REFRIGERANTS
s tep reduction, the slower-than-expected move away from R404A in 2015 and 2016 has led to pressure on other refrigerants.
The car ac market, as required by the MAC directive, stopped using R134a in new vehicles from the beginning of 2017 and can now o nly use a refrigerant with a GWP below 150. R1234yf is now the refrigerant of choice for new vehicles. Older cars still require R134a for service requirements. However, the stationary market has continued to use R134a in new equipment without change.
Despite compressor and equipment approvals f or R513A, R450A, R1234yf and R1234ze which all have much lower GWP than R134a, many end users have chosen to go with R134a for new equipment that is expected to last for the next 15-25 years. As with R404A, the choice to remain with what has been used before may prove costly i n the long run. This is because a retrofi t may be required in the future as the F-Gas phase-down steps, every three years, impact upon the amount of CO 2 eq tonnes that can be placed on the market. The slower the market moves in general to lower GWP refrigerants for new equipment, the greater the pressure on the basket of refrigerants being used.
Emerson, Bitzer, Danfoss, Embraco, Tecumseh and others all have compressors approved for R134a alternatives, whilst chiller manufacturers such as Trane, Carrier, Airedale and Johnson C ontrols all have approved lower GWP options to R 134a.
For new equipment, always check what the equipment manufacturers have approved for their components as this can also be a useful g uide for existing systems, although the choice h ere is between R513A and R450A. Both are n on-flammable with a GWP which is less than h alf of that of R134a. R513A is an azeotropic blend of R1234yf and R134a, whilst R450A is a near azeotropic blend of R-1234ze and R134a. Guidance for retrofitting R134a to either R513A or R 450A can be found in the producers own retrofi g uidelines, or the compressor manufacturer b ulletins on converting systems with their compressors. They note that R513A has similar capacity and effi ciency to R134a, whilst R450A has slightly better effi ciency but lower capacity. Discharge temperatures of R450A and R513A a re similar or marginally lower than R134a, which could result in a slightly larger operating window. R513A has a higher mass flow rate than s flow rate,
R134a, whilst R450A has a lower mass fl fl
but both should stay within the normal range o f a properly sized expansion device. For both r efrigerants, valve superheat settings should be set to 8-10K. All conversion guidelines recommend having access to PT charts or
c omparator information when doing a conversion. Whilst the same POE oil as used with R134a can be used, it is prudent to do an oil change to re- f resh the oil and change the filter drier. Old seals m ay also need changing if degraded.
Prior to a conversion, always try to attain some baseline data for R134a, so that a comparison can be made.
For new equipment, the compressor and own retrofitfi
equipment manufacturer guidelines and selection data should be used. R513A, R450A, R1234yf and R1234ze all off er much lower GWP solutions to R134a and the choice of any of these options is much more sustainable than R134a under the F-Gas phase-down steps.
With the producers pushing up the price of R 134a to such an extent that R513A, R-450A and R 1234ze are all much cheaper, it gives an added incentive to move away from R134a much faster. If the market remains slow to move away from R134a, then we can expect prices of R134a to keep rising.
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