INTRODUCTION

The vapour compression refrigeration system is based upon the fact that fluids absorb heat while changing from a liquid phase to vapour phase and reject heat while changing from a vapour phase to a liquid phase. The temperature during the phase change remains constant. However, the temperature varies with the pressure and the fluid. In vapour compression system, the refrigerant condenses and evaporates at temperatures and pressures close to the atmospheric conditions. The closed refrigeration cycle is used in which refrigerant does not leave the system. The refrigerant alternately condenses and evaporates. During evaporating the refrigerant absorbs its latent heat from the brine (salt water), which is used for circulating it around the cold chamber. While condensing, it gives out its latent heat to the circulating water of the cooler. The vapour compression system is used in a small domestic refrigerator to big industrial refrigeration systems.