conditioning refrigerants must be submitted to the U.S. 

Environmental Protection Agency (USEPA) and found acceptable under its Significant New 

Alternatives Policy (SNAP) Program. So far (2014), approximately 17 different refrigerants, 

and 3 alternative technologies, have been found acceptable under the SNAP Program (USEPA 

2013). The majority of these refrigerants were aimed primarily at the retrofit of CFC-12 cars 

and found very little, if any, use. HFC-134a was until recently the only refrigerant accepted 

by the OEMs and quickly became the only refrigerant used in new equipment, with a few 

model year 1992 vehicle types using HFC-134a and all types by model year 1995 (MACS, 

2003).

Three of the refrigerants found acceptable have GWPs less than 150: HFC-152a, HFC-1234yf 

and R-744 (CO2). All are subject to certain use conditions (for details see the particular 

sections covering these refrigerants). The use conditions that apply to all substitute mobile AC 
2014 TOC Refrigeration, A/C and Heat Pumps Assessment Report 219

refrigerants are required by the USEPA to reduce the flammability and/or toxicity risks from 

these refrigerants as well as to avoid mixing of different refrigerants.

Joint regulations from the USEPA and the National Highway Traffic Safety Administration 

set requirements for corporate average fuel economy (i.e., average miles per gallon or liters 

per 100 kilometers) and tailpipe emissions (i.e., grams CO2-equivalent per mile or kilometer). 

Although these regulations do not require specific choice of refrigerants, utilizing low-leak 

designs and/or low-GWP refrigerants offer additional pathways to comply partially with the 

requirements. In addition, credits were offered for (1) improvements in air conditioning 

systems that reduce tailpipe CO2 through efficiency improvements, and (2) for reduced 

refrigerant leakage through better components and/or use of alternative refrigerants with 

lower global warming potential. These regulations were enacted first for model years 2012 

through 2016. That rule allowed OEMs to achieve credits in advance of the regulations for 

design changes in model years 2009 through 2011, a stipulation that helped spur more leaktight and fuel-efficient systems. The second set of regulations applies to model years 2017 

through 2025. USEPA expects that the credits offered in this program will incentivize the 

uptake of low-GWP refrigerants; USEPA estimated that uptake of HFC-1234yf would reach 

20% in model year 2017 vehicles, rising linearly to 100% by model year 2021 vehicles 

(USEPA and NHTSA, 2012b). One U.S. OEM committed to convert some models to HFC1234yf refrigerant by MY2013 (General Motors, 2010); one of these models has been sold in 

the U.S. and elsewhere since 2012. A Japanese OEM also offered one MY2013 model with 

HFC-1234yf, and other models are expected with MY2014 designs (Automotive News, 

2013). Atkinson, 2014 provides a list of 9 car types which use HFC-1234yf in the US market.

In June, 2013, U.S. President Obama announced a Climate Change Action Plan. Amongst 

other initiatives, the President committed the USEPA to “use its authority through the 

Significant New Alternatives Policy Program to encourage private sector investment in lowemissions technology by identifying and approving climate-friendly chemicals while 

prohibiting certain uses of the most harmful chemical alternatives” (US President, 2013). One 

prohibition proposed by USEPA is to prohibit the use of HFC-134a in light-duty motor 

vehicles beginning with MY 2021 (USEPA, 2014). This proposal has not been finalized as of 

December 2014. 

USEPA has a new drive schedule that is required to be run from 2016. Initially the credits are 

determined strictly by a menu driven formula, but from 2017, the new AC17 test schedule 

must be run and the resulting CO2 emissions must support the credit before it can be applied. 

This drive schedule is a dynamic one with solar load applied in a test chamber. (Nelson, 2012 

and Brakora, 2013).

Buses and Trains

There are no particular legal restrictions on Buses and Trains refrigerant, apart from those 

discussed above. However, the bus industry follows closely the developments in passenger 

cars and the trains industry has to date followed closely the development of hermetic and 

semi-hermetic systems similar to the stationary air-conditioning market. Given possible safety 

implications of the low-GWP alternatives, however, it may be that bus and train MAC 

systems will eventually use a different set of refrigerants than those used in light-duty 

vehicles.
220 2014 TOC Refrigeration, A/C and Heat Pumps Assessment Report

Annex C: Not-In-Kind Alternatives

The refrigeration technologies described in this annex are all far away from a serialproduction status. However, OEMs and suppliers do work on the development of these 

systems because they have a certain potential to become interesting alternative options for a 

time horizon which goes beyond 2020. For some even that seems unlikely considering the 

long history of effort for them.

Air cycle (Brayton cycle): These systems have the advantage of using air as refrigerant which 

is environmentally very benign. However, they have comparatively very low energy 

efficiencies and cooling capacities (see Liebherr, 2010).

Thermoelectric heating and cooling: Thermoelectricity (TE) is one of the simplest 

technologies applicable to energy conversion based on the properties of couples of materials 

that can use electric energy to operate as heat pumps providing active cooling or heating. 

Small pieces of thermoelectric material (TE elements) are connected to form a Peltier couple: 

one element is of p-type, the other one of n-type; they are electrically connected in series (by 

means of a copper plate) and thermally in parallel. A set of such couples forms a TE-module. 

Cost and efficiency (maybe also capacity) are currently the main issues limiting the 

application of thermoelectric heat pumps only to specific uses like, for example, the 

automotive seats air conditioning.

Magneto caloric heating and cooling: Since 1975, many experimental prototypes of 

magnetic refrigerators at room temperature have been developed with different configurations 

and operating conditions (see for example Vasile, 2005, Yu, 2010, and Sciullo, 2011). 

Recently relevant progresses have been achieved both for applications in the automotive 

domain as well as for stationary application (e.g. vending machines and domestic 

refrigerator).

The magneto caloric effect results in a temperature increase within a magneto caloric material 

when a magnetic field is applied owing to a reversible energy transfer from the magnetic field 

to the material; the material reaches the initial lower temperature once the magnetic field is 

removed. 

Thermo acoustic heating and cooling: Although the phenomenon that temperature gradients 

along a tube can provoke (pressure) oscillations in gases has been known for more than 150 

years, it was the work of Rott (1980) which brought about the breakthrough for further 

investigations.

The corresponding thermodynamic cycles are the Brayton (standing wave machine) and 

Stirling (travelling wave machine) cycle. As working fluid often helium is applied (Swift 

2002). 

The environmentally benign working fluid as well the possibility to use the waste heat from 

the engine could lead to future applications of thermo acoustics in MAC systems (see for 

example Zink, 2010, and Zoontjens, 2005). Although recent investigations show the 

feasibility of these refrigerators (Bassem, 2011), significant further research and development 

of this technique are necessary.

Sorption heating and cooling: Sorption cooling based on the re-use of waste heat (e.g. 

exhaust gas or cooling jacket) has been evaluated within several projects in the last decade 

(see for example Tamainot-Telto, 2009 and Vasta, 2012). 
2014 TOC Refrigeration, A/C and Heat Pumps Assessment Report 221

The heavy duty truck application has a higher potential due to higher waste heat amount and 

less severe constraint in terms of weight and size.

In addition to that, sorption systems offer the opportunity of long-term thermal storage.
222 2014 TOC Refrigeration, A/C and Heat Pumps Assessment Report
2014 TOC Refrigeration, A/C and Heat Pumps Assessment Report 223

Chapter 11

_________________________________________________________

Sustainable Refrigeration

Chapter Lead Authors

Holger König

Paulo Vodianitskaia

Co-Authors

Radhey S. Agarwal

Bassam Elassaad

Dave Godwin

Contributors

Martien Janssen

Alexander C. Pachai

Andy Pearson

Richard DeVos
224 2014 TOC Refrigeration, A/C and Heat Pumps Assessment Report
2014 TOC Refrigeration, A/C and Heat Pumps Assessment Report 225

11 Sustainable refrigeration

11.1 Introduction

Sustainability of refrigeration and air conditioning systems is a major factor affecting the

choice of alternative refrigerants. In this chapter both equipment and systems from 

concept to end-of-life are described. It includes sections on the direct and indirect impact 

of refrigerants on emissions and the tools used to assess such impact; equipment lifetime 

considerations and the regulations covering equipment design, installation, and operation; 

as well as energy management considerations for systems, buildings, and processes.

By discussing all aspects of refrigeration systems affecting sustainability, the chapter 

tackles aspects that affect the environment globally and hence have become crucial in the 

search of alternative refrigerants. Care was taken to include examples from many 

countries and regions since sustainability refers to the biosphere and human society as a 

whole.

11.2 Sustainability applied to refrigeration

Refrigeration impacts the ability of global sustainability in many ways. Economic, 

environmental and social impacts - some positive, other negative – are produced throughout 

the life cycle of the refrigeration equipment, from the extraction of its raw materials until end 

of life. 

While keeping focus on possible environmental impacts of refrigeration treated throughout 

the report - namely the depletion of the stratospheric ozone layer and global warming - a 

wider range of relevant environmental, as well as social considerations, are briefly described 

in this section, for consideration by decision makers. 

Sustainable manufacture of systems is gradually becoming part of the decision making 

process for manufacturers who used to base their design on cost grounds rather than for 

environmental compliance leading to the acceptance of lower efficiency systems in some 

cases. Designers today are faced with dilemma of designing smaller units for sustainability 

reasons vs. larger ones for efficiency purposes. For example, a 15 to 20 K design temperature 

difference used for air-cooled condensers results in, smaller heat exchangers which use less 

material; however, it is possible to get improved efficiency by using larger heat exchangers 

which use more raw material and are more expensive. There is no clear guidance on 

optimizing these design decisions, even though there are today some best practices like the 

use of recycled aluminium in heat exchangers, greater use of plastics and other synthetic 

materials from renewable sources.

11.2.1 Sustainability principles

The most widely known definition for sustainable development is the one presented by the 

Brundtland report: "to meet the needs of the present without compromising the ability of 

future generations to meet their own needs" (Brundtland Commission, 1987). The same 

overall goal can be expressed in more specific terms: four necessary and sufficient conditions 

for a sustainable society were proposed (Holmberg, 1996), and submitted to extensive peer 

review. These conditions are stated as follows:

"In a sustainable society, nature is not subject to systematically increasing of:

1. Concentrations of substances extracted from the Earth's crust

2. Concentrations of substances produced by society

3. Degradation by physical means, and, in that society...
226 2014 TOC Refrigeration, A/C and Heat Pumps Assessment Report

4. People are not subject to conditions that systematically undermine their capacity to 

meet their needs." (Ny, 2006)

These general principles are affected by environmental and social aspects.

11.2.2 Environmental aspects

Some ecological aspects related to refrigeration derived from the principles i, ii, and iii, 

disclosed in section 11.2.1, are:

i. Extraction of resources: energy from fossil fuels, mining of materials such as copper, 

(used in tubing, heat exchangers, and winding of electric motors), zinc, fluorite 

(European Commission, 2011) and other scarce materials (here understood as 

proportional to the rate a substance is being extracted, relative to its natural 

concentration in the environment), aluminum, iron, rare earth products, use of fossil 

substances as raw materials for refrigerants (virtually all refrigerants except water and 

ammonia), use of fossil fuels and mineral oil in compressors and other moving parts. 

Despite of recycling efforts, the combined production levels of copper, zinc, and 

fluorite reached 30.4 Mt in 2006, representing an increase of 20 % over the 

production levels in 1999 (Lottermoser, 2010).

ii. Emission of man-made substances: emissions of refrigerants, solvents, paints & other 

surface treatment materials, and the incineration of materials are a major part the 

direct emissions of greenhouse gases. Indirect emissions related to the lifecycle of 

refrigeration systems form the other part.

iii. Degradation of fertile ecosystems: Examples are food conservation, metals and nonmetals mining, water usage, oil extraction, landfill of waste materials.

11.2.3 Social aspects

Refrigeration and air conditioning relate mainly to the social need of physical and 

psychological wellness, from health and safety conditions prevailing along the value chain, 

including consumer safety, to the availability of healthy food and reduction of food waste by 

appropriate refrigeration, thermal comfort and avoidance of thermal stress provided by air 

conditioning.

However other social needs should also be considered when coupling the refrigeration 

business to the sustainability imperative, such as:

 Learning through: awareness, education, proper training of employees and 

technicians; and

 Equity and fairness, supported by: ethical conduction of business, fair trade, fair 

marketing, low cost equipment coupled with high energy efficiency to the extent 

commercially feasible.

11.2.4 Assessment tools

The following assessment tools treat of particular aspects related to sustainability:

Total Equivalent Warming impact (TEWI) is a measure of the global warming impact of 

equipment based on the total related emissions of greenhouse gases during the operation of 

the equipment and the disposal of the operating fluids at the end-of-life. TEWI takes into 

account both direct fugitive emissions, and indirect emissions produced through the energy 

consumed in operating the equipment. TEWI is measured in units of mass in kg of carbon 

dioxide equivalent (CO2-eq.). The TEWI equation can be found in (EN, 2008) and (Fischer, 

1991). It can be evaluated in conjunction with seasonal profiles of temperatures and capacity.
2014 TOC Refrigeration, A/C and Heat Pumps Assessment Report 227

Life Cycle Climate Performance (LCCP) is a concept that incorporates the TEWI 

considerations and additionally includes direct and indirect greenhouse emissions from the 

manufacture of the active substances. Active substances are components and the working 

fluids such as the refrigerants (IPCC, 2005). Various studies of LCCP have included for 

instance the fugitive emissions of a refrigerant from production until installation in 

equipment, the embodied energy or GHG emissions associated with producing the refrigerant, 

and the GHG emissions associated with extracting materials and producing components of an 

air-conditioning or refrigeration system.

Both LCCP and TEWI include a measure of the efficiency of the product and give a better 

indication than a simple GWP reference of what the greenhouse gas emissions associated with 

the use of air-conditioning and refrigeration equipment will be. LCCP and TEWI calculations 

provide more information on the sustainability of air-conditioning and refrigeration 

equipment than GWP or energy efficiency alone; therefore, these methodologies should be 

used when comparing products and systems.

Social and Socio-Economic Life Cycle Assessment (S-LCA) is a social impact (and 

potential impact) assessment technique that aims to assess the social and socio-economic 

aspects of products and their potential positive and negative impacts along their life cycle 

encompassing extraction and processing of raw materials; manufacturing; distribution; use; 

re-use; maintenance; recycling; and final disposal. S-LCA complements the more usual 

environmental Life Cycle Assessment (E-LCA) with social and socio-economic aspects. It 

can either be applied on its own or in combination with E-LCA. S-LCA assesses social and 

socio-economic impacts found along the life cycle (supply chain, including the use phase and 

disposal) with generic and site specific data. It differs from other social impact assessment 

techniques by its objects: products and services, and its scope: the entire life cycle. Social and 

socio- economic aspects assessed in S-LCA are those that may directly affect stakeholders 

positively or negatively during the life cycle of a product. They may be linked to the 

behaviour of enterprises, to socio-economic processes, or to impacts on social capital. 

Depending on the scope of the study, indirect impacts on stakeholders may also be 

considered. S-LCA provides information on social and socio-economic aspects for decision 

making, instigating dialogue on the social and socio-economic aspects of production and 

consumption, in the prospect to improve performance of organizations and ultimately the 

well-being of stakeholders (UNEP, 2009).

Sustainability Life Cycle Assessment is a qualitative technique to determine the degree of 

conformity of an actual product or system to sustainable conditions, through the identification 

of gaps in knowledge or potential impact, which would need focused quantitative assessments 

(NY, 2006).

11.2.5 Opportunities for improvement

Some relevant opportunities for the industry aiming to achieve sustainability improvements 

along the lifecycle of a refrigeration system are:

 Close progressively the production-consumption loop of materials manufactured from 

minerals, especially scarce materials such as copper, zinc and fluorine; 

 Reduce the emissions of GHG while reducing the dependence on oil. This can be 

achieved by focusing on energy efficiency, and by increasing the share of fossil-free 

energy during life cycle;

 Reduce progressively the use of virgin raw materials, minimize emissions, upcycle 

waste, reuse water, and check responsible management of substances along the value 

chain;

 Manage and progressively phase out persistent, bio accumulative and other hazardous 

substances to the environment and health from the materials inventory;
228 2014 TOC Refrigeration, A/C and Heat Pumps Assessment Report

 Establish codes of ethical conduct for suppliers along value chain and use them as 

effective management tools;

 Reduce the use of packaging materials;

 Ensure refrigerant conservation.

Such improvements may be facilitated with:

 Development of standards that measure and report the relative sustainability of 

products and processes

 Awareness raising through the value chain

 Education on sustainability and its implications

 Regulations and political actions defining technical conditions

 Integration of social and environmental externalities into corporate governance and 

reporting

 Financial incentives to take account of environmental damage 

11.3 Direct impact of refrigerants

Most of the halocarbon refrigerants including CFCs, HCFCs and HFCs are either ozone 

depleting or global warming or both. Therefore, emissions of these refrigerants have direct 

impact on the environment. Refrigerants are not only used in new equipment and appliances 

but there is a recurring consumption in servicing during the useful working life of the 

equipment. Consumption of refrigerants for servicing is more than what is being used in the 

manufacturing of new equipment. In the worst cases, the entire refrigerant charged and used 

for servicing over the useful working life of refrigeration and air-conditioning equipment is 

gradually emitted to the environment. Efforts are being made to reduce the impact of these 

refrigerants on the environment by refrigerant management and conservation techniques. 

11.3.1 Design criteria for charge minimization and leak tightness

Charge minimization

Charge minimization is one important factor for conservation of refrigerant. Minimization of 

the refrigerant charge would not only reduce the global consumption of refrigerants but it 

would also reduce their impact on climate by reducing the quantity of possible emissions that 

could be emitted during catastrophic leak events, during the working life of equipment and 

end of life of equipment. Historically, little attention has been given to minimize charge 

quantities. The charge amount is only specified for small equipment especially for capillary 

fitted units where the performance of the unit is highly affected by the charge quantity. Other 

systems are charged on the site and charge quantity is rarely pre-calculated or specified. 

Recognizing the importance of the charge minimization, industry is paying attention to this 

aspect by employing designs for lower storage of refrigerant. In case of unitary airconditioning systems with hermetic compressors, the majority of refrigerant is banked in the 

compressor and heat exchangers, especially in the condenser. Systems are designed with mini 

channel heat exchangers to reduce the internal volume of the condenser, and compressors are 

designed for reduced oil. Significant efforts are also being made to design and develop 

supermarket refrigeration equipment by using secondary loop and cascade systems that use a 

much smaller refrigerant charge than traditional refrigeration system. It should be noted that 

there may be negative effects of charge minimization: some systems may be sensitive to a 

charge deficit leading to an increase in energy consumption and even a system failure. 

Another typical trade-off situation is the choice between direct and indirect systems. The 

latter systems tend to minimize the direct emissions of fluids, but might increase the indirect 

emissions due to the increased losses. There is a balance to ensure good efficiency despite 

minor leakage and reduced direct emissions.
2014 TOC Refrigeration, A/C and Heat Pumps Assessment Report 229

Overcharging of equipment is common, especially in systems with receivers, as the amount of 

refrigerant contained in refrigerant receivers is not always known. Refrigerant receivers are 

equipment components that contain excess refrigerant that migrates through the system as a 

result of changes in ambient conditions. Therefore, refrigerant receivers should be designed or 

selected in a proper way. On the other hand design criteria’s for varying ambient conditions 

and operation parameters are often not commonly known. For such equipment, field charging 

is often continued until the charge is considered satisfactory. Without the check of weighing 

the charge, the circuit could be overfilled with two harmful consequences: (1) a potential 

release of refrigerant, and (2) the possibility of transferring the entire charge into the receiver. 

The receiver-filling ratio, therefore, has to be limited during nominal operation, and an 

inspection tool (indicator, level, etc.) must be provided.

More detailed information has been published recently by IIR-IIF (IIR, 2014)

There is a trend in the market to move towards what is referred to a critically charged. In these 

systems it is very important not to charge more on the system than it is designed for. This 

helps not overcharging the system but it also requires more skills from the persons working 

on the system.

Another trend from legislation side is the move from look more on the leak potentials rather 

than look at the charge size. The potential leak can come from any connections, flanges, 

valves, compressor and motor assemblies etc. The likelihood of a pipe or a vessel should 

become leaky is minimal in a well-designed system. Leaks, however, tend to come when 

valves or flanges have been serviced. The authorities like to look at potential leak and the 

advantage is that you can deal with it already at the design phase. You can count the flanges

and you can calculated all sealings and connections and in this way determine what leak rate

you can have and where the leaks might be.

Reduction of emissions through leak tightness

Leak detection of the equipment in production or assembly is a basic element, both in 

constructing and servicing of cooling equipment, as it makes it possible to measure and 

improve conservation of refrigerant. Leak detection must take place at the end of construction 

by the manufacturers, at the end of assembly in the field by contractors, and during regularly 

scheduled maintenance of equipment by service technicians. 

Beside other code of good practice and refrigeration standards covering requirements for leak 

testing and tightness, there are three general types of leak detection methods: 

1. Global methods indicate that a leak exists somewhere, but they do not locate the 

leaks. They are useful at the end of construction and every time the system is opened 

up for repair or retrofit;

2. Local methods pinpoint the location of the leak and are the usual methods used during 

servicing; 

3. Automated performance monitoring systems indicate that a leak exists by sensing 

changes in equipment performance and alerting operators. 

Industry both in developed and developing countries, in recent years, have improved design 

for leak tightness in the air-conditioning and refrigeration equipment manufactured after the 

Montreal Protocol. In addition existing equipment/appliances have often been modified with 

new devices, such as high-efficiency purge devices for low-pressure chillers that have 

significantly lowered refrigerant emissions. Design changes have been made with regard to 

leak tightness in response to growing environmental, regulatory, and economic concerns 

associated with refrigerant emissions.
230 2014 TOC Refrigeration, A/C and Heat Pumps Assessment Report

11.3.2 Reduction of emissions through installation, servicing and maintenance

The installation of refrigeration equipment plays a very important role in terms of equipment 

life, energy consumption, trouble free operation, and refrigerant conservation. Use of proper 

installation techniques should be followed to ensure joints that can withstand vibration, 

temperature and thermal cycling stresses. Proper cleaning of joints and evacuation to remove 

air and non-condensable gases will minimize the future service requirements. For nonhermetic equipment, the installer should ensure the proper charge is provided. The installer 

should also seize the opportunity to find manufacturing defects before the system begins 

operation. 

The Montreal Protocol has globally sensitized the servicing community as well as the endusers to use good servicing practices and reduce the emissions of refrigerants through 

awareness programmes. Servicing practices have improved especially in some of the sectors 

mainly because of training of servicing personnel engaged in these sectors. Unsustainable 

servicing practices—such as topping-up refrigerant without repairing leaks, or leak testing 

with high-ODP or high-GWP refrigerants—are avoidable. Instead, refrigerant recovery, 

recycling, reclamation and destruction, discussed below, should be practiced. 

Technicians must study the service records to determine the history of leakage or malfunction 

and energy consumption trends. Technicians should also measure performance parameters to 

determine the operating condition of the cooling system. Fixing leaks and defects early will 

help avoid catastrophic failures that may contaminate or release the entire refrigerant charge. 

Technicians should determine the best location from which to recover the refrigerant and 

assure that proper recovery equipment and recovery cylinders are available. Proper 

maintenance documents like logbooks enable the user to monitor the frequency of repairs as 

well as the amount of refrigerant recovered, added and emitted.

In addition, periodical cleaning of refrigeration equipment not only enhances the proper 

operation of the system but also reduces the frequency of system failure. 

Training of technicians is essential for the proper handling and conservation of refrigerants, 

the optimized operation of the equipment, the control or reduction of energy consumption, 

and avoids loss of stocked food when refrigerant and lubricant come in contact with it due to 

improper handling. Such training should include information on the environmental and safety 

hazards of refrigerants, the proper techniques for recovery, recycling, reclamation and leak 

detection, and local legislation regarding refrigerant handling. The European standard EN 

13313 describes the competence developments necessary for all levels, from system design to 

commissioning and servicing.

11.3.3 Refrigerant recovery, recycling, reclamation and destruction 

This section provides an overview of refrigerant conservation. Additional details can be found 

in previous RTOC report (UNEP, 2011). 

In the last few decades, there has been an increasing emphasis on conservation of refrigerants 

and reduction of emissions that has led the industry to develop a specific terminology which 

is used in this report (ISO, 1999):

 Recover: to remove refrigerant in any condition from a system and store it in an external 

container.

 Recycle: to clean the extracted refrigerant using oil separation and single or multiple 

passes through filter-driers which reduce moisture, acidity, and particulate matter. 

Recycling normally takes place at the field job site.
2014 TOC Refrigeration, A/C and Heat Pumps Assessment Report 231

 Reclaim: to reprocess used refrigerant to virgin product specifications. Reclamation 

removes contaminants such as water, HCl and HF reaction products, other acids, high 

boiling residue, particulates/solids, non-condensable gases, and impurities including other 

refrigerants. Chemical analysis of the refrigerant is required to determine that appropriate 

specifications are met. The identification of contaminants and required chemical analysis 

are specified by reference to national or international standards for new product 

specifications. Reclamation typically occurs at a reprocessing or manufacturing facility.

 Destroy: to transform used refrigerant into other chemicals in an environmentally 

responsible manner.

Refrigerant recovery 

Recovery of refrigerant, especially CFC-12 and H-CFC-22, has become an integral part of 

servicing practices in most of the countries, especially for systems having relatively large 

charge quantities. The incentives for refrigerant recovery are the cost of refrigerants and 

environmental protection. The regulatory framework is also a driving force for recovery of 

refrigerant especially in non-Article 5 countries. In developing countries, the continuing 

replacement of old CFC-based refrigerators in favour of new ones, many of them containing 

HFC as refrigerant, and the rapidly growing market of HFC-based room air conditioners, 

increases the importance of regulations aiming to avoid venting of refrigerants during 

equipment repair.

Refrigerant recovery equipment reduces emissions by providing a means of temporary storage 

of refrigerants that have been removed from systems undergoing service or disposal. Such 

equipment is used to temporarily store recovered refrigerant until the system is ready to be 

recharged. The recovered refrigerant may also be used in other equipment or sent for 

destruction. Refrigerant recovery equipment may have the added capability of recycling of 

refrigerants.

Refrigerant recovery equipment has been developed and is available with a wide range of 

features and prices. Some equipment with protected potential sources of ignition also exists

for recovery of flammable refrigerant. Although liquid recovery is the most efficient, vapour 

recovery methods may be used alone to remove the entire refrigerant charge; however, in 

order to reach the vacuum levels that are required in some countries for larger systems, 

vapour recovery is used after liquid recovery (Clodic, 1994). Testing standards have been 

developed to measure equipment performance for automotive (SAE, 1990) and nonautomotive (ISO, 1999) applications. Such standards, as a part of common service procedures, 

should be adopted by regulating authorities. 

Refrigerant recycling 

Refrigerant recycling conserves refrigerant during the service, maintenance, repair, or 

disposal of refrigeration and air-conditioning equipment. Refrigerant recovery and recycling 

equipment should be made available to service technicians in every sector. The logistic 

process should be easy to understand and cover all players from point of sales to the customer, 

and back to point of return. It may be noted that due to incompatibility issues and the array of 

refrigerants used that refrigerant recovery/recycling equipment intended for use with one 

refrigerant and/or type of air-conditioning system may not be adequate to service other 

refrigerants or sectors. 

Recycling reduces oil, acid, particulate, moisture, and non-condensable (air) contaminants 

from used refrigerants. The recycling performances can be measured on standardized 

contaminated refrigerant samples according to test methods (AHRI, 2012). Since the quality 

of recycled refrigerant cannot be proven by analysis, restrictions are imposed on the use of 

recycled refrigerants.
232 2014 TOC Refrigeration, A/C and Heat Pumps Assessment Report

Currently, the automotive air-conditioning industry typically reuses recycled refrigerant 

without reclamation in a different owner’s system. Acceptance in other sectors depends on 

national regulation, recommendation of the system manufacturers, existence of reclamation 

services, variety and type of systems, and the preference of the service contractor and owner. 

Reuse of recovered refrigerant requires strict adherence to good practices including 

identifying the refrigerant type. Mixed refrigerants are often costly to separate which may 

result in the sale of cross-contaminated refrigerants. For most refrigerants there is a lack of 

inexpensive field instruments available to measure the contaminant levels of recycled 

refrigerant after processing; hence in countries where access to qualified laboratories is 

limited and shipping costs are prohibitive, caution is required to prevent unintentional mixing 

of refrigerants. 

Refrigerant reclamation 

Recovery and reclamation of used refrigerants can, to a certain extent in some countries, meet 

the servicing requirements as well as conserve refrigerant and reduce emissions to the 

environment. Reclamation is the processing of used recovered refrigerant back to almost 

virgin specifications. Reclamation also extends the lifespan of the refrigerant as well as the 

equipment and decreases the dependency on virgin refrigerant by placing it back into service. 

Reclaimed refrigerants are tested and verified to meet specifications that are similar to newly 

produced refrigerants product specifications, such as those provided in (AHRI, 2012). The 

reclaimed refrigerants can be repacked and sold to new users.

Reclamation is essentially a market-driven industry. If there is no demand for a particular 

refrigerant, the costs to send recovered refrigerant to reclamation facilities will be a 

disincentive to reclaim. Efforts must be initiated early with refrigerant supply companies to 

take back refrigerant for reclamation. Many service establishments will not be able to afford 

storage for recovered refrigerants yet the cost of sending small quantities of recovered 

refrigerant to reclamation facilities is also a disincentive to reclamation efforts. Such 

disincentives promote venting or reuse of stockpiled refrigerant. Care should be taken by 

policy makers to eliminate parallel (and potentially illegal) routes to market. Such avoidance 

of improperly reclaimed used refrigerants requires strict auditing of the refrigerant distribution 

chain. Enforcement is required to insure that these refrigerants do not contain incompatible 

components such as R-40, methylchloride. Documented refrigerant control through its life 

cycle can avoid illegal trade of counterfeit refrigerants.

Small capacity portable refrigerant reclamation equipment have also been developed and are 

available with varying features. Such equipment is capable of reclaiming about 80 kg of 

refrigerant per hour. 

The use of reclaimed refrigerant has the advantage of avoiding possible system breakdowns, 

as a direct result of contaminated refrigerant, which might lead to refrigerant emissions. As 

reclaimed refrigerant meets new product specifications, it may have the support of equipment 

manufacturers who maintain warranties on their equipment. Another advantage is that the 

quantification of refrigerant recovered are easily obtained. However, reclamation does require 

a costly infrastructure, which may only prove viable when the potential for financial return of 

recovered refrigerant is sufficient to overcome the initial investment of the enterprise 

performing reclamation. 

Refrigerant destruction

There is worldwide recognition of the need for destruction of unwanted ODS refrigerants 

because of ozone and climate benefits from the avoided emissions of ODS. The destruction of 

ODS banks has the potential to earn carbon credits through global carbon markets, broadly 

divided into the compliance market and the voluntary market. The compliance market for 

GHGs is based on a legal requirement where, at an international (e.g., Clean Development 
2014 TOC Refrigeration, A/C and Heat Pumps Assessment Report 233

Mechanism) or national and regional level (e.g., European Union Emission Trading Scheme), 

those participants must demonstrate that they hold the carbon credit equivalents to the amount 

of GHGs that they have emitted in order to meet their GHG reduction obligations. In some of 

these markets, the carbon credits resulting from ODS destruction are not considered for 

compliance generally because ODS are not included in the Kyoto Protocol and are being 

phased out. 

The voluntary markets have also been in operation where individual organisations voluntarily 

commit to actions and projects to offset their GHG emissions. The voluntary carbon market 

also established standards for ODS destruction as carbon offset projects. Standards such as 

The Climate Action Reserve (CAR) and the Verified Carbon Standard (VCS) provide carbon 

credits for ODS destruction (CAR, 2013; VCS, 2014). Since 2010, there has been a relatively 

low demand for carbon credits in the voluntary markets.

Normal conditions where recovery, recycling, and reclamation under a good logistical system 

are prevalent should lead to fairly low requests for destruction in the refrigeration industry. 

This is especially the case where the demand for ODS remains high. A need for destruction 

facilities may be created in instances where regulations forbid the service use or export of 

ODS. The general method of destruction is based on incineration of refrigerants and on 

scrubbing combustion products that contain particularly aggressive acids, especially 

hydrofluoric acid. Mainly, their resistance to hydrofluoric acid limits the number of usable 

incinerators. CFCs and more particularly halons, burn very poorly. In order to be incinerated, 

they must be mixed with fuels in specific proportions.

The Parties to the Montreal Protocol, recognizing the benefits of destruction of unwanted 

ODS in an environment friendly manner, approved processes, through decision IV/11 as early 

as in 1992. Since then, the list of approved destruction processes has been updated a number 

of times. Presently, there are 16 destruction processes approved.

There are a number of destruction facilities based on the approved destruction processes by 

the Montreal Protocol, especially in non-Article 5 Parties and in some Article 5 Parties. 

Currently, there are limited facilities to destroy unwanted ODS refrigerants in most 

developing countries.

11.4 Indirect impacts due to energy use

By its very nature, the use of energy to accomplish refrigeration draws a valuable resource as 

the power generation systems consume fuel and, in many cases emit CO2 and other pollutants. 

The refrigerant selection impacts the energy consumption of the refrigeration system due to its 

thermodynamic nature in many ways. The indirect emissions operating the refrigeration 

systems during its lifetime contribute in many cases far more compared to the direct impact. 

The more important is the participation of renewable sources to the power grid, the less 

prevalent is the indirect impacts from energy use.

Designing and efficiently maintaining HVAC&R systems contributes by a large factor to the 

reduction of GHG related to the air conditioning and refrigeration industry through cutting 

“indirect emissions”. Consequently, using measurement for the global warming effect of 

refrigerants that take into consideration indirect emissions is a more representative way for 

selecting environment friendly refrigerants than a simple comparison by direct emissions 

alone. Also the introduction of minimum energy performance standards (MEPS) has helped 

drive energy efficiency to higher levels than if those standards had not been applied, and that 

the cost of not complying with those standards will have an adverse effect on cutting GHG 

emissions.
234 2014 TOC Refrigeration, A/C and Heat Pumps Assessment Report

Energy efficiency is the measure of the amount of energy input to a machine to deliver a 

required output. It is measured in units of energy output or work done by the machine vs. the 

power input to the machine. However, energy efficiency for the HVAC industry can be 

measured at different levels: individual components, cooling and heating systems, or a 

building as a whole. The efficiency at each level contributes to that of the other level up and 

depends on the proper design and application of components at the particular level.

Energy efficiency parameters are measured at certain conditions at which the machine is 

working and will have different readings if those conditions change. For most air-source air 

conditioning machines, this includes the ambient air conditions and the room temperature that 

the machine is expected to deliver. An air conditioner operating in a high ambient temperature 

condition will generally be less efficient than one working in an outside temperature of 35°C 

or below.

11.4.1 Energy efficiency improvements

The discussion around energy efficiency is closely related to the one on alternative 

refrigerants. The guidelines from paragraph 15 of Decision XIX/6 require countries benefiting 

from investment projects, to implement conversion technologies that minimise the effects on 

climate. By converting to more energy efficient products, countries will minimise the 

consumption of electric power leading to a reduction in the carbon emissions from power 

plants. Emissions of CO2 in grams per kWh of electric power generated vary by fuel type or 

amount of renewable energy as well as plant design; emission factors are approximately 443 

for natural gas, 778 for oil and 960 for coal. Depending on the sources of electric power in a 

particular country, each kWh saved will contribute to a reduction of up to a kilogram of CO2. 

An analysis by the European Commission on residential air conditioners reckons that "most of 

the environmental impacts (and life cycle costs - LCC) are attributable to the use-phase." 

(European Commission, 2009b). This shows the importance of understanding energy 

efficiency in any discussion about climate impact of air-conditioning and refrigeration 

equipment. Moreover, it is important to note that climate impact may also be reduced by the 

use of renewable energy sources; however, this does not mean that countries with low-carbon 

electric grids do not have to keep the pressure on higher energy efficiency standards 

especially when electric grids are regionally interconnected.

11.5 Equipment life cycle considerations: equipment design, operation, 

maintenance, and end-of-life

Concepts and selection criteria for alternative refrigerants in various applications for each 

sector of the HVAC&R industry are presented in other chapters of this Assessment Report. 

The common criteria among the different sectors are the necessity to design, operate, and

maintain efficient systems that operates with minimized emissions, both direct and indirect.

For refrigeration and air-conditioning systems, the most important design criteria in an 

optimized operation is reducing indirect emissions due to energy efficiency measures over the 

lifetime of the equipment. In the design phase, the optimization process is a result of product 

innovation (such as part load design considerations of compressors, heat exchangers, and 

components), integration of the refrigeration equipment into the heating system for heat 

recovery, and utilization of power grid based controls. Those technical design criteria are 

linked to regulations and standards as well as voluntary agreements by industry.

In U.S. buildings, space cooling and refrigeration accounted for 13.7% of the site and 21.3% 

of the primary energy use, in 2010 (USDOE, 2011). Additional energy is consumed for 

heating via reversible heat pumps, primarily in the residential sector. 16% in Germany have 

been reported (Arnemann, 2013), while the EU estimates that 55% of the primary energy in 

used by heating (Hudson, 2014). Buildings account for 40% of the world’s energy use with 

the resulting carbon emissions substantially more than those in the transportation sector 
2014 TOC Refrigeration, A/C and Heat Pumps Assessment Report 235

(WBSCD, 2009). Estimated energy saving potential with available state-of-the-art technology 

is around 35-40% (FKT, 2009) per annum. A study by the German Research Council shows 

that it will be technically possible to achieve potential energy savings of 40% until 2020, if 

accompanying political measures are taken (FKT, 2012). In emerging markets like Brazil, 

RAC sales rocketed from 1 million units in 2003 to 3.3 million units in 2012 (Eletrobras 

Procel, 2013). 

As examples, the following energy savings achieved by voluntary agreements have been 

documented:

- Supermarket refrigeration: 5.5%/year (period 2004-2012 (Heinbokel, 2011)

- Domestic refrigeration: 27% over 10 years (Preuß, 2011); 40 % over 7 years (Silva, 2003)

- Refrigeration in air conditioning systems: 2%/year (Brinkmann, 2009)

In the position paper (FKT, 2012) by the German Research Council it is stated that 

considerable energy savings can be achieved through the optimum design of a system rather 

than just optimizing the design of components. Other savings can be obtained from the 

control, operation, and maintenance of the system.

The same study found that savings up to 40% can be achieved through:

- Efficient control, operation and design of systems (around 10%)

- Reduction of effective temperature differences on heat exchangers (around 12%)

- Use of efficient drives (around 3%)

- Reducing cooling / heating demand (around 7%)

- System improvement by designing in compliance with the annual temperature profile, use 

of heat recovery, thermal storage (around 8%)

In Europe, the successful implementation of energy savings through commitments by the 

industry and by Eco-Design Requirements (European Commission, 2009b) in relation to the 

foreseeable requirements from the legislature led to a significant competitive advantage for 

manufacturers undertaking those voluntary commitments.

As for the direct effect of the refrigerants used, here too there are opportunities to improve the 

life-cycle sustainability of refrigeration systems. As discussed in Section 11.6, if a refrigerant 

with poor environmental properties is used, careful management of that refrigerant is 

necessary throughout the lifecycle of the equipment. This entails designing equipment for low 

leaks, maintaining and operating equipment to prevent emissions, and finally properly 

recovering the refrigerant when the equipment is disposed or replaced.

11.5.1 Equipment design

From an engineering point of view, the design of components such as compressors or 

electrical drives has a possibility for limited improvement of a few percentage points in terms 

of efficiency compared to ideal theoretical efficiency. Main improvements can be made 

through controls and smart electronic integration, minimized heat exchanger temperature 

differences and other measures described above. To address the direct effect, equipment can 

be designed to use alternative low-GWP refrigerants and/or to reduce emissions. These types 

of improvements are either driven by cost, product innovation or by enforced standards 

requirements. 

Environmental sustainability, including efficiency and refrigerant management 

considerations, can be achieved at different levels in the design phase by taking the following 

technical and regulatory criteria into consideration: 
236 2014 TOC Refrigeration, A/C and Heat Pumps Assessment Report

Technical considerations: 

 Meeting customer design requirements, including the proper specification of annual 

cooling/heating demands;

 Minimizing refrigerant usage and choosing alternative refrigerants that meet energy 

efficiency requirements; 

 Integrating the technical design of equipment into larger system or whole-building design; 

 Eliminating competing targets in the decision making process: low first cost versus high 

efficiency. 

Regulatory considerations:

 Refrigerant regulations specifically for those refrigerants targeted for a phase-down, for 

example the European Union F-Gas (European Union, 2012) regulations;

 Agreements for achieving high energy efficiency and/or low consumption and emissions 

of refrigerants, for example the German agreement VDMA 24247 for energy efficiency 

in supermarket refrigerating systems” (VDMA, 2011);

 Equipment energy efficiency ratings, for example “eco design” Directive 2009/125/EC, 

“establishing a framework for the setting of ecodesign requirements for energy-related 

products (European Union, 2009);

 Standards provided by global organizations or industry associations, for example 

International Standards Organization (ISO), European Committee for Standardization 

(CEN) or the American Society of Heating, Refrigerating, and Air Conditioning 

Engineers (ASHRAE)5.

The decision of which equipment to use during the design stage is often faced by competing 

targets: low first cost investment versus high energy efficiency affecting the cost of energy 

over the lifetime of the system and the GHG emission. To resolve this conflict between low 

first cost, operating cost and refrigerant emissions, new financing methods and evaluation 

criteria for the technical operation of systems in terms of their contribution to the environment 

are being developed. These financial mechanisms can contribute significantly to the reduction 

of energy consumption and refrigerant emissions and thus to system design. To be really 

relevant, these mechanisms must be able to account for an adequate balance between life 

cycle cost and LCCP.

Refrigerant selection

Sustainability aspects are being included as regulatory requirements (EU F-gas law) and third 

party standards such as the US AHAM Refrigerator Sustainability Standard (AHAM, 2012). 

A lifecycle approach is typically used to provide a complete analysis of the impact on the 

environment over the expected lifetime of the product containing refrigerant.

Many of the factors that influence energy efficiency are included in Table 11-1 “Refrigerant 

Selection Criteria”. The efficiency of components, as well as efficiency losses such as 

pressure drops, have a large effect on the overall energy efficiency of the application. Energy 

efficiency in turn has a significant impact on the Total Equivalent Warming Impact (TEWI), 

the mass of refrigerant needed, the use of resources such as fuel, and end of life disposal 

requirements. Energy consumption is greatly affected by the selection of refrigerants, 

especially considering the lifetime of the equipment. 

For example, a typical 10 kW cooling capacity system with a SEER of 13 in the USA will use 

over 44000 kWh over its lifetime based on the life cycle cost estimator proposed by the U.S. 

Energy Star Program (Energy Star, 2014). This system will typically have 2 kg of refrigerant 

charge. The CO2 emissions due to the energy consumption of 44000 kWh are 30.3 metric 

 

5 www.iso.org and www.ashrae.org
2014 TOC Refrigeration, A/C and Heat Pumps Assessment Report 237

tonnes of CO2, based on the USA power grid, which is 45 % coal-based. The equivalent CO2 

emissions due to the direct release of the refrigerant charge are 2.7 metric tonnes, which is 

less than 10 % of the lifetime CO2 emissions.

Design considerations for safety can sometimes counter the design for energy efficiency and 

lead to more CO2 emissions. For example, isolating heat exchangers for sake of safety or 

toxicity can affect the heat transfer efficiency either positively or negatively. 

Refrigerant criteria and properties provide a basis for the selection of a refrigerant in an 

application in support of the intermediate factors. Properties and selection criteria of 

significance are shown in Table 11-1. 

Table 11-1: Refrigerant selection criteria

Selection criteria Factors / Properties and 

Impact

Expected development

Climate impact refrigeration systems 

contribute to global warming 

by energy consumption and 

emissions of refrigerants

higher acceptance for products and 

technologies with lower TEWI;

stronger regulations might lead to phase 

out of high GWP fluids

Energy efficiency More than 80% of emissions 

are related to operation 

(depending upon the 

conditions).

Higher full load and annualized 

efficiency requirements resulting in

stricter regulations and

better adjustment to local requirements 

and conditions. Industry transition from 

prescriptive full-load efficiency to a 

systemic approach.

Refrigerant Cost Cost and design factor Market price reduction

Commercial availability Market penetration driven by 

local demand 

availability globally is limited by local 

phase-out regulations;

global manufacturer will develop local 

solutions with different refrigerants

Technological level Increase of energy optimized 

operation, leak reduction, safe 

handling and use, education 

and training 

Development of “smart” products 

which requires less know-how by 

operators

High ambient 

temperature fitness

Design factor and operation 

requirement, reduction in 

energy efficiency related to 

refrigerant critical temperature

system adjustment to ambient 

conditions (larger HX, refrigerants with 

low compressor discharge 

temperatures), 

optimization for annual operation or 

local conditions by "intelligent" design

Safety Related to adjustments of the 

technical design of products 

and to user know-how.

Cost and design factors.

Lack of local regulation

Increasing “intelligence” of the 

technical system including handling of 

risks and operation, result to increase of 

safety level as lower safety might not be 

accepted by society. 

Flammability Risks associated with the use 

of flammable refrigerants are 

due to the concurrent existence 

of: 1. leakage, 2. flammable 

concentration and 3. Source of 

Ignition (SOI). In general these 

risks can be reduced to 

acceptable levels by means of 

Increase of flammable refrigerants’ 

market share and know how to use them

Due to flammable nature of new 

(unsaturated HFC) and known 

refrigerants (such as HFC-32, HFC152a, HC-290, HC-600a, NH3) it is 

expected that the application, design 

know-how, service practices and 
238 2014 TOC Refrigeration, A/C and Heat Pumps Assessment Report

technical adjustments which 

might result in higher costs.

Lack of local regulation.

procedures, education, training, as well 

as adoption of technical standards for 

safe use of these flammable refrigerants 

will be developed within the next 3-5 

years6. 

 

6

Safety requirements for flammable refrigerants classified as A2L, A2, and A3 are described in chapter 

2 of this report
2014 TOC Refrigeration, A/C and Heat Pumps Assessment Report 239

Annex 1 - TEAP Refrigeration, Air Conditioning and Heat Pumps 

Technical Options Committee (RTOC) - Membership status 12/14

 Co-chairs Affiliation Country

Lambert Kuijpers A/genT Consultancy (TU Eindhoven) The Netherlands

Roberto de A. Peixoto Maua Institute of Technology, Sao Paulo Brazil

Members Affiliation Country

Radhey S. Agarwal IIT New Delhi India

James M. Calm Engineering Consultant USA

Radim Cermak Ingersoll Rand Czech Republic

Guangming Chen Zhejiang University, Hangzhou China

Jiangpin Chen Shanghai University China

Denis Clodic EREIE Consultancy France

Daniel Colbourne Consultant UK

Richard DeVos General Electric USA

Sukumar Devotta Consultant India

Martin Dieryckx Daikin Europe N.V. Belgium

Dennis Dorman Trane USA

Bassam Elassaad Consultant Lebanon

Dave Godwin U.S. EPA USA

Marino Grozdek University of Zagreb Croatia

Samir Hamed Petra Industries Jordan

Kenneth E. Hickman Consultant USA

Martien Janssen Re/genT The Netherlands

Makoto Kaibara Consultant Japan

Michael Kauffeld Fachhochschule Karlsruhe Germany

Jürgen Köhler University of Braunschweig Germany

Holger König Consultant Germany

Richard Lawton CRT UK

Tingxun Li Guangzhou San Yat Sen University China

Petter Nekså SINTEF Energy Research Norway

Horace Nelson Consultant, University Kingston Jamaica

Carloandrea Malvicino Fiat Ricerche Italy

Tetsuji Okada JRAIA Japan

Alaa A. Olama Consultant Egypt

Alexander C. Pachai Johnson Controls Denmark

Andy Pearson Star Refrigeration Glasgow UK

Per Henrik Pedersen Danish Technological Institute Denmark

Rajan Rajendran Emerson USA

Giorgio Rusignuolo Carrier Transicold USA

Alessandro Silva Bitzer USA

Paulo Vodianitskaia Consultant Brazil

Asbjorn Vonsild Danfoss Denmark
240 2014 TOC Refrigeration, A/C and Heat Pumps Assessment Report
2014 TOC Refrigeration, A/C and Heat Pumps Assessment Report 241

Annex 2 - Contact details for authors, co-authors and contributors to 

the 2014 RTOC Assessment Report (to be completed)

Dr. Radhey S. AGARWAL

Professor, Mechanical Engineering 

Department, IIT Delhi, 

Senior Advisor and Co-ordinator 

Sector Phase out Plan Unit (SPPU)

Ozone Cell, Core-4B, 2nd Floor

India Habitat Centre, Lodhi Road

New Delhi- 110 003

India

Mobile : +91 981 136 1865

Email: agarwalrsa@gmail.com,

rsagarwal@sppu-india.org

Mr. Nigel AMSCHWAND 

Engineering Consultant

GEA Refrigeration Africa (Pty) Ltd

PO Box 36815

Chempet 7442

South Africa

Tel.: +27 (0)21 555 9000

E-mail: nigel.amschwand@gea.com

 

Mr. James M. CALM, P.E.

Engineering Consultant

10887 Woodleaf Lane

Great Falls, VA 22066-3003 

USA

Tel: +1 703 636 9500

E-mail: jmc@jamesmcalm.com

Dr. Radim ČERMÁK

Ingersoll Rand, IR Engineering and 

Technology Center Prague 

Florianova 2460 

253 01 Hostivice

Czech Republic 

Tel.: +420 257 109 597

Fax: +420 251 562 187

E-mail: radim_cermak@eu.irco.com

Prof. Jiangping CHEN 

Shanghai Jiaotong University

Dongchuan Road, 800 

Shanghai 

P.R. China

Tel: +86 3420 6775

Fax: +86 3420 6087

Email: jpchen@sjtu.edu.cn;

jpchen70@aliyun.com

E-mail: jpchen@sjtu.edu.cn

Prof. Guangming CHEN

Institute of Refrigeration and Cryogenics

Zhejiang University

Hangzhou 310027, Zhejiang 

P.R. China

Tel.: +86 571 8795 1680

E-mail: gmchen@zju.edu.cn

Dr. Denis CLODIC

Emeritus Research Director

President of innov. company ERIE

CEP Mines-ParisTech

13, Rue du Pies 

91120 Palaiseau 

France

Tel.: + 33 1 8038 4132

E-mail : denis.clodic@ereie-sas.fr

Dr. Daniel COLBOURNE

PO Box 4745

Stratford-upon-Avon

CV37 1FE

United Kingdom

Tel: +44 1789 268 285

E-mail: d.colbourne@re-phridge.co.uk

Mr. Richard DEVOS 

Technical Director

GE Appliances

11822 Springmeadow Ln

Goshen, Ky 40026

USA

Tel.: +1 502 314 4530

E-mail: devosr03@gmail.com

Dr. Sukumar DEVOTTA

T2/301 Skycity

Vanagaram Ambattur Road

Vanagaram

Chennai 600095

India

Mobile: +91 44 26530830

Tel.: +91 44 2653 0830

Email: sdevotta@gmail.com
242 2014 TOC Refrigeration, A/C and Heat Pumps Assessment Report

Mr. Martin DIERYCKX

Daikin Europe N.V.

Zandvoordestraat 300

Oostende 8400

Belgium

Tel: +32 59 55 86 14

E-mail: dieryckx.m@daikineurope.com

Mr. Dennis DORMAN

Director 

Compressor Technology and Development

The Trane Company

Ingersoll Rand

3600 Pammel Creek Road

La Crosse, WI 54601

USA

Tel.: +1- 608 787 1829 

E-mail: dennis.dorman@trane.com

Mr. Bassam ELASAAD

P.O. Box 70494

Antelias

Lebanon

Tel.: +961 7692 6086 

E-mail: belassaad@gmail.com

Mr. Dave GODWIN 

Environmental Protection Specialist

Stratospheric Protection Division

U.S. Enviromental Protection Agency

1200 Pennsylvania Avenue, NW

Mail Code 6205-T

Washington, DC 20460

USA

Tel.: +1 202-343-9324

E-mail: godwin.dave@epa.gov 

Asst. Prof. Dr. Marino GROZDEK 

University of Zagreb 

Faculty of Mechanical Engineering and 

Naval Architecture 

Ivana Lucica 5 

10000 Zagreb

Croatia

Tel.: +385 1 6168 564 /Fax: +385 1 6168512

E-mail: marino.grozdek@fsb.hr

Mr. Samir HAMED 

Petra Engineering Industries Company

Research and development manager

Amman

Jordan

Tel.: +962 795 601358

Fax: +962 640 51086

E-mail: s-hamed@petra-eng.com.jo, 

samirhamid1971@gmail.com

 

Mr. Kenneth E. HICKMAN 

Building Efficiency Group 

Johnson Controls 

631 S. Richland Ave. 

York, PA 17403

USA

Tel.: +1- 717 771 7459 

E-mail: kenneth.e.hickman@jci.com

Mr. Martien JANSSEN 

Re/genT BV

Lagedijk 22

5705BZ Helmond

The Netherlands

Tel.: +31 492 476365

E-mail: martien.janssen@re-gent.nl

Web: www.re-gent.nl 

Mr. Makoto KAIBARA

5-17-16 Tsukinova 

Otsu-Shi Shiga

520-2152 Japan

Tel.: +81-77-543-0585

E-mail: mike-kai@hi-ho.ne.jp

Prof. Dr. Michael KAUFFELD

Institute of Refrigeration, 

Air Conditioning and Environmental 

Engineering

Karlsruhe University of Applied Sciences

Moltkestrasse 30

76133 Karlsruhe

Germany

Tel.: +49 721 925 1843

Fax: +49 721 925 1915

E-mail: michael.kauffeld@hs-karlsruhe.de
2014 TOC Refrigeration, A/C and Heat Pumps Assessment Report 243

Prof. Dr.-Ing. Jürgen KŐHLER 

Institut für Thermodynamik (IfT)

Institute of Technology 

University of Braunschweig 

Hans-Sommer-Str. 5 

38106 Braunschweig

Germany

Tel.: +49 531 391 2625

Website: www.ift.tu-bs.de

E-mail: j.koehler@tu-bs.de, 

koehler.ift@t-online.de 

Dipl. Ing. Holger KŐNIG

ref-tech engineering 

Director 

Berger Halde 26

88079 Kressbronn 

Germany

Tel.: +49 7543-9134-72

Mobile: +49 175 520 4942

E-mail: holger.koenig@ref-tech.de

Dr. Lambert KUIJPERS

(co-chair RTOC)

(Technical University

POB 513, Eindhoven)

A/genT Consultancy

Mgr. Boermansstraat 15

5911BA Venlo

The Netherlands

Tel.: +31 77 354 6742

E-mail: lambert.kuijpers@kpnmail.nl

Dr. Richard LAWTON 

Cambrigde Refrgeration Technology

140 Newmarket road

Cambrigde

U.K.

E-mail: rlawton@crtech.co.uk

Mr. Tingxun LI 

Engineering School

Sun Yat-sen University

No.135 Xingang Xi Road, Guangzhou, 

510725, 

P.R.China

Fax: +86 2633 1115

Mobile: +86 135 3350 9330

E-mail: litx@hotmail.com

Mr. Carloandrea MALVICINO 

FCA Italy S.p.A.

C.so Settembrini, 40 – Gate 8 - Building 6 –

1st floor – B5aS

10135 Torino

Italy

Tel.: +39 011 003 8811 

Mobile: +39 33 5130 3416

E-mail: 

carloandrea.malvicino@fcagroup.com

Prof. Dr. Ing. Petter NEKSÅ

SINTEF Energy Research

Energy Processes

P.O.Box 4761 Sluppen

7465 Trondheim 

Norway

Mobile: +47 92 60 65 19

E-mail: Petter.Neksa@sintef.no

Mr. Horace NELSON 

Technical Consultant- Univ. of Technology 

24 Arnold Road

Kingston 4

Jamaica, W.I.

Tel.: +1 876 328 6167 / 429-7994

E-mail : horacen@msn.com

Mr. Tetsuji OKADA 

Japan Refrigeration and Air conditioning 

Industry Association

President

3-5-8 Shibakoen, Minato-ku, Tokyo, Japan

Tel.: +81 3-3432-1671

E-mail: t-okada@jraia.or.jp

Dr. M. Alaa OLAMA

Ref & AC consultant

6 Refaa Beck Street, Khalifa Mamoun

Heliopolis, Cairo

P.C. 11341

Egypt

Tel: +20 10060 99950

E-mail: alaaolama@gmail.com

Mr. Alexander Cohr PACHAI

Johnson Controls Denmark

Christian D.X's Vej 201

8270 Hoejbjerg

Denmark

Tel.: office +45 87 36 70 00

Mobile: +45 29 22 71 59

E-mail.: alexander.c.pachai@jci.com
244 2014 TOC Refrigeration, A/C and Heat Pumps Assessment Report

Dr. Andy PEARSON

Star Refrigeration Ltd 

Thornliebank Ind. Estate, Nitshill Road 

Glasgow G46 8JW 

United Kingdom 

Tel.: +44 141 638 7916

E-mail: apearson@star-ref.co.uk

Mr. Per Henrik PEDERSEN

Danish Technological Institute

Center for Refrigeration and 

Heat Pump Technology

2630 Taastrup

Denmark

Tel.: +45 72 20 25 13

E-mail: prp@dti.dk

Prof. Dr. Roberto de Aguiar PEIXOTO 

(co-chair RTOC)

Maua Institute of Technology 

Department of Mechanical Engineering

Praça Mauá 01

Sao Caetano do Sul

Sao Paulo - 09580-900 

Brazil

Tel.: +55 11 4239 3021

E-mail: robertopeixoto@maua.br

Mr. Rajan RAJENDRAN 

Vice President, 

Systems Innovation Centre and 

Sustainability

Emerson Climate Technologies

1675, West Campbell Road

Sidney, Ohio 45365

USA

Tel.: +1 937 498 3580

E-mail: rajan.rajendran@emerson.com

Mr. Giorgio RUSIGNUOLO

Vice President Engineering Refrigeration

Carrier Corporation

Carrier Parkway, Building TR20

Syracuse, New York 13221

USA

Tel.: +1 315 432 7062

E-mail: Giorgio.rusignuolo@carrier.utc.com

Mr. Alessandro SILVA

BITZER Scroll, Inc.

6055 Court Street Road

Syracuse, New York 13206

USA

Tel.: +1 315 433 2439

E-mail: asilva@bitzerscroll.com, 

alessandroesilva14@gmail.com

Mr. Paulo VODIANITSKAIA

HAPI Consultancy

Rua João Colin, 1285 s.3

89204-001 Joinville SC

Brazil

Tel.: +55 47 34 22 15 02

E-mail: paulo@hapiconsult.com.br

Mr. Asbjørn VONSILD 

Refrigerants and Standards

Danfoss A/S

Automatic Controls

Albuen 29 

6000 Kolding 

Denmark

Tel.: +45 2372 5559

E-mail: alv@danfoss.com