Comparison of state-of-the-art CO2 alternative refrigeration systems for supermarkets.

This paper investigates the state-of-the art features of CO2 trans-critical booster systems. The performance of various modified features have been compared to the standard CO2 booster system. Subsequently, the performance of the defined state-of-the-art CO2 system is compared to natural refrigerant-based cascade, HFC/HFO-based DX and indirect refrigeration solutions, and propane water-cooled plug-ins operating in cold and warm climates. The results indicate that flooded evaporation and parallel compression are the most promising features of the state-of-the-art CO2 system. This compact and environmentally friendly system is the most energy efficient solution in cold climates, and is also an efficient solution in warm climates, with comparable efficiency to cascade and HFC/HFO DX systems, but with no existing or potential limitations.