Experimental research on the concentration distribution characteristics of dual-temperature refrigeration system using R290/R600a based on separation condensation

In this paper, R290/R600a dual-temperature refrigeration system based on separation condensation approach with two evaporators is experimentally investigated. Refrigerant concentration distribution characteristics of zeotropic mixture R290/R600a are obtained through gas chromatography method. Moreover, the difference between charged concentration and circulating concentration are explored. The results show that circulating refrigerant concentration at different sampling positions deviate from charge refrigerant concentration. The circulating refrigerant concentration of low boiling component R290 at compressor discharge port is 11.9% higher than its charged concentration. Based on the analysis of refrigerant concentration deviation relationship, the experimental prediction correlations on circulating refrigerant concentrations are obtained. In addition, the effects of operation parameters including compressor frequency and ambient temperature on concentration distribution are also investigated. The present work provides a guide for refrigerant circulating concentration prediction and selection of charged refrigerant composition. Furthermore, this could reveal an in-depth understanding on refrigerant circulating concentration distribution characteristics.