ASHRAE approves Daikin refrigerant as R474A
A new Daikin refrigerant announced last year as a more efficient alternative to R1234yf in electric vehicles has been designated as R474A by ASHRAE and given an A2L classification.
The new gas was developed to reduce the energy draw of the heating and cooling systems in electric vehicles and thus improve the vehicles’ range. It blends R1234yf with 23% of a new hydrofluoro-olefin refrigerant HFO1132(E), which ASHRAE has now also separately approved and designated R1132(E) with a B2 safety rating. It is said to possess a GWP below 1.
Unlike conventional internal combustion engined vehicles, in winter electric vehicles cannot use the engine waste heat for heating the interior and must draw the power from the battery. Previous research has shown that the capacity of a R1234yf vehicle heat pump system reduces by up to 40% when the ambient temperature drops from 0℃ to -10℃. This is recognised as a significant problem in colder climates by motor manufacturers.
Initial tests are said to have shown that the refrigerant provides good performance for heat pump function in electric vehicles in cold regions and good cooling performance in warm climates.
Daikin holds a number of patents on R1132(E), for both its production and its application in a variety of different blends, including R474A.
HFO1132(E) is one of three possible forms, or isomers, of the chemical difluoroethylene. All possess the same chemical composition, but are differentiated by their arrangement of atoms. The others are HFO1132(Z) and R1132a, a refrigerant recently registered with ASHRAE by Koura.