Retrofitting of a r-12 based domestic refrigerator to run on r-134a

Abstract

The possibility of operating a domestic vapour compression refrigerator system by replacing its existing Chloro-Fluro-Carbon (CFC, or R-12, or Freon-12) refrigerant with the Ozone friendly new refrigerant R- 134a has been investigated. A safe and convenient procedure of recovering the existing CFC based refrigerant whose Ozone Depletion Potential (ODP) and Global Warming Potential (GDP) indices are very high, is presented. A simple, safe and cost effective procedure of preparing the system in terms of only a change in the capillary length and recharging the new refrigerant R134a along with the compatible lubricant have been established. Separate tests have been carried out with the CFC based refrigerant and with R134a charged to the vapour compression refrigerator respectively without making any changes to the system components. Results of these two have been used a base case in comparing the performance indices and operating parameters. Subsequently, comparison of the performance indices and operating parameters have been made by conducting tests with R134a, for 25%, 30% and 35% increments of the capillary tube length. Tests have been conducted and for three thermostat settings and out without thermally loading the refrigerator.