RETROFITTING WITH NON-CFC SUBSTITUTES

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RETROFITTING WITH

NON-CFC

SUBSTITUTES

September 1994

OzonAction Information Clearinghouse OzonAction Programme

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DISCLAIMER

This preliminary document is provided by the United Nations Environment Programme's Industry and Environment (UNEP IE) as an information paper on retrofitting with non-CFC substitutes in refrigeration sector. The paper presents abstracts/summaries of studies concern-ing retrofittconcern-ing of domestic refrigeration, mobile air conditionconcern-ing (MAC), centrifugal chillers, cold storage and food processing facilities, and commercial refrigeration. Some of the abstract summaries are extracted directly from the source cited. Others, however, have been edited to improve clarity of the extract, or to target the key points relevant to the subject of this paper. In furnishing the information contained in this document, UNEP does not make any warranty or representation, either express or implied, with respect to its accuracy, completeness or utility; nor does UNEP assume any liability of any kind whatsoever resulting from the use of, reliance upon, any information, material, or procedure contained herein, including but not limited to any claims regarding health, safety, environmental effects or fate, efficacy, or performance, made by the source of the information.

Mention of any company, association, individual, or product in this preliminary list is for informational purposes only, and does not constitute a recommendation of any such company, association, individual, or product, either express or implied by UNEP.

Trade Marks

All products mentioned in this list are trademarks of their respective companies. Updates

This is a "living" document that will be updated on a regular basis. If you know any paper or information sources that should be included in the future versions, please send the information to UNEP IE.

UNEP IE

Attn: Mr. Rajendra M. Shende Tour Mirabeau

39 - 43 quai André Citroën 73759 Paris Cedex 15 France

REVIEW

The information in this document has been reviewed by:

Dr. Lambert Kuijpers, Chair, UNEP Technology and Economic Assessment Panel; Co-Chair, UNEP Refrigeration, Air-Conditioning, and Heat Pumps Technical Options Com-mittee.

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Dr. Lindsey Roke, Member of UNEP Refrigeration, Air-Conditioning, and Heat Pumps Technical Options Committee.

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BACKGROUND

What is retrofit in the field of refrigeration?

Retrofit is the process by which the equipment currently using an ODS refrigerant is made to run on a non-ODS refrigerant, without major effects on the performance of the equipment, and without significant modifications/changes for the equipment, ensuring that existing equipment operates until the end of its economic life.

Why retrofit

Imminent CFC-shortages would threaten the useful life of the appliances of CFC-equipment. As CFC shortages increase, the cost of CFCs will rise, along with operating costs of the equipment. Retrofit refrigerants and technology are available for most applications. By retrofitting the equipment, you enable it to operate past the CFC's phase-out dead lines, and the equipment lifetime exceeds the phase-out dates.

Existing plants which have reached the end of their economic lifetime, should be replaced with new refrigeration equipment based on non-ODS refrigerants and technologies.

This document

The Executive Committee of Multilateral Fund in its 10th meeting decided to defer all retrofitting projects pending an assessment report by OORG (Ozone Operations Resource Group) on the status of retrofit, cost, reliability, cost effectiveness, and comparative benefits. This document is based on information available at the OAIC (OzonAction Information Clearing House) of UNEP IE/PAC.

It is expected to provide assistance to Article 5 countries in assessing various options, and to provide input to the process of formulation of proposed strategic options (to be formulated by the Secretariat and other implementing agencies) to enable the Executive Committee to take a policy decision on the subject.

RETROFIT STUDY INFORMATION

Retrofit study involves the joint effort by equipment manufacturer, equipment owner, service agency, refrigerant manufacturer and research institute.

Study and experiments on retrofitting have to address the following problems: Technical

i) Pressure and temperature level, performance and capacity

ii) Compatibility of lubricants and refrigerants with construction, sealing and insulation materials

iii) Refrigerant and lubricant solubility (eg. capillary tube plugging)

iv) Chemical and humidity residues and their impact on lubricants, refrigerants, materials and operation performance

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v) Storage/handling of lubricants and refrigerants, with regard to moisture interaction vi) Redesign of compressor and other components

vii) Field tests/reliability Others

vii) Time consumption for retrofitting

viii) Cost of retrofitting (equipment, lubricant, refrigerant)

Typical retrofit may involve one or many of the following changes/justifications: Lubricant

Desiccant filter (dryer) Expansion valve

Compressor (gearbox, speed, motor) Insulation and seal materials, elastomers

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R E TR O F ITTI N G WI T H NO N-CF C SU BST IT U T ES 7 P o ssi b le re fr ig er a n t c a n d id a te s f o r re tr o fi t Re pl ac e-P ur e c o mpounds Bl ends % A S H RA E me nt for CF C-11 H C F C -123 CF C-12 H C F C -2 2 H CF C-22/ H C F C -124/ H C F C -142b 60/ 25/ 15 ( H F C-134a H C F C -22/ H C F C -124/ H C F C -142b 65/ 25/ 10 ( H F C-152a H C F C -22/ H C F C -124/ H F C-152a 52/ 33/ 15 R-401a H C F C -22/ H C F C -124/ H F C-152a 61/ 28/ 11 R-401b H C F C -22/ H C F C -124/ H F C-152a 33/ 52/ 15 R-401c H C F C -22/ 600a /H CF C-142b 55/ 4/ 41 R-406a R-290/ R-600a ( p ropa ne /i sobut an e) 50/ 50

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R E TR O F ITTI N G WI T H NO N-CF C SU BST IT U T ES Re pl ac e-P ur e c o mpounds Bl ends % A S H RA E me nt for 8 R-502 H C F C -2 2 H CF C-22/ H C F C -124/ H C F C -142b 65/ 25/ 10 H F C-134a H C F C -22/ H F C-143a /H F C -125 47/ 46/ 7 H C F C -22/ H F C-125/ R-290 38/ 60/ 2 R-402a H C F C -22/ H F C-125/ R-290 60/ 38/ 2 R-402b H C F C -22/ R-218/ R-290 75/ 20/ 5 R-403a H C F C -22/ R-218/ R-290 56/ 39/ 5 R-403b H F C-125/ H F C-134a /H F C -143a 44/ 4/ 52 R-404a H F C-32/ H F C-125/ H F C-134a 20/ 40/ 40 R-407a H F C-32/ H F C-125/ H F C-134a 10/ 70/ 20 R-407b H F C-125/ H F C-143a 50/ 50 R-507

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INTRODUCTION

TO

EXTRACTS/SUMMARIES

This paper presents abstracts/summaries of studies concerning retrofitting of domestic refrig-eration, mobile air conditioning (MAC), centrifugal chillers, cold storage, and commercial refrigeration, highlighting benefits and problems. Some of the abstract summaries are extracted directly from the source cited. Others, however, have been edited to improve clarity of the extract, or to target the key points relevant to the subject of this paper.

The extracts are presented in the following order: 1) excerpts from UNEP Technical Options Reports

2) according to the categories of alternatives (e.g. HFC-134a retrofitted for CFC-12), and in chronological order.

This information is provided for reference purposes only, and does not imply that UNEP endorses, recommends, nor approves of any of the options mentioned in this paper.

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DOMESTIC REFRIGERATION

Extracts from:

Refrigeration, Air Conditioning and Heat Pumps Technical Options Committee, 1991:

Report of the Refrigeration, Air Conditioning and Heat Pumps Technical Options Committee. Nairobi: UNEP, 1991.

Retrofit:

(i) Primary replacements: CFC-12

Most manufacturers consider that there will be an adequate supply of CFC-12 available from production and reclaim sources to satisfy the needs until a total phaseout is accomplished. Some manufacturers have even initiated their own reclaim efforts for capture of CFC-12 from domestic units in the field.

(ii) Ternary blend

The ternary blend HCFC-22/HFC-152a/HCFC-124 was initially mentioned as a service refrigerant. At present, activity in this market seems to have subsided since the ternary requires an alkylbenzene lubricant. In some countries, such as New Zealand, this is still a possibility since most of their units are brought back to the shop for repair, where changing the oil, if required, is a simple process. However, it can still be done since larger amounts of mineral oil (20-30%) can remain in the system.

(iii) HFC-134a

Field tests using HFC-134a and ester lubricants to service both automotive and larger commercial CFC-12 open-drive and semi-hermetic systems are giving encouraging results. However, little work is being done on servicing small hermetic compressor capillary systems. Such systems have additional problems to be addressed, e.g., the need to ensure that no traces of paraffinic compounds remain that might block capillaries and the desirability of lengthening the capillary. If a method of flushing out CFC-12 systems and recharging them with HFC-134a is developed, it is probable that a compressor change will be required. Work is progressing on an oil for use in hermetic systems and the situation is likely to become clearer by late 1992. An updated version of this document will be available November 1994.

HFC-134a retrofit for CFC-12 1993

UNEP IE: Catalogue of Technologies for Protecting the Ozone Layer, Refrigeration, Air

Conditioning and Heat Pumps. Norway, 1993.

HFC-134a is a leading candidate in replacing CFC-12 in refrigerators and freezers. Problems:

Studies show from 1% less to 7% higher energy consumption than CFC-12. Problem of finding suitable lubricants. HFC-134a has very low solubility and mineral oil does not mix well in HFC-134a, which could contribute to the following problems:

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poor oil return back to the compressor, resulting in possible compressor failure fouling of expansion valves and heat exchanger surfaces, leading to reduced system

performance

Ming-Shan Zhu, Li-Zhong Han, Xiao-Yu Zhao, 1993: Dismantling inspection and retrofit

of domestic refrigerator with HFC-134a. Paper presented at the 1993 International CFC

and Halon Alternatives Conference, 20-22 October 1993, Washington, D.C., U.S.A., pp. 81-85

A modified SNOW FLAKE model BCD-191 refrigerator was retrofitted, adapting the compressor, and using ester oil.

Benefits

Energy consumption of the HFC-134a refrigerator equalled that of CFC-12. Thermal perfor-mances met national standards. Problems found when using HFC-134a in an unmodified refrigerator were avoided. (These included the carbonization problem of the HFC-134a, the suitable lubricant oil, accurate cleaning of the old system, redesign of the compressor and matching of each component).

1992

Davey, J.P, et al, Rhône-Poulenc, 1992: Field experience in retrofitting Isceon 134a and

Isceons 69-S and 69-L.

Benefits

Isceon 134a was identified some years ago, as ideal non-flammable, zero-ODP replacement for CFC-12.

Problems

Immiscible with mineral oils traditionally used with CFC-12. PAGs were used, but revealed an inherent and significant problem, namely high hygroscopicity. Improved lubrication and better handling characteristics achieved with use of synthetic polyol ester based materials.

Ming-Shan Zhu et al., 1992: Experimental research on domestic refrigerators using

HFC-134a as refrigerant. Paper presented at the 1992 International Refrigeration Conference:

Energy Efficiency and New Refrigerants, July 14-17, 1992, Purdue University, West Lafayette, Indiana, USA. pp. 241-247

Benefits

Satisfied all national Chinese standards. Problems

Without modification of the refrigerator, consumption of electricity was slightly higher than CFC-12, volumetric capacity was slightly smaller, and pull down was slightly slower.

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Conclusion

Increasing compressor displacement by an appropriate amount can decrease energy con-sumption. In order to lower energy consumption while using HFC-134a as a refrigerant, changes must be made to the compressor, condenser, evaporator, capillary tube, etc. Therefore, further study of component matching is necessary.

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Has shown the best result with regard to energy consumption. Problems

Flammability: The safety risk is quite small in domestic refrigerators because the units have charges of only a few hundred grams. Has approximately 5% less volumetric refrigerating capacity than CFC-12. Typical modifications needed are:

change of lubricant

adjustment or change of expansion device change of desiccant filter

Comparison of replacement refrigerants HFC-134a and HFC-152a 1993

Vineyard, Edward; Swatkowski, Leonard. 1993: Energy efficiency of HFC-134a versus

HFC-152a. Paper presented at the 1993 International CFC and Halon Alternatives

Con-ference, 20-22 October 1993, Washington, D.C., U.S.A. pp. 86-91

In an effort to evaluate the trade off between efficiency and safety of the two alternative refrigerants HFC-152a (flammable) and HFC-134a (non flammable), energy consumption tests were performed by 6 refrigerator/freezer manufacturers as part of a joint project.

Conclusion

Results showed no statistically significant difference between the efficiencies of HFC-134a and HFC-152a. Thus, HFC-134a is a more acceptable substitute for CFC-12 in refrigerator-freezers than HFC-152a assuming safety is the main difference between the two alternatives. However, other issues, such as global warming potential and ozone depletion potential, influence the selection of replacement refrigerants and could outweigh the effects of the reduced safety of HFC-152a and other flammable refrigerants, such as hydrocarbons.

MP39 retrofit for CFC-12 1993

Hua Xiao-Long and Chen Wei, 1993: The comparison of the performance of MP39 DuPont

blends and CFC-12 in refrigerator/freezers. Paper presented at the International

Conference on CFC and Halon Alternatives, 20-23 April, 1993, Beijing, China, pp. 159-164

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After proper modification of the refrigeration system, the energy consumption of a refrigerator using MP39 mixture should be close to that of CFC-12. More detailed research of modifying capillary load and refrigerant changes is being done. Input power, capacity, are higher and energy consumption is about 5% higher. Refrigeration capacity of MP39 is larger than that of CFC-12, and the input power of the compressor is larger too.

Case study from Lindsey Roke, Fisher and Paykel Refrigeration Division, New Zealand in response to retrofitting query by OAIC, 1993.

100 domestic CFC-12 refrigerator cabinets serviced with MP39 (50% 22/30% HCFC-124/ 20% HFC-152a)

Benefits

Oil not changed. Costs no more than servicing with CFC-12 except for the refrigerant price difference (as filters should always be changed on servicing anyway).

Conclusions

Refrigerant bottle must be checked for leakage, and blends should be charged from liquid line from cylinder, otherwise composition of refrigerant can be altered. Cabinets should be clearly labelled to avoid future mixing of refrigerants. Filter dryer changed.

See also summary of The CFC File (New Zealand) on p. 5 for further comments on SUVA MP39.

1992

DuPont, 1992: "DuPont SUVA MP refrigerant blends: properties, uses, storage and

handling". Delaware: DuPont, 1992

Benefits

Comparable in capacity and efficiency to CFC-12 system. Problems

Due to fact that these blends are not true azeotropes, their compositions change at boiling point, causing "temperature glide". The amount of glide will depend on the system design, and may or may not affect performance. SUVA MP refrigerant blends will decompose at high temperatures, producing toxic and irritating compounds. It is important to follow recommendations for handling and use.

Kuijpers, L.; de Wit, J.A.; Benschop, A.A.J.; Bivens, D.B., 1991: Optimization of the

efficiency of the ternary refrigerant blend HCFC-22/124/152a in domestic freezer equipment.

Benefits

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composition was stated to yield an energy efficiency comparable to CFC-12. Could be an ideal candidate in the domestic refrigeration sector, where reliability of compressor operation and energy efficiency are important aspects.

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MOBILE AIR CONDITIONING

Extracts from:

Report of the Refrigeration, Air Conditioning and Heat Pumps Technical Options Committee. Nairobi: UNEP.

Presently no chemical or blend of chemicals has been proven to be able to directly replace CFC-12 without substantial retrofit costs.

HFC-134a retrofit for CFC-12 Retrofit costs

The upper limit of retrofit costs would result from complete system replacement with HFC-134a compatible components at an estimated service level cost of US $ 1000-2500 per vehicle. Estimating the average cost of retrofitting a MAC system to use HFC-134a or the blend involves accounting for those system control devices, components and materials that are currently known to be incompatible with the given refrigerant and hence, require replacement during retrofit. Such items are shown in Table 10.1 for both candidate refrigerants and both types of A/C systems. The average retrofit cost based on service level parts and labour costs is estimated to be US $ 217. It should be noted that the components requiring replacement for retrofit are rarely, if ever, changed during normal service. As a result, retrofit costs are in addition to any costs needed to keep the system operating. The current average repair cost to maintain an operating A/C system is estimated to be US $216 (MACS, 1992). Thus the overall average cost to repair and retrofit a system to use a non-CFC is estimated to be US $ 433.

Retrofit summary

There are currently two candidate retrofit solutions that vehicle manufactures, chemical companies, government agencies, and service groups are carefully considering. At this point in time, however, retrofit refrigerant technology must be considered an emerging technology and has not yet resulted in a usable retrofit refrigerant; substantial work needs to be done. An updated version of this document will be available November 1994.

1994

Foster, K. School of Automative Engineering, Croydon Institute, South Australia: Mobile

Air Conditioning, Workshop on the Protection of the Ozone Layer. Jakarta 11 - 15 April

1994.

The general guidelines are very similar when retrofitting to HFC-134a or MP52. HFC-134a requires mineral oil to be flushed out. Flushing agent to be used are CFC-12 or dry nitrogen. CFC-12 must be recovered. MP52 do not require flushing. Small system modifications required.

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Society of Automotive Engineers (SAE): Several documents developed on the request of US EPA to identify alternate refrigerants and retrofit procedures for conversion of CFC-12 mobile air conditioning systems. USA 1994.

(ISO) SAE J1657 Selection Criteria for Retrofit Refrigerants to Replace R12 in Mobile Air Conditioning. This includes flammability, ozone depletion, toxicity and other refrigerant and lubricant compatibility requirements to be usable in mobile A/C systems.

(ISO) SAE J1658 Alternate Refrigerants Consistency Criteria for Use in Mobile Air Conditioning Systems. Blend refrigerants consist of more than one substance, this document identifies the proper handling procedure, vapor or liquid phase, and identifies when the remaining container can not be used due to improver blend consistency.

(ISO) SAE J1659 Vehicle Testing Requirements for Replacement Refrigerants for use in R12 Mobile Air Conditioning Systems. This requires certain vehicle tests which must be conducted to establish any system performance changes due to the aøternate refrigerant.

(ISO) SAE J1660 Fittings and Labels for Retrofit or R12 Mobile Air Conditioning Systems to R134a. This document covers modification of service fittings and labels for retrofitted vehicles in preventing future system damage and contamination of the refrigerant supplies. (ISO) SAE J1661 Procedure for Retrofitting R12 Mobile Air Conditioning Systems to R134a. This covers the retrofit modification and system processing procedure to reduce the remaning system R12 residue to less than 2%, which is required to reduce future contamination of the R134a refrigerant supply when the vehicle is served.

(ISO) SAE J1662 Material Compatibility With Alternate Refrigerants. Seals, hoses and "O" rings used in CFC-12 systems may not compatible with some alternate refrigerants and could break down causing system failures. This document covers test procedures for establishing material compatibility.

1993

Automotive Consulting Group, Michigan USA, 1993: CFC-12 Phase-Out Analysis and the

Determination of the Required Strategic Reserve. Final Report, presented to the American

Automobile Manufacturers Association and the Association of International Automobile Manufacturers, November 3, 1993.

Cost information: ACG determined the mix of retrofit solutions from information provided by eight different automakers. The information was weighted based upon market shares, to determine a composite average:

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Mix of Vehicles at Various Retrofit Price Points

Age of Vehicle $100-250 $150-500 $400-750 Total

1 - 2 years old 29 % 22 % 49 % 100 % 3 - 4 years old 29 % 18 % 53 % 100 % 5 - 6 years old 25 % 21 % 55 % 100 % 7 - 8 years old 12 % 21 % 67 % 100 % 9 - 10 years old 7 % 21 % 72 % 100 % more than 0 % 0 % 100 % 100 % 10 years old

Mobile Air Conditioning Society, 1994: Guidelines for Automotive Air Conditioning

Retrofit. MACS 1994, Convention Issue, Sahara Hotel, Las Vegas.

R-12 systems were designed for R-12, and as long R-12 is available to service these systems, this is the preferred refrigerant. The mobile A/C industry identified R-134a as the replacement refrigerant for CFC-12 fleet after considering many things; compatibility, flammability, usable with existing service programs, meet the costumers requirements. The paper gives guidelines and procedures for retrofitting from CFC-12 to HFC-134a in automotive air conditioning: 1. Check system. Includes leak detection and identifying other part failures.

2. Remove R-12 from the system 3. Lubricant removal

4. Retrofit part replacement. (Seals/O-rings, hose material, compressor, desiccant, con-denser, refrigerants controls, lubricant.)

5. Install service ports 6. System labels 7. System evacuation 8. Charge system with R-134a 9. Leak check system 10. Check system operation

1993

Abraham, Anthony W.: The availability of parts for retrofit after warranty OEM and

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Alternatives Conference, 20-22 October 1993, Washington, D.C., U.S.A. pp. 312-316 Problems

There are differences between CFC-12 and HFC-134a with regard to capacity, coefficient of performance, and compression ratio. Cleaning of the system and providing the system with HFC-134a compatible components and lubricant. The author recommends strict adherence to SAE 1660 and 1661 specifications that the system be cleaned properly.

Dekleva, T.W.; Colmery, S.H.; Bresnaham, John, 1993: Fleet trials with vehicles retrofitted

to Klea 134a refrigerant and Emkarate RL lubricants; a perspective after two years on the road. Paper presented at the 1993 International CFC and Halon Alternatives Conference,

20-22 October 1993, Washington, D.C., U.S.A. pp. 294-30 Benefits

Many of the barriers to introducing mobile air conditioning retrofits are being successfully addressed through the considerable efforts of the industry. Available data suggests that vehicles retrofit under a range of conditions show good performance and durability. Service practices for retrofit vehicles are considered comparable to vehicles running on CFC-12. The current status of our fleet studies continue to show results and promise for the introduction of HFC-134a as a retrofit refrigerant. Performance levels appear to be acceptable for the majority of owners and conditions, and there have been no systematic performance or durability issues.

Low toxicity. Thermophysical characteristics similar to CFC-12. Residual system CFC-12 appears to be a manageable partner.

Observations

Some question still exists about the use of epichlorohydins with PAGs and certain HNBRs with CFC-12/mineral oil, but by-in-large, it appears that most other materials existing in CFC-12 systems (with the exception of Viton) can withstand retrofitting to HFC-134a.

Rubber hoses: Available literature suggests that HFC-134a permeates through rubber hoses up to 50% faster than does CFC-12.

Desiccants: The total available information suggests that, while replacing the desiccant with new HFC-134a compatible material is preferred, using the XH-5 material will not lead to catastrophic results.

Hobbs, Arthur, 1993: Supply, distribution, and availability of mobile air conditioning parts

for retrofit of CFC-12 systems to HFC-134a. Paper presented at the 1993 International

CFC and Halon Alternatives Conference, 20-22 October 1993, Washington, D.C., U.S.A. pp. 304-311

In the last four years, Four Seasons has retrofitted its own vehicle fleet. Testing of this fleet is continuous with very favorable results.

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Conclusions

The service technicians must be trained to understand that each vehicle will perform differently. Refrigerant charge, condenser size, and air flow will play an important role in a successful retrofit.

Rolotti, Gustavo; Brubaker, Michael, 1993: Experience in retrofitting CFC-12 auto air

conditioning systems with Forane HFC-134a: a system performance perspective. Paper

presented at the 1993 International CFC and Halon Alternatives Conference, 20-22 October 1993, Washington, D.C., U.S.A. pp. 275-284

This paper provides a case history examination of the experience of retrofitting a group of 17 factory installed vehicles from CFC-12 to Forane HFC-134a. Vehicles used in this test represented a cross section of model years, system types, domestic and foreign makers, compressor types etc.

Benefits

Most drivers seem to be satisfied with their system's performance after the retrofit. No short term compressor failures were encountered. There seems to be no difference between the performance of the systems in the flushed vs. the non-flushed groups. No Forane HFC-134a chemical degradation has been detected during the 5 month duration of this test.

Observation

A simplified oil flushing procedure could be utilized that does not require excessive labour.

Changing to HFC-134a has been mainly based on demands from the automotive engineering sector for a substitute with pressure limits and thermodynamic properties comparable to CFC-12.

There is no clear choice of lubricant for retrofit purposes, both PAGs and esters are being evaluated and recommended. Both lubricant types are considerably more hygroscopic than mineral oil, and should therefore be handled more carefully. PAG lubricants are claimed to have better miscibility with remaining mineral oil in the system.

Problems:

A number of changes are necessary.

Change of lubricant necessary. Two possible lubricant types have been identified, namely

POEs and PAGs.

Change of desiccant material. This is due to the smaller size of the HFC-134a molecule

and chemical compatibility problems with conventional CFC-12 drier materials.

Replacement of hoses. Permeation rates through conventional CFC-12 hoses (e.g. based

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with polyamide (nylon) barrier material have been developed, which reduce permeation considerably.

Change to elastomer seal materials that are compatible with HFC-134a and lubricant.This

depends on recommendations of car manufacturer.

Replacement or adjustment of high pressure cut-out switch. As high-side pressures are

generally somewhat higher with HFC-134a than with CFC-12, a higher set-point is required.

Replacement or adjustment of expansion valve. (optional). In systems with thermostatic

expansion valve, the static superheat setting should be increased.

Zurer, Pamela S., 1993: Looming ban on production of CFCs, halons spurs switch to

substitutes. From Chemical and Engineering News, 15 Nov 1993, pp. 12-18

About 140 million cars with CFC-12 systems are on the road in the U.S. today. In 1991, the auto industry estimated retrofitting costs would range from $200 to $1200 per car, depending on the make, model, and year. Besides removing the CFC-12, which is incompatible with HFC-134a, it was thought that hoses, O-rings, the lubricant, and, in some cases, even the compressors would have to be replaced. But after a few years of experience with retrofitted vehicles, it appears the high end of the cost range may have been overestimated.

Costs

Volvo has already started supplying its dealers with retrofitting kits. "We are pricing the kits low to encourage customers to take the environmentally beneficial option" of retrofitting, said Richard Reina of Volvo Cars of North America's regulation and compliance office. Volvo set the suggested retail price of the required parts at $45. Adding the approximately $21 charge for 2 lb of HFC-134a and another estimated $200 for labour, the total charge comes to less than $300.

Benefits

In many cases, fewer modifications to the original air-conditioning systems will have to be made than were originally feared. For example, it was originally thought that rubber hoses would have to be replaced, according to Thomas W. Dekleva, ICI's North American technical service manager, but in fact, they work very well, and in some cases, HFC-134a leaked less. The lubricant has a big effect on reducing leakage.

Conclusion

Dekleva said that most of the air conditioners on ICI's test cars performed just about as well with HFC-134a as with CFC-12. He found it especially telling that none of the vehicles' owners took ICI up in its offer to convert their cars back to CFC-12 at the end of the trial.

Case study from John Bresnahan, of ICI Australia Operations Pty Ltd, in response to UNEP IE/PAC retrofitting query.

Conversion using KLEA-134a

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Conclusion

After two years, 100 vehicles show acceptable performance for the majority of owners and conditions.

Benefits

Existing CFC-12 hoses do not need to be replaced if they are working adequately on CFC-12. This significantly reduces conversion cost for the motorist.

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1992

Bateman, D., 1992: New refrigerants for MAC. Paper presented at the Asia-Singapore conference on the phasing out of ozone depleting substances, 5-7 October 1992, Singapore. For comparison with MP52, see summary under Bateman, D.: 1992, under the heading of "SUVA MP52" below.

Benefits

Provides cooling properties similar to CFC-12. To optimism the performance of HFC-134a in new a/c systems, many components need to be redesigned: lubricants, compressor, desiccant, hoses, evaporator, and condenser. These hurdles have been overcome due to significant development effort by the vehicle, component and chemical manufacturers, and a worldwide transition to HFC-134a systems in new vehicles has begun.

Problems

HFC-134a is not compatible with mineral oil, and there is debate as to the necessity of flushing of old system to remove the mineral oil. PAG lubricants have been chosen for the first commercial vehicles using HFC-134a. Lubricant development will continue and there is likely to be an evolution to second generation lubricants in the mid to late 1990s.

Conclusion:

DuPont believes there are two viable options: HFC-134a and SUVA MP52. Neither is a drop-in replacement and both will require some retrofit. ... We believe in many situations that MP52 will be the lower cost option while providing customer satisfaction. In many other cases, retrofit cost of MP52 will be similar to HFC-134a.

Dekleva, T.W., et. al., 1992: Retrofitting MAC systems with HFC-134a - an update. Paper presented at the 1992 International CFC and Halon Alternatives Conference, Sept 29 -Oct 1, 1992, Washington, USA. pp. 697-705

In continuing fleet trials and laboratory testing, HFC-134a combined with ester lubricants appear to offer acceptable levels of performance and systems compatibility.

Problem

Previous work has shown what HFC-134a may be expected to permeate more from both rubber and nylon lined hoses than does CFC-12, at similar temperatures. This permeation can be reduced by the presence of synthetic lubricants

McNeal Morris, James: 1992: Ozone depletion and the automobile aircon industry. Paper presented at the Asia-Singapore Conference on the Phasing Out of Ozone Depleting Substances, 5-7 October 1992, Singapore.

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No problem has been experienced with the use of HFC-134a in our compressors as a retrofit refrigerant for CFC-12 ( with a limited amount of vehicle testing complete).

Mineral oils need to be changed to a lubricant compatible with HFC-134a. Work being done by ICI and Sanden in using an ICI ester oil as a drop-in lubricant with HFC-134a, offers significant advantages to the service industry. At present, ester oil seem to be a better lubricant than PAG oil, because they mix well with HFC-134a, and appear to be miscible with existing mineral oils. Japanese manufacturers do not advise using blends so we will go direct to HFC-134a for retrofitting.

Roke, Lindsey, 1992: Report from the Technical Options Committee on Refrigeration. Paper presented at the Asia-Pacific conference on the phasing out of ozone depleting substances, 5-7 October 1992, Singapore

Australia is notable for automotive air conditioning conversions where they are finding that it is generally proving little more difficult to apply HFC-134a than to apply ternary blends. In both cases barrier hoses are highly desirable if not essential to cut emission losses. Note though, that many cars being built today are already fitted with such barrier hoses even though they are still using CFC-12. This certainly appears to be a good move by the automobile manufacturers. HFC-134a has a slightly lower critical temperature than CFC-12, and each conversion has to be evaluated on its own merit. In other words it is a system-specific conversion.

Problems

Capillary blocking: It is necessary to make sure that contaminants are not on the system, as they are liable to deposit towards the end of the capillary and reduce flow by some 15-20%. The technique for handling this problem is to make sure that there is no contamination in the system.It is essential to keep moisture levels to the minimum.

SUVA MP52 retrofit for CFC-12

Bateman, D., 1992: New refrigerants for MAC. Paper presented at the Asia-Singapore conference on the phasing out of ozone depleting substances, 5-7 October 1992, Singapore. This is a 3 component blend, containing HCFC-22, HFC-152a, HCFC-124.

Benefits

Good environmental properties. DuPont has selected a mixture of mineral oil with alkylbenzene lubricant, eliminating the need to flush the system, as laboratory tests have confirmed that alkylbenzene and the MP52 are compatible with residual CFC-12 and mineral oil. MP52 is not flammable. Provides cooling properties similar to CFC-12.

Conclusion:

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replacement and both will require some retrofit. ... We believe in many situations that MP52 will be the lower cost option while providing customer satisfaction. In many other cases, retrofit cost of MP52 will be similar to HFC-134a.

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Blends retrofit for CFC-12 1994

George H. Goble: Some Safety Studies of a Ternary Refrigerant. Paper presented at the 1994 International Refrigeration Conference at the Purdue University, USA in July 1994. The paper presents the blend HCFC-22/600a/HCFC-142b as a drop-in replacement refrigerant both for CFC-12 and for R-500. The paper covers safety related issues, testing performed to date, and results of fractionation and flammability testing. The blend is recommended by ASHRAE SPC-34 to be classified in the lowest toxicity group and as a non-flammable refrigerant (A1/A2). If the blend is fractionated and leaks, some compositions may be "weakly" flammable. The flammability is still less, the lower and upper ingnition limits is higher and the heat of combustion is lower than for the highly flammable and explosive refrigerants (e.g. propane/butane). R-406a has been used in automobiles, semi trucks, vending machines, ice machines etc. There have been several cases of hoses burning in mobile A/C, due to mechanical defects or related problems, but no reports of problems related to flammability.

1993

There is considerable reluctancy in the industry to move toward retrofit solutions based on refrigerants other than HFC-134a. Mixtures based on HCFC-22/HFC-152a/HFC-124 have been proposed as retrofit blends although:

Problems

Differences in hose permeation rates probably will lead to loss of the HCFC component over some time (preferential leak). Retrofit will require change of desiccant, and maybe also of lubricant to alkylbenzene.

Experience

1. In the US, a number of blends or chemicals claimed to replace CFC-12 have been produced. Behind such names as "GHG", "Alaska Cool" and "Arctic Chill" , which are claimed to be safe CFC-12 substitutes, one may find combinations of HCFC-22, HCFC-142b, HFC-152a, R-176, isobutane and even CFC-12. Some of these compounds will destroy the existing CFC-12 desiccant which may lead to clogging of the expansion device, and some are flammable or explosive. If systems containing such blends are brought to a workshop for service or repair, there is considerable risk of contaminating recycling equipment and of spreading these compounds to other vehicles through containers, etc.

2. Results from a fleet retrofit study by ICI in Australia and the USA are reported. Vehicles range in age from 1985-models to 1992-models, and ten different types of compressors and varying expansion valves/orifice tubes are included. All systems are based on ester lubricant after retrofit. Preliminary results are good, indicating essentially equivalent capacity and no

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particular problems of operation. Long term effects remain to be investigated.

1992

George H. Goble: A Drop-in CFC-12 Replacement for Automotive Airconditioning. Paper presented at the 1992 International Refrigeration Conference on Energy Efficiency and New Refrigerants at the Purdue University, USA in July 1992.

The paper presents the blend H22/600a/H142b as a transition fluid, to replace CFC-12 in automotive air conditioners. The blend has the composition 55/8/37 (later developed into R-406, with the composition 55/4/41), and ODP = 0.057. It is compatible with mineral oil. The blend is tested in 150 vehicles with only one failure, and the failure was not due to refrigerant change. Due to the content of isobutane, the blend is miscible with mineral oil. The air delivery is colder than for CFC-12. The condensing temperature is higher than with CFC-12, but not high enough for refrigerant-oil breakdown. The paper discusses testing of silane-based dessicant and sealant additives to reduce leakages, and reviews flammability for the blend and for the compound of the blend after leakage. The paper suggest that the blend can customized for hot climates.

Personal communication 1994

Personal communication from REFAC Consultants (February 1994)

Recent trials have demonstrated that successful retrofits can be achieved with a minimum of component changes and little system cleaning. I understand that the original view that retrofit required almost complete removal of the existing mineral oil has now been shown to be an unnecessarily conservative one. This is important in reducing the time, and hence cost of retrofit. ICI has conducted extensive vehicle fleet trials which support the above conclusions. Personal communication from DuPont (January 1994)

The Australian government has undertaken a significant automotive air conditioning retrofit effort using DuPont's MP 52 blend and are very satisfied with the results. Singapore has undertaken the task of retrofitting all of their taxi air conditioning units with the MP 52 blend; again with excellent results. These retrofits, using blends, have cost about $200 U.S./vehicle and performance problems or equipment failures have not been detected. While UNEP and member companies are trying to insure that there will not be shortages of CFC-12 in developing countries, it should be recognized that logistics of supply and specific volumes have not been worked out and some supply disruption should be expected.

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CENTRIFUGAL CHILLERS

Report of the Refrigeration, Air Conditioning and Heat Pumps Technical Options Committee. Nairobi: UNEP.

Centrifugal chillers are designed for specific refrigerants. Direct refrigerant substitutes can only be made in cases where the properties of the substitute refrigerant are nearly the same as those of the refrigerant for which the equipment was designed.

HCFC-123 retrofit for CFC-11 Benefits

HCFC-123 became available in 1989 for retrofit into existing CFC-11 chillers. Problems

It is a more aggressive solvent than CFC-11. Non-metallic materials may have to be replaced with materials which are more compatible with HCFC-123. Materials used in the motors of older hermetic chillers may not be compatible with HCFC-123, putting motor reliability at risk or requiring motor replacement. The dielectric strength of HCFC-123 is much lower than that of CFC-11 raising questions about viability with some high voltage motors. System capacity may be reduced by between 0 and 20% depending on the matching of the compressor to the load and heat exchanger effectiveness.

Preliminary results from toxicology tests for HCFC-123 obtained in mid-1991, led to recommendations that exposure of personnel to HCFC-124 in an 8 or 12 hour workday be limited to a 10ppm (or lower) time weighed average concentration. This means that machinery rooms for HFC-123 chillers must be equipped with sensitive detectors, adequate ventilation systems, and means to alert operators in the event of a significant leak or spill. These precautions have not been taken in the past for CFC chiller. ASHRAE Standard 15R now requires similar precautions for CFCs and HCFCs as well. Changeout of the compressor to a higher-capacity model or purchase of additional chillers may be necessary. Cycle efficiency will be reduced by at least 1-2%

HCFC-141b retrofit for CFC-11

HCFC-141b has more or less the same properties as HCFC-123 and could be used as a replacement candidate for CFC-11 as well.

HCFC-134a retrofit for CFC-12 Benefits

Available since 1991 for retrofit in centrifugal chillers. Problems

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Its use requires higher tip speeds than CFC-12, so impeller and/or gearbox replacementä is necessary. Typically, oils used for CFC-12 are not miscible with HFC-134a. PAG oils developed for HFC-134a are not compatible with CFC-12 residues, thus requiring thorough flushing of the systems before replacement. Ester oils seem to have overcome this problem. Some desiccants (e.g. activated alumina) commonly used in CFC-12 systems are not compatible with HFC-134a.

HCFC-124 retrofit for CFC-114

This has been suggested as an alternative to CFC-114 in centrifugal chillers such as those used in naval applications. It is not readily available for use in either new or retrofit chillers. (1991) Problems

HCFC-124 requires operation at higher pressure levels, higher compressor speeds, and smaller impeller diameters than CFC-114. HCFC-124 is not suitable for use in existing systems in most cases because the pressure levels will exceed design ratings and complete compressors replacement is necessary.

HFC-152a/HCFC-124/HCFC-22 mixture for CFC-12 Benefits

It is compatible with conventional refrigeration oils. Problems

It is not readily available because HCFC-124 is not in large production. The mixture is likely to have degraded heat transfer performance in the flooded evaporators and shell side condensation normally used in centrifugal chillers. Thus there is likely to be a significant performance penalty when substituted in existing chillers. Servicing such a system brings on new difficulties because any vapour losses will change composition and performance. Measuring and changing equipment are not available to mitigate this problem.

HCFC-22/HCFC-142b mixture retrofit for CFC-12 This azeotropic mixture is being used in France to retrofit systems using CFC-12. Benefits

Both components of the mixture are available commercially. The mixture is not flammable to the proportions used to emulate CFC-12 (but flammable proportions can be encountered as a result of spills or losses).

An updated version of this document will be available November 1994.

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1993

The compatibility of HCFC-123 with construction materials must be considered. For large centrifugal chillers, it may be necessary to replace compressor impellers/gears to ensure the required performance is maintained.

Benefits

It is currently the only available candidate to replace CFC-11 in existing centrifugal chillers. Current lubricants used with CFC-11 are fully miscible at all operating conditions, and it is not necessary to switch to another lubricant.

Problem

HCFC-123 is a strong solvent toward plastics and elastomers and selling and weight change may occur. Thus it is necessary to change O-rings, and other parts made of plastics or elastomers, with parts qualified by manufacturers for use with HCFC-124.

Yan Zu Qing, 1993: Research on the application of HCFC-123 as an alternative of CFC-11

in centrifugal chillers. Paper presented at the International Conference on CFC and

Halon Alternatives, 20-23 April, 1993, Beijing, China. pp. 382-387 Benefits

Most of the constructive materials in the chiller are compatible with both CFC-11 and HCFC-123, although neoprene O-rings, rubber gaskets and certain insulating materials of motor will be deteriorated by HCFC-123 due to its strong solvent nature. Non-combustible.

Problems

Refrigerating cycle efficiency is lowered 2-5%. Capacity decreased by 10-15% on average. Performance curve of the compressor becomes steeper and surging more often with HCFC-123 if used directly as an alternative. Additional requirements necessary for the machine room.

1992

March Consulting Group, 1992: CFCs in the UK refrigeration and air conditioning

industries: usage and the scope for substitution: a study for the Department of the Envi-ronment carried out by March Consulting Group. United Kingdom.

HCFC-123 can be considered a retrofit fluid. Problems

There may be a need to change the impeller of the compressor, its speed of rotation and in some cases the electric motor. Indications from the PAFT toxicity testing programme gives some doubt about R-123 as benign tumours have been identified in rats subject to high doses. Some

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manufacturers are worried about using R-123.

Siebert, Bruce, 1992: Factors in converting centrifugal chillers to HCFC-123. Paper presented at the 1992 International CFC and Halon Alternatives Conference, Sept 29-Oct 1, 1992, Washington, USA. pp. 271-275

Benefits

Only 2% the ODP of CFC-11

Problems

2-5% less efficient than CFC-11. Because of greater mass of HCFC-123, there isä a reduction in the capacity of chillers designed for CFC-11 of 5-20%. Entire system mustä be reviewed before conversion. including such factors as age of equipment, maintenance history, con-sideration of replacing components.

Arnaud, D., 1993: An example of successful retrofit with HFC-134a in the industrial field. Paper presented at the 1993 International CFC and Halon Alternatives Conference, 20-22 October 1993, Washington, D.C., U.S.A. pp. 193-202

This paper discusses a successful retrofit of a CFC-12 centrifugal compressor system to HFC-134a. The project was a cooperative operation involving cooperation among Elf Atochem, York France, and Elf Lubricants. The experiment was done on one of the three centrifugal compressors used in the chlorine liquefaction process stream at Jarrie (France) and one from Elf Atochem's biggest electrolysis reactor. The retrofit was done in 6 main steps:

1. Installation evaluation and achievement of baseline determination with CFC-12 (4 days) 2. Purging and flushing of original mineral oil (1 week)

3. Replacement of the compressor shaft seal (1 day) 4. Recovery of CFC-12 charge.

5. Charging with HFC-134a (2 days) 6. Validation with HFC-134a (5 days) Benefits

More economical than buying a new HFC-134a centrifugal machine. Conclusion:

A viable a low cost HFC-134a retrofitting technology has been developed and tested with success on an industrial CFC-12 centrifugal compressor.

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The retrofitting was made almost one year ago and has demonstrated the durability of existing CFC-12 equipment at a very low acceptable cost.

Personal communication Personal Communication from DuPont (January 1994)

DuPont has worked with all of the major chiller manufacturers and developed a plan to totally displace CFCs from its 560 industrial and process chillers. This family of chillers represents a wide range of sizes and includes CFC-11, CFC-12, CFC-113, CFC-114, and R-500 (CFC-12/HFC-152a) units. While some old or obsolete have had to be replaced, most have been retrofitted. The entire programme will cost about 90 million US dollars vs. an estimated replacement cost of 1-2 billion US dollars if all units had been replaced. Therefore, the retrofit is running below 10% of the installed cost of new units. Efficiency and capacity changes have been seen in both direction; some positive and some negative. Chiller retrofits must be looked at on an individual basis but the industry is becoming very proficient at the retrofit technique for all of the units made by international equipment producers.

Personal communication from REFAC Consultants (February 1994)

The vast majority of CFC-12 centrifugal chillers can be retrofitted to HFC-134a, irrespective of age. Post 1989 CFC-11 chillers from the manufacturers in the developed countries are "HCFC-123 retrofit ready". For pre-1989 chillers, open drive machines can be fairly easily retrofitted, hermetic systems generally require conversion to open drive which is a major modification rather than a "retrofit" and will not be economic for older machines. If thereä is spare capacity the retrofit of a CFC-12 chiller can be relatively simple with only minor engineering changes. To achieve a similar capacity to the existing CFC-12 duty more expensive gearbox changes are involved. It is then very difficult to give any general figure for retrofit costs and any attempt to provide one by reference to an individual project is likely to be misleading.

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COLD STORAGE AND FOOD PROCESSING

1994

Malek, A., CETIM, 1994: Preliminary considerations on retrofitting a cold storage to

non-CFC fluids. Paper presented at the 1994 IIR International Conference for New

Applications of Natural Working Fluids in Refrigeration and Air Conditioning, May 10-13, 1994, Hannover, Germany. The study has been prepared on consultation with UNEP IE/PAC OzonAction Programme.

HCFC-22, HFC-134a, and ammonia are compared as alternative refrigerants to CFC-12 in cold storage. The refrigerants are compared with regard to thermodynamic and physical properties, coefficients of performance, components (modifications necessary), material compatibility, toxicity and safety considerations.

Ammonia has a great advantage of high thermal and thermodynamic performances, in addition to being a natural fluid. Specific analysis of each particular case must be performed before a retrofitting fluid is definitely selected.

1993

HFC-134a is an alternative refrigerant to CFC-12 in cold storage. Studies show from 1% less to 7% higher energy consumption than CFC-12. Problem of finding suitable lubricants. HFC-134a has very low solubility and mineral oil does not mix well in HFC-HFC-134a, which could contribute to the following problems:

poor oil return back to the compressor, resulting in possible compressor failure

fouling of expansion valves and heat exchanger surfaces, leading to reduced system performance

Shaw, D.A, T. Chadderton, R.M.Kemp, Meat Industry Research Institute of New Zealand: Retrofitting R12 and R502 Refrigeration Systems with Non-CFC Refrigerants. Paper presented in proceedings from commissions B1, B2, D1, D2/3, Cold Chain Refrigeration Equipment by design, 15 - 18 November 1993.

The paper presents a case study of retrofitting of a small walk-in meat chiller which has been converted from CFC-12/mineral oil to HFC-134a/syntetic ester lubricant. It also describes how a retrofit from R-502 to HFC azeotrope blend (AZ50) is going to take place. Eight months after the HFC-134a retrofit, almost half of the refrigerant had leaked fromä the system, but no major leaks could be found. The lost charge was replaced and the servicing procedure upgraded. Otherwise, no major component failures have occured and the equipment has been operating satisfactory for 10 months. The CFC-12 to HFC-134a retrofit gave the following results:

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It may be possible to reduce the mineral oil content to 1% in only two flushes for a wide variety of systems.

The time between oil changes may be spread out over a prolonged period if necessary, so that hte retrofit can work in around existing production schedules.

Filter-dryers may need to be replaced at more regular intervals than for CFC-12, to prevent the build-up of moisture in the system.

Refrigerant leakage should be reduced by improving the integrity of the refrigeration system.

Chadderton, T. & Kemp, R.: Drop-In Alternatives for CFC Refrigeration Systems. Meat Industry Research Institute of New Zealand. 1993.

CFC usage in the food industry has been investigated, and an international database of literature on CFC alternatives has been set up. Drop-in alternatives for CFC-12 and R-502 have been investigated. Ternary blends are investigated. The blends are zeotropic, and with leaks the composition may change. It is therefore essential with a good maintenance practise to minimize the problem.

CFC-12 alternatives:

HCFC-22. Are prefered for "familiar" reasons. Results in high discharge pressure and temperature. Considerable expenses.

HFC-134a. New lubricant has been developed. Special retrofit procedures has to be followed, including flushing of the system to get the mineral oil content down to less than 1 %. Capacity loss of appr. 10 % compared to original CFC-12 system. HFC-134a involves significant time an cost, and should only be considered for systems in good condition. MP39, a ternary blend. "Virtual" drop-in refrigerant.

R-502 alternatives:

69L, a ternary blend. Claimed to be a "straight" drop-in, only minor changes are necessary. Oil change is not required. Capacity increase of 2 - 7 %, and also increase in COP compared to R-502.

HP80, a low-temperature ternary blend. Similar performance properties as R-502. Special retrofit procedures has to be followed, including flushing of the system.

1992

Corr, S., Gregson, R. D., Tompsett, G., ICI Chemicals and Polymers Ltd.: Retrofitting

large refrigeration systems with R-134a. Paper presented at the 1992 International

Refrigeration Conference - Energy Efficiency and New Refrigerants. 14 - 17 July 1992, Purdue University, USA.

Case Story: Retrofit of a food processing refrigeration system with R-134a. One of two identical machines with separate primary refrigerant circuits and a common second refrigerant circuit, located in a refrigerated chocolate storage area, was retrofitted. The system was retrofitted

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according to ICI's retrofit procedures. The lubricant was changedä to ester oil with a viscosity to match ISO VG68 mineral oil saturated with CFC-12. To ensure that all traces of CFC-12 and other contaminants was removed, the system was evacuated with the triple evacuation method: system was repeatedly evacuated to a pressure of 1 mm Hg absolute or lower. COP-measurements showed a slight increase.

Isceons 69-S and 69-L.

Isceon HFC-134a was identified some years ago, as ideal non-flammable, zero-ODP replacement for CFC-12. Immiscible with mineral oils traditionally used with CFC-12. PAGs were used, but revealed an inherent and significant problem, namely high hygroscopicity. Improved lubrication and better handling characteristics achieved with use of synthetic polyol ester based materials.

Isceon 69-S and 69-L was jointly developed as CFC-free drop-in alternatives to R-502. They are non-flammable, although containing a flammable, and near-azeotropic. No hardware changes of any description are required in a retrofit employing ISCEON 69-S an 69-L. Refrigeration capacity and energy efficiency increases slightly (COP increases appr. 6-8 %), discharge temperature slightly decreasing.

Rhône-Poulenc chemicals, March 1992: Isceons 69-S and Isceons 69-L - Case Studies. The paper presents successful case studies of retrofitting from R-502 in cold storage and commercial with Isceon 69-S and 69-L.

Isceon 69-S in cold stores, eg. with the patented Star Refrigeration low pressure receiver system. Same (or slightly better) capacity and efficiency as a identical unit with R-502, no problems with lubrication or oil return. Low temperature cold storage,

Isceon 69-L is used as retrofit refrigerant in a number of supermarkets, eg. using 4 x 20 HP four cylinder Bitzer compressors. No hardware changes necessary. Isceon 69-L was chosen because of high discharge temperature in the unit. Isceon 69-L is also used in a Maneurop GLT 28 compressor at frozen food display cases at fish market, low temperature air cooled system. Isceon 69-L offers up to 6-7% improved energy efficiency and refrigeration capacity.

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COMMERCIAL REFRIGERATION

1994

Allied Signals Chemicals. Refrigeration Report, An Update from Allied Signal on the

Progress of Environmentally Acceptable Fluorocarbon Alternatives, page 2 & 3: Texas Supermarket Preparing for Future with Allied Signal's Genetron AZ-50. January 1994.

Allied Signal and Copeland are working together, to ensure optimum system performance when retrofitting from R-502 to AZ-50, an azeotropic mixture of HFC-125/HFC-143a. The article describes a conversion of a supermarket from R-502 to AZ-50. The existing equipment, a Copeland 15 hp Discus 4D compressor, was cooling 32 feet of low-temperature, frozen-food® display case. The equipment was checked for proper operation before the conversion; expansion-valve superheat, head pressure and oil pressure, suction pressure and temperature, discharge pressure, compressor amperage, voltage, and ambient temperature.

No major modification was done with the equipment. The mineral oil was replaced with polyol ester-based lubricant. To reach the maximum remaining mineral oil content, five percent, the lubricant was changed three times, with 72 hours operation time between each change. Discharge pressure is about 20 psi higher with AZ-50 than with R-502, no other significant changes occurs. Future retrofits of similar systems are estimated to cost approximately US $ 1,500.

1993

HFC-134a is an alternative refrigerant to CFC-12 in cold storage. Studies show from 1% less to 7% higher energy consumption than CFC-12. Problem of finding suitable lubricants. HFC-134a has very low solubility and mineral oil does not mix well in HFC-HFC-134a, which could contribute to the following problems:

poor oil return back to the compressor, resulting in possible compressor failure

fouling of expansion valves and heat exchanger surfaces, leading to reduced system performance

Lawson, C. Curtis, DuPont Fluorochemicals: Alternative Refrigerants for Retrofit of

Existing CFC-12 and R-502 Commercial Refrigeration Systems. Presented at the

Inter-national Conference on CFC and Halon Alternatives, Beijing, P.R.C, April 20-23, 1993. The paper provides an overview of the alternative refrigerant candidate from DuPont, and discuss retrofit procedures and equipment retrofit experiences with alternatives for servicing existing CFC-12 and R-502 refrigeration equipment. Over 5000 super markets and restaurants has been converted successfully into DuPont's alternative refrigerants.

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CFC-12:

MP39 for medium temperature stationary equipment, down to -23°C. Comparable capacity. Alkylbenzene lubricant.

MP66 for low temperature, below -23°C (and as replacement for R-500 in medium temperature applications). Comparable capacity. Alkylbenzene lubricant.

MP52 for automotive air conditioning systems.

HFC-134a. Requires more extensive system preparation and equipment modifications than the blends. Lower capacity, might require a bigger compressor for low temperature systems. Polyol ester lubricant required, two-three oil flushes.

R-502

HP80 Comparable capacity and discharge temperature, preferable when high discharge temperature might be a problem. Alkylbenzene lubricant. Polyol ester can also be used, but require two-three oil flushes.

HP81 Slightly higher efficiency. Alkylbenzene lubricant. Polyol ester can also be used, but require two-three oil flushes.

HP62, longterm alternative (does not contain HCFC). Requires more extensive system preparation. Slightly lower capacity and slightly higher compressor ratio at low tem-perature, may require a bigger compressor. Polyol ester lubricant required, two-three oil flushes.

Conversion Retrofit Step

1. Establish base line data with CFC-12 or R-502

2. Remove CFC-12 or R-502 from system into recovery cylinder 3. Drain mineral oil

4. Charge system with approved lubricant 5. Replace filter drier

6. Evacuate the system

7. Charge with alternative refrigerant 8. Start up system and optimize charge

The CFC File, (New Zealand) Issue 1, July 1993 Benefits

R-134a is the best option for CFC-12 systems. DuPont's SUVA MP39 is another alternative, albeit interim because it contains HCFC-22. The price of HFC-134a has fallen by around 50% since the beginning of 1992, and should continue to fall as world-wide production increases. The price of CFCs is increasing world-wide, with CFC-12 doubling in price since January 1992.

1992

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Isceon HFC-134a was identified some years ago, as ideal non-flammable, zero-ODP replacement for CFC-12. Immiscible with mineral oils traditionally used with CFC-12. PAGs were used, but revealed an inherent and significant problem, namely high hygroscopicity. Improved lubrication and better handling characteristics achieved with use of synthetic polyol ester based materials.

Isceon 69-S and 69-L was jointly developed as CFC-free drop-in alternatives to R-502. They are non-flammable, although containing a flammable, and near-azeotropic. no hardware changes of any description are required in a retrofit employing ISCEON 69-S an 69-L. Refrigeration capacity and energy efficiency increases slightly (COP increases appr. 6-8 %), discharge temperature slightly decreasing.

Rhône-Poulenc chemicals, March 1992: Isceon 69-S and Isceon 69-L - Case Studies. The paper presents successful case studies of retrofitting from R-502 in cold storage and commercial with Isceon 69-S and 69-L.

Isceon 69-S in cold stores, eg. with the patented Star Refrigeration low pressure receiver system. Same (or slightly better) capacity and efficiency as a identical unit with R-502, no problems with lubrication or oil return. Low temperature cold storage,

Isceon 69-L is used as retrofit refrigerant in a number of supermarkets, eg. using 4 x 20 HP four cylinder Bitzer compressors. No hardware changes necessary. Isceon 69-L was chosen because of high discharge temperature in the unit. Isceon 69-L is also used in a Maneurop GLT 28 compressor at frozen food display cases at fish market, low temperature air cooled system. Isceon 69-L offers up to 6-7% improved energy efficiency and refrigeration capacity.

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RETROFIT IN GENERAL

1993

Heap, R.D., A.R. Lawton, Cambridge Refrigeration Technology, United Kingdom:

Retrofitting to Alternative Refrigerant - How Effective is it? Paper presented in

pro-ceedings from commissions B1, B2, D1, D2/3, Cold Chain Refrigeration Equipment by design, 15 - 18 November 1993.

The paper discussed retrofits of CFC-12 and R-502 systems with HFC-134a and blends. Several clip-on container refrigeration units has been retrofitted from CFC-12 to HFC-134a, and the lubricant used is polyolester-based. R-502 refrigeration tower units are retrofitted to HCFC-69S. The paper concludes that retrofitting to alternative refrigerants is effective and worth while, but for some equipment there can be refrigeration capacity losses at ISO rating conditions which are unacceptable in some applications. For such equipment, machinery modifications may be necessary. In retrofitted containers, the advantages of a single refrigerant, HFC-134a for both new and retrofitted equipment will outweigh the benefits of tailored blends for particular applications in most cases. For other transport-related systems using CFC-502, blends provide a good solution. In this application, the global warming effects of likely refrigerant loss are negligible compared with the effects due to the associated power generation.

Transport Refrigeration

Fleck, J. G., Blue Star Line (NZ) Ltd: Field Experience with Container Refrigeration Units

Retrofitted with Alternative Refrigerant and Synthetic Oil. Paper presented in proceedings

from commissions B1, B2, D1, D2/3, Cold Chain Refrigeration Equipment by design, 15 -18 November 1993.

20 marine clip on units designed for refrigeration Port Hole Containers has been observed in a research program on retrofitting to HFC-134a and polyol ester lubricant. The units had identical design, 10 were 5 years old and 10 were 3 years old. Half of the units were then retrofitted, and the rest were serviced and had an oil and dryer change. The units were observed for 12 months, to detect differences in operation, air delivery temperature, failures etc. The results showed that good, well designed, generously proportioned systems, having compressors with good volumetric efficiency and positive displacement lub oil systems can be retrofilled with some confidence. Losses in refrigeration capacity can be expected in existing plants, but these can be minimized by carefull consideration and tesing prior to the conversion and checking of the performance of the system components. The evaporator and compressorcapacities appear to restict HFC-134a at low evaporating temperatures, and it is also advisable to check the gas velocities in the piping system.

Personal Communication from Morten Skjennem, Thermo King, Norway. Thermo King, Norway has converted several units for road transport to ODS-free refrigerants. All Thermo Kings refrigeration units was previously using alkylbenzene lubricants. It is

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important to follow the retrofit procedures.

247 low temperature units retrofitted from R-502 to 69L.

Evaporation temperature down to appr. -29°C. No lubrication change was necessary. Customers claim that energy requirement has decreased. There seems to be less compressor failures with retrofitted units than with R-502-units.

7 medium temperature units retrofitted from CFC-12 to HFC-134a.

Evaporation temperature down to appr. -0°C. Lubricant changed to polyol esteroil. 2 units retrofitted from HFC-134a to 69 L.

The retrofitting was done in order to increase the refrigeration capacity in the low tem-perature range. Lubricant changed to alcylbenzen lubricant.

Due to less expensive retrofitting, Thermo King is also preparing for retrofitting from CFC-12 to MP66 for old equipment.

RETROFITTING WITH NON-CFC SUBSTITUTES