Performance Improvement of a Heat Pump Assisted Solar Water Heating System

Abstract

Details of a heat pump assisted solar water heating system, is briefly described. Refrigerants compromising of Fluorocarbons and Chlorofluorocarbons have been generally used as the working fluid. But due to its ozone depletion effect and high Global warming potential, they have been replaced by synthetic refrigerants such as R22, R134 etc. The heat pump utilizing such refrigerants has shown to attain efficiencies (COP) of the order only about 2 to 3. In this paper an attempt has been made to find out the reasons for such low efficiencies and the possibility of using CO2 (R744) as the working fluid in heat pump assisted solar water heating systems. CO2 is one of the few natural refrigerants which is neither flammable and nor toxic. It is commonly obtainable and does not affect the global environment like other refrigerants. A few changes to be made in the experimental set up to improve the performance of the heat pump are discussed.