CO2 heat pump systems

After the CFCs and the HCFCs were deemed unfit as working fluids in refrigeration, air conditioning, and heat pump applications, there has been a renaissance for carbon dioxide technology. Heat pumps is one of the application areas where theoretical and experimental investigations are now performed by an increasing number of research institutions and manufacturers. This paper gives an overview of some of the current activities in the CO, heat pump field. Discussed are the important characteristics of the transcritical CO, process applied to heat pumps, and also discussed are theoretical and experimental results from several heat pump applications. Provided that calculations and system designs are performed on the premises of the working fluid, and that test plants are constructed and operated to fully exploit the specific characteristics of both the fluid and the tran critical process, the results show that CO, is an attractive alternative to the synthetic fluids. Competitive products may be launched in the near future. (C) 2002 Elsevier Science Ltd and IIR. All rights reserved.