THERMAL MODELING AND ENERGY-CONSERVATION STUDIES ON FREON RANKINE-CYCLE COOLING SYSTEM WITH REGENERATIVE HEAT-EXCHANGER

This communication presents a thermodynamic analysis and assessment of a Freon fluid Rankine cycle cooling system. The system consists of tw o subsystems-Rankine engine (RE) power cycle and a vapour compression (V-C) refrigeration cycle. The heat engine subsystem consists of a boi ler, turbine, condenser and a feed pump while the cooling subsystem co nsists of a mechanical compressor, condenser, evaporator and an expans ion valve. A number of working fluid combinations for the RE cycle and V-C cycle subsystems have been chosen on the basis of their thermodyn amic properties and their suitability judged in terms of the performan ce parameters, namely, the thermal efficiency of the power cycle and t he coefficient of performance (COP) of the refrigeration cycle. A rege nerative heat exchanger (RHE) is incorporated in the RE cycle to impro ve the cycle efficiency and achieve energy conservation. The effects o f various operation parameters, namely, component temperatures, adiaba tic expansion/compression efficiencies and effectiveness of the RHE on the overall COP have been assessed. It is found that R114 + R22 give the best overall system performance and the presence of the RHE improv es the system COP significantly. The effect of V-C cycle condenser tem perature is more pronounced as compared to that of the RE cycle conden ser and similarly the effect of evaporator temperature in the V-C cycl e is more pronounced as compared to that of the boiler in the Rankine cycle subsystem.