Tesot refrigeration

R22 replacement made easy

John Poole of Refrigerant Solutions offers an application-based approach to replacing R22.
R22 replacement made easy
AS EVERYONE will be aware, in less than 12 months time it will be unlawful to top up systems with virgin R22 (even if purchased before the end of 2009), which also means that stocks of R22 also cannot be used to keep equipment running beyond the end of this year. Only recovered R22 will be permitted for sale and use after this date.

What to do, then, to replace R22 in such a short time frame? The scale of the problem is little short of daunting with many thousands of systems currently operating on R22. This unique refrigerant remains the most widely used gas in the acr industry today, with over an estimated 100,000 tonnes in use in Europe.

During the transition away from CFCs to HFCs, retrofitting directly from a CFC (eg R502) to a HFC (eg R404A) was found to be both costly and in many cases technically unsatisfactory.

The oil in the system needed to be replaced by a synthetic lubricant, which in some cases was not practical, and there were many cases of a deleterious effect on the seals.

This is the reason why interim refrigerants were introduced to replace CFCs without the requirement to change the oil or change any of the hardware. These transitional substances contained at least one HCFC component in the blend which facilitated oil return and enabled plant and equipment to be time expired.

Clearly, any replacement for R22 must be non ozone depleting which rules out this type of compound.

HFCs, such as R407C, are not soluble in mineral and alkyl benzene lubricants and new synthetic oils have been developed. These new lubricants pick up moisture rapidly which can cause severe problems if not properly controlled and are considerably more expensive than the traditional oils.

Having learnt from the experiences with replacing CFCs and the problems incurred with retrofitting directly to HFCs, Refrigerant Solutions (RSL) started work on replacements for R22 which could be used with the existing lubricant in the system, provide a similar performance to R22 and of ,course, have a zero ODP.

In finding the best match for R22, RSL, based on its knowledge of existing R22 applications, selected condenser pressure, energy efficiency and compressor volumetric capacity as the major thermo-physical design criteria.

Early in the development it was recognised that these criteria could reasonably be matched with those of R22 using potentially acceptable blends, but that no single blend or fluid could be formulated to mirror the performance of R22 across the range of applications at both medium to high and low temperatures where R22 is commonly found.

After considerable research work, RSL decided to develop three products to match R22 in its main applications.
RS-44 (R424A)
RS-44 is a direct drop-in replacement for R22 in ac applications in systems with a capillary as well as an expansion device. There is no need to change the lubricant since, as with all the RS series of refrigerants, RS-44 is compatible with mineral, alkyl benzene and POE oils. RS-44 has been designated an ASHRAE number of R424A with an A1 classification.

A testing programme showed that, compared to R22, RS-44 had a higher COP, lower head pressures, lower discharge temperatures and pressures, a similar performance and good oil return with all types of oils including both traditional and the new synthetic lubricants.The lower discharge temperatures experienced with using RS-44 provides significant operating benefits.

Trials with RS-44 have shown energy savings from 10 to 20% compared to R22 when RS-44 is retrofitted into the same system while achieving similar capacity.

RS-45 (R434A)

RS-45 is a potential option for OEMs and can also be used to replace R22 across the range of applications and temperatures including ac and low temperature refrigeration.

RS-45 is a capacity match for R22 but should not be used in systems with a capillary. RS-45 replaces R22 at both higher temperatures and lower temperature applications where an expansion device is present.

RS-45 is a near azeotropic blend with a glide of 1.5°C, one third that of R407C, which facilitates its use across a wide temperature range and provides significant benefits in the case of flooded systems. RS-45 has a COP which matches R22, similar discharge pressure to R22, identical compression ratio, is non flammable (ASHRAE safety classification of A1) and a considerably lower discharge temperature than R22 which provides significant operating benefits including a much lower risk of oil degradation.

RS-52 (R428A)

RS-52 is similar to R507 in its performance with high capacity at low temperatures. RS-52 has been designed as a replacement for R502 and the interim ozone depleting blends (eg R402A, R403B, R408A and R411B), but is also an excellent replacement for R22 at low temperatures where the system is designed to withstand R502 pressures.

The high capacity of RS-52 at low temperatures is a prominent feature of this new refrigerant. RS-52 has a temperature glide of less than 1°C, and is also suitable for use in flooded systems.

Refrigerant Solutions Ltd
0161 926 9876
1 March 2009


A . Syamala
02 January 2017 07:09:06
Dear sir/mam I have an air-conditioning test rig with refrigerant R22 . But for my project work I want to change the refrigerant without any modifications in the existing system hardware.can you please suggest the best alternative for that which is available in India . During our search we have found some like R407c and R410A but some are saying that to use those modifications are required for expansion valve.so a little bit confused regarding that.could you please suggest . thank you
Godfrey Lubega
06 November 2016 09:50:03

 Please assist me with the best replacement of R22a gas with out  altering of the existing system. We have several LG, Samusang, Balton etc air conditioners ranging from 18,000 to 49,500 Btu/h capacities? What is the probable one?

01 November 2016 04:13:51

421a is hands down the best alternative on the market. No system modifications and almost identical pressures and temps to R22

Carl Smith
20 September 2016 03:35:06

I am basically retired but as anyone in the industry knows you can never really retire unless it's in a pine box. With R-22 now out I'm getting mixed signals on the best replacement. My old Supplier is suggesting R407C which has it's drawbacks in oil compatibility.This same problem? was raised in the transition from R11 to 134 and I know hundreds of cases of no oil change -no problem. My supplier does not handle R424A and I don't want to take a chance on an unknown(to me)  My specific case is 60k condenser to coil with TXV . I have a small leak that I have used the pretty red bubble detector and my Infinity sniffer and cannot find the leak. Whats the prospect of Cliplight or NuCalgon sealants using any of the 400 refrigerants? total system charge is about 7-8 lbs and it lost 4 lbs in two years. I guess my insecurity stems from no experience in the newer refrigerants. I am way old school, started this in 65. 

Gary Hupfer
13 August 2016 17:35:58

I need to replace an expansion valve in a small R22 refrigerant system, 1-2 lbs capacity. The compressor is brand new, just replaced by another contractor. I have already recovered the refrigerant in the system, but I don't know if it R22 or if it was replaced with something else. I am waiting on the valve which by the way, has a capillary tube and thermo bulb, but I need to know what would be the easyist readily accessible replacement refrigerant to recharge with. I need to have this done by wednesday. Can you help me?

Ansis Dimiters
13 July 2016 15:22:19

Dear sir


i have an air conditioning unit which has R22 Gas due to this gas not available in the market which gas would you recommend as a replacement. 

28 April 2016 13:29:42

Well, I would like to share here the best alternate or drop in replacement for R22a refrigerant, It's an EPA approved product as well as available in half of the price this product available in. So buy R424a refrigerant and save money.

06 March 2016 21:41:51

please clariffy the best out of best refrigerant to used for the replacement of r22 without ant changes to the the system

mahmoud ali
17 February 2016 17:46:33

 we used R22 in our vcm plant to condense HCL gases and we want to phase out this ref. because of Montreal protocols .

 How you can help us ? 

18 August 2015 08:21:59

Thanks for shared great information about r22 replacement refrigerant. I would like to also share with you one great that in USA market available r22 replacement called r424a refrigerant. This product main benefit is, its an EPA approved product and half price of r22. So purchased it and save money.

By Nitin N Mhatre
01 March 2009 00:01:00
Please intimate me which is the best replacement of R22 without modification of existing system ?
Is valve seals are required to be replaced ? is this practical as no details of seals available
some says use R417 a and others say use R-407c with oil change ?
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