Studies on Performance Improvement of an R744 Transcritical Refrigeration System Using Dedicated Mechanical Subcooling

摘要

Due to low critical temperature, the performance of a conventional, single-stage R744-based transcritical refrigeration cycle drops drastically when the heat sink temperature is high. However, the performance can be enhanced by subcooling the refrigerant at the gas cooler exit. The present study is carried out to investigate the performance of an R744-based refrigeration cycle integrated with an R744-based auxiliary cycle to subcool the refrigerant at gas cooler exit. This modified cycle is termed as the cycle with dedicated mechanical subcooling (CDMS). This modified cycle is shown to give superior performance compared to the conventional cycle and cycle with internal heat exchanger. For this proposed cycle, the important operating parameters are optimized based on thermodynamic analysis. The results reported in this study are helpful in designing R744 transcritical refrigeration system integrated with auxiliary subcooling cycle.