TECHNOLOGY OPTIONS FOR CFC USAGE IN REFRIGERATION SYSTEM

Abstract

With the awareness to safeguard the environment from the refrigerants which cause the depletion of ozone level in the stratosphere_ region and leads to global warming of the atmosphere, has motivated the refrigeration s-c' enti s'ts-and - engineers to consider various technology options for CFC's usage in 'refrigeration systems. Evolution of alternate refrigerants to replace some of the commonly used environmentally unacceptable refrigerants is one of the options, considered here. The present work aims to study an azeotropic mixture of R22(36%), R -152a(24%) and R - 124(40%) as probable refrigerant to replace R-12 in the existing refrigeration units. The thermodynamic behaviour of the mixture has been analysed by the vapour pressure data of Didion and Bivens. The vapour pressure data has been plotted on LnP-1/T diagram and a pressure temperature correlations has been formulated. Detailed thermodynamic properties of the ternary mixture has been established over a wide range of temperature and pressure, extending the method developed for binary mixture by Agarwal to the ternary mixture. The method employs 'the Redlich-kwong equation of states, the properties, viz., the enthalpy, entropy and the specific volume of saturated liquid, vapour and superheated vapour have been computed, the pressure-enthalpy diagram for the mixture has been plotted. Using the evaluated data of mixture the pressure-enthalpy diagram of the proposed azeotropic mixture has been developed. Vapour compression cycle analysis has been carried out to determine the performance of the system using the proposed azeotropic mixture and the R-12. Finally canparative performance of the two refrigerants have been reported. (