Drop-in replacements enable users to replace CFC and HCFC refrigerants with minimum inconvenience and cost while not losing out on performance
AS THE ban on HCFCs grows ever closer the need to think about contingency plans for the replacement of HCFC-based equipment grows ever more pressing. A ban on new equipment running on HCFCs is already with us and, under EU regulations, there will be a ban on the use of virgin HCFCs for servicing from January 1, 2010 and a ban on the use of all HCFCs, including recycled materials, from January 1, 2015.

However, there is an alternative to expensive plant replacement. There are now a number of zero-ODP drop-in replacements on the market.

The RS series of refrigerants from Refrigerant Solutions Ltd (RSL) comprises a series of zero-ODP drop-in replacements for both HCFCs and CFCs. These new products aim to enable users of ODS to change out their systems to non-ozone-depleting replacements with minimum inconvenience and cost while not losing out on performance across the range of applications that are common in the refrigeration and air conditioning industries.

All of the RS refrigerants are non-ozone-depleting, non-flammable, drop-in replacements for CFCs and HCFCs which can be used with the existing oil in the systems, and there is no need to make any changes to the hardware. They can also be used with existing traditional lubricants, such as mineral and alkylbenzene oils.

R424A

RS-44, now with the ASHRAE number R424A, is designed to replace R22 in air conditioning equipment. It can be used in systems with a capillary as well as an expansion device.

Following extensive tests, RSL claims that RS-44 demonstrated a higher COP compared to R22, 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.

Trials with RS-44 have shown energy savings ranging from 10% to 20% compared to R22 when RS-44 is retrofitted into the same system while achieving similar capacity. Companies which have converted away from R22 to RS-44 are said to include Cable & Wireless in the UK, and Loblaws supermarket in Canada.

OEM replacement

RS-45 is a potential option for OEMs and can also be used to replace R22 across the range of applications and temperatures in both air conditioning and low temperature refrigeration. In common with all the RS range of refrigerants, RS-45 can be used with the traditional as well as the new synthetic lubricants.

RS-45 is a capacity match for R22 but should not be used in systems with a capillary. RS-45 replaces R22 at higher temperatures and is said to be particularly effective at lower temperatures where an expansion device is present. With its low glide (less than half that of R407C), RS-45 is said to provide significant benefits in the case of flooded systems.

CFC replacements

While the use of CFCs was banned in Europe from the end of 2000, RSL says there is still a market for zero-ODP drop-in replacements. In the case of R12, the HFC R134a was the natural replacement and is generally well accepted particularly in the automobile industry for air conditioning of vehicles. However, retrofitting existing equipment from R12 to R134a, which involves cleaning out the mineral oil and replacing with a synthetic lubricant, is a time consuming and costly operation. There are interim blended refrigerants which help to avoid this process but these largely contain R22 and will, therefore, be phased out along with R22 under the new European Regulation. In addition, such blends containing R22 are unsuitable for use in mobile air conditioning applications because of leakage through the hoses and for this reason are not recommended by the manufacturers.

RS-24 is a zero-ODP drop-in replacement for R12 which is compatible with all types of lubricants. RS-24 is suitable for all applications where R12 has been used including automotive air conditioning, cellar cooling, transport refrigeration, domestic refrigerators, cold stores, dairy chillers, vending machines, hermetic and semi hermetic systems. According to RSL, RS-24 provides excellent oil return, has a comparatively low atmospheric lifetime and has a higher capacity than both R12 and R134a.

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.

RS-44, RS-45 and RS-52 all have considerably lower discharge temperatures than R22.

A-Gas

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