Daimler, Audi, BMW, Porsche and VW to develop CO2 MAC systems - Third time lucky?

By Janaina Topley Lira, Mar 07, 2013, 13:06 3 minute reading

After a clear commitment in 2007 to use CO2 as the refrigerant in mobile air conditioning (MAC), reconfirmed in 2008, and followed by a subsequent preference for the chemical refrigerant 1234yf, Daimler, backed by four leading carmakers has taken yet another U-turn, announcing the further development of CO2 technology as a “sustainable and safe solution”. The group has the support of German automotive association VDA.

As reported by the German Press Agency dpa and reflected in leading German media sources such as Handelsblatt, Spiegel, Stern, ntv and FOCUS, five German carmakers have announced that they will drive the development of CO2 (R744) technology in MAC systems. However, out of the manufacturers’ group, only Daimler R&D development chief Thomas Weber is quoted as saying “We are delighted that we were able to agree on this sustainable and safe solution together with Audi, BMW, Porsche and Volkswagen, with the involvement of the VDA.”
 
Daimler regards the technical challenges for developing MAC systems for high-pressure CO2 technology to be “manageable”. In Geneva Weber told journalists that for safety reasons 1234yf, so far favoured by the automotive industry, would not be considered an alternative and “for this reason we have clearly tasked our engineers to develop a CO2 MAC system.”

The announcement is the latest twist in a story that has attracted widespread public attention in Germany and beyond, following Daimler’s findings in September 2012 that the chemical refrigerant R1234yf is unsafe for use in its cars. Discussions since Daimler’s announcement have centred around questions regarding the flammability and toxicity of 1234yf, its potential harm to passengers and rescue personnel, and its potential impact on ecosystems and the atmosphere. German Federal Environmental Agency UBA, as well as leading researchers from Germany and Switzerland, and automotive clubs like ADAC, have all disputed the viability of 1234yf and/or openly backed CO2 refrigerant as the only long term viable and safe alternative in MAC systems.
 
Third time lucky?

Daimler’s announcement, made public during the Geneva Motor Show on Wednesday, is the 3rd confirmation concerning the development of CO2 MAC systems made in the last 6 years. The first VDA statement in favour of R744 was released in September 2007, reconfirmed in October 2008. In 2009, German carmakers turned away from CO2 to choose a chemical refrigerant that had only been tested to a lesser extent. Then, in September 2012, it was confirmed by real-life tests performed by Daimler that the synthetic substance 1234yf is flammable under various accident scenarios and component configurations in different car models. While other carmakers back 1234yf, Daimler announced that it would not use the flammable gas due to the release of toxic HF, considered a serious risk for the health of passengers and any persons near a burning car. Instead, CO2 has resurfaced as a safe refrigerant, although it remains a technologically challenging solution that requires further development time.
 
Now that four other leading German manufacturers are backing Daimler’s decision, closing ranks, this raises the question of how reliable yesterday’s announcement really is. MAC suppliers ready to provide components and complete R744 systems back in 2008/2009 had stalled most developments on these systems after the VDA members shifted away from CO2 towards 1234yf. Over the years, R744.com has reported extensively about the subject. 
One media source reporting from Geneva now states that Daimler will award a contract to one MAC system supplier for R744 technology. 
 
In the coming days R744.com will publish a series of follow-up articles on this issue. 

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By Janaina Topley Lira

Mar 07, 2013, 13:06




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