Report: Daimler, BMW, VW, Porsche and Audi to develop CO2 MAC systems
08 March 2013
R744.com. The German Press Agency (dpa) reported that Daimler, Audi, BMW, Porsche and VW will develop CO2-based mobile air conditioning (MAC) systems as an alternative to using R1234yf. (Earlier post.)
In September 2012, Daimler announced that based on internal testing, it would would not use the low global warming potential (GWP) refrigerant R-1234yf in its products (earlier post) due to safety concerns and that it wanted to continue using the current R134a after 1 January 2013—the date at which European regulations required the shift to a MAC solution with a GWP of less than 150. Daimler was subsequently joined by BMW, VW, Porsche and Audi.
R134a has a GWP of 1,300; R1234yf of 4; and R744 (CO2) of 1.
In response to Daimler, SAE International convened a fourth International Cooperative Research Project (CRP1234-4) team to review relevant research and testing to finalize the risk assessment of the use of the low global warming potential R1234yf in mobile air conditioning systems. In February 2013, SAE reported that as the CRP team continues to review relevant research and testing to finalize the risk assessment, the high level of confidence that R1234yf can be used safely in automotive applications continues to grow. (Earlier post.)
According to the dpa report, Daimler regards the technical challenges for developing MAC systems for high-pressure CO2 technology to be “manageable”.
In 2007, the German Association of the Automotive Industry (Verband der Automobilindustrie, VDA) came out in support of CO2 (R-744) as the choice for the next-generation low GWP refrigerant. Subsequently, the European industry shifted to R1234yf.
Resources
R1234yf – A new, safe and environmentally friendly refrigerant for mobile air conditioning (VDA presentation, 17 Sep 2012)
At long last. CO2 in non-toxic, non-flammable and its global warming effect is trivial compared to the hydrocarbons that it replaces as a coolant. Only drawback is that it needs higher pressure compressors that are more expensive than those currently used. However, for safety and environmental reasons future refrigeration systems should all be required to use CO2.
Posted by: Account Deleted | 08 March 2013 at 04:32 AM
R134a GWP is 1,300; R1234yf is 4; and R744 (CO2) is 1.
The GWP for CO2 is not significantly different than R1234yf.
But the CO2 working pressure of 1000 to 3000 will increase cost and decrease reliability.
Sounds like a perfect fit for the MBs and VWs I have owned.
Posted by: ToppaTom | 09 March 2013 at 08:13 AM