Investigation of the effect of superheating on the performance of a refrigeration system using low temperature different refrigerant blends in porous media

Abstract

A comparative experimental investigation on the effect of superheating of R‐22, R‐404A, R‐407C, and R‐422A as low‐temperature refrigerant blends on the performance of a vapor compression refrigeration system is conducted. Empty and porous evaporators with porosities of (40%, 43%, and 45%) are used during the tests, to predict good alternatives to the refrigerant R‐22, which has high ozone depletion potential and high global warming potential. Condensation, evaporation temperatures, degree of subcool are kept constants at 40°C, −26°C, and 6°C (±0.5°C), respectively. The effect of superheating on the compressor discharge temperature, evaporating pressure drop, evaporating capacity, volumetric refrigeration capacity and coefficient of performance (COP) of these refrigerants has been analyzed. Refrigerants, R‐422A and R‐404A showed greater performances than that of R‐22. The percentages of increase in evaporation capacities of R‐407c, R‐22, R‐404A, and R‐422A are approximately 144%, 168%, 146.3%, and 161.5%, respectively, when changing the degrees of superheat from 6°C to 16°C and changing the porosity from empty evaporator to 40%. The percentages of increase in COP are approximately 319%, 320%, 312%, and 350%, respectively. The percentages of increase in evaporation capacities of R‐422A and R‐404A when compared with R‐22 under the same conditions are 18.6% and 8.8%, respectively, while the percentages of increase in COP when compared with R‐22 are 17% and 12%, respectively.