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Sustainable car A/C discussed in Japan |
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Discussions over the choice of refrigerant for mobile air conditioning and related technical challenges pursued this week at a specialized symposium in Tokyo, Japan. Improving modeling and the vehicle’s cabin comfort took, however, a more prominent role.
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2008-01-31
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Over 300 Japanese and international experts discussed the biggest challenges affecting mobile air conditioning systems at the JSAE event in Tokyo, on 29 and 30 January 2008. With the Title “Review of Automotive Air-Conditioning 2008 – For a More Comfortable Cabin and Global Environment”, the event gave some clues of how the industry might solve current technical & environmental barriers.
Several presentations thus dealt with ways of improving passenger’s comfort through air conditioning, and simulation models to improve the systems. The key issue of the choice of refrigerant emerged once again during discussions, ahead of the next VDA Wintermeeting on Alternative Refrigerants in Austria in mid-February. Comparisons between R744, R152a and HFO-1234yf took place, with presentations from European, American and Japanese experts.
R744, R152a or HFO-1234yf?
Opening the second day of the conference, Stephen O. Andersen, from EPA, referred to the background of refrigerant’s choice, with increasing concern for climate change: “The world has changed... and there is no going back. We need to reduce both direct and indirect emissions from mobile air conditioning sources”. He insisted on the need for one global solution as the best way to ensure emissions reductions.
Andersen confirmed that both R152a and R744 are very close to obtain final approval under the SNAP process in the USA (Significant New Alternatives Policy program), which would allow their use in the North American Market. At the same time, the SNAP approval process for HFO-1234yf has recently been initiated. For this refrigerant, he explained, the option of a secondary loop is being considered by the industry to ensure safety.
Honeywell and DuPont, on their turn, made a joint presentation about HFO-1234yf. While the companies showed that promising testing by car manufacturers is underway regarding toxicity and performance, the main focus was on the refrigerant’s flammability. No further details were disclosed concerning costs or the volume produced so far for testing purposes.
The chemical companies also explained that they are planning the steps to comply with new EU regulation on chemicals (REACH). A pre-registration of the substance is planned by December 2008, while full Registration would be done in December 2010, one month before the entry into force of the ban on R134a. Registration under REACH is needed for the refrigerant to be allowed in the European market.
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R744 life-cycle and future improvement
Representatives from JAMA (Japan Automobile Manufacturers Association) presented a comparison between different refrigerants under a life-cycle approach. A debate followed over the data for CO2-based systems (R744) in the analysis, which differed from other presentations.
Concerning updates on R744 technology, Obrist Engineering focused on the potential to further reduce indirect emissions by optimizing the system.
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The company referred to different options to combine efficiently an R744 air conditioning with a heating unit. Options would be to integrate a heat pump or a hot gas system. On the other hand, to increase the performance at high temperature conditions and improve overall efficiency, Obrist recommended introducing either an ejector system or a compressor expander. Combining different measures could result in an overall 10% reduction of the total vehicle emissions, according to the company.
Marc Chasserot, from Shecco, presented new details for the next version of R744.com, due April 2008. New services will include a technical forum, R744 wiki, job platform and user-generated news.
Other technical challenges
Simulation tools also played an important role in the Tokyo Symposium. In cooperation with the Japanese Supplier Calsonic Kans, the company LMS presented a Thermal Management simulation of three different CO2-based systems. The presentation showed advantages of using a single platform to exchange and connect models in order to do an interaction analysis. This, according to LMS, can help improve the overall system’s efficiency,
Other presentations during the event included:
- Heat Transfer Enhancement in Heat Exchangers
- Thermal regulation for increased comfort in vehicles’ cabin
- Air Quality & ventilation
Background
The Symposium “Review of Automotive Air-Conditioning 2008 – For a More Comfortable Cabin and Global Environment”, took place on 29-30 January in Tokyo, Japan. Organized by the Society of Automotive Engineers from Japan (JSAE), the event helps Japanese and international professional explore the latest challenges and innovations on mobile air conditioning systems.
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More information:
 JSAE Conference Program
› Read the article: "R744, R152a and HFO-1234yf – Torino update", 4 Dec 2007
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