Effects of Sub-Cooling on the Performance of R12 Alternatives in a Domestic ‎Refrigeration

Abstract

This paper presents experimental results of investigation of effects of sub-cooling on the ‎performance of four ozone-friendly alternative refrigerants (R32, R152a, R143a, and R134a) in ‎a domestic refrigeration system. The study was performed using a system designed for R12 with ‎the aim of finding drop-in replacement for the refrigerant. The results obtained showed that the ‎sub-cooler in the refrigeration system positively affected the system performance and all the ‎investigated refrigerants benefited from the performance improvement. Increase in sub-cooling ‎effectiveness reduces the compressor work input and increases the system refrigeration capacity. ‎Also, increase in the degree of sub-cooling, reduces the pressure ratio, and increases both the ‎refrigerant mass flow rate and coefficient of performance (COP) of the system. The comparison ‎of the performance of R12 and the investigated alternative refrigerants showed that R152a and ‎R134a have the most similar performance characteristics to R12, with R152a having a slightly ‎better performance. These two refrigerants are the best replacement for R12 in domestic ‎refrigeration system. The performances of R32 and R143a were significantly lower than that of ‎R12‎