Performance Evaluation of Hydrofluorocarbon and Hydrocarbon Vapour Compression Refrigeration Systems: A Novel Experimental Approach

Retrofitting is found to be an economical approach while switching from HFC to eco-friendly HC refrigerants, without replacing the existing HFC compressor based vapour compression refrigeration system (VCRS). The present work presents the performance comparison of R134a and R600a refrigerants used in HFC compressor based VCRS and also compared with R600a used in HC compressor based VCRS. The results revealed that for optimum working of the retrofitted VCRS, about 43% less mass charge of R600a was required than R134a refrigerant. The R600a mass charge was further reduced to about 10% more when used in the HC compressor based VCRS. The compressor inlet and outlet characteristics such as pressure and temperature were reduced on using R600a in both, retrofitted and the HC compressor based VCRS. The R600a improved the refrigeration effect by about 6% in the retrofitted system and it became about 1.27 times in HC compressor based VCRS, as compared to R134a. Additionally, R600a also offered a power saving advantage of about 5% in the retrofitted system which improved to about 9% in HC compressor based VCRS. The coefficient of performance (COP) was enhanced using R600a, by more than 11% and 26% in retrofitted and a system with HC compressor instead of an HFC compressor, respectively. As compared to R134a filled HFC compressor based VCRS, the pull-down temperature in the retrofitted system and both temperature and time were reduced for R600a filled HC compressor based VCRS. All these factors support the adoption of R600a refrigerant in HC compressor based VCRS.