Experimental Investigation of Condensation of Refrigerants R134a and R12 in Air Cooled Horizontal Condenser

Abstract

With the phasing out of ozone depleting refrigerants under the Montreal protocol 1987 researches on alternatives to new refrigerants (HFC’s) and (HC ’s) are made to replace refrigerants (CFC) and (HCFC) in air-conditioning and cooling systems that destroy the ozone layer . Most of the refrigerating systems specially the domestic units replaces R12 by R134a, this study make a comparison of performance between the two cycles specially in the condenser where the main difference between R12 and R134a, while in the evaporating where the pressure of the refrigerant determines the evaporator temperature and therefore the cooling capacity of the system ,the two refrigerants are close in behavior. In this study, the experimental results of heat rejected at condenser, coefficient of performance, the experimental condensing heat transfer coefficients of R12 and R134a, in a horizontal copper finned tube with an outer diameter of 10mm are presented at different mass fluxes ,and different ambient air temperatures during condensation under annular flow . A correlation has been developed from the data obtained, the refrigerant side heat transfer coefficients obtained from experimental study is different by 5%-12% from that computed from the correlations developed by Shah , cited in [ 1,2].