USA: DuPont is trialling a new lower GWP refrigerant blend as possible “drop-in” replacement for R404A in transport refrigeration systems.

R404A has been the preferred refrigerant for commercial refrigeration due is its low compressor discharge temperature but is coming under increasing pressure for bans and phase-outs due to its high GWP of 3943.

RW_Advert2Several lower GWP options have been proposed, based on blends of HFCs and HFOs, but these have all exhibited higher discharge temperatures and in some applications will require external compressor cooling. One such blend with higher discharge temperature is DuPont’s DR33. Now designated R449A, DR33 has a GWP of just 1282 but there is a need for a refrigerant that more closely matches the discharge temperature of R404A in applications such as transport refrigeration.

13609938_lDuPont’s new refrigerant R452A, aka XP44 and DR34, is described as a non-flammable blend that closely matches the properties and performance of R404A, including a similarly low compressor discharge temperature. It is considered particularly suitable for transport refrigeration where compressor cooling is difficult to manage under a wide range of ambient conditions.

With a GWP of 2140, it might not be considered a low GWP gas but at virtually half the GWP of R404A it would have considerable environmental appeal as a drop-in alternative.

R452A is said to have good miscibility with POE lubricant and test results are said to have shown no significant loss of cooling capacity or increase of input power compared to R404A. Compressor discharge temperatures are only slightly higher.

It comprises R32, R125 and R1234yf.

Further tests are now to be conducted looking at the thermodynamics and heat transfer properties of the blend, including its use with different types and models of compressors and systems.

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