Thermodynamic Analysis of a Cascade Refrigeration System with R744/R290 Mixtures

This investigation thermodynamically analyzes a cascade refrigeration system which uses an eco-friendly refrigerant R744/R290 mixture in the circuit with lower temperature as a working fluid. It has zero ODP. Condensing temperature, evaporating temperature, and cascade temperature difference with and without the effect of superheating and subcooling of both circuits are the operating parameters and design parameters considered in this investigation. In the present study, thermodynamic analysis of an eco-friendly alternative new refrigerant (mixture of R744 and R290) was proposed and performed with five refrigerants such as R407c, R408a, R410a, R404a, and R417a, which are in the higher temperature circuits of a cascade refrigeration system. MAT-LAB software was performed in terms of temperature in evaporator, temperature in condenser and difference in cascade temperature to develop an expression mathematically for excellent COP, most favorable evaporating temperature of R744/R290 mixture and most favorable mass flow ratio of high temperature refrigerant to that R744/R290 mixture.