Regeneration of Rock Temperature Using Solar Thermal Energy Storage in Ground Source Heat Pump Systems—Sustainability for Regions with Both Heating and Cooling Needs

The storage of thermal energy within the ground serves as a method to balance irregular energy consumption for heating throughout the year. This principle revolves around the accumulation of thermal energy during the summer months, allowing for its utilization for heating buildings during the winter months. This paper focuses on the technique of storing heat energy in the ground, known as borehole thermal energy storage (BTES), via borehole heat exchangers (BHE), which are designed to harness shallow geothermal energy for heating and cooling purposes. The model of regenerating heat in rocks, after subcooling of the ground in winter months, could be conducted by storing solar energy using a panel collector. The method of solar heat regeneration on a real building with a high number of BHEs was analyzed, with special attention on certain restrictions. In climates such as northern Croatia with cold winters and warm to hot summers, where besides heating loads there are certain cooling loads present, the implementation of this ground temperature regeneration method on the cooling and heating efficiency of heat pumps was studied. This paper presents research on the possibility of using this field as a BTES system coupled with solar collectors in a climate with both heating and cooling loads present.