Özet:

In this study, a cascade refrigeration system comprising gas and vapor compression cycles operating at ultra-low temperature was designed. In the thermodynamic analyses, R744, R404A, and R410A refrigerants in the high temperature cycle (HTC), and R1150, R170, and R23 in the low temperature cycle (LTC) were used. Thermodynamic analyses were carried out using the Engineering Equation Solver package program. Outputs considered were: system performance(COP), compression ratio, mass flow ratio and HTC cascade outlet temperature. Results show that, at different LTC condenser temperature values, R404A/R23 has the highest COP value, in the LTC, R23 has the highest compression ratio, while R1150 has the lowest one, in the HTC, R404A has the highest compression ratio, while R744 has the lowest one, the performance of the system increased with the decrease of the mass flow ratio.

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