PRELIMINARY THERMODYNAMIC ASESSEMENT OF A REFRIGERATION SYSTEM WITH A PCM BASED DEFROSTING

This article presents a preliminary thermodynamic evaluation of a refrigeration system using phase change materials (PCM) for defrosting. The objective of this study is to highlight the potential of heat recovery during the operation of the refrigeration system and its subsequent use in the defrosting process. The system is analyzed energetically, considering both the cooling and defrosting cycles using PCM-RT 35 HC. Input data were experimentally measured on a vapor-compression refrigeration system installed in a freezing chamber located in the university campus. The analysis includes the following refrigerants: R32, R404a, R134a, R290, R600a, R600, R1234yf, and R1234ze.The results indicate that as the defrosting time increases, the refrigerant flow rate required for PCM-based defrosting decreases. Furthermore, it was observed that R600 requires the smallest refrigerant flow rate, while R404a requires the highest to defrost the same mass of ice. The analysis reveals that R32 is the most suitable refrigerant for PCM-based defrosting, followed by wet or dry refrigerants (R404a, R134a, R290) and, finally, isentropic refrigerants (R600, R600a, R1234yf, R1234ze). Additionally, it is noted that as the condensing temperature increases, the recoverable heat increases for R32, R404a, R134a, and R290, but decreases for isentropic refrigerants such as R600a, R600, R1234yf, and R1234ze. This analysis was conducted using a computational model implemented in the Engineering Equation Solver software.