Thermodynamic Performance Analysis of Hydrocarbon Based Domestic Refrigeration System

Abstract

The use of synthesized refrigerants has several environmental concerns. The most widely used substances like hydro fluorocarbons (HFCs), chlorofluorocarbons (CFCs) and hydro chlorofluorocarbons (HCFCs) have either high global warming potential (GWP), high ozone depletion potential (ODP) or long atmospheric life time. With the growing demand of healthier atmosphere, the study of other alternative substances is very important. This paper presents theoretical thermodynamic performance analysis of hydrocarbon based domestic vapour compression refrigeration system. Propane (R-290), isobutane (R-600a) and butane (R-600) were used. Then, the results were compared with the performance of currently most commonly used tetrafluoroethane (R-134a). These hydrocarbons have zero ODP and very negligible GWP. Different parameters, like coefficient of performance (COP), refrigeration effect, compressor work input and compressor discharge temperature were investigated. Evaporator and condenser temperatures, subcooling, superheating and compressor isentropic efficiency were the variables used for this study. MATLAB software has been used in the mathematical analysis. COP values were found comparable to that of R134a. All the hydrocarbons investigated gave beyond 150% refrigeration effect compared to R-134a for the same mass flow rate. But this was at the expense of higher compressor work input. This research also revealed that the compressor discharge temperature is much lower for R-600a and R-600. Generally, these hydrocarbons showed that they are a good alternative to R134a based on the thermodynamic point of view.