Performance Analysis of R12 Alternatives in Adiabatic Capillary Tube of a Vapour Compression Refrigeration System

Abstract

In this work, the performance of alternative refrigerants in adiabatic capillary tube was investigated experimentally in a vapour compression refrigeration system. The mass flow rate was determined at a series of condensing temperatures, degree of sub-cooling and at various lengths of capillary tube. The average mass flow rate of R152a and R134a were 1.2% lower and 1.9% higher than that of R12 respectively, at the same operating conditions. The coefficient of performance (COP) obtained using R134a and R152a refrigerants were very close to that of R12 with only 2.6% and 1.3% reduction respectively, while the COPs obtained using R23, R32 and R143a were significantly very low. The performance obtained in a refrigeration system differs among individual selected alternative refrigerants. The differences are larger for R143a, R32 and R23, and the deviation from the performance of R12 is in that order, while the differences are smaller or negligible for R134a and R152a. The best overall performance is obtained using R152a