Abstract
Natural refrigerants such as carbon dioxide (R744) are gaining increased interest as industry searches for alternatives with minimal environmental impacts. However, R744-based systems have lower operating efficiencies as compared to hydrofluorocarbon-based systems, particularly in hot climates. Implementing pressure exchanger (PX) technology may enable R744 systems to operate over a broader range of operating temperatures. A PX consists of narrow longitudinal channels positioned radially around a rotating cylinder. High- and low-pressure fluids flow into the PX and exchange pressure, creating an intermediate-pressure flow. In this paper, the design of the PX will be discussed, and a model of the PX will be developed. Refrigeration system designs implementing the PX will be presented. It will be shown that the PX has the potential to boost the coefficient of performance (COP) of R744 systems by over 25% compared to standard transcritical R744 booster systems.
