THERMODYNAMIC ANALYSIS OF MULTI EVAPORATOR VAPOUR COMPRESSION REFRIGERATION SYSTEM WITH INDIVIDUAL COMPRESSOR USING MIXED REFRIGERANT AND COMPARISON WITH PURE REFRIGERANT

Abstract

Thermodynamic analysis is carried out which is based on the energy and exergy analysis of multi evaporator refrigeration system with individual compressor and multiple expansion devices using flash chamber at different temperatures of both evaporator and condenser for R12, R134a, R436a (0.52R290 / 0.48R600a) and R436b (0.56R290 / 0.44R600a). The properties of blend refrigerant (R290/R600a) are calculated using Refprop and a computational model is developed using engineering equation solver. The present work has been carried out for food freezing plant (fishes, fruits, vegetables) which works on multi evaporator vapour compression refrigeration system for evaporator-1 in the range of -300C to -150C, evaporator-2 in the range of -60C to 100C and the condenser in the range of 250C to 440 C. Performance parameters (total work input for the system, the coefficient of performance (COP), exergy destruction (ED) for whole system, exergy destruction ratio (EDR), exergetic efficiency) are calculated over these ranges of temperature and compared all these refrigerants. After the performance evaluation of the system for different refrigerants, it is found that R436b (0.56R290 / 0.44R600a) has the highest COP and Exergetic Efficiency, it has also the least Total Work Input for the system and Exergy Destruction. Now it is concluded that R436b is the best among all other refrigerants which are used for the system, and it has zero GWP. Thus it is recommended that it can be used for the replacement of R134a in the household refrigerator and food freezing plant.