Design and rating of an integrated mechanical-subcooling vapor-compressionrefrigeration system

Subcooling of the refrigerant at the exit of the condenser in a simple vapo r-compression refrigeration system allows the refrigerant to enter the main cycle evaporator with low quality. Thus, allowing the refrigerant to absor b more heat in the evaporator; thereby improving the coefficient of perform ance (COP) of the system. In an integrated mechanical-subcooling vapor-comp ression refrigeration system, the subcooling is performed by utilizing a sm all integrated vapor-compression refrigeration cycle, known as the subcoole r cycle. This subcooler cycle is coupled to the main cycle at the exit of t he condenser and it utilizes the main cycle condenser for rejecting the hea t. In this paper, thermodynamic models of an integrated mechanical subcooli ng system are developed to simulate the actual performance of the subcoolin g system, particularly with respect to the subcooler saturation temperature in addition to heat exchanger areas. It is demonstrated that the performan ce of the overall cycle is improved over the corresponding simple cycle. Th is improvement is found to be related to the refrigerant saturation. temper ature of the subcooler. The model is also used for predicting an optimum di stribution of the total heat exchanger area between the evaporator and cond enser. (C) 2000 Elsevier Science Ltd. All rights reserved.