Thermodynamic analysis of two dual-purpose compression refrigeration systems with eco-friendly refrigerants in different climates

In this study, two types of dual-purpose compression refrigeration systems including single-compressor and dual-compressor (cascade) with different eco-friendly refrigerants to achieve two temperature ranges above zero and below zero have been investigated. The purpose of this study is to investigate the annual energy consumption of dual-purpose refrigeration systems with eco-friendly refrigerants and also to investigate the parameters affecting the efficiency of these systems. Studies have shown that the cascade system has a higher efficiency than single-compressor system and the best refrigerant in terms of performance in this system is R290. It was also found that in the single-compressor system only R134a refrigerant is applicable and the other refrigerants in the evaporator create pressure under atmospheric pressure. Also, this system is only applicable in hot and humid climates for all seasons of the year, while the cascade system is applicable in all seasons of the year and in all climates. Comparison of these two systems shows that assuming the total load capacity of the refrigerator is constant, increasing the cooling load in the low temperature range leads to increased energy consumption of the cascade system. Also founded that the annual energy consumption of cascade system is 7% lower than single compressor in the case of equal distribution of cooling load between two temperature ranges.