Yearly performance of all-in one CO2 booster systems for refrigeration, heating and air-conditioning

The strong demand for phasing out refrigerants with high global warming potential (GWP) has pushed the research towards the study of sustainable alternatives like natural refrigerants. Carbon dioxide is increasing its market share in the field of commercial refrigeration and is proving to be a viable solution for the replacement of hydrofluorocarbon (HFC) systems. The purpose of this paper is to study different solutions that can improve the performance of a CO2 booster system for supermarket applications. A steady-state model of the refrigeration cycle has been developed to simulate the hourly performance of the investigated solutions across a year. The studied refrigeration system integrates also heat exchangers for the air-conditioning and heat recovery, for sanitary hot water production and space heating. The use of parallel compression, overfed evaporators, as well as evaporative gas -cooler has been considered in the analysis. The boundary conditions of the model are based on field measurements of an existing system located in Northern Italy. A comparison of the yearly performance of the proposed solutions is made in terms of coefficient of performance and energy consumption for locations with different climates.