Geothermal storage integration into a supermarket’s CO2 refrigeration system

This paper investigates the integration of geothermal storage into state-of-the-art CO2 trans-critical booster systems. The objective is to evaluate the impact of this integration on energy efficiency. Three scenarios of integration are studied including stand-alone and integrated supermarket building systems. The results show that for a stand-alone average size supermarket, heat recovery from the CO2 system should be prioritized over a separate ground source heat pump. Extracting heat from the ground by an extra evaporator in the CO2 system has also little impact on this supermarket annual energy use. However, in the case of supermarket integration with a neighboring building where the supermarket provides heat to the neighbor, geothermal storage integration can reduce the total annual running cost of the two non-integrated buildings by 20–30% with a payback time of less than 3.5 years. The results also show there is no need for a separate ground source heat pump