Integration of a Rotary Pressure Exchanger in CO2-Based Refrigeration System: Thermodynamic Modeling and Energy–Environmental Benefits

Abstract

Abstract. This article presents a comprehensive investigation into a sustainable and energy-efficient refrigeration solution for supermarkets operating in warm to hot climates. The study explores the integration of a Pressure Exchanger (PX) into a CO2 transcritical refrigeration system to enhance its commercial and environmental viability. The novelty lies in the development of a thermodynamic model for the PX, derived from computational fluid dynamics simulations across ambient temperatures ranging from 13 °C to 40 °C, thereby encompassing both moderate and hot climatic zones. The proposed system demonstrates annual energy savings of 4.16–6.57% compared to a multi-ejector CO2 system (EJ_OV) and achieves a 10.8–24.2% reduction in carbon footprint relative to an R448A system. The gas-cooler pressure, receiver pressure, and the rotor speed are identified as the key variables affecting the performance of the PX. The PX is capable of delivering a pressure lift between 3.18 bar and 53 bar, resulting in a COP enhancement of 3.96–14.26% over the EJ_OV system, and 21.13–52.96% and 2.75–39.16% over R404A and R448A systems, respectively. Annual energy savings are most pronounced in warm and hot climatic regions, while installations in some of the locations with milder climates offer greater economic advantage due to favorable electricity tariffs and regulatory incentives. Overall, the findings establish the PX-integrated CO2 system as a technically robust, environmentally sustainable, and commercially promising pathway for next-generation supermarket refrigeration.