Exergy Analysis of CO₂ Centrifugal Reverse Brayton Cycle

The centrifugal reverse Brayton cycle (CRBC) is a novel refrigeration cycle that harnesses the conversion of inertial potential energy to pressure energy, enabling efficient compression and expansion processes through centrifugal and centripetal flows of the working fluid within a rotating tube. This offers a promising potential for improving the refrigeration efficiency of conventional gas refrigeration cycles. Building on previous studies, this study employs a thermodynamic model to conduct a parametric analysis of the CRBC to explore the thermodynamic efficiency and loss distributions of the cycle, providing a theoretical foundation for system evaluation and enhancement. Results show that, under the same inlet air temperature, an optimization possibility exists for the heater inlet temperature. The system experiences substantial exergetic losses during the centrifugal isothermal compression flow, adiabatic compression, and centripetal adiabatic expansion flow, each at approximately 20%. Conversely, the exergetic losses during the air-cooling process and the centrifugal adiabatic compression process are comparatively low and demonstrate an inverse relationship with the inlet temperature of the gas heater. The exergetic efficiency of the CRBC reaches 19.2%, which significantly surpasses the values of 8.1% for the CO₂ reverse Brayton cycle, 4.9% for the open-air reverse Brayton cycle, and 2.3% for the closed-air reverse Brayton cycle.