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

## MONTREAL PROTOCOL

ON SUBSTANCES THAT DEPLETE

THE OZONE LAYER



# UNEP

2014 R EPORT OF THE 

# R EFRIGERATION 

# , A IR 

# C ONDITIONING AND 

# H EAT 

# P UMPS



# T ECHNICAL 

# O PTIONS 

# C OMMITTEE



# 2014 Assessment2014 TOC Refrigeration, A/C and Heat Pumps Assessme nt Report

2 

## UNEP 2014 R EPORT OF THE 

## R EFRIGERATION 

## , A IR 

## C ONDITIONING AND 

## H EAT 

## P UMPS



## T ECHNICAL 

## O PTIONS 

## C OMMITTEE



## 2014 A SSESSMENT2014 TOC Refrigeration, A/C and Heat Pumps Assessme nt Report 3



### Montreal Protocol On Substances that Deplete the Ozone Layer



## UNEP 2014 R EPORT OF THE 

## R EFRIGERATION 

## , A IR 

## C ONDITIONING AND 

## H EAT 

## P UMPS 

## T ECHNICAL 

## O PTIONS 

## C OMMITTEE



## 2014 A SSESSMENT

The text of this report is composed in Times New Ro man.

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, Ozon e Secretariat

Date: February 2015

No copyright involved Printed in Kenya, 2015



### ISBN2014 TOC Refrigeration, A/C and Heat Pumps Assessme nt Report

4 DISCLAIMER

The United Nations Environment Programme (UNEP), th e 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 organisat ions that employ them do not endorse the performanc e, worker safety, or environmental acceptability of an y of the technical options discussed. Every industr ial operation requires consideration of worker safety a nd proper disposal of contaminants and waste produc ts. Moreover, as work continues - including additional toxicity evaluation - more information on health, environmental and safety effects of alternatives an d replacements will become available for use in sel ecting among the options discussed in this document.

UNEP, the TEAP co-chairs and members, the Refrigera tion, AC and Heat Pumps Technical Options Committee, co-chairs and members, in furnishing or distributing this information, do not make any warr anty or representation, either express or implied, with respect to the accuracy, completeness, or utility; nor do they assume any liability of any kind whatsoever resulti ng from the use or reliance upon any information, m aterial, or procedure contained herein, including but not li mited to any claims regarding health, safety, envir onmental effect or fate, efficacy, or performance, made by t he 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 implie d 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 Technica l Options Committee acknowledges with thanks the outstanding contributions from all of the individua ls and organisations who provided technical support to committee members. In developing this report, parti cularly the chapter lead authors were instrumental.

The names of chapter lead authors, co-authors and c ontributors 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 a nd do not necessarily reflect the views of any spon soring 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 t his report.2014 TOC Refrigeration, A/C and Heat Pumps Assessme nt Report 5 

### UNEP 2014 R EPORT OF THE 

### R EFRIGERATION 

### , A IR 

### C ONDITIONING AND 

### H EAT 

### P UMPS



### T ECHNICAL 

### O PTIONS 

### C OMMITTEE



### 2014 A SSESSMENT



## Table of Contents

KEY MESSAGES ......................................

................................................... ............................................... 11

R EFRIGERANTS

.................................................. ................................................... ..................................... 11 D OMESTIC APPLIANCES

.................................................. ................................................... ......................... 11 C OMMERCIAL REFRIGERATION

.................................................. ................................................... .............. 11 I NDUSTRIAL SYSTEMS

.................................................. ................................................... ........................... 12 T RANSPORT REFRIGERATION

.................................................. ................................................... ................. 12 A IR

- TO

- AIR AIR CONDITIONERS AND HEAT PUMPS

.................................................. .................................... 12 W ATER HEATING HEAT PUMPS

.................................................. ................................................... .............. 12 C HILLERS

.................................................. ................................................... .............................................. 13 V EHICLE AIR CONDITIONING

.................................................. ................................................... ................. 13 S USTAINABLE REFRIGERATION

.................................................. ................................................... ............. 13

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

................................................... ........................ 15

R EFRIGERANTS

.................................................. ................................................... ..................................... 15 D OMESTIC APPLIANCES

.................................................. ................................................... ......................... 15 C OMMERCIAL REFRIGERATION

.................................................. ................................................... .............. 16 I NDUSTRIAL SYSTEMS

.................................................. ................................................... ........................... 16 T RANSPORT REFRIGERATION

.................................................. ................................................... ................. 17 A IR

- TO

- AIR AIR CONDITIONERS AND HEAT PUMPS

.................................................. .................................... 17 W ATER HEATING HEAT PUMPS

.................................................. ................................................... .............. 18 V EHICLE AIR CONDITIONING

.................................................. ................................................... ................. 19 S USTAINABLE REFRIGERATION

.................................................. ................................................... ............. 20

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

................................................... .............. 21

R EFRIGERANTS

.................................................. ................................................... ..................................... 21 D OMESTIC APPLIANCES

.................................................. ................................................... ......................... 21 C OMMERCIAL REFRIGERATION

.................................................. ................................................... .............. 22 I NDUSTRIAL SYSTEMS

.................................................. ................................................... ........................... 23 T RANSPORT REFRIGERATION

.................................................. ................................................... ................. 23 A IR

- TO

- AIR AIR CONDITIONERS AND HEAT PUMPS

.................................................. .................................... 24 W ATER HEATING HEAT PUMPS

.................................................. ................................................... .............. 25 C HILLERS

.................................................. ................................................... .............................................. 26 V EHICLE AIR CONDITIONING

.................................................. ................................................... ................. 26 S USTAINABLE REFRIGERATION

.................................................. ................................................... ............. 28

1 INTRODUCTION ......................................

................................................... ..................................... 31

1.1 M ONTREAL P ROTOCOL DEVELOPMENTS

.................................................. ......................................... 31 1.2 T HE UNEP T ECHNOLOGY AND E CONOMIC A SSESSMENT P ANEL

.................................................. ... 32 1.3 T HE T ECHNICAL O PTIONS C OMMITTEE R EFRIGERATION , A/C AND H EAT P UMPS ............................ 35 1.4 R EFRIGERATION , 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 I NTRODUCTION

.................................................. ................................................... ............................ 43 2.1.1 Refrigerant progression ...........................

................................................... ........................... 432014 TOC Refrigeration, A/C and Heat Pumps Assessme nt Report

6 2.1.2 Unsaturated hydrofluorochemicals ..................

................................................... ................... 43 2.1.3 Recent assessment on current and future refrigerant s 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 purpo ses ............................................... .. 46 2.1.7 Selection of refrigerant...........................

................................................... ............................. 48 2.1.8 HCFC-22 replacements...............................

................................................... ........................ 49 2.2 R EFRIGERANT DESCRIPTIONS

.................................................. ................................................... ...... 49 2.3 D ATA SUMMARY

................................................... ................................................... ......................... 54 T ABLE 2-9: D

ATA SUMMARY FOR AZEOTROPIC REFRIGERANT BLENDS

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

................................................... ................................. 57 2.4 C ONCLUDING REMARKS

.................................................. ................................................... .............. 59 2.5 R EFERENCES

.................................................. ................................................... ................................ 59

ANNEX TO CHAPTER 2 - SAFETY STANDARDS AND REGULATIO NS ....................................... 64

R EFERENCES

.................................................. ................................................... ......................................... 68

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

................................................... ............................ 71

3.1 I NTRODUCTION

.................................................. ................................................... ............................ 71 3.2 O PTIONS FOR NEW EQUIPMENT

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

................................................... .................... 72 3.2.2 Conversion of HFC-134a domestic refrigerators to lo w 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 ............................... 7 7 3.3 O PTIONS FOR EXISTING DOMESTIC REFRIGERATORS

.................................................. ....................... 78 3.4 E ND

- OF

- LIFE DISPOSAL

.................................................. ................................................... ................ 79 3.5 C ONCLUDING REMARKS

.................................................. ................................................... .............. 79 3.6 R EFERENCES

.................................................. ................................................... ................................ 79

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

................................................... ................. 85

4.1 I NTRODUCTION

.................................................. ................................................... ............................ 85 4.2 A PPLICATIONS

.................................................. ................................................... ............................. 85 4.3 O PTIONS 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 O PTIONS FOR EXISTING EQUIPMENT

.................................................. ................................................ 95 4.5 R EFERENCES

.................................................. ................................................... ................................ 96

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

................................................... ............................ 101

5.1 I NTRODUCTION

.................................................. ................................................... .......................... 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 A PPLICATIONS

.................................................. ................................................... ........................... 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 O PTIONS FOR NEW EQUIPMENT

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

................................................... ........................... 109 5.3.2 Hydrofluorocarbons ................................

................................................... .......................... 1102014 TOC Refrigeration, A/C and Heat Pumps Assessme nt 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 O PTIONS 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 S ERVICE REQUIREMENTS

.................................................. ................................................... ........... 114 5.6 C ONCLUDING REMARKS

.................................................. ................................................... ............ 114 5.7 R EFERENCES

.................................................. ................................................... .............................. 114

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

................................................... .................. 119

6.1 I NTRODUCTION

.................................................. ................................................... .......................... 119 6.2 O PTIONS FOR NEW EQUIPMENT

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

................................................... ............... 119 6.2.2 Vessels ...........................................

................................................... .................................... 123 6.3 O PTIONS FOR EXISTING EQUIPMENT

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

................................................... ............ 124 6.3.2 Vessels ...........................................

................................................... .................................... 125 6.4 C ONCLUDING REMARKS

.................................................. ................................................... ............ 126 6.5 R EFERENCES

.................................................. ................................................... .............................. 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 ........ ................................................ 13 7

7.1 I NTRODUCTION

.................................................. ................................................... .......................... 137 7.2 E QUIPMENT TYPES

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

................................................... ................... 138 7.2.2 Split (non-ducted) residential and commercial air c onditioners ....................................... ... 139 7.2.3 Multi-split air conditioners for commercial and res idential .......................................... ...... 140 7.2.4 Split ducted air conditioners (residential and comm ercial) ........................................... ...... 140 7.2.5 Ducted commercial packaged (self-contained) air con ditioners ......................................... . 140 7.3 O PTIONS 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 O PTIONS 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 H IGH AMBIENT CONSIDERATIONS

.................................................. ................................................. 1 52 7.5.1 Performance of alternatives under high ambient temp eratures .......................................... . 1532014 TOC Refrigeration, A/C and Heat Pumps Assessme nt Report

8 7.5.2 Measures to design and optimise air-conditioners fo r high ambient conditions.................. 156 7.6 C ONCLUDING REMARKS

.................................................. ................................................... ............ 157 7.7 R EFERENCES

.................................................. ................................................... .............................. 157

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

................................................... ................. 169

8.1 I NTRODUCTION

.................................................. ................................................... .......................... 169 8.2 H EAT PUMP TYPES , IMPLICATIONS AND TRENDS

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

................................................... ............................. 169 8.2.2 Heat pump implications and trends .................

................................................... .................. 171 8.3 O PTIONS FOR NEW EQUIPMENT

.................................................. ................................................... .. 172 8.3.1 HFC-134a and HFC blends R-407C, R-417A and R-410A . ................................................. 1 72 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 R EFRIGERANT CHARGE L EVELS

.................................................. ................................................... . 176 8.5 O PTIONS FOR EXISTING SYSTEMS

.................................................. .................................................. 176 8.6 C ONCLUDING REMARKS

.................................................. ................................................... ............ 176 8.7 R EFERENCES

.................................................. ................................................... .............................. 177

9 CHILLERS ..........................................

................................................... .......................................... 181

9.1 I NTRODUCTION

.................................................. ................................................... .......................... 181 9.2 T YPES 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 O PTIONS 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 O PTIONS 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 A LTERNATIVES FOR HIGH AMBIENT CONDITIONS

.................................................. ..................... 190 9.6 C ONCLUDING REMARKS

.................................................. ................................................... ............ 190 9.7 R EFERENCES

.................................................. ................................................... .............................. 191

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

................................................... .................... 197

10.1 I NTRODUCTION

.................................................. ................................................... ..................... 197 10.2 D ESCRIPTION OF SYSTEMS AND CURRENT AND FUTURE APPLIC ATIONS OF MOBILE AIR CONDITIONING
SYSTEMS

.................................................. ................................................... ............................................. 197 10.2.1 Refrigerant cost and recharge .....................

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

................................................... .......................... 198 10.3 O PTIONS FOR N EW AND F UTURE M OBILE A IR C ONDITIONING S YSTEMS ................................... 200 10.3.1 Passenger Car and Light Truck Air Conditioning\ ...

................................................... ... 200 10.3.2 Bus and Rail Air Conditioning .....................

................................................... ................ 208 10.4 O PTIONS FOR EXISTING S YSTEMS

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

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

................................................... ...................... 209 10.5 C ONCLUDING R EMARKS

.................................................. ................................................... ....... 209 10.6 R EFERENCES

.................................................. ................................................... ......................... 210

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

................................................... ..................................... 217

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

................................................... ................. 225

11.1 I NTRODUCTION

.................................................. ................................................... ..................... 225 11.2 S USTAINABILITY APPLIED TO REFRIGERATION

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

................................................... ...................... 225 11.2.2 Environmental aspects .............................

................................................... ..................... 226 11.2.3 Social aspects ....................................

................................................... ........................... 2262014 TOC Refrigeration, A/C and Heat Pumps Assessme nt Report 9

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

................................................... ......................... 226 11.2.5 Opportunities for improvement .....................

................................................... ............... 227 11.3 D IRECT IMPACT OF REFRIGERANTS

.................................................. .......................................... 228 11.3.1 Design criteria for charge minimization and leak ti ghtness ........................................... . 228 11.3.2 Reduction of emissions through installation, servic ing and maintenance ....................... 230 11.3.3 Refrigerant recovery, recycling, reclamation and de struction ........................................ 230 11.4 I NDIRECT IMPACTS DUE TO ENERGY USE

.................................................. .................................. 233 11.4.1 Energy efficiency improvements ....................

................................................... ............... 234 11.5 E QUIPMENT LIFE CYCLE CONSIDERATIONS : EQUIPMENT DESIGN , OPERATION , MAINTENANCE , AND END

OF

- 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 ................................................ 23 9
ANNEX 2 - CONTACT DETAILS FOR AUTHORS, CO-AUTHORS A ND CONTRIBUTORS TO THE 2014 RTOC ASSESSMENT REPORT (TO BE COMPLETED) .....

................................................... .. 2412014 TOC Refrigeration, A/C and Heat Pumps Assessme nt Report

102014 TOC Refrigeration, A/C and Heat Pumps Assessme nt 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 a ssociated equipment), the system energy efficiency, the safety and convenience of applicabi lity, environmental issues and many more.

 The perfect refrigerant does not exist, and is unli kely 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 alternativ es are proposed which create a challenge in finding the right refrigerant for each applicati on. One aspect of particular importance is that refrigerants with low direct impact on climate chan ge 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 ar e replacements for HCFC-22. Of the new refrigerants twelve are blends of saturated HFCs an d unsaturated HFCs (HFOs) of which seven blends are with class 2L flammability. 

### Domestic appliances

 Globally, new refrigerator production conversion fr om 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 refri gerator production will use HC-600a (possibly with a small share applying unsaturated H FC 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 u sing HFC-134a are fastly growing in the EU. HPCDs using R-407C and HC-290 have also bee n introduced. Alternative refrigerant solutions that are being explored inclu de 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 signi ficant market share in Europe and in Japan.

 Because of their high GWP, R-404A and R-507 are see n as refrigerants in many non-Article 5 countries as refrigerants to be replaced and, depen ding 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 CO 2 systems are recognized as viable option especially in moderate temperature countries. The technology i s now spreading to other areas and development of concepts for hot climates is ongoing

.

 Plug-in units with air and/or water cooled condense rs 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 Assessme nt 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 educ ation and training of designers and operators.

 Although HFCs are technically feasible for large in dustrial systems, the market sector is extremely cost sensitive and more expensive refrige rants are not favoured due to the large charge quantity required. 

### Transport refrigeration

 Low-GWP candidates for transport refrigeration incl ude R-744, hydrocarbons, and HFC blends; however, various challenges are currently p reventing them from widespread use. Intermodal container applications are at the forefr ont of developments; here the R-744 based system is available.

 In the case of a regulation banning the use of refr igerants 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 low er and performances are close.

 Cryogenic and eutectic systems consist of potential ly 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 sy stems in Article 5 countries and to some extent in existing systems in non-Article 5 countri es.

 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 ha ve a medium to low GWP and are flammable that are being considered and evaluated b y research entities and enterprises, meaning there is some degree of uncertainty over fu ture selection of alternatives. 

### Water heating heat pumps

 For water heating heat pumps most systems commercia lised 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. Th e main parameters in the selection of alternatives when switching over from HCFC-22 are e fficiency, 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 hav e 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 Assessme nt Report 13



### Chillers

 The phase-out of ozone depleting refrigerants in ch illers 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 refri gerants, however, to a lesser extent.

 A number of new refrigerants with lower global warm ing potentials have been proposed for use in chillers. Evaluations by manufacturers and o ther laboratories are underway, but it is not clear which ones will be selected for commercializa tion. Tradeoffs are apparent among GWP, energy efficiency, safety, and applied costs.

 Climate effects from chillers are dominated by thei r 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, regulato rs, and users. 

### Vehicle air conditioning

 Now, at the end of 2014, it looks like as if more t han one refrigerant will be used in the coming years for new car and light truck air condit ioning. HFC-134a will remain largely adopted worldwide, HFC-1234yf will continue its gro wth 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 devel opment.

 The worldwide spread of the two new refrigerants (H FC-1234yf and R-744) will be governed significantly by additional aspects like safety, co sts, regulatory approval, system reliability, heat pump capability (especially for electric drive n 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. I t is also unclear if the bus and train sector will follow these trends. The use of hydrocarbons or ble nds of hydrocarbons has not received support from vehicle manufacturers due to safety co ncerns. 

### Sustainable refrigeration

 Refrigeration addresses fundamental human needs. In order to become more sustainable, the industry may consider the enhancement of current pr actices to: minimize the extraction of natural resources; avoid the emission of man-made s ubstances such as refrigerants and solvents; protect fertile ecosystems from mining, w ater usage, and landfill of waste; promote education for sustainable production and consumptio n.

 From the persepective of refrigeration, air conditi oning, and heat pumps, sustainability mainly refers to energy efficiency, use of renewable energ y, and other options to reduce GHG emissions and the use of natural resources. In apar ticular, the responsible choice and management of refrigerants are important sustainabi lity aspects.2014 TOC Refrigeration, A/C and Heat Pumps Assessme nt Report

142014 TOC Refrigeration, A/C and Heat Pumps Assessme nt 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 a ssociated equipment), the system energy efficiency, the safety and convenience of applicability, enviro nmental 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 ex ist and is unlikely to come into existence. Choices will therefore include existing low GWP refrigerant s (e.g. R-717, R-744 or HCs) and the newly applied or developed chemicals. Many new alternativ es 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 fla mmable to some extent.

What is left to be achieved

The industry will keep searching for the right cand idate 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 syste m or even a change of system topology. The search is a t rade-off between cost, safety, energy efficiency, while limiting the need for redesign. One particula r concern is the acceptance of flammability in some form or the other.

The way forward

There is a complex selection process ahead, where t he market will need to find out which of the many proposed new and old refrigerants will be used in e ach application. Part of the complexity is that the market is unlikely to be able to support many diffe rent refrigerants for the same application.

This will result in a period in time, likely to las t a couple of decades, where the industry will have to work with both the currently established refrigeran ts as well as new refrigerants addressing ozone depletion and/or climate change concerns. In the lo ng 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 fr om the use of ODS was essentially completed by 2008. HC-600a or HFC-134a continue to be the ref rigerant 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 applic ations, due to cost implications and flammability.

The heat pump clothe (laundry) dryer (HPCD) using H FC-134a is fastly growing in the EU, with manufacturers from both the EU and Japan. HPCDs usi ng 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 ref rigerator production will use HC-600a (possibly with a small share applying unsaturated HFC refrige rants) 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 Assessme nt Report

16 The way forward

A number of improved energy efficiency design optio ns are fully mature, and future improvements of these options are expected to be evolutionary. E xtension of these to an all-global domestic market would yield significant benefit, but is generally c onstrained 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 r efrigerants from supermarket systems. The phase-out of HCFC-22, being the dominant refrigerant in Artic le 5 countries, is important for supermarkets, where it can be replaced by high-GWP refrigerants s uch as R-404A or R-507A or lower GWP options from the R-407 family (R-407A, C or F) or the low G WP options such as R-744 or HCs. For standalone equipment, large global companies have taken commitments to phase-out, where low GWP HFCs, CO 2 , 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 cur rent low-GWP options require a significant technical background to implement, particularly for e.g., two-stage CO 2 systems, this in high ambient temperature conditions. So the HFC refrigerant blen ds, 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 re frigerants in commercial refrigeration. For the low refrigeration capacities of stand-alone systems, ma ny 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 opt ions open. The phase-out of high GWP refrigerants is a c ertainty, 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 ind ustrial systems, particularly in Europe, Scandinavi a and North America. The most common refrigerant in t hese systems is R-717, used in a few cases in cascade systems with R-744. Safety standards and re gulations 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 Eur ope and North America, for example in France and New Jersey, where regulations make it more diff icult 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 availab le low GWP alternative to HCFC-22 for industrial systems in the currently available group of HFCs an d unsaturated HFCs. The options for addressing the HCFC phase-out in Article 5 countries are there fore to find ways to use R-717, to accept the highe r refrigerant cost for existing HFCs or to develop a suitable low GWP fluorinated refrigerant.2014 TOC Refrigeration, A/C and Heat Pumps Assessme nt Report 17 The way forward

The main conclusion drawn from this survey is that greater training of designers, installers, operator s and maintenance crews is required to facilitate the move away from ozone depleting substances in all subsectors of industrial systems. New fluids are un likely to be developed for the majority of industri al 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 remai n in the future. However, there are some niche applications that use high GWP HFCs, which applicat ions need to be addressed in the future.



### Transport refrigeration

Current status

The vast majority of trucks, trailers, vans and int ermodal containers uses the non ozone depleting refrigerants R-404A and HFC-134a. While most new ve ssels use HFC refrigerants, new fishing vessels increasingly use R-717 or R-744. However, t he installed base at sea is still largely dominated by HCFC-22. The industry has been focusing on numer ous environmental issues, making progress in reductions of engine pollution emissions, fuel cons umption, 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 be ing 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. Coop eration 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 E urope for new production in 2015), R-448A and R-449A (GWP around 1400), R-744. In a longer time f rame, other HFC blends and -within certain charge limits- possibly hydrocarbons or other flamm able alternatives will be addressed. Lower GWP refrigerants will also be gradually applied in vess els when their applications mature in other segment s and gain more confidence. Cryogenic and eutectic sy stems 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 i s estimated to be in excess of 1 million tonnes. In new systems, HCFC-22 is only being used in Article 5 co untries. 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 Assessme nt Report

18 What is left to be achieved

In general there is still a significant proportion of the sector throughout almost all Article 5 count ries that remains to be shifted from HCFC-22 to a zero O DP alternative. Because of the high GWP of R410A, investigations into medium and low GWP altern atives 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 a ir conditioning systems primarily consisting of HFCs and unsaturated HFCs, such as R-444B, R-446A a nd R-447A. Although there is concern over the use of R-410A in high ambient temperatures, app ropriate design measures can be used to help remedy the relatively greater degradation in perfor mance; 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 differe nt manufacturers and countries will opt for a varie ty of alternatives before any single option is chosen (if at all). In the meantime, investigations will cont inue into medium GWP flammable HFCs, HFC/unsaturated HFC blends and HCs for normal operating conditions as well as high ambient temperature cond itions.



### Water heating heat pumps

Current status

Air-to-water and water-to-water heat pumps have exp erienced significant growth in Japan, Australia, China, and Europe during the last ten years. HCFC-2 2 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 Japa n 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 h eat 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, co st effective, safe and easy to use solution. It is expected that other regions will follow the tendenc y 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 t he necessary safety regulations in relation to thei r 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 us ed 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 ch illers is moving along well. The CFCs have been essentially phased out for new equipment and the CF C banks are decreasing in existing chillers. The current generation of chillers using zero-ODP refri gerants had been introduced without a sacrifice in2014 TOC Refrigeration, A/C and Heat Pumps Assessme nt 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 c hillers and had been recently announced in vapour compression based chillers. The use of HCFC-22 in n ew equipment has been phased out in developed countries; many Article 5 countries also have stopp ed 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, ther efore, 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 high er-GWP refrigerants currently in use.

The way forward

Testing of new, lower GWP refrigerants started seve ral years ago and is continuing. At this juncture i t is not clear which refrigerants may be selected for commercialisation. Tradeoffs are apparent among GWP, energy efficiency, safety, and applied cost. R efrigerants that are non-flammable with the A1 refrigerant safety classification generally have GW Ps of 600 or more. Refrigerants with low GWP (<150) generally are flammable. All flammable refri gerants require special safety considerations. A2L refrigerants will not be widely used without change s 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 syst ems, but there are still cars in use especially in Article 5 countries. In order to meet the EU MAC Di rective 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-1 234yf, 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 syst ems 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. Mo st new bus or train air conditioning systems are currently equipped with the refrigerants HFC-134a o r 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 o ne 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) ma y 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 condi tioning market will be significantly governed by additional considerations like safety, costs, regul atory approval, system reliability, heat pump capability (especially for electric driven vehicles ) and servicing. At the moment, it cannot be forese en2014 TOC Refrigeration, A/C and Heat Pumps Assessme nt Report

20 whether or not the old and the new refrigerants wil l see parallel use in the market for a long period of time. Without existing regulations it is also uncle ar whether the bus and train sector will follow the se trends.



### Sustainable refrigeration

Current status

Refrigeration, air conditioning, and heat pump equi pment are vital means to address the human fundamental needs in areas such as food conservatio n, food security, health care, water heating, and thermal comfort worldwide. There are however a numb er of negative environmental impacts from the use of such equipment that need to be minimized thr ough 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 assessmen t when choosing new refrigerants, by reducing CO 2 emissions along the equipment life cycle, and throu gh environmentally sound and socially fair end of life procedures.

The way forward

Enhancement towards sustainability demands proper n ational and regional regulation, expansion of voluntary programs aiming higher levels of energy e fficiency, adoption of state-of-the-art energy management technologies, use of life cycle assessme nt tools, expansion of awareness and training initiatives across the industry value chain.2014 TOC Refrigeration, A/C and Heat Pumps Assessme nt Report 21



## Executive Summaries of all Chapters

Refrigerants
The chapter discusses and provides tabular summarie s for identifiers as well as physical, safety, and environmental data for refrigerants and includes br ief descriptions of refrigerants treated in this re port.

Whatever refrigerant is chosen will always have to be a balance between several factors, the availability and cost of the refrigerant (and the a ssociated equipment), the system energy efficiency, the safety and convenience of applicability, enviro nmental issues and many more.

The perfect refrigerant does not exist, and is unli kely 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 prop osed which create a challenge of finding the right refrigerant for each application. In some cas es this may be as simple as changing the refrigeran t, while in most cases this will require redesign of t he 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 flammabl e to some extent.

So far 21 refrigerants obtained standardized design ations and safety classifications since the 2010 RTOC assessment report. One new molecule HCFC-1233z d(E) is in this group of new refrigerants and is an unsaturated HCFC (also referred to as HCFO) w ith potential to replace HCFC-123. Approximately one quarter of the new refrigerants a re blends which are replacements for HCFC-22. Of the new refrigerants twelve are blends of satura ted 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 refr igeration, but represent a small fraction of total units.

Globally, new refrigerator production conversion fr om the use of ODS was essentially completed by 2008. HC-600a or HFC-134a continue to be the refrig erant options for new production. No other new refrigerant has matured to become an energy-eff icient and cost-competitive alternative. Refrigerant migration from HFC-134a to HC-600a is e xpected to continue, driven either by local regulations on HFCs or by the desire for reduced gl obal warming impact from potential emissions. Excluding any influence from regulatory interventio ns, it is still projected that by 2020 about 75% of new refrigerator production will use HC-600a (po ssibly with a small share by unsaturated HFC refrigerants) and the rest will use HFC-134a.

According to some industrial sources, initial devel opments to assess the use of HFC-1234yf in domestic refrigeration have begun, but it is not be ing pursued with high priority, as in automotive applications. Given the cost disadvantage, flammabi lity and investment requirements for product development, HFC-1234yf suffers significant disadva ntages. 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 n oise, portability or no access to the electrical2014 TOC Refrigeration, A/C and Heat Pumps Assessme nt Report

22 energy distribution network. In the absence of uniq ue drivers, no identified technology is cost or efficiency competitive with conventional vapour-com pression technology for mass-produced domestic refrigerators.

The other domestic appliance covered in this chapte r is the heat pump clothe (laundry) dryer (HPCD). It is included in this chapter for the firs t time and the title has been accordingly modified as “Domestic Appliances” instead of “Domestic Refriger ators” 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. Thes e 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 refrigera nt solutions are being explored, including R-744, HC-600a and low GWP HFCs.

Non-Article 5 countries completed conversions of ne w 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 pr oducts containing ozone depleting refrigerants are now approaching the end of their life cycle. Field conversion to non-ODS refrigerants has significantl y lagged original equipment conversion. The distribut ed and individual proprietor character of the service industry is a barrier to co-ordinated effor ts to convert from ODS refrigerants. Field service procedures typically use originally specified refri gerants. Refrigerant blends developed specifically for use as drop-in service alternatives have had limite d success.

Both mandatory and voluntary energy efficiency regu lation programs catalysed industry product efficiency development efforts. A number of improve d energy efficiency design options are fully mature, and future improvements of these options ar e 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 produc t 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 fie ld charged) installed mainly in small shops and restau rants, and self-contained or stand-alone units (refrigerant is factory charged). On a global basis , HCFC-22 continues to represent a large refrigeran t 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 th e last decade, HCs --for low refrigerant charge systems-- and CO 2 --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 H CFC-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 develope d countries. Lower GWP HFC and HFC blends, hydrocarbons and CO 2 are replacing R-404A and HFC-134a in new stand-alo ne equipment. Minimum energy standards have been issued or update d in many countries making a new competition between manufacturers in order to reach higher ener gy efficiency in stand-alone systems.

Condensing Units: Condensing units are designed for several capacitie s 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 a ll Article 5 countries. For new systems, R-404A is still the leading choice, and intermediate blends s uch 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 Assessme nt Report 23

Supermarket systems: The size of centralised systems can vary from refri gerating 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 countr ies, HCFC-22 is still the dominant refrigerant used in centralised systems. In Europe, new systems have be en mainly charged with R-404A; R-744 is now taking a significant market share with improved ene rgy 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 CO 2 at the low and the medium temperature levels. For large supermarkets, the cascade system is preferred with CO 2 at the low temperature level and CO 2 or HFC-134a at the medium temperature level. Distribut ed 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 refr igerant content by more than 50% and to drastically lower refrigerant emission levels. For developing c ountries, 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 ha s 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 refriger ants R-717 and R-744. This transition is slow and is constrained by a lack of trained personnel and l ack of experience of the local end-users. It has be en 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 operatio nal experience and lessons learned from existing systems. This conclusion has been reinforced by sev eral recent fatal accidents in Article 5 countries. These accidents appear to be caused by the acceptan ce 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 Sta ndardization (ISO).

In markets where R-717 is accepted as the preferred refrigerant there is no indication of any likeliho od 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 refrigeran t price and long term availability in bulk quantities then new fluids, which are expected to be even mor e expensive than current HFCs will not be any more su ccessful. There are a few exceptions to this general rule. For example, HFC-1234ze(E) has been d emonstrated in large district heating systems as a possible replacement for HFC-134a, however its pe rformance is not any better than HFC-134a which is already limited in application and efficiency co mpared for example with R-717. HFC-1234ze(E) has also been demonstrated in centrifugal chillers whic h 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 twent y 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 b e 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 comprisi ng delivery of chilled or frozen products by means of trucks, trailers, vans, intermodal containers an d boxes. It also includes the use of refrigeration and2014 TOC Refrigeration, A/C and Heat Pumps Assessme nt Report

24 air conditioning on merchant, naval and fishing ves sels 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, diffe rences 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 eff iciency, but the safety risks in transport refrigeration applications appear significant and m ust be mitigated. On the other hand, R-744 has been tested in the field since 2011. Its non-flammable c haracteristics make R-744 attractive, but the gap i n efficiency in high ambient temperatures and the lim ited component supply base are limiting its penetration into the market.

Recently there has been an initiative to consider t he design and service best practices for flammable and high pressure refrigerants which it is hoped wi ll lead to a fast track ISO standard on how these refrigerants can be applied to intermodal container refrigeration. The framework of this initiative ha s not yet been set.

In the case of a regulation banning the use of refr igerants 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 performa nces are relatively close. Candidates include but are not limited to R-407A, R-407F, R-448A, R-449A a nd R-452A.

One also sees “non-conventional” solutions such as open loop systems or eutectic systems. These solutions offer specific advantages in some transpo rt routes, furthermore, the fact that vehicles are HFC free and that the supporting installation can b e HFC free will continue making them attractive.

New information about vessel type and existing refr igerant 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 futur e. The designers must factor in specific safety requir ements, space and reliability, but in general, they closely follow developments in industrial and air-c onditioning systems.

Based on research, the road vehicle fleet size prev iously estimated at 4 million --in the 2006 and 201 0 RTOC Assessment Reports-- has been downsized to 2 m illion. 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 st ill 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 so me 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 Artic le 5 countries continue to utilise HCFC-22 as the predominant refrigerant in air conditioning app lications, although several major producing countries within Asia, Middle East and South Americ a are now initiating HCFC Phase-out Management Plans (HPMPs) to introduce non-ODS alter natives.

R-410A is the dominant alternative to HCFC-22 in ai r-conditioners and is being used in manufacturing in most non-Article 5 and several Article 5 countri es. 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 currently2014 TOC Refrigeration, A/C and Heat Pumps Assessme nt Report 25

decreasing although it is still preferred in for re gions with high ambient temperatures. The other mai n 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 an d R-447A (but also many currently without R-number designations).

Except for R-744, all of the medium and low GWP alt ernatives are flammable and should be applied in accordance with appropriate regulations and/or s afety standards (that are continuously under development), considering refrigerant charge amount , risk measures and other special construction requirements. Some safety standards limit the syste m 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 regulation s 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 A tex directive). Most manufacturers apply the safety standards. Some countries are introducing bans on i mports of HFC-containing air conditioners.

HC-290 and HC-1270 are mainly considered for system s with smaller charge sizes, whilst the operating pressures and capacities are similar to H CFC-22 and the efficiency is higher than HCFC-22. Split air conditioning systems using HC-290 have be en available in Europe and Australia, are in production in India and HCFC-22 equipment productio n 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 curre ntly under evaluation for systems with smaller charge sizes due to flammability. The operating pre ssure 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 co nditioners and has recently been applied in split u nits in several countries and some OEMs are also conside ring 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-410 A. 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 h ave been assigned R-numbers, such as R444B, R-446A and R-447A, whilst most are still unde r 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 GW Ps) and class 2L (medium GWPs). Currently, most of these mixtures are not commercially availab le 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 repl acement for HCFC-22 in air conditioners principally because of their low volumetric refrigerating capac ity.

A major concern in some regions is the efficacy of the various alternatives to HCFC-22 in high ambient conditions (particularly R-410A). Whilst th is problem for R-410A can be addressed through design and selection, work has fairly recently been carried out on a number of other alternatives, suc h as HC-290 and some of the new blends of HFCs and un saturated HFCs, that show that performance degradation with higher ambient temperatures is sim ilar to or not notably worse than with HCFC-22. Another issue is the possible impact on required re frigerant 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, whe re additional (safety) measures would then have to be applied to the equipment. Systems using low-G WP 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 the re are heat pump water heaters, space heating heat pumps and combined space and hot water heat pumps. The required warm water temperature affects2014 TOC Refrigeration, A/C and Heat Pumps Assessme nt Report

26 the selection of refrigerant. Heat pump systems are more efficient at lower sink temperatures, but eac h product must fulfil the required operating temperat ure. The main use of heat pumps is to replace fossi l fuel water heating systems. This is done with the p urpose 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 an d have direct impacts on the selection of the refrigerant.

Most heat pumps commercialised today make use of no n-ODS refrigerants. Refrigerants used are R-410A, HFC-134a, R-407C, HC-290, HC-600a, R-717 an d R-744. The majority of new equipment uses R-410A. In some Article 5 countries, HCFC-22 i s 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 rel ated to pressure, lubrication and contamination control are well known. Replacements are commercial ly 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. T he 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. Repl acements such as HFC-32 and other low-GWP HFC blends are under way to become commercially ava ilable.

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-13 4a 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 glo bal warming impact. The issue, then, is to determine which of the new refrigerants has high en ergy efficiency in chillers while being safe to use and having acceptable application costs. Though mos t HFCs in use today are considered to have relatively high GWPs, this is not a governing facto r for chillers because emissions are minimal.

The required global phase-out of HCFCs and the needto manage the lifetime operation of HCFCbased equipment, coupled with concerns to reduce gl obal 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 rep lace 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 o r blends which may contain HFCs, HCs, and/or unsaturated HFCs. A number of the new candidates ha ve 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 candidat es successfully.



### Vehicle air conditioning
In spite of existing regulations in the US (support ing the use of low-GWP refrigerants) and legislatio n in Europe (banning the use of refrigerants with GWP > 150), the overwhelming majority at present2014 TOC Refrigeration, A/C and Heat Pumps Assessme nt Report 27

(year 2014) of the newly sold passenger cars and li ght trucks worldwide are still equipped with air conditioning systems, which use HFC-134a as refrige rant.

At the end of 2014 it looks likely that more than o ne 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) ma y be implemented and R-744 is expected to be implemented by 2017. All options have GWPs below th e 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 uncle ar whether the bus and train sector will follow these trends.

The global warming impact is almost identical for t he above mentioned refrigerant options when considered on a global basis and in comparison to t he CO 2 tailpipe emissions. Adoption of any of the refrigerant choices would therefore be of similar e nvironmental benefit. The decision of which refrigerant to choose will have to be made based on other considerations. Here, especially safety, cos t, and system reliability are important concerns, but also other aspects have to be taken into account, l ike regulatory approval, heat pump capability, suitabil ity for hybrid electric vehicles, servicing, and ri sk of illegal use of high-GWP refrigerants in systems des igned for low-GWP refrigerants. In the year 2012, HFC-1234yf seemed to be the worldwide accepted alte rnative 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 d evelop 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-1234y f, these decisions are subject to change as the OEMs continue their pursuit of alternative refriger ants to meet regulatory requirements and other concerns mentioned above.

Owing to safety concerns hydrocarbons and their ble nds are not considered as viable refrigerant options by OEMs. Although HFC-1234yf is also flamma ble, it has a lower heat of combustion, burning velocity and minimum ignition energy compar ed to hydrocarbons, and has been the subject of several safety assessments by OEMs and other resear ch 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-ki nd refrigeration concepts. However, the development status of such refrigeration technologi es, like sorption, thermoelectric or magneto calori c systems, are still far away from serial production and presently show very poor price competitiveness and poor system performance and efficiency. These c oncepts 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 h ermetic electrically driven compressors introduces new challenges for any new alternative r efrigerant.

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 th e 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 Assessme nt Report

28 

### Sustainable refrigeration
Refrigeration, air conditioning, and heat pump equi pment are vital means for sustainability to address the fundamental needs of humans in areas su ch as food conservation, food security, healthcare, water heating, and thermal comfort worl dwide. 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 mini mized by:

a. The use of assessment tools enabling manufacturers to plan for continual improvement of the design and operation of their equipment. A numb er of available assessment tools are referenced in this chapter.

b. The careful choice of refrigerants with lower envir onmental 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 a s those in the development process, stresses the need of conveying updated, unbiased in formation 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 r efrigerant emissions, through:

 Charge minimization through simple measures such as checking the amount of refrigerant being charged, or by innovative technol ogies such as cascade systems and secondary loops;

 Improved design for leak tightness;

 Care taken during manufacturing, installation, serv ice, and maintenance;

 Refrigerant conservation, using commercially availa ble equipment for recovery, recycling and recovery, as well as destruction of r efrigerants at the end of life.

d. The reduction of CO 2 emissions from energy use, achievable through:

 Minimum energy efficiency performance standards app lied through national regulation;

 The use of renewable energy sources; and

 Better energy management related to smart grid tech nologies, waste energy analysis, heat recovery, and anti-cyclical storage.

e. The adoption and enforcement of responsible nationa l and regional policies, legal requirements, and voluntary initiatives aiming to r educe refrigerant emissions through ban on venting and other measures.

f. Environmentally sound end-of-life procedures in res ponse to the growing demand of national and regional regulations.2014 TOC Refrigeration, A/C and Heat Pumps Assessme nt Report 29 

## Chapter 1

___________________________________________________ _______ Introduction

Chapter Lead Authors

Lambert Kuijpers Roberto de A. Peixoto2014 TOC Refrigeration, A/C and Heat Pumps Assessme nt Report

302014 TOC Refrigeration, A/C and Heat Pumps Assessme nt 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 n egotiations resulted in the Vienna Convention for the Protection of the Ozone Layer, a dopted 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 c ountries Egypt, Ghana, Kenya, Mexico, Panama, Senegal, Togo and Venezuela, as wel l as the European Community, signed the Montreal Protocol on Substances that Deplete th e Ozone Layer. The Montreal Protocol entered into force on January 1, 1989. This interna tional 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 halo ns 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 indica ted that depletion had already occurred. Consequently, many countries called for further act ions to protect the ozone layer by expanding and strengthening the original control pr ovisions of the Montreal Protocol, and they decided that a first assessment should be carr ied out in the year 1989. Numerous assessments followed.

The 23rd Meeting of the Parties, held in Montreal i n Bali, Indonesia, November 2011, considered the 2010 Assessment Reports, next to a l arge number of other issues. Parties decided to request the Assessment Panels to update their 20 10 reports in 2014 and submit them to the Secretariat by 31 December 2014 for con sideration by the Open-ended Working Group and by the Twenty-Seventh Meeting of the Part ies 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 f or the reduction and elimination of ozone-depleting substances through the use of alter natives, taking into account their impact on climate change and overall environmental performance; (d) Technical progress on the recovery, reuse and d estruction of ozone-depleting substances; (e) Accounting for: the production and use in vario us applications of ozone-depleting substances; ozone-depleting substances in inventori es; ozone depleting substances in products; and the production and use in various app lications of very short-lived substances; (f) Accounting of emissions of all relevant ozone-d epleting substances with a view to updating continuously use patterns and co-ordinatin g 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 Asse ssment Reports-- forms the direct response to the above-mentioned decision.2014 TOC Refrigeration, A/C and Heat Pumps Assessme nt Report

32 

### 1.2 The UNEP Technology and Economic Assessment Pan el Four Assessment Panels were defined in the original Montreal Protocol as signed 1987, i.e. Assessment Panels on (1) Science, and on (2) Enviro nmental Effects, (3) a Technical Assessment and (4) an Economics Assessment Panel. T he Panels were established in 1988- 89; their Terms of Reference can be found in the Me eting Report of the 1st Meeting of the Parties, held in Helsinki in 1989. Under the Techni cal 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 Tech nical 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 on e from an Article 5 country. After the discussions on methyl bromide held at the meeting i n Copenhagen, the Methyl Bromide Technical Options Committee was founded at The Hagu e in early 1993. From 1993 until 2001, the UNEP Technology and Economic Assessment P anel (TEAP) had 7 standing Technical Options Committees (TOCs). In 2001, the E conomics Options Committee was disbanded, which resulted in a number of 6 Committe es. 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 So lvents 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 th e 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 equipm ent, of use patterns, of trade, imports and exports etc. In the case of the Medical and the Met hyl Bromide Technical Options Committees, the emphasis of the work has largely sh ifted to the evaluation and recommendation of certain essential (MTOC) and crit ical (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 re duction schedule for production and consumption was defined for the period 2013-2030, w ith a freeze in 2013 and a servicing tail until 2040. Apart from the specific percentages, th e decision mentioned:

“....To encourage Parties to promote the selection of alternatives to HCFCs that minimize environmental impacts, in particular impacts on cli mate, as well as meeting other health, safety and economic considerations” and “....To agree that the Executive Committee, when deve loping and applying funding criteria for projects and programmes, and taking into accoun t paragraph 6, give priority to costeffective projects and programmes which focus on, inter alia :2014 TOC Refrigeration, A/C and Heat Pumps Assessme nt Report 33

“Phasing-out first those HCFCs with higher ozone-de pleting potential, taking into account national circumstances”, and “Substitutes and alternatives that minimize other i mpacts on the environment, including on the climate, taking into account global-warming pot ential, energy use and other relevant factors.”

In this decision it became clear that climate consi derations, i.e., a focus on substitutes with an overall low climate impact, became very important i n the conversion away from HCFCs.

As a first consequence of Decision XIX/6, the Parti es requested the TEAP and its RTOC in Decision XIX/8, to report on the status of substitu tes and alternatives to HCFCs under high ambient conditions. The report was done by a Subcom mittee of the RTOC, and submitted to Parties in a preliminary form in 2009 and in its fi nal form in 2010.

In 2008, Parties requested the TEAP and its committ ees, 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 info rmation 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 alternati ves, 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 r eport 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 assessmen t reports to be submitted by the end of 2014, requesting information on the costs of altern atives to HCFCs, on alternatives that were technically proven, economically viable, environmen tally benign, and which could be used in high ambient temperature conditions.

The information requested for these Task Force repo rts was very much related to the information requested on how to deal with a convers ion from ODS (particularly HCFCs) to environmentally sound alternatives (which definitio n includes low global warming characteristics). For the report under Decision XXI V7, Parties requested to update information on alternatives, but also to identify b arriers and restrictions to the adoption of environmentally sound alternatives, as well as an e stimation of the approximate amount of alternatives with negative environmental impacts th at could be avoided. The Task Force XXIV/7 report elaborated on the methodological appr oach, gave a long description of the alternatives that would be environmentally sound, i n particular for the RAC, foams, as well as the fire protection and solvents sectors. It also d etermined amounts on alternatives with negative environmental impacts that could be avoide d (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 envi ronmentally sound, easy and safe to use (also in high urban densities), alternatives that w ould 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 r equested 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 alte rnatives.2014 TOC Refrigeration, A/C and Heat Pumps Assessme nt Report

34 The XVV/5 reported in two steps, with a draft repor t for the OEWG in 2014 and a final report for the MOP of the Parties in that same year. The r eport presented a long list of alternatives available and alternatives that would become availa ble, it listed GWPs and costs for alternatives as far as information was available an d mentioned information related to the operation under high ambient conditions -- where av ailable. It reported on alternatives and future developments for the refrigeration, AC, foam s, fire protection, medical uses and solvents sectors.

The XXV/5 report also presented demand scenarios fo r the period up to 2030 for environmentally sound alternatives to ODS for the s ectors refrigeration and AC and foams. BAU scenarios were defined for non-Article 5 and Ar ticle 5 Parties, and it was decided to present two mitigation scenarios for the demand, ba sed upon bans for certain refrigerant (blowing agent) chemicals in certain years. In thes e scenarios it was shown that the demand in the RAC sector was very much dominant over the dema nd in other sectors. The assumption of two types of mitigation scenarios showed that the g rowth of high global warming alternatives could be curbed. This would be possible with certai n plausible (partly already ongoing) measures in non-Article 5 countries. Furthermore, s tringent (but still plausible) measures as of 2020-2030 could lead to a real reduction of the dem and for non-environmentally benign alternatives during the period 2020-2030 in Article 5 countries.

As an example, the XXV/5 Task Force reported that t he first (MIT-1) scenario could cumulatively deliver a saving of 3,000 Mtonnes CO 2 -eq. by 2030 and that the second (MIT-2) could deliver 11,000 Mtonnes CO 2 -eq over that same time period.

As a result of the discussions concerning the infor mation provided in the XXV/5 report, Parties requested an update of the report via Decis ion XXVI/9. This report is expected to be delivered by a TEAP Task Force in the course of 201 5, that is, after that this 2014 Assessment Report has been published. Amongst other informatio n, the XXVI/9 report will use information from the XXV/5 Task Force report and fr om the RTOC 2014 Assessment Report.

The information collected for the various Task Forc e 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 Inte rnet (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 g uidelines 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 updat e information on nominations and operational procedures of the TEAP and its technica l committees, also related to the duration of appointments and various other procedures. Deliv ery 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 disclosur e and conflict of interest guidelines for the TEAP and its technical options committees and t emporary subsidiary bodies. Decision XXV/6 requested information on issues such as the i mplementation as well as the proposed configuration of the TOCs as of 1/1/2015; it also r equested 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 Pump s 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 Opt ions Committees. The six Committees consisted of more than 120 experts from a large num ber of countries (for a list, see the annex2014 TOC Refrigeration, A/C and Heat Pumps Assessme nt Report 35

to the Technology and Economic Assessment Panel Rep ort 2014). The 2014 Refrigeration, AC and Heat Pumps Assessment forms an important par t 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 pee r review before final release. The final version of the reports will be distributed internat ionally 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”) f orms part of the UNEP review pursuant to Article 6 of the Montreal Protocol.

It is part of the 2014 assessment work of the Techn ology and Economic Assessment Panel (requested by the Parties in Montreal (Decision XXI II/11)). The information collected (particularly in the form of the Executive Summarie s) will also be part of the Technology and Economic Assessment Report 2014, as well as the ove rall 2014 Synthesis Report composed by the three Assessment Panel co-chairs, the beginn ing 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 proper ties, on the different R/AC application areas and one chapter on sustainable refrigeration. The s tructure of the report was chosen more or less similar to the structure of the 2010 RTOC Asse ssment Report.

Table 1-1: "Member countries" of UNEP's Refrigerat ion, 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 i n the specific sector, and the chapter was chaired by a Chapter Lead Author - who did the larg er part of the drafting and the coordination.

The 2014 RTOC included 40 representatives from Asia n, European, Middle-East, Latin and North American companies, universities and governme nts, as well as independent experts (see Table 1-1). These representatives have been fu ll (reporting) members; as resource persons the RTOC also had a small number of reviewi ng members.

Affiliations of the members are listed in Table 1-2 (40 organisations (including consultancies) were involved in the drafting of the report). The n ames 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, preliminar y 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 German y (Karlsruhe), December 2014.2014 TOC Refrigeration, A/C and Heat Pumps Assessme nt Report

36 Table 1-2: Affiliations of the members of UNEP's T echnical Options Committee on Refrigeration, A/C and Heat Pumps 1 A/genT Consultancy (Tech. Univ., Eindhoven) Nethe rlands 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 in stitutions 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., bet ween 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 fo r a study by the Chapter Lead Authors before the RTOC Meeting in December 2014. The RTOC members in plenary decided on2014 TOC Refrigeration, A/C and Heat Pumps Assessme nt Report 37

whether or not to amend the text on the basis of th e 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 Co nditioning and Heating AHRI Air Conditioning, Heating and Refrigeration In stitute AREMA AC and Refr Equipment Manufacturers Associati on of Australia CAR Chinese Association of Refrigeration CHEAA China Household Electric Appliances Associati on CRAA Chinese Refrigeration and Air Conditioning Ass ociation DKV German Refrigeration Association EIA Environmental Investigation Agency EPEE European Partnership for Environment and Energ y Eurammon European Industry Association for Ammonia etc. JRAIA Japanese Refrigeration and Air-conditioning I ndustry 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 fluoroc arbons) SAE Society of Automobile Engineers (via members At kinson, Hill) Shecco A Market Development Expert helping companie s 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 Zealan d)



### 1.4 Refrigeration, air conditioning and heat pumps

1.4.1 General remarks Refrigeration, air conditioning and heat pump appli cations 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 d ifficult to give but as an average for the developed countries, its share in electricity use i s 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 continuou sly refrigerated. While the yearly consumption of electricity may be huge, and where t he investment in machinery and equipment may approach US$100,000 million, the valu e 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 ch emicals (such as CFCs in the past, and HCFCs in Article 5 countries in the foreseeable fut ure) have been and still are difficult to estimate.

Refrigeration and air conditioning applications var y enormously in size and temperature level. A domestic refrigerator has an electrical input bet ween 50-250 W and contains less than 30- 150 g of refrigerant (dependent on the type of refr igerant), whereas industrial refrigeration and cold storage is characterised by temperatures b etween -10 C and -40 C, with electrical inputs up to several MW and refrigerant contents of many hundred kilograms. Air2014 TOC Refrigeration, A/C and Heat Pumps Assessme nt Report

38 conditioning and heat pumps may show evaporation te mperatures between 0 C and +10 C, significantly different from refrigeration applicat ions, 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 re frigeration, (iii) comfort air conditioning, from air cooled equipment to water chillers, includ ing 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 n umber of separate chapters or sections.

Options and aspects for the refrigeration vapour co mpression cycle deserve most attention, since it is unlikely that during the next 10-20 yea rs other principles will take over a substantial part of the market. In all application sectors desc ribed in the separate chapters in this report, most of the attention is focused on the vapour comp ression 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 vapo ur compression cycle is rather complex, since a large number of parameters need to be inves tigated 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 atm ospheric lifetime.

These selection criteria were elaborated upon in va rious chapters of various UNEP RTOC Assessment Reports, and these selection criteria ha ve not changed during the last years. Since then, it is the emphasis on the emissions of greenh ouse 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 parti cular, depends on the availability of sufficient energy and on the availability of effici ent 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 i n the developed countries, and the CFC phase-out in the developing countries, which was sc heduled for 2010, has been completed. Where HCFCs have been largely phased out in the dev eloped countries, the phase-out in the Article 5 countries is now asking full attention. I n both developed and developing countries, HFCs have so far been important substitutes for CFC s and HCFCs. In many applications, alternatives to HCFCs have become commercially avai lable, as pure HFCs, as blends of HFCs or as non-HFC alternatives. Therefore, HFCs ha ve gained a large share of the replacement market. In particular the necessary inc entives remain to be provided to Article 5 countries to transition from HCFCs to non-HCFC refr igerants, which will include both HFCs and non-fluorocarbon alternatives.2014 TOC Refrigeration, A/C and Heat Pumps Assessme nt Report 39

It should be noted, however, that the changing refr igerant options are only part of the driving force for innovations in refrigeration and A/C equi pment. 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 compressio n methods such as absorption, adsorption, Stirling and air cycles etc. may become more import ant; 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 a nd 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 (stil l) widely used in many sectors, low GWP HFCs and low GWP HFC blends are now increasingl y being applied. Ammonia and hydrocarbons enjoy growth in sectors where they can be easily accommodated, and for certain applications, CO 2 equipment is being further developed and a large nu mber of CO 2 demonstration installations have been extensively t ested on the market. It may well be that CO 2 will take a substantial part of the commercial ref rigeration equipment market. Water is used and may see some increase in use in limited ap plications. Work is being done by several committees in developing standards to permit the ap plication of new refrigerants, and it is the intent of companies to reach world-wide accepted li mits in those different standards.

Similarly, energy efficiency research is partly spu rred by the role of energy production in carbon dioxide emissions. Options for energy effici ent operation of equipment form an important issue in each of the chapters of this 201 4 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 aspec ts. It elaborates on Ozone Depleting Potentials, and on ODP and GWP data for reporting p urposes. 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 e fficiency improvements etc. Particularly the energy efficiency aspect plays an important rol e 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 c old storage, chapter 6 with transport refrigeration. Chapters 7 and 8 deal with air condi tioning and heat pumps. Chapter 9 deals with the various aspects of chillers, which include s important considerations on energy efficiency. Chapter 10 describes the options for mo bile air conditioning; in a first instance, it deals extensively with HFC-134a, but it also evalua tes 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 i n refrigeration.

All chapters have drafted an executive summary; the se summaries were put together and are presented in the first part of the report. The exec utive summaries are preceded by a shortened2014 TOC Refrigeration, A/C and Heat Pumps Assessme nt Report

40 (“abstract”) executive summary (e.g. for policy mak ers) which has been abstracted from the separate executive summaries. This is again precede d by key messages derived from the abstract executive summaries.2014 TOC Refrigeration, A/C and Heat Pumps Assessme nt 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 Vonsild2014 TOC Refrigeration, A/C and Heat Pumps Assessme nt Report

422014 TOC Refrigeration, A/C and Heat Pumps Assessme nt Report 43



## 2 Refrigerants

2.1 Introduction Since the 2010 assessment report 21 refrigerants ob tained standardized designations and safety classifications. One new molecule, HCFC-1233 zd(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 clim ate and ozone concerns, in particular by reducing the GWP of the refrigerant and replacing o zone-depleting substances.

The search for new refrigerants addresses both clim ate 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 encompasse s four phases based on defining selection criteria (Calm, 1997; Calm, 2012):

 1830s-1930s – whatever worked: primarily familiar s olvents and other volatile fluids including ethers, ammonia (NH 3 , R-717), carbon dioxide (CO 2 , R-744), sulphur dioxide (SO 2 , R-764), methyl formate (HCOOCH 3 , R-611), HCs, water (H 2 O, R-718), carbon tetrachloride (CCl 4 , R-10), hydrochlorocarbons (HCCs), and others; man y of them are now regarded as “natural refrigerants” (more exactl y non-fluorinated since nearly all actually are synthesized, refined, or at least indu strially purified).

 1931-1990s – safety and durability: primarily chlor ofluorocarbons (CFCs), hydrochlorofluorocarbons (HCFCs), ammonia, and wate r (mostly used in absorption cycles).

 1990-2010s – stratospheric ozone protection: primar ily HCFCs (for transition use), hydrofluorocarbons (HFCs), ammonia, water, hydrocar bons, and carbon dioxide.

 Beyond 2012 – global warming mitigation: to be dete rmined, but likely to include refrigerants with very low (< 10 -3 ) or no ozone depletion potential (ODP), low global warming potential (GWP), and high efficiency; likel y 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 refrigeran ts with high GWPs, the major refrigerant manufacturers have pursued unsaturated fluorochemic als. They are chemicals consisting of two or more carbon atoms with at least one double b ond between two or more of them as well as fluorine, hydrogen, and possibly also chlorine o r other halogens. Unsaturated fluorocarbons also are identified as fluoro-alkenes or fluoro-ole fins. Double carbon-carbon bond(s) make(s) the compounds more reactive. The result is short at mospheric lifetimes and, thereby, very low ODPs and GWPs.2014 TOC Refrigeration, A/C and Heat Pumps Assessme nt Report

44 The unsaturated HFC (also identified as hydrofluoro -alkene or hydrofluoro-olefin, HFO) family is a focal example with varying extents of h alogenation, in part, as a trade-off between flammability associated with a lower degree of stab ility 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 unsaturat ed HFCs or more broadly unsaturated hydro-halochemicals is uncertain, though a number o f initial studies looking at the trifluoroacetic acid (TFA) build up resulting from the use of unsaturated HFCs in mobile airconditioning indicate manageable environmental impa cts (Kajihara, 2010; Luecken, 2010; Papasavva, 2009).

2.1.3 Recent assessment on current and future refrigerant s and GWP There are a number of studies providing assessments of a broad number of alternative refrigerants.

For example, the AHRI Low-GWP Alternative Refrigera nts Evaluation Program (AHRI/AREP) phase 1 evaluated more than 30 new refr igerants (AHRI, 2013), most of them blends and most of them based on unsaturated HFCs m ixed with traditional HFCs. The refrigerant categories and corresponding 100 year G WP 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 34-201 3) assigns a safety class for each refrigerant, for instance “A2L”. The first letter o f the safety class describes the toxicity, A for lower level of toxicity and B for higher level of t oxicity, while the second part is the2014 TOC Refrigeration, A/C and Heat Pumps Assessme nt Report 45

flammability of the refrigerant: 1 (no flame propag ation), 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 GW P and flammability. A low GWP can be achieved by having the refrigerant break down quick ly 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 mandator y 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 a mount 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 influen ce, for instance national legislation and building codes. The requirements for flammable refr igerants are very similar across the different flammability classes, the different flamm ability 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 var ious markets will split-up with regard to the classes of flammability. The acceptance of flam mable refrigerants and the appropriate updates of standards and legislation is clearly a c ontemporary 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 inst antaneous or sustained metrics such as the global temperature potential (GTP) (Shine, 2005; Ho dnebrog, 2013; see §8.7 of (IPCC, 2014) for detailed discussions of instantaneous GTP and s ustained GTP).

In this chapter both 20 year GWP and 100 year GWP v alues are listed. The advantage of 20 year GWP over 100 year GWP is that a 20 year time h orizon 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 m ore commonly used and the popularity of a metric is important to the efficiency of communic ating the climate impact. Also the 100 year GWP is better at differentiating between subst ances with longer lifetimes, although this seldom applies to currently used non-ODS refrigeran ts. An example is PFC-116 and HFC143a; the difference in 20 year GWP is less than 20 % while the difference in 100 year GWP2014 TOC Refrigeration, A/C and Heat Pumps Assessme nt Report

46 is more than a factor of 2. As long lived substance s can be used in small amounts in blends with short lived substances to create lower GWP ble nds, 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 climat e impact is the product of the GWP and the amount (in kg) emitted, so even though CO2 is c lassified in Table 2-3 as ultra-low GWP, the amount emitted by the human civilization is lar ge 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 hig h, and high GWP. The purpose of this feature is to allow simple references to all refrig erants 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 u ncertainties are of the order of ±20% and ±30% for 20- and 100-year horizons. For shorter liv ed 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 t he picture is further complicated since, for historical reasons, GWPs for hydrocarbons are i ndirect GWPs, which include breakdown products such as CO 2 , as opposed to the GWPs for HCFCs, HFCs etc., whic h 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 effici ency of the refrigerant in the given application. Emissions from energy production may h ave 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 purpo ses The ODP and GWP data presented in this chapter are based on international scientific assessments and reflect the latest consensus determ inations on potential impacts. However, the reduction requirements and allocations under th e Montreal Protocol, emission reductions and reporting pursuant to the Kyoto Protocol, and p rovisions in many national regulations pursuant to them use older, adopted values.

Table 2-4 compares the latest consensus ODP data (W MO, 2014) and (WMO, 2011) to the “regulatory” ODPs used in the Montreal Protocol (UN EP, 2012). Table 2-5 similarly contrasts the latest consensus GWPs, for a 100 year integrati on, with those used for reporting and emission reductions under the Kyoto Protocol from I PCC (1995).2014 TOC Refrigeration, A/C and Heat Pumps Assessme nt Report 47

Table 2-4: Scientific and regulatory ODPs for sel ected 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 (CO 2 ) 1 1 1 12014 TOC Refrigeration, A/C and Heat Pumps Assessme nt Report

48 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 s ystems 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 applicat ion will be a compromise of the above criteria. Other than zero ODP, the rest of the para meters will to be traded-off against one another to arrive at the optimum for each type of s ystem and application. In particular the carbon emissions include both the “direct” and “ind irect” contribution of the product over its life time. A number of approaches have been documen ted in the literature including: Total Equivalent Warming Impact (TEWI), Life Cycle Climat e Performance (LCCP), Multilateral Fund Climate Impact Indicator (MCII) and other meth ods.

For new refrigerants for existing systems, there ar e 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 t he 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 negli gible 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 reason able cost).

There are a number of other parameters that should be considered. However, in practical terms it is unlikely that any of the commercially a vailable refrigerants can meet all of the above criteria and therefore some compromise should be anticipated.

A refrigerant that is capable of replacing an exist ing refrigerant without changing any major components, including the oil, is sometimes referre d 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 refrig erant type, and the trade-offs mentioned above may affect the performance and durability of the system.2014 TOC Refrigeration, A/C and Heat Pumps Assessme nt Report 49

2.1.8 HCFC-22 replacements The challenge of reducing the use of HCFC-22 has le d to the development of refrigerants specifically designed to replace HCFC-22 in existin g equipment or replace HCFC-22 in new systems without the need for significant design cha nges.
A main differentiator between the HCFC-22 replaceme nts is whether the refrigerant is miscible with the mineral oil often used with HCFC- 22.

The refrigerants which are more miscible with miner al oil typically contain a minute amount (< 4%) of hydrocarbon to increase the miscibility a nd help the oil return to the compressor. These refrigerants typically have safety classifica tion A1 and include: R-417A, R-417B, R417C, R-422A, R-422B, R-422C, R-422D, R-422E, R-424 A, R-425A, R-428A, R-434A, R438A, and R-442A.

The refrigerants that are designed to fit the therm odynamic properties of HCFC-22 refrigerants, but not to be used with the mineral o il often used with HCFC-22 includes: R404A, R-407A, R-407B, R-407C, R-407D, R-407E, R-407 F, R-421A, R-421B, R-427A, R444B, and R-507A. While they typically have the saf ety classification A1, some of the more recent HCFC-22-like blends (specifically R-444B) ha ve the safety classification A2L.

When changing refrigerant in a system there is alwa ys recommended to check gaskets, elastomeric seals, and other materials for compatib ility with the new refrigerant, and there is a risk that exposure to HCFC-22 has changed the prope rties of polymer materials to the point where they will not function correctly or exasperat e leakage after a refrigerant change. There may also be a need for other system modifications t o 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 fo r replacing HCFC-22 with system designs adapted to e.g. R-717, R-744, HCs, HFCs, or other n ewly developed molecules.



### 2.2 Refrigerant descriptions The most important refrigerants discussed in this r eport 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 refrigera nt designation numbers below 400 and from 600 and up, while designation numbers in the 4 00’s and 500’s are mixtures of two or more components. The 400 series are blends with a t emperature glide, known as zeotropes. If the glide is large then exchangers need to be desig ned 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: 201 4) of each refrigerant is stated, and where ISO 817 does not list the refrigerant, the sa fety 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 replaceme nt 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 s ubstance for ODP and has a2014 TOC Refrigeration, A/C and Heat Pumps Assessme nt Report

50 defined ODP of 1. It is a low pressure refrigerant, with similar pressure as

HCFC-123, and has often been replaced with this ref rigerant.
CFC-12 CFC-12 was introduced in 1931 as a replaceme nt to flammable and or toxic

refrigerants used at the time (Calm, 1997) and has been popular in both refrigeration applications and chillers for air-con ditioning. 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 a pplications.
HCFC-22 HCFC-22 was originally used for low tempera ture refrigeration and later airconditioning, and is today the most popular HCFC re frigerant. 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 mi llion metric tonnes at the global level. The energy efficiency of this refrige rant became a reference for the validation of its substitutes: R-404A in commer cial and industrial refrigeration and R-407C and R-410A in air conditio ning. HCFC-22 has a medium pressure similar to R-404A and R-407C, and a s seen in section 2.2.2 below, alternatives to HCFC-22 has been getting att ention in the industry.
HFC-32 HFC-32 was originally used as a component ofrefrigerant 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 clas sed as A2L. The efficiency of HFC-32 systems are higher than R-410A but less t han HCFC-22. Discharge temperatures are higher than R-410A and HCFC-22 and thus some mitigation device or controls may be necessary for handling th e discharge temperature of the compressor especially at high ambient temperatu res.

HCFC-123 HCFC-123 is mainly used in centrifugal chi llers 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 refrigera nt blends such as R-404A and R410A to lower discharge temperature and reduce flam mability 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 a s an A1 refrigerant. Energy efficiency is good, provided that pipes and heat ex changers are suitably sized.

HFC-152a HFC-152a has performance characteristics s imilar 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 co nditioning 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 simil ar to HCFC-22 and HC-290. The lower flammability limit is about 4 times highe r than for HC-290 allowing for a higher charge to be used and thereby higher c ooling capacity to be achieved compared with a system using HC-290.

HFC-245fa HFC-245fa has found limited use in centri fugal chillers, high temperature heat

pumps, and organic Rankine cycle (ORC) power genera tion cycles and is2014 TOC Refrigeration, A/C and Heat Pumps Assessme nt Report 51 classified as B1. Because the high temperature heat pump and ORC are still emerging markets the use may increase. It has opera ting 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 un der most conditions, including high ambient, as well as having low disch arge 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 refriger ation 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 h ave a high temperature lift in a single stage system, hence it being the primar y substitute for R-501. R404A is also used in industrial refrigeration, espe cially 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 o f other 407 refrigerants but in

slightly different proportions. It was originally d eveloped 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. Ho wever, 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 o f other 407 refrigerants but in

slightly different proportions. It has been used wi dely in air conditioning, chiller and heat pump systems, especially to help t he transition from HCFC-22. It is classed as A1. The efficiency is acceptable a nd 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 o f other R-407 refrigerants but in

slightly different proportions. It is used as a rep lacement 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, c hiller and heat pump systems and

is classified as A1. The pressure of R-410A is high er than HCFC-22, the R-407 series and R-404A. Generally the efficiency is equi valent to HCFC-22, especially at lower temperatures, although efficien cy 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 refri geration 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.2014 TOC Refrigeration, A/C and Heat Pumps Assessme nt Report

52 R-444B R-444B can replace HCFC-22 in new AC equipme nt without major

modifications as its pressures are similar. It is c lassified as A2L. R-444B matches the capacity of HCFC-22 with a marginally l ower 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 de sign.

R-446A R-446A can replace R-410A in AC equipment an d is classified as A2L.

Efficiency of R-446A systems is comparable to R-410 A whilst the capacity is lower than R-410A and discharge temperatures are sl ightly higher. Due to its relative higher critical point compared to other re frigerants, R-446A performs well at high ambient temperatures.

R-447A R-447A can replace R-410A in AC equipment an d is classified as A2L. The

efficiency of R-447A systems is at the same level a s R-410A, the capacity is slightly lower and discharge temperatures are sligh tly higher than R-410A. Due to its relative higher critical point compared to o ther refrigerants, R-447A performs well at high ambient temperatures.

R-448A R-448A can replace R-404A in existing and ne w refrigeration equipment and is

classified as A1. This refrigerant has capacity and efficiency similar to R-404A. However, its notable temperature glide may influenc e system design.

R-449A R-449A can replace R-404A in new refrigerati on equipment and is classified as

A1. This refrigerant has a capacity marginally high er 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 equi pment. It is classified as A1. When used in reciprocating or scroll compressors, t his refrigerant produces efficiency levels comparable to HFC-134a, although the capacity is lower.

R-507A R-507A is used widely in commercial refriger ation 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 h ave a high temperature lift in a single stage system (thus being adopted as a r eplacement for R-502). It is also used in industrial refrigeration, especially w hen 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 refri gerant 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 smal l 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 efficien cy. The vapour pressure and refrigerating capacity is similar to HCFC-22. Howev er, R-717 has a very high discharge temperature, so for lower temperature app lications two-stage-2014 TOC Refrigeration, A/C and Heat Pumps Assessme nt Report 53 compression is normally needed. It is not practical ly compatible with copper and copper alloys, which limits the system to welde d 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, H 2 O) is used as refrigerant in vapour compression cyc les at very

low pressures, high compression ratios and high vol umetric flow rates, leading to larger system sizes and a cost premium. It has a lso been tested for high temperature heat pumps with promising results, espe cially 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 absor bent, or as absorbent of ammonia.

R-744 R-744 (carbon dioxide, CO 2 ) 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 v ery low critical temperature, the cycle efficiency declines as the t emperature before the expansion device increases and other features are n eeded to achieve similar (to HCFC-22) efficiency values at higher ambient condit ions. Compared to a basic cycle, 10–20% energy efficiency improvement can be achieved by applying an ejector instead of an ordinary expansion device (Ha fner, 2012) although using an expander alone can bring the efficiency to withi n 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 cann ot be utilised, technology options such as additional compression stages and i nter-cooling may be adopted in the system design. These additional feat ures add to the complexity and cost of the system.

HCFC1233zd(E) HCFC-1233zd(E) is an unsaturated HCFC and has simil ar pressure to that of

HCFC-123. It is classified as A1. When used with ce ntrifugal compressors, this refrigerant produces efficiency levels similar to H CFC-123, allowing the design of systems with very high energy efficiency.

HFC1234yf HFC-1234yf is an unsaturated HFC and can replace HF C-134a in same systems

since the pressure-temperature characteristics are almost identical, It is classified as A2L. In general this refrigerant prod uces 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 b e 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 properti es the efficiency is good under most conditions, including high ambient, as w ell as having low discharge temperatures.2014 TOC Refrigeration, A/C and Heat Pumps Assessme nt Report

54 

### 2.3 Data summary This section summarizes physical, safety, and envir onmental 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; Tab le 2-8 is the summary for zeotropic refrigerant blends, while Table 2-9 covers azeotrop ic refrigerant blends.

Table 2-7: Data summary for single component refr igerantsRefrigerantDesignationChemical FormulaChemical NameMolecular WeightBoiling Point (°C)ATEL/ODL (kg/m3)LFL (kg/m3)Safety ClassAtmosphericLifetime (Years)Radiative Efficiency(W/m/ppm)GWP 100 YearGWP 20 YearODP

Methane series

CFC-11 CCl 3 F trichlorofluoromethane 137,4 24 0,006 2 NF A1 52 0,26 5 160 7 090 1

CFC-12 CCl 2 F 2 dichlorodifluoromethane 120,9 -30 0,088 NF A1 102 0,32 10 300 10 800 0,73
CFC-13 CClF 3 chlorotrifluoromethane 104,5 –81 ND NF A1 640 0,25 13 900 10 900 1

BFC-13B1 CBrF 3 bromotrifluoromethane 148,9 –58 ND NF A1 72 0,30 6 670 7 930 15,2

PFC-14 CF 4 tetrafluoromethane

(carbon tetrafluoride) 88,0 -128 0,40 NF A1 50000 0,09 6 630 4 880

HCFC-22 CHClF 2 chlorodifluoromethane 86,5 -41 0,21 NF A1 12 0,21 1 780 5 310 0,034

HFC-23 CHF 3 trifluoromethane 70,0 -82 0,15 NF A1 228 0,18 12 500 10 800

HCC-30 CH 2 Cl 2 dichloromethane (methylene chloride) 84,9 40 ND NF B1 0,4 0,03 9 33

HFC-32 CH 2 F 2 difluoromethane (methylene fluoride) 52,0 -52 0,30 0,307 A2L 5,4 0,11 704 2 530

HC-50 CH 4 methane 16,0 –161 ND 0,032 A3 12,4 3,63e-4 30 85

Ethane series

CFC-113 CCl 2 FCClF 2 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 CClF 2 CClF 2 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 CClF 2 CF 3 chloropentafluoroethane 154,5 -39 0,76 NF A1 540 0,20 7 310 5 780 0,26
PFC-116 CF 3 CF 3 hexafluoroethane 138,0 -78 0,68 NF A1 10000 0,25 11 100 8 210

HCFC-123 CHCl 2 CF 3 2,2-dichloro-1,1,1- trifluoroethane 152,9 27 0,057 NF B1 1,3 0,15 79 292 0,01

HCFC-124 CHClFCF 3 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 CHF 2 CF 3 pentafluoroethane 120,0 -49 0,37 NF A1 31 0,23 3 450 6 280

HFC-134a CH 2 FCF 3 1,1,1,2-tetrafluoroethane 102,0 -26 0,21 NF A1 14 0,16 1 360 3 810

HCFC-142b CH 3 CClF 2 1-chloro-1,1- difluoroethane 100,5 -10 0,10 0,329 A2 18 0,19 2 070 5 140 0,057

HFC-143a CH 3 CF 3 1,1,1-trifluoroethane 84,0 -47 0,48 0,282 A2L 51 0,16 5 080 7 050
HFC-152a CH 3 CHF 2 1,1-difluoroethane 66,1 -25 0,14 0,130 A2 1,6 0,10 148 545

HC-170 CH 3 CH 3 ethane 30,1 -89 0,008 6 0,038 A3 5,5 20

Ethers

HE-E170 CH 3 OCH 3 methoxymethane (dimethyl ether) 46,1 -25 0,079 0,064 A3 0,015 0,02 1 1
Propane series

PFC-218 CF 3 CF 2 CF 3 octafluoropropane 188,0 -37 0,34 NF A1 2600 0,28 8 900 6 640

HFC-227ea CF 3 CHFCF 3 1,1,1,2,3,3,3- heptafluoropropane 170,0 -16 0,19 NF A1 36 0,26 3 140 5 250

HFC-236fa CF 3 CH 2 CF 3 1,1,1,3,3,3- hexafluroropropane 152,0 -1 0,34 NF A1 242 0,24 8 060 6 940

HFC-245fa CHF 2 CH 2 CF 3 1,1,1,3,3- pentafluoropropane 134,0 15 0,19 NF B1 7,9 0,24 882 2 980

HC-290 CH 3 CH 2 CH 3 propane 44,1 -42 0,09 0,038 A3 12,5 days 5 182014 TOC Refrigeration, A/C and Heat Pumps Assessme nt Report 55 Cyclic organic compounds PFC-C318 -(CF 2 ) 4 - octafluorocyclobutane 200,0 -6 0,65 NF A1 3200 0,32 9 540 7 110 Hydrocarbons
HC-600 CH 3 CH 2 CH 2 CH 3 butane 58,1 0 0,002 4 0,038 A3 4 15
HC-600a CH(CH 3 ) 2 CH 3 2-methylpropane (isobutane) 58,1 -12 0,059 0,043 A3 6,0 days ~20 74

HC-601 CH 3 CH 2 CH 2 -

CH 2 CH 3 Pentane 72,2 36 0,0029 0,035 A3 3,4 days ~20 74

HC-601a CH(CH 3 ) 2 CH 2 -

CH 3 2-methylbutane

(isopentane) 72,2 27 0,0029 0,038 A3 3,4 days ~20 74
Inorganic compounds

R-702 H 2 Hydrogen 2,0 -253 A3 R-704 He Helium 4,0 -269 NF A1

R-717 NH 3 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 N 2 Nitrogen 28,0 -196 NF A1 R-740 Ar Argon 39,9 -186 NF A1

R-744 CO 2 carbon dioxide 44,0 -78c 0,072 NF A1 1,37e-5 1 1 Unsaturated organic compounds
HC-1150 CH 2 =CH 2 ethene (ethylene) 28,1 –104 ND 0,036 A3 3,7 14
HCFC1233zd(E) CF 3 CH=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 CF 3 CF=CH 2 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) CF 3 CH=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 CH 3 CH=CH 2 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 blendsRefrigerantDesignationRefrigerantComposition(Mass %)MolecularWeightBubble Point/Dew Point (°C)ATEL/ODL(kg/m3)LFL (kg/m3)Safety ClassGWP 100 YearGWP 20 YearODP

R-401A R-22/152a/124 (53,0/13,0/34,0) 94,4 -34,4/-2 8,8 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/-3 0,8 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/-2 3,5 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/-3 8,7 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/-3 6,7 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/-3 5,6 0,27 NF A1 1 500 3 900 R-407F R-32/125/134a (30,0/30,0/40,0) 82,1 -46,1/-3 9,7 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/-2 7,5 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/-2 9,7 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 N F A1 2 100 4 400 R-410B R-32/125 (45,0/55,0) 75,6 -51,5/-51,4 0,43 N F A1 2 200 4 6002014 TOC Refrigeration, A/C and Heat Pumps Assessme nt Report

56 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 0,2 8 NF A1 2 600 5 200 R-421B R-125/134a (85,0/15,0) 116,9 -45,7/-42,6 0,3 3 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/-3 1,3 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 0,0 02 1 0,039 A3 1,6 5,5 R-433A R-1270/290 (30,0/70,0) 43,5 -44,6/-44,2 0,00 5 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 0,00 6 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 0,07 3 0,032 A3 12 43 R-436B R-290/600a (52,0/48,0) 49,9 -33,4/-25,0 0,07 1 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/-2 4,3 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 –5 0,3/–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 7002014 TOC Refrigeration, A/C and Heat Pumps Assessme nt 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 refrigeran t blendsRefrigerantDesignationRefrigerantComposition(Mass % )MolecularWeightNormal BoilingPoint (°C)ATEL/ODL(kg/m3)LFL (kg/m3)Safety ClassGWP 100 YearGWP 20 YearODP

R-500 R-12/152a (73,8/26,2) 99,3 -33,6/-33,6 0,12 N F 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 N F 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 10 0 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 0,0 87 0,056 A3 3,3 9,8 R-511A R-290/152a (95,0/5,0) 44,8 -42,18/-42,1 0,09 2 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 seco nd priority and ASHRAE 34 (ASHRAE 34-2013) as third priority.

Molecular Weight: Calculated from the sum of atoms making up the mol ecule (based on the chemical formula). The atomic weights are from IUPA C (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 t hird priority.

Atmospheric Lifetime: Values are taken from Table 5.1 and Table 5.3 in ( WMO, 2014) where available, (IPCC, 2014) is used as 2 nd priority, (WMO, 2011) is used as 3 rd priority, and (IPCC, 2007) is used as 4 th priority.

Radiative Efficiency: Values are taken from (IPCC, 2014) where available and (IPCC, 2007) is used as 2 nd 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 2 nd priority, (WMO, 2011) as 3 rd priority (HC-290), Table 2-14 and 2-2014 TOC Refrigeration, A/C and Heat Pumps Assessme nt Report

58 15 in (IPCC, 2007) as 4 th

priority (HE-E170 and hydrocarbons), and for the r emaining refrigerant (HC-600a, HC-601, HC-601a) the approxim ation of ~20 from (UNEP, 2011) is reused. When considering the GWP values for other h ydrocarbons, 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 p roduct). 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 2 nd priority, (WMO, 2011) does not contain GWP 20 year numbers for the remaining refrigerants therefor (IPCC, 2007) is use d as 3 rd priority. Where values are not available from the above sources (HE-E170 and hydro carbons, 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 GWP x (y) =aGWP x (y)/aGWP CO2 (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 practic ally removed from the atmosphere within the first 20 years and no additional radiative forc ing will be added between the 20 th and the 100 th year. This makes it possible to estimate GWP (20 y ear):

(eq. 2.1)

GWP for hydrocarbons includes breakdown products (a s opposed to the GWP for HFCs), part of the GWP will come from CO 2 , 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 3 rd 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 u ncertainty for the GWP values is on the order of ±20% for very long lived gases and even larger f or shorter lived gases.

Refrigerant Composition, Bubble Point/Dew Point (°C ), Safety Class: ISO 817 (ISO 817:2014) 1 st

priority, ISO 5149 (ISO 5149:2014) in principle 2 nd priority, ASHRAE 34 (ASHRAE 34-2013) 3 rd priority. No information for these tables were sim ultaneously 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 t he 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 Assessme nt Report 59



### 2.4 Concluding remarks
This chapter discussed and provided tabular summari es for identifiers as well as physical, safety, and environmental data for refrigerants inc luding 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 a ssociated equipment), the system energy efficiency, the safety and convenience of applicabi lity, 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 t han most of the currently used substances, and ozone depletion concerns with the replacement r efrigerants 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 re frigerants with lower flammability (2L), raising the question of how to handle flammab ility.

The perfect refrigerant does not exist, and is unli kely to come into existence. The choice will therefore be a selection between the existing low G WP 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 refri gerant for each application. One of the important aspects is that refrigerants with low dir ect impact on climate change are often flammable to some extent.

There is a complex selection process ahead, where t he industry will need to find out which of the many proposed new or old refrigerants will be u sed 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 s earch is a trade-off between cost, safety, energy efficiency, and limiting the need for redesi gn.
Part of the complexity is that the market is unlike ly to be able to support many different refrigerants for the same application. This will le ave 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 Refrigeran ts American Society of Heating, Refrigerating, and Air-Conditio ning Engineers (ASHRAE), Atlanta, GA, USA Calm, 2012 Calm, J. M., 2012. Refrigerant Transitio ns... Again. Moving Towards

Sustainability. Proc. ASHRAE/NIST Conf., American S ociety of Heating Refrigerating, and Air-Conditioning Enginee rs (ASHRAE), Atlanta, GA, USA
Calm, 1997 Calm, J. M., Didion, D. A. 1997. Trade-O ffs 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 (ASHR AE), Atlanta, GA, USA Chen, 2012 Chen, Z. H., 2012. Research on Rotary Co mpressors Based on R-290

Technology. Proc. UNEP conference on technologies f or high2014 TOC Refrigeration, A/C and Heat Pumps Assessme nt Report

60 ambient conditions, Dubai, UAE Hafner, 2012 Hafner, A., Försterling, S., Banasiak, K. 2012. “Multi-Ejektoren

Konzept für R-744 Supermarkt-Kälteanlagen”. Proc. D KV-Tagung, AA III.06, Würzburg, Germany Hodnebrog, 2013 Hodnebrog, Ø., Etminan, M., Fuglest vedt, J. S., Marston, G., Myhre,

G., Nielsen, C. J., Shine, K. P., Wallington, T. J. , 2013. Global Warming Potentials and Radiative Efficiencies of Ha locarbons and Related Compounds: A Comprehensive Review. Rev. Ge ophys., 51, 300–378, doi:10.1002/rog.20013 IPCC, 1995 Intergovernmental Panel on Climate Chang e (IPCC) of the World

Meteorological Organization (WMO) and the United Na tions Environment Programme (UNEP), 1996. Climate Change 1995 — Contribution of Working Group I to the Second Asses sment Report of the Intergovernmental Panel on Climate Change. Edit ed by J. T. Houghton, L. G. Meira Filho, B. A. Callander, N. Ha rris, A. Kattenberg, and K. Maskell, Cambridge University Pr ess, 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. Contributi on of Working Group I to the Fourth Assessment Report of the Inte rgovernmental Panel on Climate Change [Solomon, S., D. Qin, M. Ma nning, Z. Chen, M. Marquis, K.B. Averyt, M.Tignor and H.L. Mi ller (eds.)]. Cambridge University Press, Cambridge, United Kingd om 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, 2 013. Anthropogenic and Natural Radiative Forcing. In: Cl imate Change 2013: The Physical Science Basis. Contribution of W orking Group I to the Fifth Assessment Report of the Intergovernme ntal Panel on Climate Change [Stocker, T.F., D. Qin, G.-K. Plattn er, M. Tignor, S.K. Allen, J. Boschung, A. Nauels, Y. Xia, V. Bex and P.M. Midgley (eds.)]. Cambridge University Press, Cambri dge, United Kingdom and New York, NY, USA ISO 817:2014 ISO 817: 2014. Refrigerants — Designat ion and safety classification.

International Organization for Standardization (ISO ) ISO 5149:2014 ISO 5149: 2014. Refrigerating systems and heat pumps — Safety and

environmental requirements. International Organizat ion for Standardization (ISO) Kajihara, 2010 Kajihara, H., Inoue, K., Yoshida, K. , Nagaosa, R., 2010. Estimation

of environmental concentrations and deposition flux es of R-1234yf and its decomposition products emitted from air con ditioning equipment to atmosphere. Proc. 2010 Int. Symposium on NextGeneration Air Conditioning and Refrigeration Techn ology, paper noNS24, Tokyo, Japan
Luecken, 2010 Luecken, D. J., Waterland, R. L., Tad donio, N., Hutzell, W. T., Rugh,

J. P., Andersen, S. O., 2010. Ozone and TFA Impacts in North2014 TOC Refrigeration, A/C and Heat Pumps Assessme nt Report 61 America from Degradation of 2,3,3,3-Tetrafluoroprop ene (HFO1234yf), A Potential Greenhouse Gas Replacement. En vironmental 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: pos sibilities 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 Temperatu re. Proc. 15 th International Refrigeration and Air Conditioning Co nference at Purdue, IN, USA Papasavva, 2009 Papasavva, S., Luecken, D. J., Wate rland, R. L., Taddonio, K. N.,

Andersen, S. O., 2009. Estimated 2017 Refrigerant E missions of 2,3,3,3-tetrafluoropropene (HFC-1234yf) in the Unit ed States Resulting from Automobile Air Conditioning. Environ mental 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 con ditioning systems in high ambient temperatures. Proc. IIF-IIR Compressor s, Papierni č ka, Slovakia Shine, 2005 Shine, K.P., Fuglestvedt, J.S., Hailema riam, K., Stuber, N., 2005.

Alternatives to the global warming potential for co mparing climate impacts of emissions of greenhouse gases. Climate C hange, 68:281- 302
Subiantoroa, 2013 Subiantoroa, A., Ooi, K. T., 201 3. Economic analysis of the

application of expanders in medium scale air-condit ioners 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 Chemistr y, Vol. 85, Issue 5, pp. 1047-1078 WMO, 2007 National Oceanic and Atmospheric Adminis tration (NOAA),

National Aeronautics and Space Administration (NASA ), United Nations Environment Programme (UNDP), World Meteoro logical Organization (WMO), and European Commission, 2007. Report No. 50, Scientific Assessment of Ozone Depletion: 2006 WMO, 2011 National Oceanic and Atmospheric Adminis tration (NOAA),

National Aeronautics and Space Administration (NASA ), United Nations Environment Programme (UNDP), World Meteoro logical 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 Meteorol ogical Organization, Global Ozone Research and Monitoring Project— Report No. 55. UNEP, 2011 UNEP, 2011. 2010 Report of the Refrigera tion, Air-Conditioning and2014 TOC Refrigeration, A/C and Heat Pumps Assessme nt Report

62 Heat Pumps Technical Options Committee, United Nati ons

Environment Programme (UNEP), Nairobi, Kenya
UNEP, 2012 UNEP, 2012. Handbook for the Montreal Pr otocol on Substances that

Deplete the Ozone Layer (Ninth Edition), United Nat ions Environment Programme (UNEP), Ozone Secretariat, Na irobi, Kenya

Website AHRI, 2013 Site for Low-GWP AREP Test reports: www.ahrinet.org/

resources/research tab - then AHRI Low-GWP Alternat e Refrigerants Evaluation Program for list of downloadable test re ports2014 TOC Refrigeration, A/C and Heat Pumps Assessme nt Report 632014 TOC Refrigeration, A/C and Heat Pumps Assessme nt Report

64 

## Annex to chapter 2 - safety standards and regulatio ns

With the introduction and potentially wide use of r efrigerants that are flammable, have higher toxicity and/or operate at notably higher pressures than the conventional ODS refrigerants or alternative non-flammable HFC refrigerants, conside ration 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 r efrigerants that exhibit these characteristics. This section summarises the main implications.

Safety classification of refrigerants

The most widely used classification of substances u nder the UN, where so-called dangerous goods receive a classification according to their m ain hazards.

Within the RAC industry, a different classification scheme is applied, where most refrigerants are assigned a safety classification, which is a fu nction 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 al so Table 2-2.

The toxicity classification is based on whether tox icity has or has not been identified at concentrations of less than 400 ppm by volume, base d on data used to determine the threshold limit value – time weighted average (TLV-TWA) or co nsistent indices. There are two toxicity classes:

 Class A: no chronic toxicity effects have been obse rved below 400 ppm

 Class B: chronic toxicity effects have been observe d below 400 ppm The flammability classification depends upon whethe r or not the substances can be ignited in standardised tests, and if so, what the lower flamm ability limit (LFL) and the heat of combustion are. There are three flammability classe s (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 v elocity of less than 0.10 m/s

 Class 2: exhibit flame propagation when tested at 6 0°C and atmospheric pressure, but have a LFL higher than 3.5% by volume, and have a h eat of combustion of less than 19,000 kJ/kg

 Class 3: exhibit flame propagation when tested at 6 0°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 p roposed for inclusion in EN 378. It is primarily intended to differentiate between HFC-152 a 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 t hat 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 tha t 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 ref rigerants is typically applied as a constraint to the amount of refrigerant that can be released into a room or enclosure, as it2014 TOC Refrigeration, A/C and Heat Pumps Assessme nt 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 ref rigerant may also applied as a constraint to the amount of refrigerant that can be released i nto a room or enclosure, as it represents the smallest quantity that could impose adverse toxicol ogical effects onto occupants.

Practical Limit There is a further safety measure for the applicati on of refrigerants, termed the practical concentration limit (PL). This represents the highe st 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 mort ality (in terms of LC50) and/or cardiac sensitisation, and/or anaesthetic or centra l nervous system (CNS) effects

 Oxygen deprivation limit (ODL)

 20% of the lower flammability limit (or 25% in ASHR AE 34) For class A1 (and A2L) and class B refrigerants, th e PL is normally based on the ATEL, whereas for A2 and A3 refrigerants it is normally d ictated 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, su ch 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 hazar dous 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 countri es elect to adopt alternative requirements than those at international level. The main interna tional 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 thi s report is identified.

Table A2-1: Scope of different international and re gional 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 [×] ×2014 TOC Refrigeration, A/C and Heat Pumps Assessme nt Report

66 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 amo ngst refrigerants that have a strong influence over the design and construction requirem ents are pressure, flammability and toxicity. Typically, the more severe these characte ristics (i.e., higher pressure, higher flammability, higher toxicity), the more onerous th e requirements are. In principle, these more onerous requirements are intended to offset the pot entially worse consequences arising from the more severe characteristics. Table A2-2 provide s a summary of the main measures that may require attention when adopting such refrigeran ts

Table A2-2: Main measures to be considered for subs tances with greater pressure, toxicity and/or flammability

Greater pressure Greater toxicity Greater flammabil ity
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, pa rticularly for flammable and higher toxicity refrigerants is the allowable and maximum refrigera nt charge. Depending upon the type of occupancy, different approaches are used to determi ne such values. Table A2-3 provides some indicative charge limits (per refrigerant circ uit) based on ISO 5149:2014 for selected situations and a number of commonly discussed refri gerants.

Although these safety standards cover requirements for flammable refrigerants, it is important to highlight that in many countries specific standa rds for equipment using flammable gases are available and are generally linked to legislati on. 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 he alth 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 s afety standards are harmonized to Atex, safety standards such as EN 1127-1 can be use d for the evaluation of flammability safety; provided that AC&R equipment meets the requ irements of such standards then deviations from the AC&R standards is acceptable if equivalent safety is demonstrated (for example, where larger refrigerant charges are neede d.) In addition to meeting the EHSRs, the general approach prescribed by flammable gas standa rds and regulations is summarised:2014 TOC Refrigeration, A/C and Heat Pumps Assessme nt Report 67

 Identification of explosion hazards and determinati on of the likelihood of occurrence of a hazardous atmosphere;

 Identification of ignition hazards and determinatio n 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 lev el of protection has been achieved;

 Consideration of and application of measures to red uce of the risks Table A2-3 provides the result of calculations for determination of allowable and maximum charge sizes (per refrigerant circuit) for a select ion of commonly discussed refrigerants.

Table A2-3: Summary of PL and charge size limits fo r selected refrigerant and occupancies according to ISO 5149Refrigerant ClassExample RefrigerantPractical Limit (g/m3)Allowable Charge in a15 m2Occupied Space(comfort)†(kg)Allowable Charge in a15 m2Occupied Space(general)* (kg)Max. Charge in anOccupied Space(Occupancy A)Max Charge in OpenAir or Machinery RoomMax Charge for aVentilated Enclosure

A1 HCFC-22 300 11.3 11.3

PL×RV δ 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 circumst ances; ‡ For systems with multiple indoor heat exchangers; † Depending upon installation conditions; * 2.5 m high room Note: Allowable and maximum charges are per individ ual refrigerant circuit Note: The values provided within this table are ind icative and determination of refrigerant charge siz e limits for particular types of systems and installation locati ons requires the use of the standard and the values within this table should not be taken as a substitute.2014 TOC Refrigeration, A/C and Heat Pumps Assessme nt Report

68 

### 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+A2:201 2, EN 378-

3:2008+A1:2012. EN 378-4:2008+A1:2012, Refrigeratio n Systems and Heat Pumps – Safety and Environmental Requireme nts IEC 60335-2-24 IEC 60335-2-24:2010, Specification for safety of household and

similar electrical appliances. Particular requireme nts for refrigerating appliances, ice-cream appliances and ice-makers IEC 60335-2-40 IEC 60335-2-40:2003+A13:2012, Speci fication for safety of

household and similar electrical appliances. Safety . Particular requirements for electrical heat pumps air-conditio ners, and dehumidifiers IEC 60335-2-89 IEC 60335-2-89:2010, Specification for safety of household and

similar electrical appliances. Safety. Particular r equirements for commercial refrigerating appliances with an incorpo rated or remote refrigerant condensing unit or compressor ISO 13043 ISO 13043:2011, Road vehicles – Refriger ant systems used in mobile

air conditioning systems (MAC) – Safety requirement s ISO 817 ISO 817: 2014, Refrigerants — Designation a nd safety classification.

International Organization for Standardization (ISO ) ISO 5149 ISO 5149: 2014, Refrigerating systems and heat pumps — Safety and

environmental requirements. International Organizat ion for Standardization (ISO)2014 TOC Refrigeration, A/C and Heat Pumps Assessme nt Report 69 

## Chapter 3

___________________________________________________ _______ Domestic Appliances

Chapter Lead Author

Sukumar Devotta

Co-Authors

Martien Janssen Richard DeVos2014 TOC Refrigeration, A/C and Heat Pumps Assessme nt Report

702014 TOC Refrigeration, A/C and Heat Pumps Assessme nt 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 domes tic refrigeration, but represent a small fraction of total units. Domestic dehumidifiers hav e not been considered in this chapter. For domestic wine coolers the same considerations as fo r domestic refrigerators apply.

Approximately 170 million domestic refrigerators an d freezers are produced annually. The vast majority are used for food storage in resident ial dwellings, with a significant minority used in offices for domestic purposes and small bus inesses for commercial purposes. Typical storage volumes range from 20 to 850 litres. Variou s fundamental design approaches and consumer convenience features are included within t he product offerings. A typical product contains a factory-assembled, hermetically sealed, vapour-compression refrigeration system employing a 50 to 250 W induction motor and contain ing 20 to 250 grammes of refrigerant. Some topics discussed below have been covered in ea rlier reports of this committee. They are briefly included here to provide a more comprehensi ve perspective. Niche market products in some cases employ alternative technologies to vapou r-compression refrigeration. The age distribution of the global installed products is ex tremely broad (Weston, 1997) with median age estimates ranging from 9 to 19 years at retirem ent. 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 chapte r is the heat pump clothe (laundry) dryer (HPCD), which is emerging in the market as an energ y efficient alternative to the electric heater dryer. It is included in this chapter for th e first time and the title has been accordingly modified as “Domestic Appliances” instead of “Domes tic Refrigerators” used earlier (UNEP, 2010). The market for HPCD is fast growing in the E U (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 va ry from 200 to 400 g, though the continued use of HFC-134a is under discussion in se veral 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 yea r (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 201 3 is estimated at 1.5 million. An American study has concluded that HPCDs have positive econom ic benefits only for households with high clothe dryer usage or with high electricity pr ices 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 warm ing potential (GWP) values of the refrigerants mentioned in this chapter are given in chapter 2 of this report.2014 TOC Refrigeration, A/C and Heat Pumps Assessme nt Report

72 

### 3.2 Options for new equipment Globally, new refrigerator production conversion fr om use of ODS was essentially completed by 2008. HC-600a or HFC-134a continue to be the ref rigerant options for new production. No other new refrigerant has matured to become an ener gy-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 desir e for reduced global warming impact from potential emissions. Excluding any influence from r egulatory interventions, it is still projected that by 2020 about 75% of new refrigerator producti on will use HC-600a (possibly with a small share by unsaturated HFC refrigerants) and th e rest will use HFC-134a. This is further discussed in section 3.2.2.

Besides the choice of alternative refrigerants, the re 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 30 o C) and high condensation temperature (up to 70 o C). 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-com petitive alternative. Concerns with the high flammability, which existed at the introductio n 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 sa fety requirements are met (e.g. IEC 60335-2- 24) and adequate risk assessment to address the fla mmable nature of the refrigerant, HC-600a is the ideal refrigerant for domestic refrigeration produc ts, giving roughly 5 % higher efficiency than HFC-134a while at the same time reducing noise leve l of the unit.

According to a recent study for a review of the Eur opean Regulation (EC) on fluorinated gases (Schwarz et al., 2013), the investment cost for a m anufacturing 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 Europe an averages. This is basically due to higher production costs related to the requirements for sa fety systems. The report also mentions that annual running costs and lifetime cost of HC-600a e quipment 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 attribu ted to a number of factors. These include general concerns regarding public safety (or the pe rception of), concerns about flammability safety and accidents (which are reflected in the re strictive national standards) and the reluctance to be one of the early movers in the region. Howeve r, during recent years this situation is changing which is discussed in section 3.2.2.

HC-600a was the standard refrigerant for European d omestic refrigerators and freezers originally and proliferated into other regions, inc luding Article 5 countries. Worldwide over 50 million appliances are produced annually with HC-60 0a. Increased energy efficiency and the low GWP of the HC-600a refrigerant reduce the clima te impact of household refrigerators, due to mitigation of direct (refrigerant) and indirect (CO 2 associated with electricity consumption) GHG emissions, compared to HFC-134a.2014 TOC Refrigeration, A/C and Heat Pumps Assessme nt Report 73

In the past, where capital resources were constrain ed, the use of binary hydrocarbon blends (HC-600a and HC-290) allowed matching the volumetri c capacity of previously used refrigerants to avoid investments required to modif y compressor manufacturing tools. These blends result in a reduction in thermodynamic effic iency versus pure HC-600a and most of the productions using blends have migrated to the u se 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 refrigera nt for domestic refrigeration since the phase-out of CFC-12. There are no significant s afety implications concerning its use. Energy efficiency is similar to that of CFC-12, although w ith continual optimization, the current HFC134a refrigeration units are considerably more effi cient than those that used CFC-12.

HFC-1234yf: It is feasible to use HFC-1234yf in domestic refrig erators and freezers and its application can be considered as some way between t he use of HFC-134a and HC-600a, since the pressure and capacity are slightly lower than f or HFC-134a and it has lower flammability characteristics than HC-600a. The lower flammabilit y 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 c hanges and investment can abate the risk to an acceptable risk level given the lower fl ammability of HFC-1234yf.

According to some industrial sources, initial devel opments to assess the use of HFC-1234yf in domestic refrigeration have begun, but it is not be ing pursued with high priority, as in automotive applications (see Chapter 10). The preli minary 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 h eat 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 inves tment requirements for product development, HFC-1234yf suffers significant disadva ntages. 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 p hase (Karber, 2012, Leighton, 2011). The same considerations with respect to flam mability as for HFC-1234yf hold. In addition, compressor adaptations are required to ma tch the reduced volumetric capacity compared to HFC-134a. Therefore, also this refriger ant 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 avail able from a large number of bottle coolers, which have been in use since many years, a nd 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 t he high pressure level, this in particular for the compressor. Further concerns are the extremely small compressor swept volume requirements and reduced thermal efficiency (Beek a nd Janssen, 2008). These concerns and the fact that other low GWP alternatives are availa ble make it unlikely that R-744 will become commercialized. Moreover, no major domestic refrigerator manufacturer is actively developing R-744 systems.2014 TOC Refrigeration, A/C and Heat Pumps Assessme nt Report

74 3.2.2 Conversion of HFC-134a domestic refrigerators to low GWP alternatives Current industry dynamics include increasing migrat ion from HFC-134a to lower GWP alternatives. Commercial conversion to date has bee n restricted to HC-600a. European production of No-frost side by side refrigerators b egan conversion from HFC-134a to HC600a in the early 2000’s. Initial conversions of au tomatic defrost refrigerators in Japan from HFC-134a to HC-600a were discussed in the 2006 repo rt of this committee (UNEP, 2006). This conversion, motivated by global warming consid erations, 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 fact ors are uniquely weighted in the North American market that has caused this delay includin g litigation costs, increased intensity by the Consumer Product Safety Commission, local regul ations 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 i nvestment cost associated with serviceability of a refrigerant that must be recove red. 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 s afety requirements in addition to third party standards prior to introduction of HC-600a to appliances.

Whilst legal concerns have so far limited the use o f HC-600a in USA, a major U.S. manufacturer introduced an auto-defrost refrigerato rs 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 E PA approved HC-600a as acceptable alternative under their Significant New Alternative s Policy Program (SNAP) for household and small commercial refrigerators and freezers, subjec t to certain conditions. Conditions included a limitation on charge to 57 g (note that substitut ion will be on an equal-molar basis, i.e. 100 grams of HFC-134a will be replaced by 57 g of HC-60 0a) and the requirement that products comply with the revised UL 250. Concurrently, the n umber 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 hydrocarb on refrigerants will continue. Excluding any influence from government regulatory interventi on, it is still projected that 75% of new refrigerator production will use HC-600a or any oth er alternative low GWP refrigerants and 25% will use HFC-134a by 2020 (UNEP, 2010). This es timated migration is shown schematically in Figure 3-1. Estimated conversion e xtents are based on the following assumptions:

1. All current HC-600a applications will continue. 2. One-half of HFC-134a applications in geographic are as 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 l imitations are a factor. 3. Three-fourths of HFC-134a applications in geographi c 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 t he advantages of HC-600a versus HFC-134a discussed earlier and production rationali zation. 4. Use of low GWP unsaturated HFC refrigerants will re quire successful addressing of numerous application criteria including: thermal st ability, hermetic system chemical compatibilities, process fluid compatibilities, con tamination sensitivities, etc., in addition to cost implications. Successful closure of any ide ntified issues will be necessary to permit proceeding with confidence for system reliab ility. 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 Assessme nt Report 75

Figure 3-1: New production refrigerant conversion t rend 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 co st to maintain product safety with introduction of flammable refrigerants. Premium cos ts are for modified electrical components, increased use of reduced voltage to avoid electrica l 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 conversio ns tend to receive priority.

3.2.3 Alternatives for tumble dryers These dryers typically use HFC-134a as a refrigeran t and charge amounts vary from 200 to 400 g. Products using R-407C and HC-290 are also be ing placed on the market and can potentially make use of the temperature glide, if h eat 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 reducti on 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 explor ed. This includes R-744, hydrocarbons and low GWP HFCs.

Low GWP refrigerants currently explored are:

 R-744 (CO 2 ): The high temperature glide at the gas cooler sid e can effectively result in an efficient drying process and possibly higher air ex it temperatures than possible with subcritical refrigerants. High costs of some compon ents and the probable need of an effective intercooler in order to reduce gas exit t emperatures are the challenges currently to be faced.

 Hydrocarbons: In principle various hydrocarbons are suitable. Supply of suitable compressors is currently very limited. Safety hazar ds 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, consider ing the relatively high amount of refrigerant required2014 TOC Refrigeration, A/C and Heat Pumps Assessme nt Report

76  Low GWP HFCs: Due to the similar characteristics as HFC-134a, this category may offer potential candidates. However, their flammability r esults in similar safety hazards as listed for the hydrocarbons, though some of these h azards 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 n oise, portability or no access to the electrical energy distribution network. Technologie s of interest include Stirling cycle, absorption and adsorption cycles, thermoelectric an d magnetic. In the absence of unique drivers such as the examples cited above, no identi fied technology is cost or efficiency competitive with conventional vapour-compression te chnology 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 suc h as campers or mobile homes for many years. Thermoelectric or Stirling cycle technologie s are used for portable refrigerated chests in applications such as medical transport. Thermoel ectric is also used for hotel units and wine storage units with moderate cooling temperature lev els.

Magnetic refrigeration is one of the not-in-kind te chnologies with possible potential for commercialization. Magnetic refrigeration does not use refrigerant and employs an active magnetic regenerator, comprising magneto-caloric ma terials exposed to an intermittent magnetic field. At lower cooling power, it possibly presents higher efficiency over conventional vapour compression. To decrease the pr ice 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 a bove 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 technol ogies for domestic refrigerators The energy efficiency of domestic refrigeration pro ducts is a topic of active consumer and regulatory interest. This topic is discussed at len gth in Chapter 11 of this report. This section contains only a condensed discussion on energy effi ciency. 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 vario us sources, amongst others the reports under the Eco-Design Directive studies (Ecocold, 20 06). These studies provided capability background used for updating European Commission mi nimum energy efficiency standards (EN-643, 2009).

Factors influencing refrigerant selection and produ ct energy efficiency include local, regional and national regulation, Eco-labelling, and third p arty standards. Globally labelling requirements and minimum standards are reviewed and upgraded on a regular basis, driving the product to reduced power consumption levels wit h corresponding reductions on global warming impact. Such standards for measurement of p roduct sustainability provide transparency and credibility in the labelling of pr oduct 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 Househol d Refrigeration Appliances, developed and endorsed by multiple stakeholders inc luding environmental, industry, government and consumers. Similar to the EU F-Gas l egislation, this standard provides a2014 TOC Refrigeration, A/C and Heat Pumps Assessme nt Report 77

calculation for the net material GWP impact of a pr oduct as the mass weighted average GWP of the product component materials.

Significant technology options to improve product e nergy 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 c ompared to results from another. A number of improved energy efficiency design options are fu lly mature, and future improvements of these options are expected to be evolutionary. Exam ples of these options include efficient compressors, high efficiency heat exchangers, impro ved low thermal loss cabinet structures and gaskets, and less variable manufacturing proces ses. Extension of these to all global domestic refrigeration would yield significant bene fit, but is generally constrained by availability of capital funds and related product c ost implications. Similarly, retooling compressor manufacturing facilities facilitated the recovery of the minor efficiency penalties incurred with the use of HC-600a/HC290 blends versu s HC-600a.

Design options with less economic justification are sometimes introduced in premium-cost models having incentive subsidies. This provides th e opportunity to mature new efficiency technologies and progress them through their indivi dual cost/experience curves. This increases the likelihood for migration of the effic iency technologies to more cost-sensitive model line segments. Options that presently have li mited or newly introduced application include variable speed compressors; intelligent con trols; system reconfigurations, such as dual evaporators; advanced insulation systems; and Deman d Side Management (DSM) initiatives requiring interactive communication with energy pro viders 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 ge neral use. A further constraint is the fact that not all energy saving measures results in a re duced 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 an d inertial losses through modulating capacity and compressor speed. Use of higher effici ency permanent magnet or linear motors is also enabled by electronic commutation co ntrols.

• Intelligent, adaptive controls allow variable contr ol algorithms that avoid optimising at seldom-experienced worst-case conditions (e.g. vari able defrost algorithms).

• Parallel dual evaporators can improve Carnot theore tical efficiency by effectively reducing required pressure ratios of the higher tem perature evaporator. Cost–effective, reliable and stable system controls need to be demo nstrated.

• Advanced vacuum panel insulation concepts have been selectively used for several years in Japan, Western Europe and the United States. The ir 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. Typica lly, such a feature on electronic models responds to the power company request for re duced energy consumption. Consequently, the appliances may postpone heated de frost, delay ice harvests or delay the start of a compressor for short periods. The applic ation 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 technol ogies 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 en ergy saving option is predominantly2014 TOC Refrigeration, A/C and Heat Pumps Assessme nt Report

78 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 ne w 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 th e end of their life cycle.

Field conversion to non-ODS refrigerants has signif icantly lagged original equipment conversion. The distributed and individual propriet or 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. Re frigerant blends developed specifically for use as drop-in service alternatives have had limite d success. The interested reader is referred to the 1998 report of this committee for an extende d discussion of field repair and conversion options (UNEP, 1998). Chapter 2 in this current rep ort 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 pr oduct 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, th e old units are bartered for new appliances using non-ODS alternatives. The cost of extensive r econfiguration potentially required to properly convert for use of alternative refrigerant s is a significant deterrent to this approach.

In the case of conversion to HC blends, safety cons iderations require that any flammable fluid accumulation within an enclosed volume must avoid t he potential within that volume for an electrical spark, electrical arc or surface tempera ture above the auto-ignition temperature of the leaked gas in air. The extent of in-service pro duct modification to assure this is dependent upon the original product configuration. The origin al equipment manufacturer is most familiar with the product construction and should be consult ed 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 thro ugh apertures in the liner in order to accumulate within the cooled volume. There is a low probability of significant gas accumulation. Additionally, electrical components l ocated 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 t his configuration is alleged to be viable as per some reports, but procedure definitio n 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 ref rigerant 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 withi n the cooled volume. Additionally, electrical components are commonly located within t he cooled volume, such as, thermostats, convective fans, defrost heaters, ligh ts, icemakers, etc., increasing the probability of an ignition source being present. Th e viability of a drop-in conversion will depend upon the extent of original construction mod ification required to achieve an acceptable configuration. Again, conversion procedu re definition by the original manufacturer is prudent and should be sought prior to decision to proceed.2014 TOC Refrigeration, A/C and Heat Pumps Assessme nt Report 79



### 3.4 End-of-life disposal The small unit charge and the geographically disper sed location of these units complicate commercial opportunities to promote recovery and re cycling 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 a re being introduced in Article 5 countries. Chapter 11 of this report addresses this and relate d 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 technolog ies 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 r efrigerants 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. Th is 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 HF C-600a products. Current estimates indicate that additional cost results from design c hanges to allow the use of flammable refrigerants in automatic defrost refrigerators.



### 3.6 References
Beek, 2008 van Beek, M and Janssen, M., “R-744 com pared to R-290 in small freezer applications,” 8 th

IIR Gustav Lorentzen Conference on National Workin g 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 - Dome stic 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 Co nference at Purdue, July 16-19, 2012 Leighton, 2011 Leighton, Investigation of household refrigerator with alternative low

global warming potential refirgerants, Thesis Facul ty 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 Effi ciency 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 Contr act No 070307/2009/548866/SER/C4”, 2013. UNEP, 1998 UNEP 1998 Report of the Refrigeration, Air Conditioning and Heat Pumps2014 TOC Refrigeration, A/C and Heat Pumps Assessme nt Report

80 Technical Options Committee, Chapter 3, Domestic Re frigeration (1998

Assessment). UNEP, 2002 UNEP 2002 Report of the Refrigeration, Air Conditioning and Heat Pumps

Technical Options Committee, Chapter 3, Domestic Re frigeration (2002 Assessment). UNEP, 2006 UNEP 2006 Report of the Refrigeration, Air Conditioning and Heat Pumps

Technical Options Committee, Chapter 3, Domestic Re frigeration (2006 Assessment). UNEP, 2010 UNEP Technology and Economic Assessment Panel Task Force Decision

XXI/9 Report, “Assessment of HCFC’s and Environment ally Sound Alternatives Paragraph 2C,” (May 2010). Weston, 1997 Roy W. Weston Inc., Recycling Rate Det erminant Study – Phase 1 Report,

Norcross, Georgia (1997).2014 TOC Refrigeration, A/C and Heat Pumps Assessme nt Report 812014 TOC Refrigeration, A/C and Heat Pumps Assessme nt Report

822014 TOC Refrigeration, A/C and Heat Pumps Assessme nt 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 Rajandran2014 TOC Refrigeration, A/C and Heat Pumps Assessme nt Report

842014 TOC Refrigeration, A/C and Heat Pumps Assessme nt Report 85



## 4 Commercial refrigeration

4.1 Introduction Commercial refrigeration is characterised by storin g and displaying food and beverages at different levels of temperature within commercial s tores with sales areas varying in size from approximately 10 m 2 to 20,000 m 2 . The refrigerating capacities of equipment vary fr om hundreds of Watts to as high as 1.5 MW. Two main le vels 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 ic e cream.
Globally, HCFC-22 continues to represent the larges t 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 CO 2 for larger supermarket applications are increasingly used in many develope d nations.

In parallel, progress has been made to improve ener gy efficiency and leak tightness, especially for centralized systems. The progressive phase-out of HCFC-22 in developing countries requires making informed choices on the b est replacement options.

AHRI launched a Low GWP Alternative Refrigerant Eva luation Program (AREP) in 2010 (AHRI, 2013). A number of new blends based on HFC-1 234yf and HFC-1234ze(E) as well as HFC-32 have been formulated to replace HFC-134a, HC FC-22, and R-404A. So, for the three groups of commercial refrigeration equipment, compa risons are now being made in order to select amongst the most energy efficient options wi th 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 component s to design systems based on delivering the cooling required at the highest ambi ent condition.

For moderate and cold climates it is an important o ption to recover heat from the refrigeration plant for heating purposes in the cold season. Cons idering 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 warm ing potential (GWP) values of the alternates mentioned in this chapter are given in C hapter 2 of this report.



### 4.2 Applications
Stand-alone equipment

are self-contained refrigeration systems and compr ise a wide variety of applications: ice-cream freezers, ice machines, beverage vending machines, and display cases. These systems are found not only in large co mmercial stores but also restaurants, convenience stores, mini supermarkets and gas stati ons. For developing countries, domestic refrigerating equipment, refrigerators, and freezer s can be found in small shops and used for commercial purposes. Stand-alone equipment are incr easingly used in developed countries in medium-size supermarkets because of ease of mainten ance of the fully-welded circuit. In Europe, and lately in other markets, this choice is also often related with the use of hydrocarbons or CO 2
. Condensing units exhibit refrigerating capacities ranging typically from 1 kW to 20 kW. They2014 TOC Refrigeration, A/C and Heat Pumps Assessme nt Report

86 are composed of one (or two) compressor(s), one con denser, and one receiver assembled into a so-called “condensing unit”, which is typically l ocated external to the sales area. The cooling equipment consists of one or more display c ase(s) in the sales area and/or a small cold room. Condensing units are typically installed in s pecialty shops such as bakeries, butcher shops, and convenience stores. In a number of super markets, one can find a large number of condensing units (sometimes up to 20) installed sid e-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 th e most used refrigerants: HCFC-22, R404A, and HFC-134a.

Centralised and Distributed systems are the preferred options in supermarkets. They op erate 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 r oom or on the roof as in the case of a distributed system. Distributed systems may be thou ght 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 circulate s from the machinery room to the sales area, where it evaporates in display-c ase heat exchangers, and then returns in vapour phase to the suction headers of the compress or racks. The supermarket cold rooms are cooled similarly. In the machinery room, racks of m ultiple compressors are installed; these utilise common discharge lines to the air cooled co ndenser 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 eac h 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 condu cted 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 he at transfer fluid - HTF (also called secondary refrigerant) is cooled and p umped to the display cases where it absorbs heat, and then returned to the primary heat exchang er. HTFs have been receiving interest because indirect systems allow for lower primary re frigerant 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 i n this section, in order to analyse the trends for refrigerant choices depending on the coo ling 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 thei r own environmental policy and choosing low-GWP refrigerants as well as energy-eff icient systems are part of the green positioning of those companies.

Bottle coolers Glass-door bottle coolers can be found in nearly ev ery 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 Assessme nt Report 87

Hydrocarbon (HC-290) bottle coolers as well as CO 2 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 energ y consumption compared to HFC134a bottle coolers, and for CO 2 12% energy consumption reduction (Pedersen, 2008). The choice of HC-290 is made by several European compan ies manufacturing those bottle coolers, while CO 2 is preferred by others, based on a different perce ption of safety risks.

Within the AHRI / AREP test program, laboratory tes ts have been performed in order to evaluate the two low-GWP HFCs: HFC-1234yf and HFC-1 234ze, and HFC-134a based blends designed to replace HFC-134a at nearly the s ame 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 develo ped in the near future.

Ice-cream cabinets R-404A and HFC-134a are the refrigerants used in ic e-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 mill ion units as assessed by a leading global company (Refrigerants Naturally, 2014).

Vending machines Vending machines for soft drinks require a signific ant cooling capacity to rapidly cool the soft drink container. The usual refrigerant charge of HF C-134a varies between 0.5 and 1 kg leading to the development of CO 2 options to compete with hydrocarbons. High-efficie ncy CO 2 cassettes have been developed by a Japanese compan y and are sold to many OEM companies for integration. The CO 2 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 CO 2 and hydrocarbons is made based on conclusions draw n from the risk analysis and the impact of possible incidents or ac cidents.

Water coolers A large number of water coolers for both bottled wa ter and tap water are installed worldwide. The refrigeration capacity is small and the refrige ration 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 hydrocarb on 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 ar e found depending on the size of the machine, as well as different technologies dependin g 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. R eport #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 star ted introducing ice machines using CO 2 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 supe rmarkets install such units instead of the cabinet cooled by a remote refrigeration system. Th e plug-in cabinets have lower installed cost, are more flexible and require less system mai ntenance, because of the fully brazed circuit. Plug-in cabinets are significantly less en ergy efficient compared to display cases2014 TOC Refrigeration, A/C and Heat Pumps Assessme nt Report

88 cooled by condensing units or compressor racks, bec ause small compressors have lower energy efficiency than larger ones.

Moreover, the condenser heat is released into the s upermarket 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 th e contrary, the heat released is a gain in winter in moderate and cold climates. Some installa tions 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, energ y efficiency can reach acceptable levels.

The refrigerant choice used to be R-404A. Since 200 7, hydrocarbon display-cases using HC290 have been proposed as a standard option in Euro pe with an energy efficiency gain ranging from 10 to 15% compared to R-404A. CO 2 systems for display cases have also been introduced by several key suppliers.

The first conclusions that can be drawn for standal one equipment are as follows:

- HFC-134a and R-404A will be phased-out progressivel y in developed countries. Due to multinational companies this phase-out is also b eginning in developing countries. There are several low-GWP refrigerant options and h ydrocarbons, CO 2 and new lowGWP HFC-based blends can be used depending on comme rcial availability.

- Addition of glass doors and LED lighting to display cases can reduce the refrigeration load thus enabling the use of flammable refrigerant s for these display cabinets within the allowable charge limits.

- Minimum energy standards have been issued or update d in the last years in North America, in Europe and in many other countries, mak ing a new competition between manufacturers in order to reach higher energy effic iency stand-alone systems; the CLASP report (Waide, 2014) estimates the possible g ains for the different standalone-equipment types between 30 and 40% compa red to the current average energy consumption.

- Eco-labelling taking into account all impacts durin g the life cycle of product (see Chapter 11) will be soon issued for commercial refr igeration in Europe, energy consumption being the main criterion to be addresse d in order to lower significantly the environmental impact of those equipment. In par allel, the amended F-gas regulation will affect refrigerant choices in this equipment.

4.3.2 Condensing unit systems Condensing units comprises one or several compresso rs, 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 standardize d 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 countrie s, 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 ha ve not yet received their ASHRAE number. Their GWPs are ranging from about 1000 to 1 700. They are designed to replace HCFC-22 or R-404A and are used either as retrofit r efrigerants 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 Assessme nt 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 c apacity 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 HCF C-22, HFC alternative-blend options that are proposed show performances close to the be nchmark reference. The results indicate that soft optimization could lead to performances o n 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 tempe rature glides varying from 4 to 7 K.

Ammonia R-717 is not used much in these systems for cost an d safety issues. However it is used in cascade systems with CO 2 in the low stage of the equipment.

CO 2 New carbon dioxide-based condensing units are sold in Northern Europe and Japan. The market penetration is low but increasing. R-744 con densing units require a double-stage design if high ambient temperatures occur frequentl y. Single-stage systems are designed for cold climates. The additional cost for a double-sta ge system is significant compared to usual HFC reference condensing units. The cost remains th e main barrier for these R-744 condensing units in certain regions, but with incre asing production capacities and financial incentives this barrier is expected to overcome soo n.
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 ope rating with HC-600a and HC-290, and for temperatures ranging from -40°C up to 0°C. Cost s for these HC-based systems can be up to 15% higher than HFC systems due to safety measur es required for flammability mitigation.

4.3.3 Centralized supermarket systems Centralized systems are the preferred option in med ium 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 ref rigeration systems varies from 400 m 2 up to 20,000 m 2 for large supermarkets.

Generally, for large supermarkets, the reference de sign 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). Severa l refrigeration system designs exist for medium to large supermarkets; these designs have an impact on refrigerant choices, refrigerant inventories, and energy efficiency. Con ventionally, they operate with racks of parallel piped compressors installed in a machinery room, typically using HCFC or HFC in direct expansion refrigeration systems. Typically t he compound compressors operate with a common condenser which provides a number of differe nt evaporators with liquid refrigerant. Places to be cooled by the system include refrigera ted 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 emi ssions in the case of component failure2014 TOC Refrigeration, A/C and Heat Pumps Assessme nt Report

90 like pipe rupture, e.g. due to excessive vibration. In addition, the numerous joints of large systems are prone to frequent leakage (especially m echanical joints), hence such systems often have refrigerant leakage rates in the order o f 15 % (Schwarz et al, 2011) or higher, typically 25%. In order to limit refrigerant emissi ons, some commercial companies have put significant effort in order to limit their annual e missions; some successes have been reported in Germany with reduction of annual emission rates lower than 10% (Kauffeld, 2013).

The different central multi-compressor refrigeratio n 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 dir ectly.

Most systems have separate MT and LT systems, but e specially systems working with R-744 combine MT and LT in one compound system. Due to sa fety and technology reasons, not all combinations make sense or are acceptable. For exam ple 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 supermarke t; but ammonia can be used safely as a high-efficiency refrigerant in an indirect supermar ket refrigeration system, see below.

The evaporator of direct expansion systems is locat ed 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 co ndenser can be used for room or tap water heating. Direct expansion systems are worldwide the dominating technology for supermarkets. The direct expansion centralized syst em is therefore often used as the reference for comparisons of energy performances and refriger ant charges.

The refrigerants for new systems are R-404A and R-7 44, especially in Europe. To a smaller extent HFC-134a is used for medium temperature appl ications, as well as R-507A in some countries, e.g. Norway. Direct expansion systems wi ll always have refrigerant-carrying pipes and components inside of the sales area which the p ublic 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, comm ercial 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 sys tems, which are common in industrial refrigeration, have been introduced in commercial r efrigeration in order to improve energy efficiency, see Figure 4-1 and 4-2. They can be use d for all refrigerants, but the development has been especially made for R-744.2014 TOC Refrigeration, A/C and Heat Pumps Assessme nt Report 91

Figure 4-1: Cascade system Figure 4-2: Booster sys tem 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-con denser 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 c an be either different or identical. In any case two-stage systems are more efficient than sing le-stage ones; the energy gain is typically of 15 to 20% and is more pronounced for high outdoo r temperatures.

Booster systems Another design, which is simpler and less costly, i s also developed and installed now in commercial refrigeration: the booster system presen ted in Figure 4-2. The low-temperature compressor rack discharges its vapour directly in t he 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 expan sion valves. A first expansion valve EV1 expands the refrigerant in the flash tank at a firs t intermediate pressure; the vapour generated by this first expansion is directly sucked by the m edium-temperature compressor rack, and the pressure of the expanded vapour leaving the flash t ank is controlled at the medium evaporation pressure by EV2. For CO 2 this design presents a great advantage because abo ve 31°C in the condenser, there is no more condensatio n and the condenser becomes a gas cooler. In the supercritical region, CO 2 is in dense gas phase at pressure around 90 bars a nd can be expanded in the flash tank at 40 bars for ex ample, and so a part of the expanded CO 2 changes to liquid phase and feeds both the medium-t emperature display-cases via the expansion valve TXV1 and the low-temperature displa y case via TXV2. For high outdoor temperatures, the booster system offers a efficienc y gain for CO 2 ; however, energy loss for2014 TOC Refrigeration, A/C and Heat Pumps Assessme nt Report

92 CO 2 systems due to supercritical operation can be over come with additional design features like ejectors, parallel compression or subcoolers.

These two designs are now installed in several thou sands of stores; cascade systems – with usually HFC-134a at the medium-temperature level – in large supermarkets and full CO 2 booster systems in larger to smaller ones. These st ores are currently mostly found in Europe, but are increasing in adoption in the rest of the w orld.

Distributed systems In the USA two designs coexist: the centralized and the distributed system. Distributed Systems consist of a number of compact compressor s ystems / condensing units with – typically - water-cooled condensers. The compressor systems are located in sound-proof boxes, which can be installed in the sales area. Wa ter pipes running through the store remove the condenser heat. The design is compact and the r efrigerant lines are short, which makes a gain in terms of reliability and limits the pressur e 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 c ooled 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 tr ansports 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 secu red machine room or in the open air, i.e. isolated with no public access, see Figure 4-3. Dur ing the last 20 years, indirect systems have been developed, mostly for the medium-temperature l evel, 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, leadin g to better energy efficiency of the lowtemperature system and allowing also the use of CO 2 in subcritical operation at the lowtemperature level. Some other designs are also poss ible where the condensation heat of the low-temperature system is directly released to the atmosphere2014 TOC Refrigeration, A/C and Heat Pumps Assessme nt Report 93 .

Figure 4-3: Indirect system at the medium-temperatu re level and direct expansion at the lowtemperature level The use of HTF with phase change offers an energy s aving potential: ice slurry for medium temperature or CO 2 for medium and low temperatures (Møller, 2003). Th rough the selection of the correct additive, ice slurry can also outper form a single-phase HTF (Hägg, 2005; Lagrabette, 2005).

Indirect systems make the primary refrigeration sys tem 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 a nd 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 additio nal energy consumption due to pressure losses of the long suction lines of direct expansio n systems. In order to prevent the energy consumption increase, it is also important to selec t 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 le aks are also possible and difficult to diagnose.

Developing country aspects In developing countries, supermarkets can be of ver y different sizes but also have a centralized machinery room as in developed countrie s; depending on the leadership of companies, one can find CO 2 cascade and booster systems in a country such as Br azil. 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 J apan 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 leve l and CO 2 or HFC-32 are under evaluation for the low-temperature level. The flamm ability of HFC-32 makes it difficult to be used in large direct expansion systems outside of J apan. More recently, lower GWP R-404A alternatives like R-448A, R-449A are undergoing fie ld trials and starting production while2014 TOC Refrigeration, A/C and Heat Pumps Assessme nt Report

94 HFC-134a alternative blends like R-450A are also be ing 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 su permarkets, using a secondary loop, HC-290 is now the preferred option. For all HCs, th e 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 venti lated machinery room and ammonia systems are always designed with secondary loops at each temperature level. Several large supermarkets operate with ammonia especially in Lux embourg and Switzerland. Ammonia can be used at the medium-temperature level, togeth er with CO 2 at the low-temperature level.

CO 2 (R-744) The real breakthroughs using CO 2 as refrigerant began around 2005 with two major ne w options: CO 2 as the only refrigerant in booster systems and CO 2 in cascade with HFCs or other refrigerants.

For using CO 2 as the only refrigerant in small, medium and large size supermarkets, CO 2 has been introduced in transcritical booster systems (F igure 4-2). The low-temperature rack operates at -33°C ± 3°C evaporation temperature. Th e medium-temperature rack operates at - 9°C ± 3°C evaporation temperature. The heat dissipa tion occurs up to 30°C depending on the outdoor temperature, and above 27°C outdoor tempera ture, the operational mode becomes transcritical. Up to now, more than 3000 transcriti cal CO 2 systems are installed, mainly in Europe (95%) (Chasserot, 2014).

CO 2 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 leve l of condensation temperature is to use usual copper tubing designed for maximum pressure of 3 MP a. 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 act ive policy of a European company, more than 50 stores are now operating with CO 2 cascade systems.

The energy efficiency of CO 2 systems is better than that of comparable HFC-syst ems at ambient temperatures below 22°C, about equal at tem peratures 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 enha ncements used for CO 2 systems will also have beneficial effects on standard HFC systems. In stallation of CO 2 systems has also begun in Asia, the Americas, and Australia. Shifting from HFCs to CO 2 can reduce the carbon footprint of supermarkets by 25% (EPA, 2010) but co uld be higher depending on the refrigerant leakage and energy recovery utilization

For moderate and cold climates it is an important o ption to recover heat from the refrigeration plant for heating purposes; e.g. for hot water heat ing and indoor air heating in the cold season. CO 2 systems are easily adapted to satisfy such demands . Considering the supermarket as an energy system for which energy use should be minimi zed may give considerable energy savings, e.g. 30% has been demonstrated (Hafner et al, 2014a).

With trials of new developments like booster system s, ejector systems, expander systems, parallel compression and systems with auxiliary mec hanical sub-cooling, the efficiency of2014 TOC Refrigeration, A/C and Heat Pumps Assessme nt Report 95

CO 2 systems may, in the future, be improved to the ext ent 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 condensin g 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 temper ature glides of 4 to 7 K are larger compared to R-404A. The consequence of the temperat ure glide is a possible distillation of the blend when a leak occurs. Servicing becomes mor e complex due to the composition change of the refrigerant blend due to the differen t 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 ch arge 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 remain ing refrigerant.

Some of the low-GWP-HFC blends are designed to repl ace HCFC-22. For the tested blends, the cooling capacity is 2 to 7% lower and the effic iency 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 so ft optimization of refrigeration systems using those blends may lead to the same level of pe rformances. Three issues are still to be addressed: safety rules for low flammability refrig erants, servicing of refrigerant blends with possible distillation due to leaks and commercial a vailability.

A new set of low-GWP R-404A refrigerant blends is a lso being introduced with GWP less than 150.

Summary for centralized systems In summary, for centralized systems a number of opt ions are available and proven; some of them require a higher technical training of contrac tors especially for two-stage CO 2 systems.

The replacement of R-404A is underway and will lead to several families of technical options with either CO 2 at all temperature levels or low-GWP HFCs at the m edium temperature operating in cascade with CO 2 at the low temperature. R-404A replacements that a re 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 le vels will also be considered but flammability concerns might limit the types of syst ems due to the current standards.



### 4.4 Options for existing equipment
This section covers the retrofit options for the in stalled 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 eq uipment will be changed based on its current lifetime, if no heavy leaks occur. However, a few o ptions 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-407 F and R-427A are now used in many developed countries as retrofit refrigerants for R- 404A depending on individual manufacturers’ approvals. These refrigerants, inclu ding R-407C, are commercially available and are also formulated to replace HCFC-22. Other H FC blends with GWP lower than 2000, such as R-448A and R-449A (and others not yet assig ned ASHRAE numbers) will be also commercially available in 2015 and will be candidat es to replace HCFC-22 and R-404A. In fact, the most important issue for the replacement of HCFC-22 in developing countries will be2014 TOC Refrigeration, A/C and Heat Pumps Assessme nt Report

96 to find replacement options at acceptable costs; gi ven 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 s chedule. 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 Evaluat ion 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.: Superm arktkälteanlage mit CO 2 als

Kälteträger – Fallstudie einer Anlage in Australien . DKV Tagung 2012, Würzburg, Germany EPA, 2010b US-EPA: Transitioning to low-GWP altern atives in commercial

refrigeration. Fact sheet, October 2010 EPA, 2014 http://www2.epa.gov/greenchill/reports-g uidelines-and-tools Finckh, 2011 Finckh, O.; Schrey, R.; Wozny, M.: En ergy and efficiency

comparison between standardized HFC and CO 2 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 comme rcial 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, Proceed ings of the 11th IIR-Gustav Lorentzen Conference on Natural Refriger ants, GL2014, International Institute of Refrigeration, ISBN 978- 2-36215-004-3. Hafner, 2014b Hafner, A.; Nekså, P.: System config urations for supermarkets in

warm climates applying R-744 refrigeration technolo gies. Case studies for selected cities. International Special Issue 2014 - United Nations Environment Programme, International Instit ute of Refrigeration, Centro Studi Galileo, Associazione d ei Tecnici del Freddo, European Energy Centre, Casale M.to, Italy, 2014 Kauffeld, 2013 Trends and perspectives in superma rket refrigeration EC. Europa Lagrabette, 2005 Lagrabette, O.: Kältetechnik im E inzelhandel – Carrefour setzt auf die

“grünen” Medien. KKA 1 (2005), S. 20 – 24
Møller, 2003 Møller, J.B. : CO 2 is keeping Supermarkets Cool. The NEWS. 8. 12.

2003
Pedersen, 2008 Pedersen, P.H.; Christensen, B.: De velopment and test of Bottle

Coolers with Natural Refrigerants , 8 th IIR Gustav Lorentzen Conference on Natural Working Fluids, Copenhagen, 2 0082014 TOC Refrigeration, A/C and Heat Pumps Assessme nt Report 97

Refrigerants Naturally, 2014

http://www.refrigerantsnaturally.com/statements/uni lever.htm
Rhiemeier, 2009 Rhiemeier, J.-M.; Harnisch, J.; Ka uffeld, 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 Conserv ation and Nuclear Safety Research Report 206 44 300, UBA-FB 0 01180/e, March 2009 Rivet, 2007 Rivet, P.: Move to HFC 410A in Refrige ration Applications. IIR 22.

Int. Congr. of Refr., Peking, China, 21. – 26. Augu st 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 s tudy for a review of Regulation (EC) No 842/2006 on certain fluorinat ed greenhouse gases. Final report, Sept. 2011
Shecco, 2014 http://www.r744.com/news/view/5816?utm_source=mail chimp&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.2014 TOC Refrigeration, A/C and Heat Pumps Assessme nt Report

982014 TOC Refrigeration, A/C and Heat Pumps Assessme nt Report 99 

## Chapter 5

___________________________________________________ ________ Industrial Systems

Chapter Lead Author

Andy Pearson

Co-Authors

Horace Nelson Mohamed Alaa Olama Alexander C. Pachai Alessandro Silva2014 TOC Refrigeration, A/C and Heat Pumps Assessme nt Report

1002014 TOC Refrigeration, A/C and Heat Pumps Assessme nt 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 pr eferred solution in most markets and new development refrigerants have not gained a sign ificant market share in this period. There have been several major accidents involving R-717 i n 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 lev els of fatality are unprecedented in traditional market sectors using ammonia and they h ave increased the emphasis on the education of technicians and engineers. In all case s the accidents would have been avoided if current international safety standards had been fol lowed.

The chapter has been expanded to include more infor mation on process cooling, industrial airconditioning and heat pumps. Several examples from different regions including many article 5 countries have been added. The ozone depletion po tential (ODP) and global warming potential (GWP) values of the refrigerants mentione d in this chapter are given in chapter 2 of this report.

Industrial systems are characterised primarily by t he 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 (heati ng systems similar in scale and application to Industrial Refrigeration systems) an d Industrial Air-Conditioning (systems for controlling air temperature in production factories , computer centres and other process areas). In addition to size of installation the distinguish ing traits of Industrial Air-Conditioning systems are that the cooling is not purely for huma n 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 “Missi on 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 ins tallations 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 gene ration is also given.

5.1.1 Background Thirty years ago chlorofluorocarbons were widely us ed 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 CF C-12, which has a critical temperature of 112°C, was common for systems of all sizes. It i s now replaced by HFC-134a for temperatures up to about 75°C. R-717 is also used i n 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-Conditionin g was less common at that time, and tended to use standard chillers with CFC refrigeran ts. The move away from CFCs in the late 1980s prompted by the Montreal Protocol presented p articular 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 King dom (Brown, 1992). In other countries the re-adoption of R-717 was more widely resisted a nd the adoption of low ODP refrigerants was coupled with widespread use of secondary refrig erant systems. For example R-502 had been common in Japan. The industrial sector there r esponded to its removal by the2014 TOC Refrigeration, A/C and Heat Pumps Assessme nt Report

102 development of compact, low charge R-717 systems an d the use of secondary systems with a limited charge of the more expensive HFC fluids (Ka wamura, 2009). In Article 5 countries where R-717 was already used for refrigeration thes e systems were retained and extended (Tarlea, 2013) (Gulanikar, 2013), but the designs u sed tended to be old-fashioned and not as efficient or safe as the new Japanese or European i nnovations. In countries with no history of R-717 use, or with no support infrastructure the so lution 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 m uch 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 wi th R-717 rather than multiple commercial systems with HCFCs. There is also a greater focus o n integration of industrial heating and cooling systems to make better use of waste heat re covery (Pearson, 2011).

In Europe regulation on the use of fluorinated gase s 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 pri marily based on concern about possible restrictions on HFCs rather than the immediate effe ct of the current rules (CGF, 2010), which are mainly aimed at commercial and mobile air-condi tioning. In the industrial sector it is likely that the adoption of R-717 and R-744 by user s who previously deployed HCFC-22 and HFC blends will reduce the energy-related global wa rming potential through increased efficiency as well as eliminating the direct global warming potential caused by refrigerant leakage. Further discussion of sustainable manufact ure 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 inst allation. 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 considerati on 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 condense r 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 ref rigeration 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 tha t 90% of the condensers sold in Europe, Russia, India and China are for R-717 systems. In N orth America the proportion is even2014 TOC Refrigeration, A/C and Heat Pumps Assessme nt Report 103

higher, at 95%. The balance that is used concerns H CFC-22, R-404A, R-507A or occasionally HFC-134a. The results are shown in Table 5-1.

Smaller industrial systems more often use air-coole d condensers, and in these cases the refrigerant is more likely to be a fluorocarbon, al though air-cooled condensers with stainless steel tubes are used in smaller R-717 systems. Tabl e 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 signif icant variations within the regions from country to country or state to state due to legisla tion 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 temp erature 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 Un ited States which followed the Montreal Protocol phase-out schedule.

Table 5-2: Estimated 2008 market value for small i ndustrial 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 ind ustrial 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 HF Cs 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 o f 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 com patible 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 incorpor ate low refrigerant charge. Uptake of R-717 in smaller systems would also be helped by the deve lopment of reliable semi-hermetic compressors suitable for R-717.

In the Middle East, Saudi Arabia and Egypt have a r elatively 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 remainin g 20% is distributed between R-717, CFCs, R-404A and HFC-134a. The phasing-out of R-502 and t he harsh high ambient temperatures in the region for a large part of the year coupled wit h the scarcity of water have resulted in the use of small capacity air-cooled condensing units o perating on HCFC-22 in many industrial systems. R-717 systems are few and are used for lar ge applications such as food processing plants, large cold stores and large industrial cool ing processes. CFC refrigeration systems are still in operation although most are near the end o f their operational life and need to be replaced.2014 TOC Refrigeration, A/C and Heat Pumps Assessme nt Report

104 In Southern Africa almost all large systems use R-7 17 and although R-744 has been trialled in some supermarkets it has not been used in industria l 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 tem perature 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 spa ce or water heating as described in chapters 8 and 9. Typical temperatures are in the r ange 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 distr ict 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 besp oke 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% o f 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 diffe rentiated from commercial systems on size alone, as many commercial office buildings have lar ge cooling loads. An industrial system requires a higher level of reliability and is subje ct 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 computi ng equipment. Other industrial airconditioning systems are primarily required to main tain 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 sys tem, the mission-critical cooling is maintained at the expense of the comfort of the occupants of t he rest of the building. Often the chillers used for industrial air-conditioning are the same t ype as described in Chapter 9 – the market information and options for future change are descr ibed 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, c alled 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) (Zy howski, 2003). The Rankine cycle uses heat to evaporate the working fluid at relatively h igh 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 expan der outlet is condensed, usually by rejecting heat to atmosphere in a cooling tower, an d the resultant liquid is pumped up to evaporating pressure by a liquid pump. The conversi on rate from thermal to electrical power varies with the pressure differences and the expans ion engine efficiency, but typically is2014 TOC Refrigeration, A/C and Heat Pumps Assessme nt 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 criti cal 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 temperatur es. The GWP of HFC-245fa is approximately 858, whereas for HFC-236fa it is appr oximately 8060, so it is likely that future commercial systems will be based on HFC-245fa (unle ss severe restrictions are placed on all high GWP HFCs). A fluorinated ketone, perfluoro-2-m ethyl-3-pentanone CF 3 CF 2 COCF (CF 3 ) 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, althou gh 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 w ith 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 limite d to use in large process plants, although a few systems have been installed in commercial build ings.



### 5.2 Applications 5.2.1 Food processing Refrigeration is used for chilling and freezing foo d during processing, in order to prolong shelf life, but it can also be used to make handlin g 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 c ooled after heat treatment to minimise spoilage. A wide variety of chilling and freezing t echniques are used, including immersion in liquid, air blast freezing in batches or in a conti nuous process and contact freezing on tables or in blocks between metal plates. The choice of pr ocess depends on the form that the product takes, whether it is wrapped or unwrapped, robust o r fragile, processed or raw. Some fruits and vegetables such as potatoes, apples and most so ft 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 froze n 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 foo d, 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 l arge capacity and require a large power input although the freezing chamber may be physical ly 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 bu t results in a shorter freezing time

Some food processes require careful control of humi dity 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 stor age 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 period s of high ambient temperature the cooling load for the incoming air can be substantially high er than the product cooling load. Failure of the cooling system would cause the product to ripen too quickly resulting in a large loss of2014 TOC Refrigeration, A/C and Heat Pumps Assessme nt Report

106 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 temp erature levels, frozen (well below 0 o C) and chilled (above 0 o C). Frozen produce must be stored below -18 o C, and it is usual to maintain the store between -22 o C and -26 o C to provide a factor of safety in the event of maj or equipment failure. Some products require lower temp eratures, for example ice-cream and similar produce is stored between -26 o C and -29 o C, and some niche market products such as some types of sushi must be kept significantly cold er, even down to -60 o C, in order to retain product quality. Chilled produce is typically held between 0 o C and 4 o C, although fruit, bakery products and vegetables are stored between 8 o C and 12 o C. 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 war ehouses. Other sites provide marshalling facilities in order to restock supermarkets on a da ily 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 temper ature 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 p roduct.

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 m oulding. These loads are relatively constant all year, and production output is affecte d 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 hea t 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 appl ications may be up to 2 kW per m 2 in comparison to a typical office load of 40 W per m 2

. The industrial cooling load is typically almost ent irely “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 d ehumidification, 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 co oling can be split into separate systems for sensible and latent cooling, then the operating tem perature 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 pr ocess heat load.

There is a significant benefit in pre-cooling the i nlet air to gas-fired turbines in higher ambient climates. For example reducing the air inlet temper ature 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 coolin g 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 centre s (Sarraf, 2012). Because of the high ambient temperatures throughout most of the year, t he uninterrupted operation of those2014 TOC Refrigeration, A/C and Heat Pumps Assessme nt Report 107

systems is “mission critical”. District cooling pro viders design multiple redundancies in their systems, since stoppage will necessitate vacating t hose premises incurring heavy fines on the operators. There is an estimated district cooling installed ca pacity 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 insta lled capacity of 420 MW. Saudi Arabia has about 400 MW district cooling capacity and is the f astest growing market. All those systems use vapour compression technology and predominantly HCFC and HFC refrigerants. In Egypt, with an estimated 350 MW total installed cap acity of district cooling, natural gas fired absorption chillers are mostly used. Some older dis trict cooling applications in the region still use CFC-11 and CFC-12 but the majority of systems a re now HCFC-22, HCFC-123 or HFC134a.

In the Gulf Cooperation Council countries (GCC), th e 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 powe r 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 millio n 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 ele ctricity. The potential for district cooling in the GCC counties between 2010 and 2030 is over 1 00 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 di vided as shown in Table 5-3 (Olama, 2012) Table 5-3: Estimated change of district cooling ca pacity 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 incorpo rate 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 p ower plant, using the excess heat from generators to drive the cooling system. In some coa stal sites, for example in Hawaii and Mauritius, deep seawater is being considered for di strict 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, dairie s, food factories and chemical processes require large amounts of heat in addition to a cool ing load. Even if the primary use of heat, for example for cooking food, cannot be achieved by hea t pumps or recovery there may be many uses for lower grade heat, such as pre-heating boil er 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. Wh en it is performing a non-productive chilling2014 TOC Refrigeration, A/C and Heat Pumps Assessme nt Report

108 process on a source of heat, whether it is at ambie nt 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 pu blic buildings, for example in Gardermoen Airport, Norway (8100 kW heating capacit y) and Akershus hospital, Norway (8000 kW heating capacity). These systems are custo m-designed, using R-717 as the refrigerant (Stene, 2008).

Even larger systems are used for district heating s ystems, with many examples in Scandinavia. The smallest of these systems are abou t 5 000 kW. Most installations use HFC134a in centrifugal compressors, with some (up to 1 5 000 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 th e sewage system (Bailer, 2006).

Steam-fired absorption systems (as described in sec tion 5.3.6) can be used to raise condenser water temperature in power plants to provide heat t o district heating networks and some industrial processes. Absorption can also be used t o boost the temperature of a proportion of a medium temperature process stream by cooling the re mainder of the stream. In this way a small part of a stream at 70°C could be raised to 1 20°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 m arket is for ice rinks, extended also to indoor ski-slopes, ice climbing walls and other ice featur es. Many older ice rink systems used direct CFC-12 or direct R-717. To change to an indirect sy stem would require replacement of the floor slab, which is a considerable capital expendi ture. 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 wit h winter Olympics. These systems usually use pumped R-717. A recently installed cross-countr y 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 Assessme nt Report 109

5.2.7 Process Refrigeration Cooling is used in a wide variety of process applic ations (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 de scribed in chapter 9 might be used, although there may still be other reasons for requi ring 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 ethylen e 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 typ ically 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 refrige rant leak rates.

Where processes produce high grade waste heat, for example flue gases from glass production, power stations, steel mills, incinerato rs 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 t o ensure that the heat production and cooling demand are well matched.

The cooling of deep mines presents another challeng e because the operating conditions are arduous and the available space is severely constra ined. 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 co oled 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 alternat ive 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 e xample 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, pa rticularly 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 offer s 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 warmi ng 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 syst ems. The major hazard presented by R717 is its acute toxicity, although its pungent odo ur ensures that low, relatively harmless concentrations are obvious and provide an early war ning of danger.2014 TOC Refrigeration, A/C and Heat Pumps Assessme nt Report

110 R-717 is flammable in relatively high concentration s, but it is difficult to ignite and as a result R-717 conflagrations are extremely rare. The produc ts of combustion are nitrogen and water, so there are no toxic consequences. The lower flamm able limit is 16%; about 5,000 times higher than the short term exposure limit, and almo st 50,000 times higher than the lowest level which can be detected by smell.

R-717 systems can be designed for very high efficie ncy, particularly with higher condensing temperatures, so in recent years it has been used m ore 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 wit h most fluorocarbons, but if oil injected screw compressors are used then the heat of compres sion can be removed by oil cooling. R717 also produces relatively high heat transfer coe fficients and requires a low massflow due to its high latent heat. The high critical temperat ure of 133°C makes R-717 very suitable for high temperature heat pumps. It is at atmospheric p ressure at -33°C, a relatively high temperature for industrial freezers. This means tha t many freezers operate at sub-atmospheric pressure, so air and moisture are drawn into the sy stem if it is not pressure-tight on the low pressure side. This unfortunate consequence is gene rally tolerated because the moisture is soluble in ammonia liquid so does not immediately c ause 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 ope rating efficiency and therefore increase electrical consumption, so system contamination sho uld not be left uncorrected (Nielsen, 2000).

5.3.2 Hydrofluorocarbons When the first HFC refrigerants, particularly HFC-1 34a, were introduced in the late 1980s to replace CFC-12 there was no obvious successor to th e 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 cool ing or two compression stages for freezer applications.

Saturated: Saturated hydrofluorocarbons include flu ids such as HFC-134a and HFC-125 and blends of fluids, mixed to provide specific advanta ges for particular applications. HFC-134a is used in small high temperature systems; it is at atmospheric pressure at -26 o C, and it requires larger compressors than R-717. Sub-atmosph eric operation is less common with HFCs because traces of moisture are liable to freez e and block the expansion valve.

HFC-134a is also widely used in centrifugal compres sors, including some very large systems used for district heating. A trial system using uns aturated HFC-1234ze(E) as an alternative to HFC-134a in district heating has been tested in Nor way ( Nørstebø, 2013 ).

There is no single fluid alternative to HCFC-22 for use in industrial systems. HFC-125 has approximately the right pressure temperature relati onship, but has an extremely low critical temperature of 66 o C, 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, w here the deficiencies in its physical properties can be offset by careful selection of th e other components of the blend. The most common blends used in the industrial sector are R-4 04A and R-507A, which are primarily mixtures of HFC-125 and HFC-143a; with the latter p roviding a higher critical temperature and hence improved efficiency. Many industrial syst ems use flooded evaporators, where the refrigerant boils in a pool. Zeotropic blends (with a temperature glide during evaporation) are2014 TOC Refrigeration, A/C and Heat Pumps Assessme nt Report 111

not suitable in these systems because the blend com ponents 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 wide ly used in industrial systems because it has a low boiling point at atmospheric pressure (-5 1.4 o C), very low glide (less than 0.2K at - 40 o C) and the critical temperature is almost the same as R-404A. The compressor swept volume required for R-410A is about 30% less than f or R-404A, so equipment costs, including installed pipework should be less, althou gh operating pressures are higher. The main barrier to its use is the high price of the re frigerant, particularly compared to R-717 and R-744. When the refrigerant inventory in a system i s in tonnes the cost of the charge may be a significant part of the total cost of the installat ion. Typical installations are therefore low capacity, low temperature, for example blood freezi ng and small pharmaceutical systems. The introduction of rules and guidance for the use of f lammability class 2L refrigerants (those that have a burning velocity less than 10 cm s -1 and 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 gl obal warming potential may give the impression that they could be a suitable alternativ e 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 se ctor, even if blended with other compounds to reduce price or flammability. An exception may b e 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-1336 mzz(Z) and the unsaturated HCFC1233zd(E) may also prove to be suitable in heat pum ps with centrifugal compressors, particularly in very large systems.

5.3.3 Hydrocarbons Hydrocarbons are not widely used in industrial refr igeration except where additional safety measures to ensure that leaking refrigerant cannot be ignited are required anyway, for example in a petrochemical plant. They offer excell ent efficiency, and compatibility with most materials and lubricants. However the precauti ons required to prevent ignition are significantly more expensive than those required fo r 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 pr essures, and requires similarly sized
compressors. 5.3.4 R-744 (Carbon dioxide) R-744 cannot be used in exactly the same way as ot her industrial refrigerants. It needs to be coupled with a higher temperature refrigerant in a cascade system due to the low critical temperature of 31 o C or else used in a transcritical system. Transcrit ical 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 in dustrial 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 s ystems because it is liquid at positive pressure down to -56 o C and the gas is extremely dense, giving very high rates of heat transfer. The pressure drop characteristics are also very fav ourable 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 temp erature applications, such as cold storage, R-744 cascade systems are likely to be slightly les s efficient than two-stage R-717, but still on a par with a single stage economised system, and mo re efficient than any system using a2014 TOC Refrigeration, A/C and Heat Pumps Assessme nt Report

112 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 s tore 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 electric ally non-conductive, does not cause fabric damage in the event of a small leak and enables sma ller heat exchangers to be used. The major challenge in these systems is that the operat ing pressure is approximately 50 bar.

5.3.5 R-718 (Water) In general R-718 is not suitable for most industria l applications because the triple point is very slightly above 0 o C, and because, despite the very high latent heat, the swept volume required for a typical cooling duty is extremely hi gh. There are a few notable exceptions: R718 has been used for a few deep mine cooling proje cts 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 f or 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 fos sil fuel for the sole purpose of driving the regenerator of an absorption system, particularly i n 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 c ooling 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 d irect fired chillers in industrial cooling. Examples are in India, Pakistan, Bangladesh and Chi na. Those units are generally fuel oil fired or gas fired. There is an increase in the foo d 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 unit s.
Indirect fired absorption units are used primarily in applications where excess boiler capacity is available in summer months and where steam or ho t 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 O DP refrigerants, but it is difficult to replicate the operating conditions of HCFC-22 and s o conversions often involve an element of2014 TOC Refrigeration, A/C and Heat Pumps Assessme nt Report 113

equipment replacement. Before committing to any lar ge scale retrofit project consideration should be given to the age of the plant, the cost o f replacement with a modern, more efficient system and the risks to continued operation of retr ofit.

5.4.1 Conversion to HFC blends There are numerous blends for the replacement of HC FC-22 in DX (superheat controlled) systems, but there is none that replicates the pres sure 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. Wher e industrial systems are converted to a blend it may also be necessary to change from miner al or alkyl benzene lubricant to a synthetic ester. Some blends are formulated with hy drocarbons 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 syste m it might be appropriate to convert the compressors and condensers to an HFC blend, but con vert the low pressure side to a secondary fluid, or even R-744 as a volatile second ary. 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-7 44. Conversion to a cascade system is possible, greatly reducing the inventory of fluoroc arbon 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 o perating as a cascade on R-744 could be limited to an allowable pressure of 25 bar gauge, h owever this is a complex retrofit and it may well be more economic to replace the whole plant, e specially 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 condense rs are suitable for either refrigerant, and pipework is probably welded steel in large applicat ions. If the evaporators are copper tube then they need to be replaced. It is imperative tha t 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 t he 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 majo rity 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 t o remove HCFC-22 from existing systems and replace it with HC-290, however it is highly li kely 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 rapi d phase out of HCFCs in Article 5 countries might be an increase of this type of conv ersion without adequate controls. There is however a case for a controlled conversion from HCF C-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.2014 TOC Refrigeration, A/C and Heat Pumps Assessme nt Report

114 

### 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 strateg y to conserve their stock of refrigerant. Setting priorities for which system to replace or c onvert first includes consideration of age of the plant, likelihood of leakage and ease of conver sion. Refrigerant which is recovered from converted systems can be recycled and stored on sit e to be used in the remaining plants. In Europe, where service with “virgin” HCFC-22 was pro hibited from the beginning of 2010, some users have banked additional refrigerant by ov ercharging 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 addition al sales of HCFC in the two years leading up to the prohibition, keeping sales artificially h igh at a time when many plants were being converted or decommissioned. If other regions imple ment 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 withi n the timeframe. This was done in Ireland, and greatly improved the effectiveness of the restr iction on virgin HCFC-22.



### 5.6 Concluding remarks

The majority of large industrial systems in some pa rts 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 HF Cs 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-7 17 and R-744. This transition is slow and is constrained by a lack of trained personnel and l ack of experience of the local end-users. It has been facilitated by corporate policy from multi national food and beverage manufacturers exemplified by the policy statement from the Consum er 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 flu id to market. It therefore follows that if any new development gains market share in industria l systems it will be a fluid developed for some other purpose, either as a refrigerant in smal ler 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 fo r 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 o f 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 Refriger ation and AirConditioning, Purdue University
Brown, 1991 Brown, A. H., 1991. “Return to Ammonia? ” Institute of

Refrigeration, London2014 TOC Refrigeration, A/C and Heat Pumps Assessme nt Report 115

Calm, 2011 Calm, J.M., 2011. “Refrigerants for deep mine refrigeration”, Proc.

IIR Congress, Prague CGF, 2010 Anonymous, 2010. “Resolution on Sustainab le Refrigeration”, The

Consumer Goods Forum, Paris CRAA, 2012 CRAA, 2012. Survey of Refrigerant consum ption for Industrial Refrigeration in China, CRAA, Beijing Gulanikar, 2013 Gulanikar, A.D., 2013. “Energy Cons ervation in Ammonia

Refrigeration System Installed for Meat Processing Unit in India” Proc 5th Ammonia Refrigeration Technology Conf., II R, Ohrid Hodnebrog, 2013 Hodnebrog, Ø., Etminan, M., Fuglest vedt, J. S., Marston, G., Myhre,

G., Nielsen, C. J., Shine, K. P., Wallington, T. J. , 2013. “Global Warming Potentials and Radiative Efficiencies of Ha locarbons and Related Compounds: A Comprehensive Review”, Rev. Ge ophys., 51, 300-378, Washington DC
Hutchins, 2005 Hutchins, G., 2005. “Mission Critica l 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 R 22 to R717, Practical

Experiences from three Industrial Plants” Proc IIR Conf Applications for Refrigerants, Aarhus
Kawamura, 2009 Kawamura, K., 2009. “Global Solution s 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 Or ganic Rankine Cycles”, 15th Int. Conf. on Refrigeration and Air-C onditioning, Purdue University Kohlenberger, 1995 Kohlenberger, C., 1995. “Gas Tur bine 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. a nd Stovall, T., 2009.

“Recovered Energy Generation Using an Organic Ranki ne Cycle System” ASHRAE Transactions Vol. 115 Part 1, Atlant a Madsen, 2009 Madsen, K., 2009. “Living without HFCs : the Danish Experience”,

Institute of Refrigeration, London
Nielsen, 2000 Nielsen, P.S., 2000. “Effects of Wate r Contamination in Ammonia

Refrigeration Systems, Danfoss, Nordberg
Nørstebø, 2013 Nørstebø, A., 2013. “District Heatin g and Cooling based on large

Heat Pumps”, Proc. HPP Workshop, Oslo NZFS, 2008 New Zealand Fire Service, 2008. Report N o F128045 “Inquiry into

the Explosion and Fire at Icepak Coolstores, Tamahe re, on 5 April 2008”, Wellington
Olama, 2011 Olama, M. A., 2011. “The National Surve y for HCFC based

refrigerants for Refrigeration Systems in the Kingd om of Saudi Arabia”, UNIDO2014 TOC Refrigeration, A/C and Heat Pumps Assessme nt Report

116 Pearson, 2009 Pearson, A.B., 2009. “Calculating Fre ezing Times in Blast and Plate

Freezers”, Proc Int. Institute of Ammonia Refrigera tion Annual Meeting, Dallas Pearson, 2011 Pearson, A.B., 2011. “Opportunities f or Combined Heating and Cooling”, Proc 4th Ammonia Refrigeration Technology Conf., IIR, Ohrid
Persichilli, 2012 Persichilli, M., Kacludis, A., Zd ankiewicz, E and Held, T., 2012.

“Supercritical CO 2 Power Cycle Developments and Commercialization: Why sCO 2 can Displace Steam”, Power-gen India and Central Asia, New Delhi Pietrzak, 2011 Pietrzak, J., 2011. “Economic Optimi sation of Refrigeration Systems

at the Design Phase”, Proc 4th Ammonia Refrigeratio n Technology Conf., IIR, Ohrid Sarraf, 2012 Sarraf, G., Fayad, W., El Sayed, T., M onette, S-P., 2012. “Unlocking

the Potential of District Cooling – The Need for GC C Governments to Take Action”, Booz and Co, Chicago
Solemdal, 2014 Solemdal, Y., Eikevik, T., Tolstoreb rov, I. and Veiby, O., 2014.

“CO 2 as a refrigerant for cooling of data-center: a cas e 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 5 th

Ammonia Refrigeration Technology Conf., IIR, Ohrid UNEP, 2011 UNEP, 2011. Report of the Refrigeration, Air Conditioning and Heat

Pumps Technical Options Committee (RTOC) 2010 Asses sment. Vartiainen, 2011 Vartiainen, J. and Salmi, J., 201 1. “District Cooling in Helsinki”,

Helsingin Energia, Helsinki Zyhowski, 2003 Zyhowski, G., 2003. “Opportunities f or HFC-245fa Organic Rankine Cycle Appended To Distributed Power Generation Syst ems”, Proc. IIR Congress, Washington DC2014 TOC Refrigeration, A/C and Heat Pumps Assessme nt Report 117 

## Chapter 6

Transport Refrigeration

Chapter Lead Author

Radim Č ermák



### Co-Authors

Michael Kauffeld Holger König Richard Lawton Alexander C. Pachai Giorgio Rusignuolo2014 TOC Refrigeration, A/C and Heat Pumps Assessme nt Report

1182014 TOC Refrigeration, A/C and Heat Pumps Assessme nt Report 119



## 6 Transport refrigeration

6.1 Introduction Transport refrigeration is a small but vital segmen t comprising delivery of chilled or frozen products by means of trucks, trailers, vans, interm odal containers and boxes. It also includes the use of refrigeration and air conditioning on me rchant, 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 transpor t, differences between containers and road vehicles should not be neglected, and may lead to d ifferent system solutions and (possibly) to different refrigerant choices. The three top candid ates in the container industry are R-744, hydrocarbons and low-GWP HFCs.

In contrast to the 2010 report, more insight is pro vided 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 n iche 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 optio ns are limited in this chapter, and the reader is advised to consult the chapters dealing with ind ustrial and air-conditioning systems.

Based on research, the road vehicle fleet size prev iously estimated at 4 million in the 2006 and 2010 RTOC Reports has been downsized to 2 milli on. 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 equipmen t, virtually all new transport refrigeration systems continue to utilize HFCs, wit h 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 fish ing vessels.

Appendix A contains a general overview and technica l 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 pro perties which lead to high energy efficiencies, the possible leakage of the refrigera nt inside the box and other failure scenarios present a safety challenge, since these refrigerant s are flammable.

Due to the lack of specific safety standards applic able to transport refrigeration, the design usually relies on safety standards for adjacent app lications, 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 oper ation for all the mentioned applications are not described (König, 2013a). Most standards rely o n the concept of “lower flammability limit” combined with a maximum charge and safety fa ctor. In a traditional concept of a transport refrigeration unit, even assuming a signi ficant charge reduction compared to today’s2014 TOC Refrigeration, A/C and Heat Pumps Assessme nt Report

120 typical charge levels, leakage inside the box would inevitably lead to concentrations above the flammability limit.

The use of higher amounts of refrigerant charge ove r the thresholds established by the existing standards would require the adoption of pr ovisions covering safe system design and safe operations. These higher amounts can be permit ted 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 incre ase complexity and may introduce an additional risk that manufacturers must consider.

Measures can include ventilation and shut-off valve s, combined with refrigerant detectors and alarm systems. Ventilation may be realized using ex plosion-proof fans, sensors, etc. Or, as alternative, the flammable refrigerant maybe isolat ed 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 t he 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-127 0, the safety issues being addressed by having a jointless evaporator and installing a dete ction system. However, this unit is not commercially available. One intermodal container ma nufacturer (MCI, 2014) announced a possible market introduction of a refrigeration sys tem with HC’s in 2018-19 subject to the boundaries of future legislation.

In summary, specific research on the use of flammab le 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 increa se the complexity of the system and/or, in case of indirect system, could penalize their effic iency.

6.2.1.2 R-744 R-744 is a promising alternative to HFC refrigerant s and its widespread use in transport refrigeration will only come when systems using R-7 44 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 technolog y and learning curve in transport refrigeration is at an early stage. All major manuf acturers have displayed concepts of units with R-744 at trade shows or have demonstrated an i nterest in R-744 solutions through research publications. One manufacturer has been te sting 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 di stribution trailer fitted with a modified version of the intermodal container system.

The annual energy consumption and the efficiency de pends on the ambient air temperature and the cargo box air temperature (refer to appendi x A 4.1 for details). Systems using R-744 are more efficient than systems using HFC refrigera nts under low-medium ambient temperature conditions. At the same ambient tempera ture, 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 refriger ation and mobile air conditioning application (see Table 6-1) show “crossover tempera tures” (= 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 Assessme nt Report 121

Table 6-1: Crossover temperature with regard to en ergy 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 ree fer 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 c ost of ownership of models used in the industry, approx. 15% of the time is estimated to b e 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 mediu m-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 loa d conditions.

Figure 6-1: Container refrigeration, comparison be tween 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 pa rt 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 refrigera tion pressure range, and are not available today. On the other hand, semi-hermetic reciprocati ng compressors are available today, and scroll compressors may become available in the futu re. This may, for the time being, adversely impact the application of R-744 in sub-se gments where open shaft compressor and scroll technologies are being utilized (for example vehicle powered truck refrigeration systems).2014 TOC Refrigeration, A/C and Heat Pumps Assessme nt Report

122 6.2.1.3 HFC refrigerants Refrigerant manufacturers are developing low-GWP HF C 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 fl ammability of these refrigerants is one of the major concerns for their use in transport re frigeration 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-flamma ble very low-GWP HFC candidates (below GWP 150).

Changes to refrigerant classification have been pro posed to mitigate the flammability concern of the medium and low-GWP HFC refrigerants. For exa mple, ASHRAE Standard 34 (2013) (since 2010 edition) and ISO 817 (ISO, 2014b) recog nize subclass 2L (= 2 low) refrigerants that are defined as class 2 refrigerants with a max imum burning velocity of =10 cm/s. The most recent revision of standard ISO 5149 (ISO, 201 4a) recognizes the fact that A2L and A3 refrigerants need to be treated differently, and pr oposes 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 sho uld be carried out to ensure compliance with occupational health and safety requirements an d other regional standards and requirements.

A calculation assuming a release of 4 kg HFC-1234yf in a 25 m 3 trailer box (80% loaded by cargo) yields concentrations that are at best compa rable to the refrigerant concentration limit (RCL) of the ASHRAE Standard 34 (2013), and above t he 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 ignit ion or self-ignition conditions could create an ignition risk. On the other hand, in personal ca rs, a sudden leakage in case of collision is usually associated with the collapse of the cabin a nd 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 expa nsion devices and other aspects.

Recent studies identified various non-flammable ble nds that offer different combination of GWP (ranging between 1300 and 2200), ease of retrof it, properties, performance and consistency with R-404A. These blends have importan t 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 t han so-called natural or unsaturated HFC (HFO) refrigerants.

The list includes and is not limited to R-407A, R-4 07F, 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 high er discharge temperatures, requiring system changes such as liquid injection in order to achieve comparable capacity, efficiency and reliability. This makes them especially suitabl e for new systems using liquid injection2014 TOC Refrigeration, A/C and Heat Pumps Assessme nt Report 123

devices. On the other hand, R-452A has the GWP of approx. 21 00 and it stands out as easiest direct drop, allowing it to achieve equivalent perf ormance as R-404A without additional system changes.

Overall, it is likely that each of these blends wil l have a role to play in the general move towards more environmentally friendly alternatives.

While in transport refrigeration the majority of th e 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. Th eir 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 syst ems entail low noise levels and low emissions of air pollutant due to the elimination o f diesel powered refrigeration. This can bring benefits at the local scale, in addition to l ower greenhouse gas (GHG) emissions in the use phase, and therefore of benefit for heavily pop ulated areas. However, the energy required to produce the liquefied gases is substantial and t herefore, 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 n itrogen, ensuring that it is a by-product of oxygen production.

Technologies currently under development include sy stems 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 deter mined by the availability of liquefied gas charging stations (see a parallel with liquefied na tural gas, or LNG, in some regions). Where available, cryogenic systems can provide an alterna tive 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 applica tions where eutectic systems represent, and will continue representing, an option for the f uture: small vans, dedicated to a specific cargo, and with a predictable and repetitive duty c ycle. Also, eutectics will continue to be an important solution in some applications in developi ng countries, where precision of temperature control is less relevant compared to th e overall fuel and system cost.

Eutectic systems generally require the use of a ref rigerant to “freeze” the eutectic. Some applications use an external system to freeze the e utectic, and the vehicle can be regarded as “refrigerant free”. The external system has a diffe rent safety, space, etc. requirement and allows for deployment of R-744 or flammable refrige rants that may otherwise have constraints for application in vehicles.

Technology in eutectics is also moving ahead, and s ome manufacturers are developing new “phase change” materials that offer high capacity/w eight ratio.

6.2.2 Vessels

HFC-134a has been the most often used alternative t o HCFC-22 in new vessels for provision refrigeration. New ships may also use R-407C or R-4 07F for air-conditioning going forward, as it is becoming widespread in other sectors. R-74 4 in cascade with R-717 is used for freezing down to -50 °C (mainly with fish as the ca rgo).

Some shipyards utilize HCFC-22 for small fishing ve ssels in Article 5 countries, but not for2014 TOC Refrigeration, A/C and Heat Pumps Assessme nt Report

124 international commercial vessels.

Large industrial systems can use R-717 or R-744 whe re it makes sense. R-717 systems are limited to ships that do not carry passengers but p rofessional crew only (due to toxicity consideration), and ships with a relatively high re frigeration capacity. This makes it suitable for large fishing vessels.

R-744 has been used as a refrigerant with own compr essors (second stage in a cascade) or a secondary coolant being circulated by pumps. When u sed 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 bee n developed and may be used for replacing HCFC-22 systems to be taken out of operat ion. 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 r efrigerant hence the passengers. In 2014, a large manufacturer launched a 50 Hz water-cooled ce ntrifugal chiller that utilizes HCFC1233zd(E) as an alternate technology to HFC-134a.

For commercial vessels and for the off-shore busine ss 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 fl uid.

The classification companies have to approve a give n 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 proces s 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 conta iners usually does not exceed 12 to 18 years, respectively. It is determined by their heav y duty and in Europe by the ATP scheme, which has a 3-year recertification period after the first 6-year in operation. HCFC refrigera nts, 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 stati onary systems.

Of the HCFC and CFC containing fluids, R-502 was wi dely used in the road transport industry after 1960, to overcome issues with HCFC-2 2. The retrofit options include R-408A, R-402A (both contain HCFC-22), R-404A or R-507A whi ch, however, require a component change.

Testing of low-GWP alternatives (below GWP 150, usu ally containing unsaturated HFCs) to the most widely used R-404A is in progress elsewher e. An AHRI AREP participant conducted side-by-side “drop in” comparisons of thr ee state-of-the-art low-GWP 2L flammable fluids (Kopecka, 2013). The evaluation sh owed that these 2L flammable fluids were not suitable for R-404A retrofit in the field.

Recent studies identified various non-flammable ble nds that offer different combination of GWP (ranging between 1300 and 2200), ease of retrof it, properties, performance and consistency with R-404A. These blends are safe, the y have GWP significantly lower than R-2014 TOC Refrigeration, A/C and Heat Pumps Assessme nt Report 125

404A, and in some cases they can be directly droppe d 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-4 07F, R-448A, R-449A and R-452A (MotaBabiloni, 2014, Minor, 2014).3

In this group of non-flammable blends, R-452A stand s out as easy and direct drop in, able to achieve equivalent performance as R-404A without ad ditional system changes. The GWP is at approx.2100. On the other hand, R-448A and R-449 A stand out as lower GWP (approx. 1400) options, requiring system changes with variou s degree of complexity (typically addition of liquid injection to limit discharge temperatures ).

At present between 3.5 and 6% of the refrigerated I SO container fleet has been found to contain counterfeit refrigerants, many containing c hlorine with an ODP (Lawton, 2012). It is assumed that refrigerant cost and limited availabil ity put a pressure to adopt inexpensive counterfeit refrigerants with the subsequent enviro nmental damage. Taxing of existing HFCs (for instance based on GWP) will likely increase th e 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 o n average. Merchant and cruise ships are among the newer equipment. The average age of a mer chant 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, 201 1).

HCFC-22 has been the dominant refrigerant in many m arine applications. Now it is being phased out gradually and many plants are retrofitte d. 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 chill ers are being used. The most used refrigerant in new ships used to be HFC-134a but also R-410A ha s 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 reasonabl e efficiency. HCFC-123 never became a real option aboard ships, possibly because of highe r toxicity.

It is anticipated that marine AC systems will follo w the development of new solutions seen in on-shore systems, perhaps with a small delay of som e years due to the long expected life of the systems onboard ships.2014 TOC Refrigeration, A/C and Heat Pumps Assessme nt Report

126 

### 6.4 Concluding remarks It is clear that, in the transport refrigeration ap plication, a unique, low-GWP or natural solution which would be ideal for new and field ret rofit applications does not exist.

In the case of a regulation banning the use of refr igerant above a certain GWP level as in the EU, HFC blends will likely play a role as a retrofi t to R-404A and (possibly) HFC-134a systems in the installed base: their GWP is signifi cantly 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 eff iciency, 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 RTO C 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 t he design and service best practices for flammable and high pressure refrigerants which it i s hoped will lead to a fast track ISO standard on how these refrigerants can be applied t o 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 advantag es in specific applications, and the fact that they are HFC free will continue making them at tractive.



### 6.5 References
AHRI, 2013 AHRI Standard 1110, 2013, Performance ra ting of mechanical

transport refrigeration units, AHRI, Arlington, VA, USA ATP, 2013 Agreement on the international carriage o f perishable foodstuffs and

on the special equipment to be used for such carria ge, 2013, United Nations, ISBN 978-92-1-139147-3 ASHRAE, 2013 ASHRAE Standard 34, 2013, Safety Stand ard for Refrigeration

Systems and Designation and Classification of Refri gerants, 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 he at pumps. Safety and

environmental requirements, CEN, Brussels, Belgium Finckh, 2011 Finckh, O., Schrey, R., Wozny, M., 201 1, Energy and efficiency

comparison between standardized HFC and CO2 transcr itical system for supermarket applications, 23rd IIR Int. Congres s of Refrigeration, August 21-26, Prague Hrnjak, 2013 Hrnjak, P., 2013, Current and alternat ive refrigerants, 2nd IIR Int.

Conference on Sustainability and the Cold Chain, Ap ril 2-4, Paris
IHS, 2013 http://www.ihs.com/products/maritime-information/sh ips/seaweb.aspx, retrieved on 2013-10-19
IMO, 2012 Lloyd’s Register, 2012, Study on the treatment of O zone Depleting

Substances used to service ships commissioned, repo rt number LDSO/ENG/Q12-02RMS/07/02 – REV 42014 TOC Refrigeration, A/C and Heat Pumps Assessme nt Report 127

ISL, 2011 Shipping Statistics and Market Review, Vo lume 55, No 8 – 2011,

Institute of Shipping Economics and Logistics ISL, 2012 Shipping Statistics and Market Review, Vo lume 56, No 1/2 – 2012,

Institute of Shipping Economics and Logistics ISO, 2014a ISO 5149, 2014, Refrigerating systems an d heat pumps -- Safety and

environmental requirements, ISO, Geneva, Switzerlan d ISO, 2014b ISO 817, 2014, Refrigerants -- Designat ion 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-GW P Alternative Refrigerants Evaluation Program König, 2013a König, H., Enkemann, T., 2013, Risk as sessment and standards

aurvey for use of flammable refrigerants in transpo rt refrigeration applications, 2nd IIR Int. Conference on Sustainabi lity 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 Risi kobewertung, DKV Jahrestagung November, Hannover
Lawton, 2012 Lawton and Cavalier, 2012, Risk Inhere nt in the Use of Counterfeit

Refrigerants, 23rd Informatory Note on Refrigeratio n Technologies, IIR, November 2012. MCI, 2014 Maersk Container Industry, EPA-HQ-OAR-201 4-0198-0089,

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 Temp erature, 15th Int. Refrigeration and Air Conditioning Conference at Purdue, July 14-17, paper #2175
Mota-Babiloni, 2014 Mota-Babiloni, A., Navarro-Esbr í, J, Barragán, Á., Molés, F., Peris,

B., 2014, Theoretical comparison of low GWP alterna tives for different refrigeration configurations taking R404A as baseline, Int. Journal of Refrigeration, Vol. 44, August, pp. 81-9 0. Möhlenkamp, 2014 Möhlenkamp, A., Lemke, N., Köhler, J., 2014, Comparison of

different refrigerants for a two-stage transport re frigeration system, 3rd IIR Int. Conf. on Sustainability and the Cold C hain, June 23-25, London Shimada, 2011 Shimada G., 2011, High Ambient Energy Efficient CO2 refrigeration

unit for supermarket and CVS, ATMOsphere Europe, Oc tober 11-12, Brussels TEAP, 2012 TEAP 2012 Progress Report, in response t o Decision XXIII-72014 TOC Refrigeration, A/C and Heat Pumps Assessme nt Report

1282014 TOC Refrigeration, A/C and Heat Pumps Assessme nt Report 129



## Annex to Chapter 6

The following sections describe technical progress and general characteristics of the transport refrigeration sector. Differences from other sector s are discussed. Fleet size and refrigerant charge estimates are provided in order to assess th e relative importance and contribution of the various sub-sectors to the refrigerant banks an d emissions.

A6.1 Requirements Technical requirements for transport refrigeration systems are extremely complex. The equipment has to operate over a wide range of ambie nt 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 tempe rature needs and even different temperatures simultaneously in different compartmen ts.

All transport refrigeration systems have to be very robust and reliable to withstand vibrations and shocks. At the same time, the systems must be c ompact to maximise cargo space, and lightweight to reduce the energy required to move t he vehicle. It is imperative that spare parts (including refrig erant) are available along transport routes world-wide. Returning to a port can be a major issu e for marine vessels in case of a refrigeration plant breakdown. This must be conside red when design changes and improvements are made and introduced. Rigorous test ing 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 bec ause of collisions with other objects. In addition, the harsh environmental conditions tend t o accelerate the equipment aging. The equipment lifetime is usually between 10 and 15 yea rs for road vehicles, railcars and intermodal containers, or less than 10 years in cas e of intensive use, and 20 to 25 years for merchant, naval and fishing vessels. Safety is a number one priority in all transport re frigeration systems, because trained and certified service personnel may not be available al ong transport routes. Safe operation is particularly essential in the case of marine vessel s, where evacuation is difficult or impossible. Safety must be either inherent in the f luids, 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 occupi ed cabin space. IHS Fairplay, the sole global issuing body of the IMO Ship, Company and Re gistered Owner numbering system, claims to register nearly 180,000 ships of 100 GT a nd 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 f ishing vessels. Refrigerated cargo ships consist of specialized refrigerated ships (reefers) , LPG carriers, nuclear fuel carriers and juice carriers. According to Lloyds Register porthole shi ps no longer exist and they have removed the survey requirements from their notation. HCFC-22 has been the dominant refrigerant used aboa rd ships (estimated 80% of present fleet). HFC-134a has been the most often used alter native to HCFC-22 in new vessels for both air conditioning and refrigeration. R-404A and R-40 7C have been used mainly to retrofit HCFC-22. New ships may also use R-410A going forwar d, 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 ves sels; primarily larger fish trawlers.2014 TOC Refrigeration, A/C and Heat Pumps Assessme nt Report

130 The typical charge size for different types of vess els is provided in Table A6-1 reprinted from the 2012 Lloyd’s report (IMO, 2012). Although the r efrigerant 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 c ontainer ships, nuclear fuel carriers and juice carriers is also very low. The only growing s ector may be the LPG carriers, while cargo containerization has increased, this has removed ca rgo from reefer ships and which have therefore declined, porthole containers and their s hips 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 201 2 Lloyd’s report quantified the inventory of ozone depleting refrigerant for 41 flag administ rations, which estimated stock was greater than 100 t, at 17,696 t. Provided that these 41 cou ntries 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 soph isticated approach, the 2012 TEAP Progress Report (TEAP, 2012) arrived at the total i nventory estimate of 27,650 t. The 2012 Lloyd’s report provided also a type-specif ic estimate of refrigerant leakage rates. The percentages were lower (5 to 15%) for cruise an d refrigerated cargo ships, and higher (on average 50%) for the fish factory and trawlers. Reg ardless 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 (leak age) 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 e stimated refrigerant charges, leakage rates and fleet sizes suggest that the fishing sector sha ll be consulted for more details.

Refrigeration systems have to comply with legislati on 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 veh icle segments: small trucks and vans with a cargo volume below roughly 19 m3, large trucks wi th 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 an d sub-urban areas, while long haul transport favors large trucks and trailers.

It is common to state the maximum refrigeration cap acity 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 N orth American market prefers to rate at box temperatures of –17.8 oC and 1.7 oC at an ambient t emperature 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 tempe rature of 30 oC.2014 TOC Refrigeration, A/C and Heat Pumps Assessme nt Report 131

The flexibility required by the carriers of perisha ble food has brought up the need for multi temperature compartment box in all categories of ve hicles, from small vans to the largest trailer. Multi-temperature equipment has been devel oped for nearly two decades to optimize different logistic scenarios. They allow the same v ehicle 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 a verage of 9% vans, 44% trucks and 41% trailers). Some operators purchase only the multi-t emperature 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 tem peratures. The refrigeration capacity during transportation varies with the actual heat l oad. Most units are able to provide heating in the cargo box, usually by means of hot gas (compres sor discharge), electricity, or independent gas heating equipment.

Majority of road and rail equipment utilizes the va pour 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 indep endent 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 temperatu re 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 consider ably smaller than anticipated previously in RTOC reports. Cavalier and Devin (Cavalier, 2013) a nalyzed UNECE, IIR, EU and expert’s figures and estimated the European Union fleet at s ome 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 trai lers, 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 se veral hundred grams and 10 kg, usually less than 6 kg for small and large trucks. Micro-ch annel 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 reduc e the greenhouse gas emissions. Technologies and designs applied today in vapour co mpression systems include: microchannel condensers to reduce refrigerant charge, he rmetic solutions to reduce leak rates, reduced number of joints and better process control s and leak testing for joint integrity. In addition to the above, many solutions are being tes ted in a limited volume base such as alternative propulsion systems (hybrid, electric, e tc.) instead of diesel engines.

There are two systems other than the vapour compres sion cycle and diesel engine system that are available in the market and used in road transp ort today. Their fleet size is currently, however, small.2014 TOC Refrigeration, A/C and Heat Pumps Assessme nt Report

132 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 ca rbon dioxide R-744 in an insulated tank. When needed, the liquid is expanded in a heat excha nger, 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 regardle ss 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 system s 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 c an be placed on a flat car. There is a small market of refrigeration systems built to handle sev ere rail and intermodal duty.

A6.4 Intermodal containers The intermodal containers category includes refrige rated ISO containers (reefers), air freight containers, and small containers and insulated boxe s.
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 refr igerated containers built annually.

The vapour compression cycle has been the only tech nology used in refrigerated ISO containers. Because the equipment lifetime is aroun d 12-15 years (up to 18 years in new equipment), and the last HCFC units were produced i n 2000, only a few HCFC units may be still in use in ocean traffic today. Current system s utilize HFC-134a or R-404A.

Approximately 60% of new units are fitted with herm etic scroll compressors, about 40% of the units are equipped with reciprocating, single o r 2-stage compressors. The current technology features have resulted in reduced refrig erant charges and reduced emissions. The typical charge is approximately 4.5 kg, some manufa cturers reporting charge of 2.8 kg HFC134a.

All container units are electricity driven due to a vailability of electric grid on ships. When used on land (trailers, flat railcars, etc.), elect ricity is supplied from the electric grid or from a diesel engine generator set (gen-set) that is mount ed on the unit front or the trailer.2014 TOC Refrigeration, A/C and Heat Pumps Assessme nt Report 133

The refrigeration performances can be tested accord ing 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 r efrigeration capacity is around 4 kW at a box temperatures of –29 oC, around 6 kW at a box te mperatures 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 e ffort in reefer container industry. Manufacturers have focused on compression technolog y, 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 bala nce between air temperature control range and energy consumption.

The safety requirements are most complex for interm odal equipment because of the various modes of transport (ship, terminal, road, rail, pub lic events), including air freight. Therefore the reefer industry and operators have established a full operation control technology reporting and documenting the different states of r eefer container positions, locations, forwarding information, as well as refrigeration sy stem related information such as cargo temperature.

Dry ice (solid carbon dioxide) and gel packs are th e most common types of coolants used for air freight transport. Dry ice is classified as “da ngerous goods” and subject to IATA regulations – mass is declared. A small number of a ir freight containers use HFC-134a in a battery-powered vapour compression cycle. The cooli ng capacity as well as the refrigerant charge is low.

Small containers and insulated boxes are usually us ed 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 refrige rated with eutectic sticks or solid carbon dioxide. They are widely used for transport of phar maceutical 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 ann ual ambient temperature profile collected by Maersk Container Industry (König, 2013b). It cov ers random container operations in a representative container fleet during a period of t hree years. The data include operations on vessel (including systems using both water-cooled a nd air-cooled condensers), rail and road, as well as operations in terminals. Temperatures be tween 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: -1 8 ° C (41%, frozen), 0 ° C (28%, chilled) and 15 ° C (17%, banana). The other temperatures represent 1 4% of the refrigerated ISO container fleet operation (König, 2013b).2014 TOC Refrigeration, A/C and Heat Pumps Assessme nt Report

134 Figure A6-2: Average annual ambient temperature of reefer container fleet (König, 2013b)2014 TOC Refrigeration, A/C and Heat Pumps Assessme nt 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 Okada2014 TOC Refrigeration, A/C and Heat Pumps Assessme nt Report

1362014 TOC Refrigeration, A/C and Heat Pumps Assessme nt Report 137



## 7 Air-to-air air conditioners and heat pumps

7.1 Introduction On a global basis, air conditioners (ACs), includin g reversible air heating heat pumps (generally defined as “reversible heat pumps”) rang ing in size from 1 kW to 750 kW comprise a vast majority of the air conditioning ma rket (the majority are less than 70 kW). In the remainder of this chapter the term air conditio ning will be used to apply to both air conditioners and air-to-air heat pumps that directl y heat air. This broad category is sometimes referred to as air-cooled or unitary equipment. The se systems cool and/or heat enclosed spaces ranging from single rooms to large exhibitio n halls. Essentially, most are electrically driven vapour-compression systems using hermetic ro tary, reciprocating or scroll compressors for units with capacities up to about 100 kW, and s ingle or multiple semi-hermetic reciprocating, scroll or screw compressors for unit s with capacities up to 750 kW. Air in the space is drawn over a coil containing evaporating r efrigerant. Heat transfer occurs between the air and the circulating refrigerant. With syste ms 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 transfe rring heat to the air.

Nearly all air conditioners manufactured prior to 2 000 used HCFC-22. The transition away from HCFC-22 is nearly complete in non-Article 5 co untries. 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 a nd 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 envir onmentally focused on the protection of the ozone layer and not on the reduction of global warm ing potential (GWP). Some Non-Article 5 countries began the transition to non-ODP alternati ves 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 accel erated phase-out similar to non-Article 5 countries.

Globally, in 2014, the majority of the installed un it 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 condi tioners were operating worldwide, representing approximately one million metric-tonne s of HCFC-22.

The scope of this Chapter includes an overview of t he 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 i mplications and lubricants and commercial availability. In addition, issues related to refrig erant charge reduction and not-in-kind technologies applied to air conditioners are also c overed. Alternative refrigerants for existing equipment, options for refrigerant replacement (onl y) and retrofit are summarised and implication of refrigerant choice for new systems u sed 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 assessme nt report is related the increased substitution of HCFC-22 and the greater considerati on 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 s ystems; this has now been completed and most major Article 5 countries have initiated t heir transition from HCFC-22. Previously, medium and low GWP alternatives were not being give n major consideration (except2014 TOC Refrigeration, A/C and Heat Pumps Assessme nt Report

138 hydrocarbons (HCs) such as HC-290) whereas now addi tional manufacturers are adopting HCs and there is also uptake of HFC-32, whilst othe rs are also considering the variety of new HFC/unsaturated HFC blends. China has made a decisi on 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 ambie nt 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 com mercial air conditioners; ducted, split residential air conditioners; and ducted commercial split, multi-split (including variable refrigerant flow, VRF) and packaged air conditioner s (commercial air cooled). In each of these categories, the term “air conditioner” includ es systems that directly cool or heat the conditioned air.

Table 7-1 summarises the typical physical and insta llation characteristics of each type of air conditioner.

Table 7-1: Typical configurations of air conditione r 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 – 3Through-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 – 3 00 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 sma ll capacity units in which all of the refrigeration system components are contained withi n 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 followi ng 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 r oom air conditioners that can be rolled from room t o room. They exhaust their condenser air through a sm all flexible conduit, which can be placed in an open window. Some portable air conditioners use a s eparate outdoor condenser, which connects, to the indoor section with flexible refrigerant piping.2014 TOC Refrigeration, A/C and Heat Pumps Assessme nt 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 emer ging air conditioning markets. However, duct-free, split type room air conditioner s are being selected more frequently as the first comfort air conditioning option in most count ries resulting in a global decline in the demand for window mounted and through-the-wall air conditioners.

These systems have average refrigerant charge level s 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 reciproca ting or scroll compressors.

Most small self-contained air conditioners historic ally used HCFC-22. As non-ODP refrigerants have been applied to these products-th e majority have used HFC blends, R-407C and R-410A. A small proportion of units are using H C-290.

Globally there are about 17 million SSC air conditi oners currently produced (Glo ё l, 2014). With service lives over 10 years, it is estimated t hat 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 c ommercial air-conditioning is done with non-ducted split air conditioners. Non-ducted split air conditioners are widely applied in commercial buildings, schools, apartments and frees tanding 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 (con densing unit) installed outside the space to be cooled or heated. The outdoor unit is connect ed 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 e xpansion device also within the condensing/outdoor unit. Compressors are typically hermetic rotary, scroll or reciprocating type; high energy saving potential comes from intro ducing inverter technology and technology is currently used in about half of new u nits.

Reversible air conditioners (heat pumps) are gainin g 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 a ir conditioners can reduce indirect CO 2 emissions by providing an efficient and cost effect ive alternative to electric resistance and fossil fuel heating. Heat pumps designed for cold c limates utilize one or more technologies to improve their low ambient performance. These techno logies include, multi-stage or variable speed compression, larger heat exchangers and enhan ced control strategies.

The vast majority of mini-split residential and com mercial 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 thes e products are HFC blends such as R410A and R-407C, whilst HFC-134a has been more domi nant in regions that experience high ambient conditions.

The current global market for these types of split systems is around 80 million units per year (Glo ё l et al, 2014).2014 TOC Refrigeration, A/C and Heat Pumps Assessme nt Report

140 7.2.3 Multi-split air conditioners for commercial a nd residential A second type of products are multi-split; essentia lly 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 sy stems is more often used in commercial buildings. Specific refrigerant charges tend from a round 0.3 kg/kW upwards, depending upon the installation characteristics. As with single sp lits, non-ducted and ducted multi-splits also offer reversible (heating) options.

Variable Refrigerant Flow (VRF) systems are a sub-c ategory of the multi-split air conditioning systems and are distinguished from reg ular multi-split systems by their ability to modulate the refrigerant flow in response to the sy stem 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 separ ate indoor spaces. The outdoor unit modulates the total refrigerant flow using various compressor capacity control methodologies, with compressor types generally being rotary or scr oll 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 1 50 kW, with an average (module) capacity of 20 kW (noting that modules are often mu ltiplexed to provide greater capacities). Approximately 1 million systems are produced each y ear (Glo ё l et al, 2014).

7.2.4 Split ducted air conditioners (residential an d commercial) Ducted, split residential air conditioners are typi cally used where central forced-air heating systems necessitate the installation of a duct syst em that supplies air to each room of a residence or small zones within commercial or insti tutional buildings. A condensing unit (compressor/heat exchanger), outside the conditione d space, supplies refrigerant to one or more indoor coils (heat exchangers) installed withi n the duct system or air handler. Air in the conditioned space is cooled or heated by passing ov er 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 con ditioners it is done less frequently. Compressor types typically include hermetic rotary, reciprocating and scrolls. The most common refrigerant in these systems was HCFC-22 unt il the period 2005 – 2010, although over the past few years the majority has transferre d to R-410A and R-407C. For residential systems, capacities range from 5 kW to 17.5 kW (ave rage 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 an nual output of about 10 million units (Glo ё l et al, 2014).

7.2.5 Ducted commercial packaged (self-contained) a ir conditioners Ducted commercial packaged air conditioners and hea t pumps are single self-contained units which comprise an integral fan and heat exchanger a ssembly which is connected by means of ducting to the air distribution system of the comme rcial structure. The other part of the package is the condensing unit, normally with an ai r cooled condenser and compressors, which are often hermetic scrolls, although hermetic and s emi-hermetic reciprocating and screw machines are sometimes employed.2014 TOC Refrigeration, A/C and Heat Pumps Assessme nt Report 141

The majority of ducted commercial packaged air cond itioners 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 a re 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 k g per kW of cooling capacity. Most ducted systems historically used HCFC-22, whilst in non-Ar ticle 5 countries R-410A is mainly used and to a lesser extent R-407C, which is used more f requently in regions with higher ambient conditions. Annual market is currently about 1 mill ion units (Glo ё l et al, 2014).



### 7.3 Options for new equipment
As discussed in Chapter 2, there are several factor s that should be considered when selecting an alternative refrigerant. Accordingly, this secti on provides a summary of the most viable HCFC-22 replacement candidates for new air-conditio ners, 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 sin gle 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-13 4a 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 tha t of HCFC-22 (Table 2-7 and 2-8).

More recently, new low- and medium-GWP blends are b eing 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 refrigera nts currently being used in these products such as HCFC-22 and R-410A (Minor, 2008, Spatz et a l., 2010). Due to their compositions, most of these blends exhibit various levels of temp erature 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 expecte d to change in the next two to three years).

Whenever an alternative refrigerant is selected, th ere must be a corresponding choice of lubricant (i.e., the base oil and appropriate addit ives) 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 partic ular HFC is generally made by the compressor manufacturer which makes the selection a fter extensive material compatibility and reliability testing.

Considering the various alternatives with medium an d 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 a ir 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 soc ietal tolerance of consequences from flammables tends to be lower than with other hazard s. Therefore appropriate measures have to be applied in order to mitigate the risk, for examp le, minimising the amount of refrigerant that can leak into occupied spaces or removing the refri gerant from the occupied space entirely,2014 TOC Refrigeration, A/C and Heat Pumps Assessme nt Report

142 ensure that probability of ignition is greatly redu ced through risk assessment and at a minimum, meet the requirements of national regulati ons and/or appropriate safety standards (where they exist); such rules are continuously und er 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 d evelop substantially lower cost aircooled air conditioning systems using HFC blends su ch 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 l ower volumetric refrigeration capacity of HFC-134a. Similarly, significant equipment redes ign is necessary to achieve efficiency and capacity equivalent to HCFC-22 systems. These desig n changes include larger heat exchangers, larger diameter interconnecting refrige rant 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 ori ginally designed for HCFC-22. However, since around 2004 many of the R-407C systems have b een 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 product s available in Europe, Japan and other parts of Asia. Because of its low saturated pressur e, R-407C is chosen as an alternative to HCFC-22 by some manufactures in the Middle East whe re 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 t o replace widely HCFC-22 in the air conditioning sector in future, at least where stand ard temperatures apply.

Performance tests with R-407C indicate that in prop erly designed air conditioners, this refrigerant will have capacities and efficiencies w ithin ± 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 i s significant but has been manageable through many years of use and experience. Counter f low 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 des igns because the refrigerant has opposite flow directions in the heating and cooling modes un less complex reversible refrigerant heat exchanger circuiting is employed.

Polyolester (POE) or polyvinylether (PVE) lubricant s can be selected for R-407C. Of these, POE is the most widely used lubricant in HFC refrig erant applications. A recent tendency is for compressor manufacturers to use POE oils in com pressors 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 Assessme nt Report 143

7.3.3 R-410A

R-410A can replace HCFC-22 in new equipment production, si nce the operating pressures are around 50-60% higher than HCFC-22. Due to its therm ophysical properties, the design of R410A units can be more compact than the HCFC-22 uni ts they replace. In addition, R-410A can have better performance in inverter type air co nditioner 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 operatin g pressures of R-410A through design changes such as thicker walls in compressor shells, pressure vessels (accumulators, receivers, filter driers etc.). In addition, the consideration s 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 v alue, 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 hi gh condensing temperatures (see Section 7.5.1).



### 7.3.4 HFC-32
HFC-32 is seen as a replacement for R-410A due to i ts medium GWP and slightly higher capacity and similar efficiency. Due to lower densi ty 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 modificat ions and with additional safety considerations given its class 2L flammability (see Annex to Chapter 2); appropriate design, application and service changes will be required fo r it to be safely applied. Another factor that must be considered with flammable refrigerants is r efrigerant reclaim and recovery requirements during servicing and at the end of the product’s li fe to protect those servicing or recycling the product. The current POE and PVE lubricants used wi th R-410A have insufficient miscibility with HFC-32 (Ota and Araki, 2010) and therefore mod ified 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 evalua tions. Barve and Cremaschi (2012) tested HFC-32 in an R-410A reversible AC, with vari ous 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 a n 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-41 0A 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 fr om -1% to +3% of R-410A with cooling COP and heating COP varying by -1% to +2% and -6% t o +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 h eating COP compared to an R-410A system. Yajima et al. (2000) reported 10% higher co oling 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 manufacture r reported that although there are some million split-type units installed there have been no incidents reported so far.2014 TOC Refrigeration, A/C and Heat Pumps Assessme nt Report

144 

### 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, con structed and installed with due consideration of its class 2 flammability (see Anne x 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 i mplies 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 fo r 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 acco rdingly (see Annex to Chapter 2), as well as due consideration to reclaim and recovery requir ements 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 refrigerati ng capacity is close, around 5% lower, to that of HCFC. Tests comparing the efficiency have f ound that the COP of HFC-161 is about 10% higher than HCFC-22 (Padalkar et al., 2011). Fu rthermore the refrigerant mass can be decreased to about half of the HCFC-22 charge. Wu e t 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 differenc e 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 efficiencie s 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-1234 yf are very similar to HFC-134a, the same general observations about its applicability i n 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 incre ased 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 t he 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, sys tems should be designed, constructed and installed with due consideration of its flammabilit y (see Annex to Chapter 2), as well as due2014 TOC Refrigeration, A/C and Heat Pumps Assessme nt 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 hig her energy efficiency and slightly lower cooling and heating capacity. In terms of improveme nts in system COP in split type and window air conditioners with HC-290, values range f rom around -4% to +20%, such as: 4-7% (Chinnaraj et al, 2010); up to 8% (Devotta et al, 2 005b); 4-12% (Jin et al, 2012); 10-15% (Li et al, 2010); 10-20% (Liu, 2007); up to 14% (Padalk ar et al, 2010); up to 11% (Park et al, 2008); up to 2% (Park et al, 2007); 1-4% (Teng et a l., 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 rate d cooling capacity. In addition, HC-290 has reduced compressor discharge temperatures and i mproved heat transfer due to favourable thermo-physical properties. Compressor manufacturer s 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, fo r example with certain additives.

The main difficulty with HC-290 is its class 3 flam mability, which creates safety concerns in application, installation and field service. Europe an and international standards limit the charge of HC-290 (see Annex to Chapter 2). Such cha rge 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/m 2 ) 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 t he amount of refrigerant, which can increase the capacity range. Similarly, control str ategies can be applied to restrict the amount of refrigerant that can leak into the occupied spac e 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 independe nt refrigerant circuits or reboiler loop, although this implies a cost increase.

Leak, ignition and fire tests demonstrated that eve n with catastrophic refrigerant leaks, only sources of ignition present in the immediate vicini ty of the indoor unit have the possibility to ignite a leak of refrigerant and consequences are i nsufficient to damage doors or windows (Zhang et al., 2013). Similar findings for develope d concentrations were reported by Li (2014a). Risk analyses on the use of HCs in air con ditioners suggest that when the requirements of safety standards are met, the proba bility of ignition during normal operation is extremely low (Colbourne and Suen, 2004). A rece nt study demonstrated that the flammability risk associated with split air conditi oners is around 100 times lower than with HC-600a domestic refrigerators (Colbourne, 2014). T he situation leading to highest risk is sudden leaks, refrigerant handling, and servicing a ctivities, thus, installation and service practices must be modified to avoid exposing occupa nts and field technicians to the additional risks associated with flammable refrigerants.

Another factor that must be considered with flammab le refrigerants is refrigerant reclaim and recovery requirements during servicing and at the e nd of the product’s life to protect those servicing or recycling the product. Current recover y and recycling practices depend largely upon national or regional regulations. For example, in E urope waste legislation implies that HCs must be recovered, whereas in many Article 5 countries, venting of HCs may be considered an2014 TOC Refrigeration, A/C and Heat Pumps Assessme nt Report

146 acceptable option, but should only be done subject to a risk assessment.

Some major Chinese and Indian manufacturers have ha d commercially available HC-290 products since 2012 and have been available in Euro pe 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 poi nt of view of both thermodynamic and transport properties, but is a class 3 flammable re frigerant. 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 C hen et al. (2011) compared HC-290 and HC-1270 in a split air conditioner and found that d espite 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 heat ing mode and results showed that the capacity of HC-1270 was 3-10% higher than that of H CFC-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 compare d with HC-290, HC-1270 has a larger capacity which is useful to reduce the speci fic charge. Similarly, the obstacles and flammability risk for use of HC-1270 in air conditi oners are similar to those of HC-290 (see Annex to Chapter 2).

Some manufacturers of room air conditioners are dev eloping 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 tempe ratures 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 cr itical 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 H FC 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 ca n be made to improve their efficiency. The efficiency of R-744 systems can be improved thr ough 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., 200 8; Wang et al., 2008; Koyama et al., 2008; Li and Groll, 2008; Peuker and Hrnjak, 2008; Kasaye r 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 ar e high; typically up 50 140 bar, with a mean system pressure near 50 bar (Ibrahim and Flemi ng, 2003). The required hydrostatic burst strength of systems operating at these high p ressures would have to be approximately 300 (Bosco and Weber, 2008) to 400 bar (see Annex t o Chapter 2). The higher operating pressures contribute to high specific cooling capac ity, thus allowing the reduction of inner diameters of tubes and lower compressor displacemen t or swept volume. The smaller component diameters result in comparable wall thick ness to address the high operating2014 TOC Refrigeration, A/C and Heat Pumps Assessme nt Report 147

pressures of R-744. Design changes required to addr ess the burst pressure requirements of R744 systems may also result in manufacturing cost i ncreases. The high cost of R-744 systems, unless resolved, is expected to substantially hinde r 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 co mpete 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 t he capacity, efficiency and reduce the peak electrical power requirements during the cooli ng 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 exp anding as more researchers conduct studies of R-744 compressors (Hubacher, 2002; Li et al., 20 00; Youbi-Idrissi, 2003; Muller and Eggers, 2008). Some of the lubricants being conside red for R-744 systems are POEs, PAO, and naphthenic mineral oil or alkyl benzene lubrica nts (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 condi tioning. 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, s ystems should be designed, constructed and installed with due consideration of its flammab ility, 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 enab les 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 exa mple, where HCFC-22 or R-407C is already used. Since it has class 2L flammability, t he appropriate safety standards should be followed (see Annex to Chapter 2). As with other fl ammable refrigerants, systems should be designed, constructed and installed with due consid eration 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 th an R-410A, which implies that it should show performance at high ambient temperatures simil ar to HCFC-22. Preliminary test results indicate that R-444B shows similar capacity and eff iciency to HCFC-22 (Sethi et al, 2014).2014 TOC Refrigeration, A/C and Heat Pumps Assessme nt Report

148 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 applicabl e in the listed equipment types and this list is no t 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 syste m remains principally the same (such as heat exchanger configuration), an increase in syste m efficiency is typically coupled with a greater specific charge due to the need of larger h eat exchanger surfaces to reduce approach temperature differences, thus larger internal volum es and refrigerant amount (ICF, 2006). As an example, in the United States, the minimum effic iency 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 meet ing 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 reduct ion is becoming an increasingly important consideration in the design of air conditioning sys tems. 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 newe r substances are likely to demand much higher costs. Furthermore, since a lower charg e 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 lo ss 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 smalle r risk (assuming no other differences in conditions). So in situations where it is desirable to reduce the risk associated with a particular refrigerant, a reducti on in charge can bring the interpretation of risk to a more acceptable level. Furthermore, certain safety standards2014 TOC Refrigeration, A/C and Heat Pumps Assessme nt Report 149 impose charge size limits for refrigerants in diffe rent situations (see Annex to Chapter 2) and through a process of charge reduction, the e xtent 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 ad dition, 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 fo r the same amount of refrigerant lost. It is important to carry out charge reduction commensurat e with system performance optimisation, also considering the impact on reverse mode operati on and defrosting (if relevant). Considerable research has and continues to be condu cted into reducing refrigerant charge levels (Fernado and Lundquist, 2005). Most large sy stem manufacturers actively pursue developments in charge reduction and there are regu lar 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 s hould be approached. Techniques include use of mini- or micro-channel heat exchangers, evap orative condensers, flat tube heat exchangers and/or pipework, smaller tube diameters, oil selection for low solubility, small internal volume compressors and avoidance or carefu l selection of liquid receivers and accumulators (GIZ, 2010). Further discussion on thi s topic is in Chapter 11.

7.3.14 Not-in-kind alternative technologies In past assessment reports, a number of potential n ew 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: a bsorption, desiccant cooling systems, Stirling systems, thermoelectric and number of othe r thermodynamic cycles. However, a search of the literature published since the previo us assessment has continued to confirm that most of these technologies have not progressed much closer to widespread commercial viability for air-cooled air conditioning applicati ons 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 unt il the end of their useful lives. When servicing these products the treatment of refrigera nt can fall into the following categories:

 Use existing refrigerant

 Refrigerant replacement only 2

 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 the ir 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 replac e the existing equipment before the end of its useful life. In non-Article 5 countries, unit r eplacement is more common because the costs

2 Usually the term “drop-in” is used for this type of replacement. However, since there are no alternati ves with identical thermophysical, safety and chemical prope rties as the existing refrigerant (e.g., HCFC-22) th en the phrase “refrigerant replacement only” is used to substitut e the term “drop-in”.2014 TOC Refrigeration, A/C and Heat Pumps Assessme nt Report

150 associated with performing a major repair or retrof it can often be greater than the cost to replace the product. The need for retrofit and repl acement 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-Artic le 5 countries of 15 to 20 years and may be longer in Article 5 countries. Therefore, implement ing recovery and reclaim programmes coupled with the availability of replacement and re trofit 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., ty pically HCFC-22).

For refrigerant replacement only, HCFC is replaced with a blend, but without changing the lubricant used in the original equipment or any oth er 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 capaci ty and/or efficiency, different operating pressures, temperatures and compressor power compar ed to HCFC.

Retrofit refers to not only changing the refrigeran t, but also system components such as lubricant (although not always necessary), filter d ryer (if required) and more extensive modifications which could include the replacement o f the compressor, refrigerant, lubricant, dryer, expansion device, and purging and flushing t he system to remove all residual lubricant from the system. Retrofitting can be substantially more costly than using existing refrigerant, replacing the refrigerant without additional change s 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 rep laced with another without necessarily having to address the refrigeration circuit compone nts and lubricant in the same way as retrofit, but because the replacement refrigerant i s flammable, the external aspects of the equipment, such as potential sources of ignition, h ave 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 capa city 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 h ave 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 alky l benzene lubricants used in nearly all HCFC-22 air conditioning systems. Thus these refrig erants 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 spl it air conditioner Spatz and Richard (2002) showed that R-417A exhibited a 10% drop in both cap acity 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 ti me between when a refrigerant has been phased out f or use in new equipment and the date at which the refrigerant may no longer be produced

.2014 TOC Refrigeration, A/C and Heat Pumps Assessme nt Report 151

by Messineo et al. (2012) found that none of the HF C blends, R-417A, R-407C and R-404A performed better than HCFC-22 when measured in fiel d trails in an air conditioning system.

Although not conventionally used for air conditione rs, 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 t han that of HCFC-22, respectively, while the average COP were increased by 10.6% and r educed by 16.0%.

In addition to the performance and efficiency impac ts 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 op erating 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 ofte n 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 coul d in principle be used as a direct replacement.

There are a number of criteria that should be achie ved 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 alternative s to HCFC-22 in air conditioners, are also deemed as suitable retrofit refrigerants for H CFC-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 widesp read 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-410 A, 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-2 2 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-4 07C capacity matched that of HCFC-22 and there was a marginal increase in COP when the o il 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 C OP 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 capac ity 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 ab le 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 du ring servicing to avoid substantial composition shift. However, because R-407C has a mo derate 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 b lends will tend to have similar practical implications as R-407C.2014 TOC Refrigeration, A/C and Heat Pumps Assessme nt Report

152 The criteria for selecting a suitable retrofit refr igerant 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 a pproach 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-2 2 (see examples in section 7.3), this practice can create a significant safety hazard bec ause of the flammability of these refrigerants. In general, HCs are not recommended f or use in systems that have not been specifically designed appropriately. If HCs are bei ng 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 inf ormation 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 performan ce of R-431A and HCFC-22 under airconditioning and heat pumping conditions. Results s howed 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, Pa rk 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 p erformance of the various HCFC-22 options for high ambient air conditioning applications; “hi gh 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 principl es result in a declining capacity and efficiency for all refrigerants as the heat-rejecti on (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 impac t 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 charg e apply, those limits may be approached at smaller capacities; in these cases additional (safe ty) 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-4 07C 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 ex hibit a steeper decline in capacity with increased ambient (outdoor) temperatures than refri gerants having higher critical temperatures. This steeper decline in capacity is o f 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, t he 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 am bient temperatures (Bitzer, 2012). If the curve is steep something must be done about the sta rting point. i.e., the reference efficiency2014 TOC Refrigeration, A/C and Heat Pumps Assessme nt Report 153

should be set at a higher level in order to compens ate 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-2 2 can be achieved at higher ambient temperatures.

Systems using low-GWP refrigerants are not currentl y available for large capacity systems in most regions with high ambient temperatures.

7.5.1 Performance of alternatives under high ambien t temperatures Table 7-3A: Comparative theoretical cycle volumetri c 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 tempe rature = +10°C; evaporator exit superheat = 5 K; suction line superheat = 0 K; volumetric efficie ncy = 100%; properties from Refprop9; reference condition for blends: dew point and mid-point (in p arentheses, if different)

Table 7-3B: Comparative theoretical cycle COP of se lected 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 tempe rature = +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-p oint (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 al ternative refrigerants at elevated2014 TOC Refrigeration, A/C and Heat Pumps Assessme nt Report

154 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 ac ceptably at ambient temperatures up to 52 ° C. The performance (capacity and efficiency) of R-4 10A air-conditioners falls off more rapidly than HCFC-22 systems at high ambient temper atures (above 40 ° C). At a condensing temperature of 70°C, both capacity and COP of R-410 A degrades by around 14% relative to HCFC-22, as shown in Table 7.3. Very few studies ar e available in the literature to illustrate the extent of performance depredation in real syste ms. In one, Domanski and Payne (2002) report on measurements of an air conditioner compar ing 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 oper ate a significant number of hours at high ambient temperatures, the system designer should ta ke into consideration the reduced high ambient capacity when sizing the equipment. For cas es where the base capacity of the unit would need to be increased to meet the building loa d 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 cond ucted simulations comparing HCFC-22 against R-410A, showing a 6% and 7% drop in capacit y 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 enhance ment on the cooling capacity of R-410A at high ambient conditions as high as 15% and an en hancement 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 prefer able to be used in air conditioning systems than HFC-32 and R-410A because the thermody namic characteristic are much closer to HCFC-22, the effect of the high temperature glid e of R-407C only has a minor effect in the new systems. As such R-407C can be considered bette r 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 H CFC-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 note d that the capacity of HCFC-22 falls by 25% and its COP reduces by 60% as the condensing temperature ri ses 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 Assessme nt Report 155

HC-290 has performance characteristics similar to H CFC-22 and the characteristics are close enough that the current products that employ HCFC-2 2 could be re-engineered to employ HC-290. HC-290 has successfully been demonstrated a s an HCFC-22 replacement in low charge, room and portable air-conditioners applicat ions (Devotta et al., 2005; Padalkar et al, 2014) for regions that experience high ambient cond itions.

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 simi lar to HCFC-22. The use of special design heat exchangers like micro channel aluminium type s howed 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-2 2 could be re-engineered to employ HC-1270. Based on theoretical cycle calculations, H C-1270 shows a 7% reduction in capacity at 70 ° C and a 3% reduction in COP relative to HCFC-22 (Ta ble 7-3).



### HFC-32
HFC-32 is being considered as an alternative to R-4 10A with a higher efficiency and capacity at high ambient temperatures, although worse than H CFC-22, where the capacity is approximately 2% less and COP 5% in theoretical cyc le calculations (Table 7-3). Discharge temperature can be from 5 K to 30 K higher than R-4 10A and HCFC-22. However, this can be managed by injection technology or wet suction c ontrol, although this implies at a cost and/or performance penalty to the AC. It can also b e tackled by adjusting the viscosity of oil (Piao et al., 2012), although this impacts reliabil ity.

A performance comparison of R-410A and HFC-32 in va pour injection cycles (Xu et al., 2012) shows HFC-32 is slightly better than R-410A a t 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. Cons istent with this, Chen (2012) showed that HFC-32 has a small relative drop in capacity c ompared 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 co mpressor technology, which may or may not incur cost implications. The use of an inje ction 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 b y the fact that it has a very low critical temperature (31 ° C) and will operate above the critical point condit ions in most airconditioning applications. Operation at these condi tions 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 effectiv e alternative to HCFC-22 or HFC refrigerants when being applied in high temperature regions (> 40 ° C).



### HFC-1612014 TOC Refrigeration, A/C and Heat Pumps Assessme nt Report

156 At a 70 ° C condensing temperature HFC-161 has a theoretical capacity and COP approximately 3% greater than HCFC-22 (Table 7-3) a nd exhibits a considerably better high ambient performance than R-410A. Practical measurem ents by Wu et al. (2012b) support these theoretical characteristics, where the relati ve COP and capacity of HFC-161 improve relative to HCFC-22 as the ambient temperature incr eases. As such, this implies interesting possibilities for countries, which experience hot c limates.



### 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 capa city at 70 ° C and a 4% increase in COP relative to HCFC-22 (Table 7-3).



### HFC-1234yf

HFC-1234yf ordinarily has performance characteristi cs similar to HFC-134a. However, considering behaviour at high ambient conditions, t he 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 theoretica l cycle calculations.



### R-444B
R-444B systems are expected to perform similar to H CFC-22 systems at high ambient temperatures; theoretical cycle performance indicat es that the capacity and COP are about 5% and 3% lower, respectively, relative to HCFC-22 (Ta ble 7-3). Tests on a split air conditioner (with modified capillary tube and evaporator circui try to account for the temperature glide) achieved identical capacity and COP as HCFC-22 at b oth 46°C and 52°C ambient (Sethi et al, 2014). The discharge temperature is also the same a s with HCFC-22.



### R-446A and R-447A
R-446A and R-447A systems are expected to perform s lightly worse compared to HCFC-22 high ambient temperatures; theoretical cycle perfor mance 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% wor se 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-condition ers for high ambient conditions There are several aspects that can be considered im portant 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 transfe r for the evaporator coils; typically using 1⁄4 inch OD tube diameters will enhance the performan ce 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. M icro channel aluminium coils can be used in order to enhance the heat transfer and to reduce th e condensing temperature at high ambient conditions, whilst larger condenser coils and speci al condenser fans also can be used to reduce the condensing temperature at high ambient c onditions. 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 Assessme nt Report 157

Special types of compressors are needed for the hig h 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 comp ensate for the lower capacity resulting from using these refrigerants. It should also be co nsidered to add vapour and/or liquid injection to an intermediate pressure area in the c ompressor to enhance the performance at high ambient conditions. Additionally techniques ca n be applied to the compressor, such as oil flooding or vapour injection, which can yield s ignificant 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 co nditioners is not recommended, especially at high ambient conditions (Chinnaraj et al, 2011; Zho u and Zhang, 2010). The wide range of temperatures make the use of capillary tubes imposs ible for sufficiently accurate control of superheat where subsequently compressor discharge t emperatures 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, wh ere the refrigerant bank for unitary air conditioners is estimated to be in excess of 1 mill ion tonnes. In new systems, HCFC-22 is only being used in Article 5 countries. The HFC ble nd R-410A is the most common alternative and to a limited extent R-407C along wi th 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 bett er 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 t o a zero ODP alternative. R-410A is increasingly becoming considered unacceptable becau se 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 con ditioning systems primarily consisting of HFCs and unsaturated HFCs, such as R-444B, R-446A a nd R-447A. Although there is concern over the use of R-410A in high ambient temp eratures, appropriate design measures can be used to help remedy the relatively greater d egradation in performance; nevertheless, work is underway to investigate this refrigerant an d 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 flamma ble HFCs, HFC/unsaturated HFC blends and HCs for normal operating conditions as w ell 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-3 2, D2Y-60, and L-41a in Air Source Heat Pump. Air-Conditioning , Heating, and Refrigeration Institute (AHRI) Low-GWP Alternat ive 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". P roc. Int.2014 TOC Refrigeration, A/C and Heat Pumps Assessme nt Report

158 Refrig. and Air Condition. Conf. at Purdue, West La fayette, 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 Cl imate 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 Resident ial 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 La fayette, IN, USA. Bitzer, 2012 Bitzer, 2012. Refrigerant Report 17, A -501-17, BITZER Kühlmaschinenbau GmbH, Eschenbrünnlestraße 15, 7106 5 Sindelfingen, Germany. Bolaji, 2011 Bolaji, B.O., 2011. Performance invest igation 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. C hallenges on the Development of A CO2 Compressor Focusing on Structural Strength an d Reliability. Proc. 8th IIR Gustav Lorentzen Confere nce 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 r eplace R22. Advanced Materials Research 243-249, 4979-4982.
Chen et al, 2012 Chen, J., Li, H., Xi, L., 2012. Pe rformance 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 elect ronic expansion valves with R22, R410A and R407C. Energy Convers Management, 50, 1033–9.
Chen and Gao, 2011 Chen, Z., Gao, B., 2011. Researc h of Lubrication Oil Appling to R-290 Rotary Compressor. Proc. IIF-IIR Int. Congr. Rrefrig. Prague, Czech Republic. Chen, 2012 Chen, Z. H., 2012. Research on Rotary Co mpressors Based on R-290 Technology. Proc. UNEP conference on technolo gies for high ambient conditions, Dubai, UAE.
Chen et al, 2011 Chen, J., Min, K., Li, F., 2011. C omparison of performance between R290 and R417A in heat pump air conditionin g water heater combination. Advanced Materials Research, 24 3-249, 4918-4922. Chin and Spatz, 1999 Chin, L., Spatz, M. W., 1999. Issues Relating to the Adoption of R-410A in Air Conditioning Systems. Proc. IIF-IIR I nt. Congr. Refrig., Sydney, Australia.2014 TOC Refrigeration, A/C and Heat Pumps Assessme nt Report 159

Chinnaraj et al, 2010 Chinnaraj, C., Govindarajan, P., Vijayan, R., 2010. Influence of electronic expansion valve on the performance of sm all window air conditioner retrofitted with R407C and R290. Th ermal Science, Supplement, Vol. 15, p383.
Colbourne et al, 2013 Colbourne, D., Hühren, R., Ra jadhyaksha, D., De Souza, L., Sahu, A., 2013. Refrigerant leakage control for R-2 90 in split type refrigeration and air conditioning systems. Pr oc. IIF-IIR, Compressors 2013: 8th International Conference on Compressors and Coolants, Papiernicka, Slovakia.
Colbourne and Suen, 2004 Colbourne, D., Suen, K. O. , 2004. Appraising the Flammability Hazards of Hydrocarbon Refrigerants using Quantitat ive Risk Assessment Model. Part II: Model evaluation and ana lysis. Int. J. Refrig., Vol. 27, 784 – 793. Colbourne, 2014 Colbourne, D. 2014. Comparative Ris k Assessment of Hydrocarbon Refrigerant in a Refrigerator and Split Air Conditioner. Proc. IIF-IIR Conf. on Natural Working Fluids, Hangzhou, China.
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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 Okada2014 TOC Refrigeration, A/C and Heat Pumps Assessme nt Report

1682014 TOC Refrigeration, A/C and Heat Pumps Assessme nt 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 heati ng, service (including domestic) water heating, and manufacturing process heating. The hea t sources are generally ambient air, water or ground-source heat. The heat sink can be air, wa ter or a process fluid. This chapter covers only systems where water is the sink (grey zone ind icated 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 pum ps 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 a nd heat pumps”.

The temperature difference between the source and s ink 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 dif ference condition. The required compressor power input is a fraction of the total useful energ y delivered. The required input power to the heat pump is mainly dictated by the heating capacit y 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 regulat ions are referring to a seasonal coefficient of performance (SCOP) defined as the useful heat de livered 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 CO 2 emission and primary energy consumption. The cost of the equipment and efficiency are most i mportant to compete with fossil fuel solutions.

In 2012 the global air to water heat pump market in creased by around 5.4 % to 1,37 million units. Both Europe and China had an increase of res pectively 7% and 11%, while Japan had a drop of 12.8% (JARN, 2013/08).

The Ozone Depleting Potential (ODP) and Global Warm ing 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, wate r, and ground) and heat sink (air, water), resulting in the following naming of heat pumps use d in this chapter as given in Table 8.1.

Table 8-1: Heat pump classification

Heat source (direct expansion or indirect expansio n 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

Combined2014 TOC Refrigeration, A/C and Heat Pumps Assessme nt Report

170 Air-source heat pumps are equipped with air-to-refr igerant 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 bri ne-to-refrigerant evaporator and brine to ground tubes combined with a circulation pump or, r efrigerant-to-ground evaporator tubes to obtain heat from the ground. The tubes in the groun d are installed horizontally one to a few meters below ground level or installed in a vertica l 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, us ing 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 he at 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 a nd a heat pump water heating unit and in some designs an additional heat exchanger. In the h eat 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 r efrigerant circuit or, for absorption cycles by both condenser and absorber, and then returned to t he 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 c ompressor 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 expansi on 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 energ y efficiency. Different from mechanical compression type heat pumps, there is not any mecha nical 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 handlin g 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, fo r moderate temperature application such as air handling units around 45 °C, for high temperatu re application such as radiant heating 55 to 60 °C, and for very high temperature application, a s 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 a t lower sink temperatures, but each product must fulfil the required operating temperat ure.
A space heating heat pump using water for distribut ion generally consists of a heat pump unit and often an additional heat exchanger unit and a w ater 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 Assessme nt Report 171

In most cases air source heat pumps are used for sp ace 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 configur ations of combined space and water heating heat pumps exist in order to optimise the s easonal 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 th e space heating function.

In order to obtain high water temperatures at low o utdoor ambient temperatures, air to water heat pump systems can utilise a multistage compress ion system or a cascade refrigerating system with different refrigerants for each stage i n the cascade.

Capacity Ranges of Water and Space Heating Heat Pum ps Table 8-2 lists the most common heating capacity ra nge 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 CO 2 during combustion, they contribute to global warmi ng. Heat pumps also contribute to global warming, but in a d ifferent way. The contribution to global warming is only related to CO 2 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 environmenta l consideration. Efficient heat pumps can reduce global warming impact compared with foss il 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 de pends on the efficiency level of the heat pump and the carbon emission per kWh of the electri city generation.

The tendency of decarbonisation of electricity stre ngthens 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, larg er heat exchangers and other special features. The majority of purchasers have not yet a ccepted the significantly higher first costs of heat pumps as a means to reduce running costs, c ompared to lower first cost fossil fuel based space and water heating systems, especially i n colder regions.

In 2013 the EU commission decided upon a common ene rgy label (commission delegated regulation No 811/2013) for hydronic heating system s comparing the primary energy efficiency of all major heat generators. This may h ave a positive impact on the heat pump applications in Europe. Minimum efficiency requirem ents are set separate for heat pumps. Both the energy label and minimum efficiency requir ements will have a major impact on the refrigerant choice. Air source heat pumps have beco me the most popular heat pump type in2014 TOC Refrigeration, A/C and Heat Pumps Assessme nt Report

172 Europe. They have experienced strong growth over th e last several years because of their economic benefits and recognition as renewable ener gy source. The positive environmental aspects and potential market growth of heat pumps m ust be taken into account when refrigerant options and limitations are considered

In Japan, heat pump water heaters using the refrige rant R-744 have become very popular in recent years under the trade name “Eco-cute” and ar e also introduced in Europe. These heat pump water heaters were launched in 2001. Between 2 008 and 2011, there were annual sales of around 500,000 units (JARN, 2013/08). An evaluat ion method for defining the annual performance factor of heat pump water heaters has b een 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 addi tional manufacturers began marketing newer, more efficient integral designs in 2010. The se new products use either HFC-134a or R-410A as the refrigerant, but the split between th em is uncertain. Predicated on the new efficiency standards and analyses used in developme nt 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 o r more units per year by 2020.

The general trend when taking new building standard s into account is that the relative importance of tap water heating will increase compa red 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 thermodynam ic 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 in direct 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 impor tant 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 uns aturated HFCs – see Chapter 2

“ Refrigerants ”) in heat pumps are ongoing, notably in several Eu ropean countries, Japan and the USA. Similar studies are underway to evaluate u se or broader use of R-744 and hydrocarbons as refrigerants in several types of he at pumps, though actual product development and commercialization are limited to Eu rope 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 pum p application in existing systems as well as in new equipment.

These refrigerants are being used in high to low te mperature water and space heating heat pumps, in countries where HCFC-22 consumption reduc tion started in advance of the Montreal Protocol. These refrigerants are used main ly 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 ma inly replace HCFC-22 in existing2014 TOC Refrigeration, A/C and Heat Pumps Assessme nt 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-4 10A 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 high er performance. Cascade heat pumps using HFC-134a and R-410A are commercialised in high temp erature combined space and hot water heating heat pumps in Europe. These heat pump s have a relatively good performance and can operate without auxiliary electrical heater s. 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 optimis ed.

Air to water split cascade systems are put on the m arket using R-410A for the low temperature and HFC-134a for the high temperature c ircuit. They guarantee high seasonal COP for colder climates even at high water sink tem peratures, while keeping the required heating capacity without auxiliary electrical heate rs. They are most used for combined space and hot water heating to replace existing boiler sy stems.

Energy efficiency of R-407C systems is typically po orer than HCFC-22, although similar COPs can be achieved if the system is carefully des igned. R-407C shows a pronounced temperature glide in practice, which can lead to op erational 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 it s effectiveness at higher temperatures.

As the cost of the refrigerant itself is minor in t he total system cost, limited differences in refrigerant cost have a minor effect. The cost of c omponents 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. F or 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 t he 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 no t 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-410 A 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, 20 00). 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 t emperature is necessary especially for high temperature water heating heat pumps and low t emperature heat source.

The direct cost of the pure HFC-32 substance is low er than R-410A, but this has limited effect on the system cost. Based on the refrigerant proper ties, 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 th e lower flammable refrigerants (class 2L by ISO 817); see chapter 2. Standard ISO-5149 is updat ed 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, so me building codes do not allow the use of flammable refrigerants in certain type of buildings . If the refrigerant water heat exchanger is2014 TOC Refrigeration, A/C and Heat Pumps Assessme nt Report

174 located in outside occupancy, the safety issue is e asier 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 i dentified in the patent literature as possible low-GWP refrigerants for heat pumps. Blend s with HFC-32 or HFC-125 may make it possible to approach the properties of HCFC-22 o r R-410A, but it results in a higher GWP than pure HFC-1234yf. As sample supply of these ref rigerants is very limited, it is too early to judge whether any of these chemicals will be commer cialised and will show acceptable performance and competitiveness in heat pump system s. Due to the price competitiveness pure HFC-1234yf is not considered as a future solut ion.

For water heating and space heating heat pumps usin g HCFC-22, R-410A, R-407C, significant design changes would be required to opt imise for HFC-1234yf. Some of the required changes include larger displacement compre ssors, larger diameter interconnecting and heat exchanger tubing and additional heat excha nger 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 te mperatures 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 c ost than that of HFC-134a. Components cost will be similar to HFC-134a, but the flammabil ity will have effect for larger systems due to the pressure vessel codes. The same restrictions as for HFC-32 apply (see Anne x 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 marke t in 2001, with heat pumps for heating of bath or sanitary water as the main application. Spa ce heating heat pumps that operate at lower water temperatures in combination with hot water he ating 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 temperatur e of R-744 results in trans-critical operation. R-744 refrigerant has been used primaril y in storage type heat pump water heater applications.

Continued growth of market for domestic hot water h eat pumps is expected in Japan, Asia and to some extent in Europe. Recently, R-744 heat pump s for domestic space heating application have been developed in Europe for use in cold clima tes if combined with very high temperature radiator type space heating. For commer cial 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 lev el of market penetration R-744 space heating heat pumps will experience. The ultimate ma rket acceptance will be determined by the system economics, energy labelling and minimum energy efficiency requirements.2014 TOC Refrigeration, A/C and Heat Pumps Assessme nt 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-74 4 may give a high performance when it is used with low temperature sources and high temperat ure sinks with a certain temperature difference between inlet and outlet water temperatu re (Steene, 2008). This makes it well suited for use in storage type heat pump water heat ers 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 a re required to get equivalent performance with R-744 for space heating alone (Nek så, 2010). To obtain high efficiency for domestic space heating application is challenging i f the difference between the high and low water temperature of the heat sink is low. System d esigns enabling a low water return temperature are then required (Nekså, 2010) or intr oduction 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, beca use of the high pressure, certain types of systems require more robust designs for pressure sa fety which adds cost, while specific tube dimensions are much smaller compared to current tec hnology which gives the advantage of compact tubing and insulation material.

The main barrier is cost of the system and energy e fficiency 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 num ber of low charge level heat pump water heater installations in Europe. While, for hydronic systems, with ventilated enclosures configuration, larger refrigerant charges are allow ed. Use in Europe has declined due to introduction of the Pressure Equipment Directive (P alm, 2008) but some compressor manufacturers are now offering compressors for HC-2 90 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. Bas ed on the refrigerant properties the equipment cost is similar to HCFC-22 while mitigati on devices for safety add some cost.

The main barriers are related to the safety. For sy stems with parts, which are located in occupied spaces, the allowable charge quantity is l imited, whereas for systems located outside, there are no major restrictions. The neces sity to ensure that technicians are appropriately trained to handle the flammability of hydrocarbons is a main barrier. For equipment manufacturers the liability aspects combi ned 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 r eturn 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).2014 TOC Refrigeration, A/C and Heat Pumps Assessme nt Report

176 The cost effectiveness is unfavourable for non-indu strial process use due to equipment and/or installations costs.

The main barriers are related to safety aspects (se e 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 i t has been shown that small capacity heat pump systems can be designed to operate with very l ow charge of ammonia (100 g of ammonia for 9 kW heating capacity (Palm, 2008).

The main obstacle for the commercialization of smal l capacity heat pump systems is the limited supply of components. Particularly, there a re no hermetic or semi-hermetic compressors for ammonia available and ammonia is in compatible 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 e ach refrigerant and type of heat pump depending on capacity levels, target energy efficie ncy 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 mo st water heating heat pumps there is no refrigerant field piping involved the option to rep lace the total unit is in many cases the better economical solution. For larger units located in pl aces 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 packag es.


### 8.6 Concluding remarks
Most heat pumps commercialised today make use of no n-ODS refrigerants. Refrigerants used are R-410A, HFC-134a, R-407C, HC-290, HC-600a, R-71 7 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 effici ency. 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 know n. 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 Assessme nt Report 177

Replacements such as HFC-32 and other low-GWP HFC b lends 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-solu tions.



### 8.7 References Fernandez N., 2008 N. Fernandez, Y. Hwang*, R. Rade rmacher, Center for

Environmental Energy Engineering, Department of Mec hanical Engineering, University of Maryland, PERFORMANCE OF CO 2 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 Assessmen t Panel, 2005. JARN, 2013/08 The Japan Refrigeration and Air Condi tioning Industry Association;

Heat Pumps overview

, August, 2013 Neskå, 1998 Nekså, P., Rekstad, H., Zakeri, G.R. an d Schiefloe, P.A.: CO 2 – 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: CO 2 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.: CO 2 - A refrigerant from the

past with prospects of being one of the main refrigerants in the future

, 9th IIR Gustav Lorentzen Conference 2010, Sydney, A pril 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 Shiger u, (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, Depar tment of Energy Processes,

Norway, CO 2 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 Sept ember 7-10, 2008 Yajima, 2000 R. Yajima, K. Kita, S. Taira, N. Domy o R32 as a solution for energy

conservation and low emission , IIR 2000 Purdue2014 TOC Refrigeration, A/C and Heat Pumps Assessme nt Report

1782014 TOC Refrigeration, A/C and Heat Pumps Assessme nt Report 179 

## Chapter 9

___________________________________________________ _______ Chillers

Chapter Lead Author

Kenneth E. Hickman



### Co-Authors

James M. Calm Martin Dieryckx Dennis Dorman Mohamed Alaa Olama Andy Pearson2014 TOC Refrigeration, A/C and Heat Pumps Assessme nt Report

1802014 TOC Refrigeration, A/C and Heat Pumps Assessme nt Report 181



## 9 Chillers

9.1 Introduction Comfort air conditioning in large commercial buildi ngs 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 p rocess cooling in commercial and industrial facilities such as data processing and communicatio n centers, electronics fabrication, precision machining, molding, and mining (particula rly in deep mines with high thermal gradients). District cooling is another application that provides air conditioning to multiple buildings through a large chilled water distributio n 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 wh ere a low-cost source of hot water or steam is available.

Chillers tend to stay in service for long periods i n the range from 20 to 40 years. Even though CFCs were phased out for new equipment in 2010, a s ignificant 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 r efrigerants. The change-over to zero ODP refrigerants required a very high investment and wa s a lengthy process. However, the current generation of chillers has proven to be highly reli able 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-G WP 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 alik e 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 r equired again.

All other considerations aside, to be acceptable, n ew refrigerants should result in products with energy efficiencies that are equal to or bette r than the refrigerants replaced. This is because the global warming effects from chillers ar e dominated by the energy-related component from their power usage. Life Cycle Climat e Performance (LCCP) models typically show that more than 95% of the climate ef fect is due to energy consumption. The direct global warming effects from refrigerant emis sions are significantly smaller. Emissions have been significantly reduced in recent years thr ough lower charge systems, low-leak designs, manufacturing and testing improvements, an d improved service practices. At the same time, chiller energy efficiency has been enhan ced 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 i s more important to climate change than prematurely changing to another intermediate refrig erant solution.2014 TOC Refrigeration, A/C and Heat Pumps Assessme nt Report

182 Fortunately, the consumer can make intelligent choi ces when alternatives are explored. The annual energy consumption can be calculated with co mputer simulation programs using the chiller(s) load profile, building loads, and weathe r data. For large and complex chiller systems, extensive modeling can provide systems and chiller solutions that minimize total energy consumption. However, smaller machines are c ommonly sold on the basis of full and/or part load rating, a simplified representatio n of energy consumption. Rating standards and rating certification programs exist in most cou ntries. AHRI Standard 550/590 (AHRI 2011) and EN 14825 are among the rating standards i n use.

Other methods used to describe the environmental ef fects of chiller operation are Total Equivalent Warming Impact (TEWI) or Life Cycle Clim ate 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 wa rming potential (GWP) of the refrigerants mentioned in this chapter are given in Chapter 2. Chapter 2 includes other refrigerant properties and a descrip tion 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 reciprocati ng piston, rotary, screw, and scroll compressors. Not all refrigerants can be used in al l compressor types because compressors generally are designed for specific refrigerants an d applications.

Water-cooled positive-displacement chillers below 7 00 kW commonly employ directexpansion (DX) shell-and-tube evaporators with chil led 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 sh ell side of the tubes. Similar to compressor technology, heat exchangers are designed for partic ular 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 tem perature glide can fractionate during evaporation and during condensation in shell-side c ondensers, 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 f or internal solution pumps and controls. Large absorption systems commonly use water and lit hium 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 wate r can be water-cooled or air-cooled.

Absorption chillers are identified by the number ofheat input levels they employ (e.g., singleeffect or double-effect), and whether they are dire ct-fired with a burning fuel, or use steam or hot water as the heat source.

Single-effect absorption applications, with lower e fficiency, 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 hos pitals. Other sites include co-generation systems where waste engine heat or steam is availab le.2014 TOC Refrigeration, A/C and Heat Pumps Assessme nt Report 183

Double-effect machines have an additional heat reco very 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 thos e 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 so urce 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-e lectricity 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, us e multiple chillers)

Table 9-1: Chiller capacity ranges

Chiller Type Approximate Capacity Range (kW) Typical Refrigerants

Scroll, rotary, and reciprocating watercooled 10 - 1,200 R-410A, HCFC-22, R-407C Less commonly, HC-290 Screw water-cooled 100 – 7,000 HFC-134a, HCFC-22 R-717Screw, 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 gre ater 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 exis ting refrigerants, refrigerant manufacturers are proposing new chemicals and blends with lower G WP. As stated in Chapter 2, the perfect, inexpensive, energy efficient, non-toxic, non-flamm able, 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 syste m. The selection process is a trade-off among GWP, energy efficiency, safety, applied cost, and l imiting the need for redesign.2014 TOC Refrigeration, A/C and Heat Pumps Assessme nt Report

184 In 2011 the U.S. Air-Conditioning, Heating, and Ref rigeration Institute (AHRI) launched an industry-wide cooperative research program to ident ify 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 res earch needs, accelerate industry's response to environmental challenges raised by the use of hi gh GWP refrigerants, and avoid duplicative work. Many refrigerant blends as well as single-com ponent refrigerants were candidates for chiller applications. A number of the proposed alte rnatives have vapour compression cycle characteristics that are close to those of the chil ler refrigerant being replaced, namely HFC134a, R-410A, HCFC-22 (and R-407C), and HCFC-123.

Test results from the Low-GWP AREP program are avai lable 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 c ommercialization from this work.

Additional information on non-fluorinated and low-G WP refrigerants for chillers is given in Section 4 of the TEAP XXIV/7 Task Force Report (TEA P, 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 ch aracteristics to consider beyond operating pressure levels, cooling capacities, and energy efficiencies. Chapter 2.1.7 presents these characteristics. The Annex to Chapter 2 inclu des 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 l ikely will not come until experience is gained in smaller limited-charge systems.

Several limitations for refrigerant selection, uniq ue to chillers, are important to note. A limitation on the application of blended non-azeotr opic refrigerants exists in large chillers with flooded evaporators and shell and tube condens ers. “Glide” in heat exchangers is a change in refrigerant temperature at constant press ure during evaporation. Flooded evaporators used in larger chillers are essentially isothermal and isobaric, so the "glide" tendency is exhibited as a composition change betwe en 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 temperatur e 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 i n DX systems, but designs must be modified to account for glide which otherwise may h andicap chiller efficiency and tends to increase heat exchanger size. Zeotropic refrigerant s with glide also require special consideration of service practices that avoid compo sition changes resulting from separation and differential leakage of blend components

Other unique refrigerant parameters that chiller de signers must take into account in choosing a refrigerant include heat transfer coefficients in l arge pool boiling evaporators and compressor discharge temperatures, particularly at low suction temperature or high ambient conditions. Heat recovery and heat pumping applications for chi llers are increasing. A refrigerant’s performance in these higher-temperature conditions will be important for these applications. Another consideration is operating pressure level a nd the related need for pressure vessel code redesign2014 TOC Refrigeration, A/C and Heat Pumps Assessme nt 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 f avorably by increased production volumes if a new low-GWP refrigerant can be used as a retro fit in existing chillers or if there are highvolume applications for a refrigerant such as use a s 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 t emperature glide which can occur with zeotropic refrigerant blends (see section 9.3.1).

Zeotropic mixtures offer the greatest flexibility i n blending refrigerants to approximate the physical and thermodynamic properties of HFC-134a - particularly the general trend of the pressure/temperature relationships. There are a num ber of A1 refrigerant candidates with low glide and capacities close to HFC-134a with GWPs ar ound 600. Candidates with low GWP (150 or less) all are in safety classes A2L or A3.

Earlier studies based on thermodynamic properties s uggest that the COP of chillers using one candidate, unsaturated HFC-1234yf refrigerant, is n ot as good as for HFC-134a (Kontomaris, 2009) and (Leck, 2010). However, a recent study bas ed 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 ch illers have been done (Kontomaris, 2010a), (Kontomaris, 2010b), (Kontomaris, 2010c), a nd (Spatz, 2008).

In Europe chillers are on the market using unsatura ted HFC-1234 ze(E) as the refrigerant. The efficiency is found to be better than HFC-1234yf an d equivalent to HFC-134a. Testing has shown that HFC-1234ze(E) has a capacity reduction o f 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 parti cular 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 w ater-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 whe re 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 succes sor 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 beca use it has a moderate GWP, good energy efficiency, and high capacity in the vapour- compression cycle. Disadvantages include flammability and operating pressure levels higher t han 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.2014 TOC Refrigeration, A/C and Heat Pumps Assessme nt Report

186 Other alternatives identified during the Low-GWP A REP program are blends that have similar or lower cooling capacities than R-410A. Se veral of the blends have temperature glides of 5.6 K or less. All of the alternatives ha ve higher estimated COPs than R-410A. None of the alternatives have a GWP <150. All of the alt ernatives 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 count ries. 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 makin g modest changes in their HCFC-22 products. R-407C has an appreciable temperature gli de (5 K) so is not suitable for use in flooded evaporators that predominate in larger chil lers. R-407C still is used in Europe, on a more limited basis in Japan as a replacement for HC FC-22, and elsewhere as one of a number of zero-ODP aftermarket drop-in options for retrofi ts. The retrofit list includes R-421A, R422D, R-427A, R-438A, and others.

The low-GWP AREP program alternatives for HCFC-22 i nclude five A1 refrigerants. Three others are A2L refrigerants. The remaining candidat es 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 equ ivalent 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 tech nology in large units, those exceeding 1700 kW capacity. Water chillers employing these co mpressors 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 the rmodynamic efficiency and operate at lower pressure levels and higher volumetric flow rates th an HFC-134a. They are HCFC-123 and HFC-245fa. HCFC-123 is a low-GWP HCFC refrigerant w hich 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 operat ing 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 Assessme nt 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 system s (see Chapter 5). There are a number of installations in Europe, the Middle East, China, an d the U.S.A. R-717 chillers are available with open drive screw compressors in the capacity r ange 100-7000 kW. Chillers with open drive reciprocating compressors are available in th e 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 u sed 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 bec ause of higher costs of air-cooled R-717 condenser coils. Information on R-717 chiller appli cations in building air conditioning is given in (Pearson, 2008a), (Pearson, 2008b), and (P earson, 2012).

R-717 is not a suitable refrigerant for centrifugal chillers because it requires four or more compressor stages to produce the pressure rise (“li ft” or “head”) required.

If the use of R-717 refrigerant in chillers is to e xpand in the capacity range served by positive displacement compressors, particularly outside Euro pe, several impediments must be addressed:

 Chiller costs typically are higher than for HCFC an d HFC chillers.

 Safety concerns with R-717 in comfort cooling appli cations can increase installation costs. Building codes in some countrie s heavily restrict applications.

None-the-less, the market for R-717 chillers is gro wing 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. Chiller s employing hydrocarbons as a refrigerant have been available for many years, though typicall y only in small capacities (up to 200 kW) per refrigerant circuit and for outdoor application s. HC-290 s used in chillers in air conditioning and industrial applications. HC-290 an d another hydrocarbon, HC-1270, are used in a limited number of small (<1200 kW) air-co oled 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 Ph ilippines are applying hydrocarbon chillers to large space cooling needs. The current market fo r 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-127 0 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 lubric ants. Chillers employing hydrocarbon refrigerants are somewhat higher in cost than HFC c hillers though modification of equipment originally designed for HCFC-22 is fairly straightf orward.

All safety codes impose strict requirements on hydr ocarbons in large refrigerant charges in chillers, particularly for indoor chiller installat ions in machinery rooms. Accordingly, hydrocarbon chillers have not been adopted in all r egions. In regions supporting hydrocarbon2014 TOC Refrigeration, A/C and Heat Pumps Assessme nt Report

188 solutions the safety concerns have been addressed b y 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. Howeve r, 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 f uture.

Hydrocarbon refrigerants are in limited use in cent rifugal chillers in petrochemical plants where a variety of very hazardous materials are rou tinely used and the staff is highly trained in safety measures and emergency response (see Chap ter 5). Hydrocarbon refrigerants have not been used in centrifugal chillers for air condi tioning due to safety code restrictions, concerns with large charges of flammable refrigeran ts, liability, and insurance issues.

R-744

R-744 air-cooled chillers have been introduced in t he 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 15 0 C or less, these systems can be equivalent in energ y efficiency and LCCP with systems employing HFCs, R-717, or HCs. R- 744 chillers are less attractive at higher ambient temperatures due to decreasing effic iency with increasing ambient temperature.

There heat recovery to generate hot water at temper atures of 60 o C or higher can be employed in a total energy strategy for a building, R-744 ch illers offer the advantage of being able to use waste heat to raise water to higher temperature s 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 g ood efficiency.

R-718 The very low pressures, high compression ratios, an d high volumetric flow rates required in water vapour compression systems require high volum etric flow axial compressor designs that are uncommon in the chiller field

. However, several research projects are active and developmental companies have attempted their commer cialization. A product was announced in 2014 using water as the refrigerant. Application s 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 chille rs and the complexity of the compressor technology. Several developmental chillers and comm ercial 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 syst ems (absorption and adsorption chillers) Absorption water chillers are a viable alternative to the vapour-compression cycle for some installations. Absorption chillers have been descri bed in Section 9.2.2.

Adsorption chillers using water and zeolite also ar e 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 employin g those refrigerants have to be supported in one of the following ways:2014 TOC Refrigeration, A/C and Heat Pumps Assessme nt Report 189

Retain/Contain : continued operation with stocked and/or reclaimed inventories in conjunction with containment procedures and equipme nt 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 (p referably having higher efficiency which reduces energy-related climate impact) using allowed refrigerants or not-in-kind alternatives,

The retrofit options depend on the specific refrige rant for which the chiller was originally designed. When any retrofit is performed, it is rec ommended 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 internatio nal standards such as ISO 5149 (ISO, 2014). It is also recommended that the manufacturer s of the equipment be consulted in any retrofit program.

9.4.1 Positive displacement chillers A positive displacement compressor inherently can b e applied to handle a number of different refrigerants and pressure ratios in a chiller if it s motor has adequate power, the compressor, tubing, heat exchangers, and other components can m eet pressure codes and regulations with the refrigerants, and the system materials and lubr icant 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 is sues 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 th e refrigerant cycle in which they are used. Direct refrigerant substitution in centrifugal chil lers 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 sp eed and/or impeller geometry can be changed easily. In the past this has been accomplis hed by gear changes in open drive chillers and with variable speed drives in both open and her metic compressor chillers. The compressor surge margin must be checked using the p roperties of the substitute refrigerant.

9.4.3 Non-vapor compression chiller replacements – absorption The most common absorption chiller is the water-lit hium bromide solution type, both direct and indirect fired versions. When comparing the siz e of a mechanical vapour compression chiller with an absorption chiller of similar capac ity, the absorption chiller is about 25 to 50 % bulkier. This factor may be crucial when retrofitti ng 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 req uire 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 tha t 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 c onsumption of the building. This reduces the capacity requirements for the transformer, elec tric switchboards, and electric conduits. Provision has to be made for suitable gas piping an d train when a natural gas fired system is used. Absorption systems do not require anti-vibrat ion mounting since they have few moving parts.2014 TOC Refrigeration, A/C and Heat Pumps Assessme nt Report

190 

### 9.5 Alternatives for high ambient conditions Chiller rating points commonly involve ambient air temperatures of 35 o C (95 o F). However, in very warm climates there is interest in knowing how chillers will perform when air temperatures reach 47 o C or even 52 o C, and also, how the design of chillers can be modi fied to improve high ambient operation.

This section focuses on air cooled chillers. The de sign 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 low er for a given ambient temperature.

Air-cooled chillers with positive displacement comp ressors (rotary, reciprocating, scroll, screw) designed for an ambient of 35 o C will operate at high ambient conditions but with reductions in capacity and COP. An illustrative exa mple is given for actual 3 ton residential air conditioners in the May 2010 TEAP XX/8 Task For ce Report. For HCFC-22, capacity was reduced by 15% and COP was reduced by 35% when the ambient temperature increased from 35 o C to 52 o C. For R-410A the reductions were 18% and 40 % resp ectively. Design changes that can improve chiller performance at high ambien t temperatures include applying a compressor with proper capacity and compression rat io 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 devi ce. 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-3 2 (an A2L refrigerant) has even less performance degradation. These refrigerants are not interchangeable because of their differing capacities, pressure levels, and lubricant requirem ents. Chiller design must be tailored for the specific refrigerant selected.

Chillers with centrifugal compressors require a dif ferent approach. Typically, additional compressor stages may be required. If condensers ca nnot be water-cooled because water is scarce or expensive, dry coolers are used. Air-cool ed 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 o n the refrigerant side of these types of condensers as compared to dry coolers. The refriger ants 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 replacem ents for HFC-134a, R-410A, and HCFC-22 have been identified for chiller applicatio ns. An “ideal” refrigerant would have nearly-zero ODP, a zero or low GWP, an A1 ASHR AE/ISO safety classification, near-zero temperature glide, energy efficiency equi valent 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 posit ive climate impact.

 Direct global warming effects from refrigerant emis sions from chillers are significantly smaller than the climate effect from the energy con sumed during the lifetime of2014 TOC Refrigeration, A/C and Heat Pumps Assessme nt Report 191 operation. Emissions have been significantly reduce d 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 effic iencies that are equal to or better than the refrigerants being replaced.

 A1 refrigerants with GWPs up to 675 offer performan ce and safety benefits for some applications.

 The ultimate goal is to choose alternative solution s that are the most energy efficient while remaining viable to chiller manufacturers, re gulators, and users.



### 9.7 References
AHRI, 2011 Standard 550/590-2011 with Addendum 1: P erformance Rating of

Water-Chilling and Heat Pump Water-Heating Packages Using the Vapor Compression Cycle, 2011. Air-Conditioning, He ating, and Refrigeration Institute, Arlington VA, USA ASHRAE, 2013 ANSI/ASHRAE Standard 15-2013, Safety S tandard for Refrigeration

Systems, 2013. American Society of Heating, Refrige ration, and AirConditioning Engineers (ASHRAE), Atlanta, GA, USA Boone, 2011 Boone, J., Adsorption Chiller, UNEP/IIR 14 th European Conference on Renewable Energy Applications in Heating and Coo ling, Edinburgh, 2011 Calm, 2011 Calm, J.M., Refrigerants for Deep Mine R efrigeration, Refrigerants

for Sustainable Development, Proceedings of the 23 rd International Congress of Refrigeration, Prague, Czech Republic, August 21-26, 2011; International Institute for Refrigeration, Pa ris, France, Paper 914 EN, 2008 EN378: 2008. Refrigerating Systems and He at Pumps – Safety and

Environmental Requirements, 2008, A1 2012 Parts 1- 4, Comite Europeen de Normalisation, Brussels ISO, 2014 ISO Standard 5149:2014. Mechanical Refrig eration Systems Used

for Heating and Cooling – Safety Requirements, Inte rnational Organization for Standardization, Geneva, Switzerla nd
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-Conditio ning 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 Refrigerant s for AC and Refrigeration, Conference on Sustainable Refrigerat ion 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,2014 TOC Refrigeration, A/C and Heat Pumps Assessme nt Report

192 and Air-Conditioning Engineers (ASHRAE), 2009 Annua l

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 C ongress, Sustainable Energy Use in Buildings, Antalya, Turke y, May 9-12
Kontomaris, 2010b Kontomaris, K., Leck, T.J., and Hughes, J., 2010. A NonFlammable, Reduced GWP, HFC-134a Replacement in Cen trifugal Chillers: DR-11, 13 th

International Refrigeration and AirConditioning Conference, Purdue University, Lafayet te, IN, USA, July 12-15
Kontomaris, 2010c Kontomaris, K., 2010. A Low GWP R eplacement for HCFC-123 in

Centrifugal Chillers: DR-2, American Society of He ating, Refrigeration, and Air-Conditioning Engineers (ASHR AE) and United Nations Environmental Programme (UNEP) Confe rence, Road to Climate Friendly Chillers – Moving Beyond C FCs 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 i n 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, presentati on, International District Energy Association (IDEA), 99 th 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 Conditio ning Engineers (ASHRAE), Atlanta, GA, USA, 50(2): 30-36
Pearson, 2008b Pearson, A., 2008. Water Chillers wi th Ammonia for Building

Services, Natural Refrigerants – Sustainable Ozone and Climate Friendly Alternatives to HCFCs, published by German Technical Cooperation Programme Proklima, German Federal Mini stry 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-Conditio ning 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), a nd Opteon TM (XP10) in a 230-RT Water Cooled Water Chiller, A HRI LowGWP AREP Test Report #7, Nov. 19, 2012 (See website below for access)
Schultz, 2014 Schultz, K., 2014. Performance of R-4 10A and R-22 Low GWP

Alternative Refrigerants at Elevated Temperatures, 15 th International Refrigeration and Air-Conditioning Conference, Purd ue University, Lafayette, IN, USA, July 14-17
Sheer, 2001 Sheer, T.J., Butterworth, M.D., and R amsden, R., 2001. Ice as a

Coolant for Deep Mines, Chapter 52, Proceedings of the 7 th International Mine Ventilation Congress, Research a nd Development Center for Electrical Engineering and Automation in Mining,2014 TOC Refrigeration, A/C and Heat Pumps Assessme nt 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 Re frigerants and Environmental Technology 2008. Kobe, Japan, Novembe r 20-21 TEAP, 2013 Decision XXIV/7 Task Force Report, Addit ional Information on

Alternatives to ODS, 2013. Report of the UNEP Techn ology 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 reports2014 TOC Refrigeration, A/C and Heat Pumps Assessme nt Report

1942014 TOC Refrigeration, A/C and Heat Pumps Assessme nt Report 195 

## Chapter 10

___________________________________________________ _______ Vehicle Air Conditioning

Chapter Lead Author

Jürgen Köhler



### Co-Authors

Radhey Agarwal Radim Č ermák Jiangping Chen Dave Godwin Carloandrea Malvicino2014 TOC Refrigeration, A/C and Heat Pumps Assessme nt Report

1962014 TOC Refrigeration, A/C and Heat Pumps Assessme nt Report 197



## 10 Vehicle air conditioning

10.1 Introduction
Vehicles (cars, trucks, buses and trains – this cha pter does not cover ship air conditioning) built before the mid-1990’s used mostly CFC-12 as t he refrigerant with some HCFC-22 use in trains. Since then, in response to the Montreal Pro tocol, 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 Ma nufacturer (OEM) refrigerant, for factory installed AC systems, was complete in all d eveloped countries. The transition to HFC134a in developing countries was completed by appro ximately 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 ar e 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 ai r 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 te chniques which might become important for vehicle air conditioning systems in the future (bey ond 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 syste m 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 oth er fields). So, Annex B provides a partial overview of the legal situation worldwide.

The ozone depletion potential (ODP) and global warm ing 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 (secon dary 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 th e refrigerant of choice for new equipment as well as retrofits of CFC-12 designs. M ost non-Article 5 countries phased in HFC-134a in new vehicles similarly to the U.S., sta rting in the early 1990s and completing this transition by the mid-1990s. Article 5 countri es followed with some models offered during the 1990s and full transition by the followi ng 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 reg ulations, 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 energ y 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 a ir conditioners (MACs) in the EU.2014 TOC Refrigeration, A/C and Heat Pumps Assessme nt Report

198 10.2.1 Refrigerant cost and recharge Passenger cars and light duty trucks have refrigera nt charge amounts from 0.3 kg to 1.4 kg. Bus and rail vehicles can have refrigerant charge a mounts from 2 kg to 15 kg and some even higher amounts.

The rise in counterfeiting is probably due to produ ction and use restrictions on some refrigerants in accordance with the 1987 Montreal P rotocol and the 1997 Kyoto Protocol and to the higher cost associated with more environment ally 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 auto motive market. Counterfeit HFC-134a containing multiple CFC, toxic, or corrosive compon ents is a serious threat destroying equipment and injuring end-users. It also has an in creasing opportunity to enter the supply chain. The issue is even more relevant in non-Europ ean countries (Coll, 2012).

So, in case that a drop-in or nearly drop-in but mo re expensive refrigerant will be chosen to replace HFC-134a worldwide, the counterfeit risk wi ll 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 (Weissl er, 2013) is estimated at US$ 40-45/lb or US$ 88-99/kg (retail prices could be 2 to 3 time s higher). The expected price of R-445A probably will be lower but there exist questions th at 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 condi tioning systems.

10.2.2 Future Trends The European Union and the United States already ha ve in place regulations that influence mobile air conditioning designs while the other cou ntries with a high density of road vehicles are rapidly moving in the same direction (for examp le Brazil, Inovar Auto, 2012).

This drives to more efficient on-board systems incl uding MACs and to the replacement of high GWP fluid with lower GWP substances.

Meanwhile the same regulations are leading to a pro gressive diffusion of hybrid vehicles in the short-medium term (3 - 10 years) that in the me dium-long term (5 - 15 years) will be further integrated with fully electric vehicles. Th ese 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 ch allenges will be met by developing and adopting technical solutions that will have to repr esent the best trade-off among economic and environmental sustainability issues.

In this framework the thermal systems and especiall y the MAC systems have a relevant role and will likely undergo a deep change where the sys tem integration will represent a relevant evolution guideline.

It is expected that the passenger cars and light du ty vehicle domain will rapidly move toward downsized turbocharged engines often coupled with d ifferent levels of hybridization to make the overall powertrain more efficient and to reduce CO 2 emissions, with effects on MACs as described below. Increased levels of transmission g ears are also occurring, moving vehicles from 4/5/6 levels to 7/8/9 levels leading to a redu ction 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 Assessme nt Report 199

To answer to the increased demand of capacity and r eduction 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 con trol strategies allowed a significant increase of system efficiencies.

New sealing concepts and improved hose materials ha ve also been developed to reduce refrigerant direct emissions and to reduce the freq uency of required maintenance or service.

The trend in the MACS service profiles over the las t 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 syste m. 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 win ter 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 3 50 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 futur e vehicles will have an electric compressor while a large part will be equipped with mechanical ly driven compressors as today due to energy balance and cost, so measures will be adopte d 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 m aterials

• secondary loop system taking benefit from its therm al inertia to store cooling power

• additional electric compressor, downsizing the belt -driven compressor

The increase of on-board electric power and the dif fusion 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 pow ertrain.

In synthesis, the evolution will produce a deeper i ntegration of the on-board thermal systems and the air conditioning will become part of it.

Plug-in Hybrids and Battery-driven Electric Vehicle s For Plug-in Hybrids (PHEV) and Battery-driven elect ric vehicles (BEV), vehicle air conditioning systems for cooling as well as heat pu mp systems for heating need to have very high energy efficiency to minimize the impact on th e 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 (batte ry, power electronics, etc.) to enhance their2014 TOC Refrigeration, A/C and Heat Pumps Assessme nt Report

200 effectiveness in case of very low ambient temperatu res partially compensating for their low efficiency and capacity. This can be achieved adopt ing a secondary loop that by collecting the heat from the on-board electronics can raise the te mperature of the heat source. In this framework, dual loop systems (with liquid cooled co ndensers 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 vehicl e mass due to the additional coolant and components which might adversely affect vehicle fue l economy at all times of vehicle usage.

For some applications the MAC system will be also u sed for battery thermal control as well as power electronics (i.e. cooling and heating).

New Refrigeration Systems The need to progressively increase the energy effic iency requires the exploitation of all available waste energies, heat included. The applic ation 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 con stant speed (highway) and where the weight and packaging constraints are less severe th an 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 all ow 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 he avy 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 carb on dioxide.

The fluid HFC-245fa has good properties for the app lication 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-13 36mzz(Z) (Kontomaris, 2014).



### 10.3 Options for New and Future Mobile Air Conditi oning Systems

10.3.1 Passenger Car and Light Truck Air Conditioning\ As already mentioned in the introduction, this repo rt concentrates on vapour compression refrigeration cycle technology for vehicle air cond itioning.

Improved HFC-134a Systems

With the introduction of the credit system in the U SA, and also upcoming legislation in Europe, more vehicle OEMs are introducing technolog ies to reduce energy consumption with HFC-134a refrigerants. Many efficiency-improving te chnologies are now being used in current production HFC-134a systems, for example, i nternal heat exchangers, oil separators in compressors, increased use of externally controlled compressors, etc.2014 TOC Refrigeration, A/C and Heat Pumps Assessme nt Report 201

HFC-1234yf Systems

HFC-1234yf systems are able to reach the same syste m 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 charg e 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-s ide volume to minimize this and in some cases there are issues with pressure drop on the li quid 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) c ost 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 la yout.

HFC-1234yf is designated as an A2L refrigerant, mea ning that it is flammable under prescribed testing conditions but exhibits a lower burning velocity than other flammable refrigerants designated as class 2 or 3 flammabilit y refrigerants (ASHRAE, 2013). The flammability potential has led to high scrutiny sur rounding the safe use of the refrigerant and possible ways to mitigate any risks.

The US EPA has studied the potential use of HFC-123 4yf 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 fo llowing additional use conditions (USEPA, 2011a):

• HFC-1234yf MAC systems must meet the requirements o f the 2011 SAE J639 standard version („Safety Standards for Motor Vehic le Refrigerant Vapor Compression Systems“), describing the safety requir ements for the use of R-1234yf in MAC systems.

• Manufacturer for MAC systems and vehicles have to c onduct and keep records of a risk assessment and Failure Mode and Effects Analys is according to the SAE J1739 standard („Potential Failure Mode and Effects Analy sis in Design (Design FMEA) and Potential Failure Mode and Effects Analysis in Manufacturing and Assembly Processes (Process FMEA) and Effects Analysis for M achinery (Machinery FMEA)“) for at least three years from the date of creation

Further requirements outside the US are based on IS O 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, 20 12) 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. fir e fighters, and cars using HFC-1234yf are as safe as those using HFC-134a. SAE standards have be en developed to cover service best practices, safety practices, technician training, a nd refrigerant purity of HFC-1234yf (SAE J2845, 2013).

Further analyses, however, have disputed these earl ier findings that the flammability and toxicity of HFC-1234yf do not lead to higher level of risks. A German car manufacturer2014 TOC Refrigeration, A/C and Heat Pumps Assessme nt Report

202 carried out a series of additional tests on HFC-123 4yf as part of a new test scenario developed in-house which goes above and beyond the legally pr escribed requirements. Under these conditions, described by the manufacturer as real-l ife, the reproducible test results demonstrate that HFC-1234yf, which is otherwise dif ficult to ignite under laboratory conditions, mixed with lubricant can indeed prove t o 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 c ar manufacturer concluded that HFC1234yf will not be used in its products (Daimler, 2 012).

Some EU countries are starting to ask for additiona l safety evaluation and preventive safety measures to assure the higher safety standards. Nev ertheless, the EU, in agreement with the Regulation that does not indicate any specific subs tance, decided to not change the regulation or allow any delay or derogation.

In response and to address the safety concerns of t he German car manufacturer, a new SAE CRP (1234-4: SAE press rel., 2013) was formed and c ontinued its process of carefully reviewing the use of HFC-1234yf by using universall y accepted engineering methods, including analysis of recent OEM testing from actua l vehicle crash data, on-vehicle simulations, laboratory simulations, bench tests, a nd over 100 engine compartment refrigerant releases. Based on this testing the CRP has found t hat the refrigerant is highly unlikely to ignite and that ignition requires extremely idealiz ed conditions, even when mixed with the lubricant as normally happens in real world conditi ons. The SAE CRP team has also identified that the refrigerant release testing com pleted by the German car manufacturer was unrealistic by creating the extremely idealized con ditions for ignition while ignoring actual real world collision scenarios. These conditions in clude 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 Ameri can, 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 Japanes e OEM made the decision (temporarily) not to use HFC-1234yf in their cars b ut 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 Ge rman car manufacturer, Germany's Federal Motor Transport Authority (Kraftfahrt-Bunde samt, 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 Technis cher 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 e ngine 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 chang e direction of refrigerant leakage flow by turning lines and adding plate or fish mout h aperture.

Two realistic scenarios have been evaluated (stage 1 and 2). The second stage intended to evaluate the dispersion of the refrigerant in the e ngine bay because of breaches that have not been created during the crash test but that could b e possible. In all of the situations no ignition2014 TOC Refrigeration, A/C and Heat Pumps Assessme nt Report 203

and no hydrogene fluoride (HF) production have been observed. A third scenario (stage 3) has been considered where the components have been manu ally 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 le vel a fire occurred in one of the four cars. The test was repeated twice more; a fire occurred i n 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 co ncentration was found at the measurement point in the vehicle interior (at the s un visor near the driver’s head). In a comparative test with HFC-134a under those same con ditions (level 3 test of this one model) no fire occurred. .

Based on these tests KBA found that compared to car s 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 typ e approval (KBA, 2013).

The Joint Research Centre (JRC) of the EU was holdi ng discussions with relevant stakeholders during the review of the safety of HFC -1234yf. This consultation process was essential to provide for transparency and confidenc e in the process, but did not entail the approval by the stakeholders of the JRC report. The refore, on behalf of the European Commission, DG ENTR and the JRC requested industry stakeholders and institutions which have conducted relevant test procedures and risk as sessments 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 proc edure 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 temperature s. The derived scenarios were extreme, but justifiable and reasonable ones, cover ing urban, extra-urban and highway driving conditions, and fully justified wit hin the scope of the vehicle testing for the purpose of product safety investiga tions.

3. Regarding the crash tests, the JRC considered th at 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 th at 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. T he JRC hence supports the evaluation of the KBA that there were no grounds fo r 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.2014 TOC Refrigeration, A/C and Heat Pumps Assessme nt Report

204 5. Finally, regarding the refrigerant release tests under Level 3, these were not taken into account by KBA as relevant input "for the asse ssment 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 extrem e conditions not yet covered in Level 1 and Level 2 testing. The research charac ter 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 co nsidering in Level 3 also the "development of engines which can be expected for t he 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 regulation s, 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 scen arios for the realistic Level 1 and Level 2 testing, the probability of Level 3 scenari os must be assumed to be far lower, and not reflecting "normal or reasonably for eseeable conditions of use" under which the General Product Safety Directive 2001/95/ EC applies.

6. Although not being part of the working group's m andate, during the meetings some measures to further improve MAC safety were present ed. Examples such as release valves in MAC circuits, fire extinguisher, reductio n of hot surfaces (thermal insulation) and additional ventilation were discuss ed 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 redu ced by 20-30% as compared to HFC-134a systems. The US EPA has studied the potential use o f 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 followi ng additional use conditions (USEPA, 2012a):

• Engineering strategies and/or mitigation devices sh all be incorporated such that in the event of refrigerant leaks the resulting R-744 conc entrations do not exceed the short term exposure level. Vehicle manufacturers must kee p records of the tests performed for a minimum period of three years demonstrating t hat 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 e mployed 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 minute s, 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). Howe ver, 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 Assessme nt Report 205

R-744, with appropriate system design and control, has been shown to be comparable to HFC134a systems with respect to cooling performance an d total equivalent CO 2 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 depe nd on an actual state of development, Strupp (2011) compared the required energy input (w hich is proportional to the CO 2 emission) of typical R-744 air conditioning systems with low, medium and high energy efficiencies to a typical HFC air conditioning syst em. With a high resolution, his comparison takes into account the climatic region, the local p opulation density, and the user behavior (how many cars are at a particular time on a partic ular 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 supp lier as compact cooling and heating systems for the particular application in hybrid an d battery driven electric vehicles (Hinrichs, 2011). In comparison to electric resistance heaters (positive temperature coefficient (PTC) heaters), which reduce significantly the vehicle fu el efficiency and hence driving range, R744 heat pumps operate at a substantial higher leve l of efficiency and offer the advantage of reducing only moderately the vehicle fuel efficienc y and hence driving range (Steiner, 2014).

Currently, technical hurdles (noise, vibration, har shness (NVH) reliability, and leakage) and commercial challenges (infrastructure development, handling, aftermarket servicing, additional costs, etc.) exist that will require res olution 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, fou r additional German car manufacturers proclaimed that they will also develo p 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 o verall 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 sy stem could be reduced by 25-30% in mass as compared to HFC-134a and with a secondary loop s ystem, typically 50%. Industry experts have discussed using HFC-152a, but only in a second ary 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 co mpartment 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 c ondenser during an accident. Prototype HFC-152a MACs and prototype vehicles using them hav e been demonstrated in the past years (for example, Craig, T, 2007 or Lemke, 2014). The o bstacles to the implementation due to the additional cost, weight increases and size constrai nts are in part compensated by the advantages in case of Stop & Start thanks to the ad ditional inertia of the system and the possibility to store cooling power.2014 TOC Refrigeration, A/C and Heat Pumps Assessme nt Report

206 The US EPA has studied the potential use of HFC-152 a 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 followin g additional use condition (USEPA, 2008):

• Engineering strategies and/or devices shall be inco rporated 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 i gnition is on.

As already mentioned in the RTOC 2010 Report, HFC-1 52a in a secondary loop system has been shown to be comparable to HFC-134a with respec t to cooling performance and equivalent CO 2 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 t o NVH and cost (for dual evaporator systems) advantages related to the secondary loop s ystem (Andersen, 2013).

With many new vehicle designs, using a secondary lo op system may have advantages for idle stop, cooling batteries or on-board electronics coo ling. It also reduces the amount of refrigerant and leak rate for multi-evaporator inst allations 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 con taining Unsaturated Fluorinated Hydrocarbons

In addition to HFC-1234yf, some zeotropic blends ar e still considered as possible candidates in vehicle air conditioning systems by many researc hers. 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. Thi s chemical company registered the lesser flammable of the two blends at the January 2013 ASH RAE meeting with a nominal mass composition of 6% (±1%) R-744, 9% (±1%) HFC-134a an d 85% (±2%) HFC-1234ze(E). It is designated R-445A. The other blend, designated R-44 4A, is 12% HFC-32, 5% HFC-152a and 83% HFC-1234ze(E) by mass and is also registered wi th ASHRAE. Presentations regarding these two blends were made at the annual SAE sympos iums 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 regula ted 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, and2014 TOC Refrigeration, A/C and Heat Pumps Assessme nt Report 2 07

if the significant temperature glide (20K and more) also proves to be manageable, R-445A would be the preferred blend because of its lower p otential 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 sim ilar 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 whi ch could lead to a concentration shift after some operating time or due to servicing. However, t he 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. C ompared to HFC-134a, R-445A has a higher high-side pressure (about 2bar) and a high er compressor discharge temperature (about 10K). Due to the high temperature glide it h as the risk of ice formation in the evaporator (Koehler et al. 2013, and Li 2013). Owin g 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 hig her 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 les ser 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 cons idered the possible use of HCs for new systems, but is awaiting proof that safety issues h ave been mitigated.

HCs or HC-blends, when correctly chosen, present su itable thermodynamic properties for the vapour compression cycle and permit high energy efficiency to be achieved with welldesigned indirect systems (same systems as the seco ndary 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 th e introduction of a compact refrigeration unit incorporating an electric compre ssor and fully sealed and pre-charged design. The compact refrigeration unit being consti tuted by two liquid cooled exchangers (chiller and condenser and where requested of an in ternal heat exchanger) is able to produce hot or cold coolant, normally a water-glycol mixtur e, and to minimize the refrigerant charge and leak.

With this perspective, the use of hydrocarbons or b lends of them becomes once again interesting, being such fluids are worldwide availa ble, cheap and with a very low environmental impact.

The use of a compact refrigeration unit with a doub le 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 wi thout 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 G ermany and US.2014 TOC Refrigeration, A/C and Heat Pumps Assessme nt Report

208 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 ra il cars, which can further be segmented to conventional trains, high speed trains, trams, subw ays, 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 usuall y 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 in habitants, there are approx. 1.6 buses and coaches, 0.1 locomotives and rail cars, and 477 pas senger 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 devel oping countries, the reverse). It may be assumed that, on average, at least 50% of the curre nt EU mass transit vehicle fleet is airconditioned. Both climate and economic conditions w ould determine the likelihood of air conditioning in transit vehicles in other regions.

Today, most buses and coaches have the entire air-c onditioning 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, especial ly 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 re duces both the charge and the leakage rate.

The predominant refrigerant used in new buses and c oaches 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 sy stems. 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 cond itioning. 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 co ach is 16.5 years. Although the rail car units are designed to last for more than 30 years, techno logical progress and fleet upgrades determine their lifetime to about 20 years. Even be fore a rail car reaches its end-of-life, a major overhaul is often performed wherein the air c onditioner is replaced.

Although limited by its volume, the mass transit ve hicle 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 (s ee for example Eberwein, 2011; Schirra, 2011; and Sonnekalb, 2012). In the year 2012 a Poli sh bus manufacturer started selling battery-driven electric busses with reversible R-74 4 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 l ike cylinder bank shut-off controls, ejectors, and two-speed planetary gearbox compresso r drives, were investigated by Kossel (2011) and Kaiser (2012).2014 TOC Refrigeration, A/C and Heat Pumps Assessme nt Report 209

The Low-GWP Alternative Refrigerants Evaluation Pro gram of AHRI investigated the use of drop-in alternative refrigerant blends in bus air c onditioning (N-13a [R-450A] and AC5 [R444A] as alternatives for HFC-134a, and L-20 [by ma ss 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 compara ble 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 v ehicles. 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. Thes e systems are not limited to electric vehicles, but can be applied also in traditional bu ses 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 b y the USEPA under the SNAP regulation for retrofit of CFC-12 systems (USEPA, 2013); howev er, many of these have seen only minimal use and some were never fully commercialize d. Retrofit to HFC-134a was approved by the OEMs and was more commonly used if a retrofi t was deemed appropriate. In a 2013 MAC survey about 6% of all cars were still operatin g 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 dec lining fleet of vehicles with CFC-12 MACs and in part due to the continued availability of re claimed 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 hydrocar bons is still occurring in various regions, particularly in Australia and to some exte nt in North America even though vehicle OEMs and some regulatory bodies do not approve of t his 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, whi le 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 hydrocarbon s (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.2014 TOC Refrigeration, A/C and Heat Pumps Assessme nt Report

210 

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## Annex to Chapter 10

Annex B: Regulatory actions affecting vehicle air c onditioning and refrigerants

This annex summarizes for several, but not all, dif ferent 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 re garding 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 b ut in whole Latin America is HFC-134a.

China : In China, the refrigerant in Mobile Air Condition ing (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 ton s. 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 ve hicle, 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 t o passenger cars and light commercial (categories M1 and N1) and covers both the emission s 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 Janu ary 1, 2017.

Due to the shortage of the low-GWP refrigerant R-12 34yf, which had apparently been chosen by most if not all OEMs, the European Commission de cided not to enforce the Directive until the end of 2012. Although the MAC systems of new ty pes of vehicles to be type approved had to be compatible with MAC directive 2006/40/ EC req uirements, manufacturers were allowed to fill new type approved production vehicles with R-134a until 31 December 2012. The European Commission (EC) has confirmed several time s 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 verify ing the conformity of production after 31 December 2012.

EU Commission Regulation (EC) No 706/2007 (EU Regul ation, 2007) includes a harmonized test for measuring leakages from mobile air conditi oning systems.

EU Commission Directive 2007/37/EC (EU Directive 20 07) limits refrigerant emissions from mobile air conditioning, using refrigerants with GW P>150, to 40 g/y for single evaporator2014 TOC Refrigeration, A/C and Heat Pumps Assessme nt Report

218 systems and 60 g/y for dual evaporator systems begi nning with new type vehicles in June 2008 and all vehicles in June 2009.

The European Regulation (EC) No 443/2009 (EU Regula tion 2009) sets emission performance standards for new passenger cars as par t of the Community’s integrated approach to reduce CO 2 emissions from light-duty vehicle. The Regulation limits CO 2 emissions per kilometer to 130 gCO 2 /km from 2012 to 2019 and 95 gCO 2 /km from 2020 onwards. The regulation includes off-cycle credit f or innovative technologies reducing the fuel consumption, so-called eco-innovations (chapte r 12 of the Regulation), but for mobile air conditioning systems that will be regulated by a sp ecific procedure. The EU is currently cooperating with the stakeholders to develop this p rocedure.

It is possible that the Regulation will be extended to all the other motor vehicle categories once the application transient on passenger cars an d light commercial vehicles is completed

India : India has comprehensive Ozone Depleting Substance s (Regulation and Control) Rules, 2000 which were put in place from July 19, 2000 und er 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 dep leting substances producers, consumers, importers, reclamation centers, destruction facilit ies, 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-condition ing 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 inv entory 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 Januar y 1, 2003 and all new manufacturing capacities were put up with HFC-134a and same is co ntinuing. 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 Dep leting 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 o f 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 i mport 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 Minis try of Health, Labor, and Welfare, Japan's Ministry of Economics Trade and Japanese Mi nistry 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 a cceptable under its Significant New Alternatives Policy (SNAP) Program. So far (2014), approximately 17 different refrigerants, and 3 alternative technologies, have been found acc eptable under the SNAP Program (USEPA 2013). The majority of these refrigerants were aime d primarily at the retrofit of CFC-12 cars and found very little, if any, use. HFC-134a was un til 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 al l types by model year 1995 (MACS, 2003).

Three of the refrigerants found acceptable have GWP s less than 150: HFC-152a, HFC-1234yf and R-744 (CO 2 ). All are subject to certain use conditions (for d etails see the particular sections covering these refrigerants). The use cond itions that apply to all substitute mobile AC2014 TOC Refrigeration, A/C and Heat Pumps Assessme nt Report 219

refrigerants are required by the USEPA to reduce th e flammability and/or toxicity risks from these refrigerants as well as to avoid mixing of di fferent refrigerants.

Joint regulations from the USEPA and the National H ighway 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., g rams CO 2 -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 additiona l pathways to comply partially with the requirements. In addition, credits were offered for (1) improvements in air conditioning systems that reduce tailpipe CO 2 through efficiency improvements, and (2) for reduc ed refrigerant leakage through better components and/o r use of alternative refrigerants with lower global warming potential. These regulations w ere enacted first for model years 2012 through 2016. That rule allowed OEMs to achieve cre dits 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 offere d in this program will incentivize the uptake of low-GWP refrigerants; USEPA estimated tha t 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 a lso offered one MY2013 model with HFC-1234yf, and other models are expected with MY20 14 designs (Automotive News, 2013). Atkinson, 2014 provides a list of 9 car type s which use HFC-1234yf in the US market.

In June, 2013, U.S. President Obama announced a Cli mate Change Action Plan. Amongst other initiatives, the President committed the USEP A to “use its authority through the Significant New Alternatives Policy Program to enco urage private sector investment in lowemissions technology by identifying and approving c limate-friendly chemicals while prohibiting certain uses of the most harmful chemic al alternatives” (US President, 2013). One prohibition proposed by USEPA is to prohibit the us e 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 f rom 2017, the new AC17 test schedule must be run and the resulting CO2 emissions must su pport the credit before it can be applied. This drive schedule is a dynamic one with solar loa d 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 c losely 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 refr igerants than those used in light-duty vehicles.2014 TOC Refrigeration, A/C and Heat Pumps Assessme nt Report

220 Annex C: Not-In-Kind Alternatives

The refrigeration technologies described in this an nex are all far away from a serialproduction status. However, OEMs and suppliers do w ork on the development of these systems because they have a certain potential to be come 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 re frigerant 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 pum ps providing active cooling or heating.

Small pieces of thermoelectric material (TE element s) 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 curre ntly the main issues limiting the application of thermoelectric heat pumps only to sp ecific 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 bee n developed with different configurations and operating conditions (see for example Vasile, 2 005, Yu, 2010, and Sciullo, 2011). Recently relevant progresses have been achieved bot h 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 reversi ble energy transfer from the magnetic field to the material; the material reaches the initial l ower 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 Bray ton (standing wave machine) and Stirling (travelling wave machine) cycle. As workin g fluid often helium is applied (Swift 2002).

The environmentally benign working fluid as well th e possibility to use the waste heat from the engine could lead to future applications of the rmo 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 w ithin several projects in the last decade (see for example Tamainot-Telto, 2009 and Vasta, 20 12).2014 TOC Refrigeration, A/C and Heat Pumps Assessme nt Report 221

The heavy duty truck application has a higher poten tial due to higher waste heat amount and less severe constraint in terms of weight and size.

In addition to that, sorption systems offer the opp ortunity of long-term thermal storage.2014 TOC Refrigeration, A/C and Heat Pumps Assessme nt Report

2222014 TOC Refrigeration, A/C and Heat Pumps Assessme nt Report 223 

## Chapter 11

___________________________________________________ ______ S ustainable 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 DeVos2014 TOC Refrigeration, A/C and Heat Pumps Assessme nt Report

2242014 TOC Refrigeration, A/C and Heat Pumps Assessme nt Report 225



## 11 Sustainable refrigeration

11.1 Introduction Sustainability of refrigeration and air conditionin g 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 s ections 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 equipme nt design, installation, and operation; as well as energy management considerations for sys tems, buildings, and processes.

By discussing all aspects of refrigeration systems affecting sustainability, the chapter tackles aspects that affect the environment globall y 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 t o the biosphere and human society as a whole.



### 11.2 Sustainability applied to refrigeration
Refrigeration impacts the ability of global sustain ability in many ways. Economic, environmental and social impacts - some positive, o ther 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 impac ts of refrigeration treated throughout the report - namely the depletion of the stratosphe ric ozone layer and global warming - a wider range of relevant environmental, as well as s ocial considerations, are briefly described in this section, for consideration by decision make rs.
Sustainable manufacture of systems is gradually bec oming part of the decision making process for manufacturers who used to base their de sign 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 de signing smaller units for sustainability reasons vs. larger ones for efficiency purposes. Fo r 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 e fficiency 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 ther e are today some best practices like the use of recycled aluminium in heat exchangers, great er use of plastics and other synthetic materials from renewable sources.

11.2.1 Sustainability principles The most widely known definition for sustainable de velopment is the one presented by the Brundtland report: "to meet the needs of the presen t without compromising the ability of future generations to meet their own needs" (Brundt land Commission, 1987). The same overall goal can be expressed in more specific term s: 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 soci ety...2014 TOC Refrigeration, A/C and Heat Pumps Assessme nt Report

226 4. People are not subject to conditions that system atically undermine their capacity to meet their needs." (Ny, 2006)

These general principles are affected by environmen tal and social aspects.

11.2.2 Environmental aspects Some ecological aspects related to refrigeration de rived from the principles i, ii, and iii, disclosed in section 11.2.1, are:

i. Extraction of resources: energy from fossil fuel s, mining of materials such as copper, (used in tubing, heat exchangers, and winding of el ectric motors), zinc, fluorite (European Commission, 2011) and other scarce mate rials (here understood as proportional to the rate a substance is being extra cted, relative to its natural concentration in the environment), aluminum, iron, rare earth products, use of fossil substances as raw materials for refrigerants (virtu ally all refrigerants except water and ammonia), use of fossil fuels and mineral oil in co mpressors and other moving parts. Despite of recycling efforts, the combined producti on levels of copper, zinc, and fluorite reached 30.4 Mt in 2006, representing an i ncrease of 20 % over the production levels in 1999 (Lottermoser, 2010). ii. Emission of man-made substances: emissions of r efrigerants, solvents, paints & other surface treatment materials, and the incineration o f materials are a major part the direct emissions of greenhouse gases. Indirect emis sions related to the lifecycle of refrigeration systems form the other part. iii. Degradation of fertile ecosystems: Examples a re food conservation, metals and nonmetals mining, water usage, oil extraction, landfil l 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 cond itions prevailing along the value chain, including consumer safety, to the availability of h ealthy food and reduction of food waste by appropriate refrigeration, thermal comfort and avoi dance of thermal stress provided by air conditioning.

However other social needs should also be considere d when coupling the refrigeration business to the sustainability imperative, such as:

 Learning through: awareness, education, proper trai ning of employees and technicians; and

 Equity and fairness, supported by: ethical conducti on of business, fair trade, fair marketing, low cost equipment coupled with high ene rgy 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 g reenhouse gases during the operation of the equipment and the disposal of the operating flu ids at the end-of-life. TEWI takes into account both direct fugitive emissions, and indirec t emissions produced through the energy consumed in operating the equipment. TEWI is measur ed 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 seas onal profiles of temperatures and capacity.2014 TOC Refrigeration, A/C and Heat Pumps Assessme nt 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 substa nces are components and the working fluids such as the refrigerants (IPCC, 2005). Vario us studies of LCCP have included for instance the fugitive emissions of a refrigerant fr om production until installation in equipment, the embodied energy or GHG emissions ass ociated with producing the refrigerant, and the GHG emissions associated with extracting ma terials and producing components of an air-conditioning or refrigeration system.

Both LCCP and TEWI include a measure of the efficie ncy 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 equip ment will be. LCCP and TEWI calculations provide more information on the sustainability of a ir-conditioning and refrigeration equipment than GWP or energy efficiency alone; ther efore, 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 an d negative impacts along their life cycle encompassing extraction and processing of raw mater ials; manufacturing; distribution; use; re-use; maintenance; recycling; and final disposal. S-LCA complements the more usual environmental Life Cycle Assessment (E-LCA) with so cial 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 d iffers from other social impact assessment techniques by its objects: products and services, a nd 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 process es, or to impacts on social capital. Depending on the scope of the study, indirect impac ts on stakeholders may also be considered. S-LCA provides information on social an d socio-economic aspects for decision making, instigating dialogue on the social and soci o-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 sustai nable conditions, through the identification of gaps in knowledge or potential impact, which wou ld 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 coppe r, zinc and fluorine;

 Reduce the emissions of GHG while reducing the depe ndence on oil. This can be achieved by focusing on energy efficiency, and by i ncreasing the share of fossil-free energy during life cycle;

 Reduce progressively the use of virgin raw material s, minimize emissions, upcycle waste, reuse water, and check responsible managemen t 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 m aterials inventory;2014 TOC Refrigeration, A/C and Heat Pumps Assessme nt Report

228  Establish codes of ethical conduct for suppliers al ong 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 th e relative sustainability of products and processes

 Awareness raising through the value chain

 Education on sustainability and its implications

 Regulations and political actions defining technica l conditions

 Integration of social and environmental externaliti es into corporate governance and reporting

 Financial incentives to take account of environment al 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, emi ssions of these refrigerants have direct impact on the environment. Refrigerants are not onl y used in new equipment and appliances but there is a recurring consumption in servicing d uring the useful working life of the equipment. Consumption of refrigerants for servicin g 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 refri geration and air-conditioning equipment is gradually emitted to the environment. Efforts are b eing made to reduce the impact of these refrigerants on the environment by refrigerant mana gement and conservation techniques.

11.3.1 Design criteria for charge minimization and leak tightness Charge minimization Charge minimization is one important factor for con servation of refrigerant. Minimization of the refrigerant charge would not only reduce the gl obal consumption of refrigerants but it would also reduce their impact on climate by reduci ng the quantity of possible emissions that could be emitted during catastrophic leak events, d uring the working life of equipment and end of life of equipment. Historically, little atte ntion 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 h ighly 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 minimizati on, industry is paying attention to this aspect by employing designs for lower storage of re frigerant. In case of unitary airconditioning systems with hermetic compressors, the majority of refrigerant is banked in the compressor and heat exchangers, especially in the c ondenser. Systems are designed with mini channel heat exchangers to reduce the internal volu me of the condenser, and compressors are designed for reduced oil. Significant efforts are a lso being made to design and develop supermarket refrigeration equipment by using second ary loop and cascade systems that use a much smaller refrigerant charge than traditional re frigeration system. It should be noted that there may be negative effects of charge minimizatio n: some systems may be sensitive to a charge deficit leading to an increase in energy con sumption and even a system failure. Another typical trade-off situation is the choice b etween direct and indirect systems. The latter systems tend to minimize the direct emission s of fluids, but might increase the indirect emissions due to the increased losses. There is a b alance to ensure good efficiency despite minor leakage and reduced direct emissions.2014 TOC Refrigeration, A/C and Heat Pumps Assessme nt Report 229

Overcharging of equipment is common, especially in systems with receivers, as the amount of refrigerant contained in refrigerant receivers is n ot always known. Refrigerant receivers are equipment components that contain excess refrigeran t 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 kno wn. For such equipment, field charging is often continued until the charge is considered s atisfactory. Without the check of weighing the charge, the circuit could be overfilled with tw o 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 li mited during nominal operation, and an inspection tool (indicator, level, etc.) must be pr ovided.

More detailed information has been published recent ly 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 requi res more skills from the persons working on the system.

Another trend from legislation side is the move fro m look more on the leak potentials rather than look at the charge size. The potential leak ca n come from any connections, flanges, valves, compressor and motor assemblies etc. The li kelihood 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 authoriti es like to look at potential leak and the advantage is that you can deal with it already at t he 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 as sembly 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 techn icians.

Beside other code of good practice and refrigeratio n standards covering requirements for leak testing and tightness, there are three general type s of leak detection methods:

1. Global methods indicate that a leak exists somew here, but they do not locate the leaks. They are useful at the end of construction a nd 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 indicat e that a leak exists by sensing changes in equipment performance and alerting opera tors.

Industry both in developed and developing countries , in recent years, have improved design for leak tightness in the air-conditioning and refr igeration equipment manufactured after the Montreal Protocol. In addition existing equipment/a ppliances 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.2014 TOC Refrigeration, A/C and Heat Pumps Assessme nt Report

230 11.3.2 Reduction of emissions through installation, servicing and maintenance

The installation of refrigeration equipment plays a ver y important role in terms of equipment life, energy consumption, trouble free operation, a nd refrigerant conservation. Use of proper installation techniques should be followed to ensur e joints that can withstand vibration, temperature and thermal cycling stresses. Proper cl eaning of joints and evacuation to remove air and non-condensable gases will minimize the fut ure service requirements. For nonhermetic equipment, the installer should ensure the proper charge is provided. The installer should also seize the opportunity to find manufactu ring defects before the system begins operation.

The Montreal Protocol has globally sensitized the s ervicing community as well as the endusers to use good servicing practices and reduce th e emissions of refrigerants through awareness programmes. Servicing practices have impr oved especially in some of the sectors mainly because of training of servicing personnel e ngaged 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 avoidabl e. Instead, refrigerant recovery, recycling, reclamation and destruction, discussed b elow, should be practiced.

Technicians must study the service records to deter mine the history of leakage or malfunction and energy consumption trends. Technicians should a lso measure performance parameters to determine the operating condition of the cooling sy stem. Fixing leaks and defects early will help avoid catastrophic failures that may contamina te 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 e quipment not only enhances the proper operation of the system but also reduces the freque ncy of system failure.

Training of technicians is essential for the proper handling and conservation of refrigerants, the optimized operation of the equipment, the contr ol or reduction of energy consumption, and avoids loss of stocked food when refrigerant an d lubricant come in contact with it due to improper handling. Such training should include inf ormation on the environmental and safety hazards of refrigerants, the proper techniques for recovery, recycling, reclamation and leak detection, and local legislation regarding refriger ant handling. The European standard EN 13313 describes the competence developments necessa ry 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 co nservation. Additional details can be found in previous RTOC report (UNEP, 2011).

In the last few decades, there has been an increasi ng emphasis on conservation of refrigerants and reduction of emissions that has led the industr y to develop a specific terminology which is used in this report (ISO, 1999):

Recover: to remove refrigerant in any condition from a syste m and store it in an external container.
Recycle: to clean the extracted refrigerant using oil separa tion and single or multiple passes through filter-driers which reduce moisture, acidity, and particulate matter. Recycling normally takes place at the field job sit e.2014 TOC Refrigeration, A/C and Heat Pumps Assessme nt Report 231

Reclaim: to reprocess used refrigerant to virgin p roduct specifications. Reclamation removes contaminants such as water, HCl and HF reac tion products, other acids, high boiling residue, particulates/solids, non-condensab le gases, and impurities including other refrigerants. Chemical analysis of the refrigerant is required to determine that appropriate specifications are met. The identification of conta minants and required chemical analysis are specified by reference to national or internati onal standards for new product specifications. Reclamation typically occurs at a r eprocessing or manufacturing facility.

Destroy: to transform used refrigerant into other c hemicals in an environmentally responsible manner.

Refrigerant recovery Recovery of refrigerant, especially CFC-12 and H-CF C-22, has become an integral part of servicing practices in most of the countries, espec ially for systems having relatively large charge quantities. The incentives for refrigerant r ecovery 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 favou r 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 a void 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 re frigerant until the system is ready to be recharged. The recovered refrigerant may also be us ed in other equipment or sent for destruction. Refrigerant recovery equipment may hav e the added capability of recycling of refrigerants.

Refrigerant recovery equipment has been developed a nd 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 liq uid recovery is the most efficient, vapour recovery methods may be used alone to remove the en tire 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 (Clod ic, 1994). Testing standards have been developed to measure equipment performance for auto motive (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 equi pment. Refrigerant recovery and recycling equipment should be made available to service techn icians 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 d ue to incompatibility issues and the array of refrigerants used that refrigerant recovery/recycli ng 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 analysi s, restrictions are imposed on the use of recycled refrigerants.2014 TOC Refrigeration, A/C and Heat Pumps Assessme nt Report

232 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 m anufacturers, existence of reclamation services, variety and type of systems, and the pref erence of the service contractor and owner. Reuse of recovered refrigerant requires strict adhe rence to good practices including identifying the refrigerant type. Mixed refrigerant s are often costly to separate which may result in the sale of cross-contaminated refrigeran ts. 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 wh ere 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 refr igerant 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 re frigerant by placing it back into service. Reclaimed refrigerants are tested and verified to m eet 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 refrigeran t 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 dis incentive to reclamation efforts. Such disincentives promote venting or reuse of stockpile d refrigerant. Care should be taken by policy makers to eliminate parallel (and potentiall y 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 refrig erants.

Small capacity portable refrigerant reclamation equ ipment 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, whi ch might lead to refrigerant emissions. As reclaimed refrigerant meets new product specificati ons, it may have the support of equipment manufacturers who maintain warranties on their equi pment. Another advantage is that the quantification of refrigerant recovered are easily obtained. However, reclamation does require a costly infrastructure, which may only prove viabl e 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 dest ruction of unwanted ODS refrigerants because of ozone and climate benefits from the avoi ded 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 voluntar y market. The compliance market for GHGs is based on a legal requirement where, at an i nternational (e.g., Clean Development2014 TOC Refrigeration, A/C and Heat Pumps Assessme nt Report 233

Mechanism) or national and regional level (e.g., Eu ropean 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 the ir GHG reduction obligations. In some of these markets, the carbon credits resulting from OD S destruction are not considered for compliance generally because ODS are not included i n the Kyoto Protocol and are being phased out.

The voluntary markets have also been in operation w here individual organisations voluntarily commit to actions and projects to offset their GHG emissions. The voluntary carbon market also established standards for ODS destruction as c arbon offset projects. Standards such as The Climate Action Reserve (CAR) and the Verified C arbon 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 mark ets.

Normal conditions where recovery, recycling, and re clamation under a good logistical system are prevalent should lead to fairly low requests fo r destruction in the refrigeration industry. This is especially the case where the demand for OD S remains high. A need for destruction facilities may be created in instances where regula tions 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 particul arly aggressive acids, especially hydrofluoric acid. Mainly, their resistance to hydr ofluoric acid limits the number of usable incinerators. CFCs and more particularly halons, bu rn very poorly. In order to be incinerated, they must be mixed with fuels in specific proportio ns.
The Parties to the Montreal Protocol, recognizing t he benefits of destruction of unwanted ODS in an environment friendly manner, approved pro cesses, through decision IV/11 as early as in 1992. Since then, the list of approved destru ction processes has been updated a number of times. Presently, there are 16 destruction proce sses 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 m any cases emit CO 2 and other pollutants. The refrigerant selection impacts the energy consum ption of the refrigeration system due to its thermodynamic nature in many ways. The indirect emi ssions operating the refrigeration systems during its lifetime contribute in many case s far more compared to the direct impact. The more important is the participation of renewabl e sources to the power grid, the less prevalent is the indirect impacts from energy use.

Designing and efficiently maintaining HVAC&R system s contributes by a large factor to the reduction of GHG related to the air conditioning an d refrigeration industry through cutting “indirect emissions”. Consequently, using measureme nt 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 perf ormance standards (MEPS) has helped drive energy efficiency to higher levels than if th ose standards had not been applied, and that the cost of not complying with those standards will have an adverse effect on cutting GHG emissions.2014 TOC Refrigeration, A/C and Heat Pumps Assessme nt Report

234 Energy efficiency is the measure of the amount of e nergy 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 efficie ncy 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 c ontributes to that of the other level up and depends on the proper design and application of com ponents at the particular level.

Energy efficiency parameters are measured at certai n conditions at which the machine is working and will have different readings if those c onditions change. For most air-source air conditioning machines, this includes the ambient ai r conditions and the room temperature that the machine is expected to deliver. An air conditio ner 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 D ecision XIX/6 require countries benefiting from investment projects, to implement conversion t echnologies that minimise the effects on climate. By converting to more energy efficient pro ducts, countries will minimise the consumption of electric power leading to a reductio n in the carbon emissions from power plants. Emissions of CO 2 in grams per kWh of electric power generated vary b y 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. Depe nding on the sources of electric power in a particular country, each kWh saved will contribute to a reduction of up to a kilogram of CO 2
. An analysis by the European Commission on residenti al air conditioners reckons that "most of the environmental impacts (and life cycle costs - L CC) are attributable to the use-phase." (European Commission, 2009b). This shows the import ance of understanding energy efficiency in any discussion about climate impact o f air-conditioning and refrigeration equipment. Moreover, it is important to note that c limate 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 inter connected.



### 11.5 Equipment life cycle considerations: equipment design, operation, maintenance, and end-of-life
Concepts and selection criteria for alternative ref rigerants in various applications for each sector of the HVAC&R industry are presented in othe r 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 minim ized 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 equip ment into the heating system for heat recovery, and utilization of power grid based contr ols. Those technical design criteria are linked to regulations and standards as well as volu ntary 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). A dditional 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 estima tes that 55% of the primary energy in used by heating (Hudson, 2014). Buildings account f or 40% of the world’s energy use with the resulting carbon emissions substantially more t han those in the transportation sector2014 TOC Refrigeration, A/C and Heat Pumps Assessme nt Report 235

(WBSCD, 2009). Estimated energy saving potential wi th 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 pot ential energy savings of 40% until 2020, if accompanying political measures are taken (FKT, 201 2). 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%/yea r (Brinkmann, 2009)

In the position paper (FKT, 2012) by the German Res earch 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. Othe r 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 system s (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 wit h 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 C ommission, 2009b) in relation to the foreseeable requirements from the legislature led t o a significant competitive advantage for manufacturers undertaking those voluntary commitmen ts.

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 final ly properly recovering the refrigerant when the equipment is di sposed or replaced.

11.5.1 Equipment design From an engineering point of view, the design of co mponents such as compressors or electrical drives has a possibility for limited imp rovement of a few percentage points in terms of efficiency compared to ideal theoretical efficie ncy. 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 consideratio n:2014 TOC Refrigeration, A/C and Heat Pumps Assessme nt Report

236 Technical considerations:

 Meeting customer design requirements, including the proper specification of annual cooling/heating demands;

 Minimizing refrigerant usage and choosing alternati ve 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 makin g process: low first cost versus high efficiency.

Regulatory considerations:

 Refrigerant regulations specifically for those refr igerants targeted for a phase-down, for example the European Union F-Gas (European Union, 2 012) regulations;

 Agreements for achieving high energy efficiency and /or low consumption and emissions of refrigerants, for example the German agreement V DMA 24247 for energy efficiency in supermarket refrigerating systems” (VDMA, 2011);

 Equipment energy efficiency ratings, for example “e co design” Directive 2009/125/EC, “establishing a framework for the setting of ecodes ign requirements for energy-related products (European Union, 2009);

 Standards provided by global organizations or indus try associations, for example International Standards Organization (ISO), Europea n Committee for Standardization (CEN) or the American Society of Heating, Refrigera ting, and Air Conditioning Engineers (ASHRAE) 5

. The decision of which equipment to use during the d esign stage is often faced by competing targets: low first cost investment versus high ener gy efficiency affecting the cost of energy over the lifetime of the system and the GHG emissio n. To resolve this conflict between low first cost, operating cost and refrigerant emission s, 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 regula tory requirements (EU F-gas law) and third party standards such as the US AHAM Refrigerator Su stainability 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 produ ct containing refrigerant.

Many of the factors that influence energy efficienc y 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 resource s such as fuel, and end of life disposal requirements. Energy consumption is greatly affecte d by the selection of refrigerants, especially considering the lifetime of the equipmen t.

For example, a typical 10 kW cooling capacity syste m 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 syste m will typically have 2 kg of refrigerant charge. The CO2 emissions due to the energy consump tion of 44000 kWh are 30.3 metric

5 www.iso.org and www.ashrae.org2014 TOC Refrigeration, A/C and Heat Pumps Assessme nt Report 237

tonnes of CO2, based on the USA power grid, which i s 45 % coal-based. The equivalent CO2 emissions due to the direct release of the refriger ant charge are 2.7 metric tonnes, which is less than 10 % of the lifetime CO2 emissions.

Design considerations for safety can sometimes coun ter the design for energy efficiency and lead to more CO 2 emissions. For example, isolating heat exchangers for sake of safety or toxicity can affect the heat transfer efficiency ei ther positively or negatively.

Refrigerant criteria and properties provide a basi s 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 pri ce reduction Commercial availability Market penetration driven b y 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 knownrefrigerants (such as HFC-32, HFC152a, HC-290, HC-600a, NH3) it is expected that the application, design know-how, service practices and2014 TOC Refrigeration, A/C and Heat Pumps Assessme nt Report

238 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
years 6

.

6 Safety requirements for flammable refrigerants cla ssified as A2L, A2, and A3 are described in chapter 2 of this report2014 TOC Refrigeration, A/C and Heat Pumps Assessme nt Report 239



## Annex 1 - TEAP Refrigeration, Air Conditioning and Heat Pumps Technical Options Committee (RTOC) - Membership sta tus 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 Jamai ca 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 Denmark2014 TOC Refrigeration, A/C and Heat Pumps Assessme nt Report

2402014 TOC Refrigeration, A/C and Heat Pumps Assessme nt Report 241



## Annex 2 - Contact details for authors, co-authors a nd 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 Č ERMÁK 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.com2014 TOC Refrigeration, A/C and Heat Pumps Assessme nt Report

242 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.de2014 TOC Refrigeration, A/C and Heat Pumps Assessme nt Report 243

Prof. Dr.-Ing. Jürgen K Ő HLER 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 K Ő NIG 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.com2014 TOC Refrigeration, A/C and Heat Pumps Assessme nt Report

244 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