USA: With R1234yf still being shunned by some German car manufacturers as the replacement refrigerant for R134a in car air conditioning systems, the engineers group SAE has been assessing two other potential alternatives. The two low GWP blended refrigerants, both developed by Mexichem, meet the requirements of the EU MAC Directive.
Operating, technical and safety assessments carried out by SAE International's MAC Refrigerant Blend Cooperative Research Programme (MRB CRP), has found the risk profile of the two blends to be equal to or better than R1234yf.

The blends are based on R-1234ze(E) with additional refrigerants that are all currently in production. AC5 is a mixture of R32, R152a and R1234ze(E) and AC6 is a mixture of CO2, R134a and R1234ze(E).

At a meeting of the MRB CRP held last month in Detroit, the team reviewed the progress of this work and decided there was a need to share information relevant to the public discussion about low GWP refrigerants for MAC applications.

Specifically the MRB CRP wants to ensure that information that it has generated regarding the performance, flammability and risk assessment of these low GWP blended refrigerants is available to be included in the important discussion regarding replacement of MAC system refrigerant. Based on a detailed fault tree analysis AC6 offers a risk profile that is equal to or better than that of R1234yf in all significant respects. AC5 is said to be comparable to R1234yf

Companies involved in the research were Behr, Bosch, Chrysler, Cinetic Filling, Daimler, Denso, Doowan, General Motors Company, Halla Visteon Climate Control, Hyundai, Jaguar Land Rover, Mexichem, Nissan, PSA, Renault, SAIC Motors, Sanden, Schrader International, Texa and Volvo Cars.