CO2 in automotive A/C systems - the refrigerant of the future?

For some time now, the use of naturally occurring substances as refrigerants in automotive A/C systems has been under debate. With carbon dioxide, a substitute is available whose direct global warming potential is negligible in comparison with the ozone-friendly R134a today in use. At BEHR GmbH & Co., suitable prototype components as well as a complete system have been developed and tried out on a testbench and in the vehicle. This allowed the competitiveness of the CO2 automotive A/C system to be demonstrated against today's standard R134a-based A/C systems. In part, it even proved possible to attain better performance figures. Not only direct reduction of the global warming potential by using CO2, but also economy in operation and uprating of the maximum performance, as and when required, provide benefits for final customers. Nevertheless, before its launch onto the market, some technical problems remain to be solved, at the same time ensuring that the system as a whole stays competitive within the constraints of the cost-to-benefit ratio.