COMPARATIVE ANALYSIS OF CASCADE REFRIGERATION SYSTEMS’ PERFORMANCE and ENVIROMENTAL IMPACTS

Authors : Ebru MANCUHAN, Barış TUNÇ, Kübra YETKİN, Cem ÇELİK

Pages : 97-108

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Publication Date : 2019-11-15

Article Type : Research Paper

Abstract :The aim of our study is to propose a theoretical model to analyze the energy efficient and environment friendly cascade system for various refrigerant pairs. In order to realize, the optimum cascade evaporation temperature insert ignore into journalissuearticles values(T OPT,CAS,E ); which maximize the performance , COP values are determined for different refrigerant pairs of the system. After the optimization, two different cases have been investigated through a thermodynamic analysis to discover the best refrigerant pair for the system. Natural refrigerant CO 2 is selected instead of R404A which has high Global Warming Potential insert ignore into journalissuearticles values(GWP); value for the low temperature cycle insert ignore into journalissuearticles values(LTC);. On the other hand, synthetic refrigerants insert ignore into journalissuearticles values(R134a, R152a); and a natural refrigerant insert ignore into journalissuearticles values(NH 3 ); are chosen for the high temperature cycle insert ignore into journalissuearticles values(HTC);. In order to determine, an energy efficient and environmentally friendly cascade system, R134a/CO 2 , R152a/CO 2 and NH 3 /CO 2 refrigerant pairs are investigated in Case 1. On the other hand , R134a/R404A, R152a/R404A and NH 3 /R404A refrigerant pairs are investigated in Case 2. In calculations, the evaporation temperature insert ignore into journalissuearticles values(T E ); is varied from -20 o C to -40 o C in LTC. The condensation temperature insert ignore into journalissuearticles values(T C ); is considered to be between 30 o C and 45 o C in HTC. Mass flow rate requirements of systems for various refrigeration capacities insert ignore into journalissuearticles values(Q Evap ); are calculated for different refrigerant pairs. Moreover, the COP max and total equivalent warming impact insert ignore into journalissuearticles values(TEWI); values of the system’s refrigerant pairs are evaluated and compared for various operating conditions .
Keywords : Cascade system, Optimization, TEWI, COP