The Frankfurter Rundschau reports that the Volkswagen Group has ordered mobile air conditioning (MAC) systems using CO2 (R744) as the refrigerant from a Japanese supplier for application in the VW Phaeton and the Audi A8. The Volkswagen Group and Daimler are both looking to CO2 as an alternate low global warming potential coolant to R-1234yf, to which Daimler originally objected in 2012, citing safety concerns. (Earlier post.)
In March 2013, the Volkswagen Group announced that it was choosing CO2 as the future low global warming potential (GWP) refrigerant for its mobile air conditioning (MAC) systems. (Earlier post.)
In response to the Frankfurter Rundschau report, Volkswagen Group said that it stood by its earlier announcement of gradually equipping its fleet with CO2 refrigerant, which is its long-term preferred refrigerant.
CO2 is an A1 refrigerant, indicating minimal toxicity and non-flammability. With its GWP of 1, it is also the refrigerant that has the least impact on climate. It has a high cooling capacity and is available worldwide at low cost in the required qualities.
Germany’s Federal Environment Agency (Umweltbundesamt, UBA) took the position in the late 2000s that the high global warming potential refrigerant R134a should be replaced by the natural refrigerant R744. However, R744 systems operate at pressures 5 to 10 times higher than R134a systems, necessitating development of high-pressure hoses, compressors and other components. This raises issues of cost, as well of durability.
Under current EU regulations, automakers have until 1 January 2017 to transition from R134a. So far, R-1234yf has the support of most automakers.