Integration of Supermarket’s CO2 Refrigeration System and Geothermal Storage

This paper investigates the energy efficiency of geothermal storage integration into the state-of-the-art CO2 trans-critical booster systems. Three scenarios of integration are studied including stand-alone and integrated supermarket building systems. The results show that for a stand-alone supermarket, heat recovery from the CO2 system should be prioritized over extracting heat from the ground, which this heat extraction can be done either by an extra evaporator in the CO2 system or by a separate ground source heat pump. In the case of supermarket integration with a nearby district heating consumer, geothermal storage integration with extra evaporator in the CO2 refrigeration system can reduce the total annual running cost of the two buildings by 19-31% and with a payback time of less than three years. This integration is beneficial if the full efficient heat recovery capacity of the CO2 system is not sufficient to provide the entire demands.QC 20190909