Performance analysis of a Brayton Barocaloric refrigeration cycle using (C9H19NH3)2CuBr4 as refrigerant

Abstract Barocaloric materials promise eco-friendly alternatives to vapour compression in refrigeration, with (C 9 H 19 NH 3 ) 2 CuBr 4 being a focus of this study. It is a highly promising barocaloric refrigerant due to the 0.4 K hysteresis temperature and operational pressure as low as 500 Bar. A reversible and irreversible Brayton Barocaloric refrigeration cycle analysis is established. For the irreversible cycle, the irreversibility during the compression and expansion process is considered in the two adiabatic processes. Performance characteristics are investigated across various indoor and outdoor temperature ranges, material operational temperature points, and operating pressures to determine the Coefficient of Performance (COP) and Dimensionless Refrigeration Capacity (DRC). The guidance for optimising the irreversible Brayton Barocaloric refrigeration cycle analysis is provided by disclosing the impact of the irreversibility of work process efficiency, timing ratio, and heat reservoir temperatures. Moreover, several specific cases are examined in detail. The results demonstrate that maximising the phase transition region of (C 9 H 19 NH 3 ) 2 CuBr 4 results in a COP of 10.8 achieved at a temperature span of 3.5 K while maintaining a 0.9-time ratio and conservative irreversibility efficiency of 0.8. This material is capable of cooling by 5.0 K with a reasonable COP of 2.5 at the 0.75-time ratio for a heat source temperature of 309 K and heat sink temperature of 314 K. Finally, this study demonstrates the potential for constructing a simple Barocaloric refrigeration system to validate the concept, with opportunities for further improvement through modifications.