This work evaluates the thermodynamic performance of three different mixed refrigerants: R744/R1270, R744/R717 and R744/RE170 in a cascade refrigeration system composed of two vapor compression cycles. Mixture composition and condensation temperature of the cascade heat exchanger were used as inputs...

This work evaluates the thermodynamic performance of three different mixed refrigerants: R744/R1270, R744/R717 and R744/RE170 in a cascade refrigeration system composed of two vapor compression cycles. Mixture composition and condensation temperature of the cascade heat exchanger were used as inputs in a parametric analysis, while outputs considered were: compressor power, refrigerant mass flow rate in both cycles, exergy destruction rate, exergetic efficiency and coefficient of performance. Systems were optimized for COP maximization, considering a fixed cooling rate of 100 kW in the evaporator. After optimization, COP increased from 18% to 32% when compared to the values obtained for pure refrigerants. R744/RE170 mixture showed the best results with a COP of 2.34, increasing exergetic efficiency up to 30% and reducing refrigerant mass flow rate in the range from 6% to 34%, compressor power between 20% to 23% and exergy destruction rate was decreased around 31% to 36%

COORDENAÇÃO DE APERFEIÇOAMENTO DE PESSOAL DE NÍVEL SUPERIOR - CAPES

001; 33003017034P8

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