Numerical study on the heat characteristics of a novel artificial seepage thermal storage based on the successive four seasons

A novel and more efficient artificial seepage thermal storage is proposed to exploit the ground temperature energy. The characteristics of the seepage and heat transfer of the working medium (i.e., water) in the thermal storage are numerically explored, based on the successive four seasons. Under the refrigeration condition in summer, the evolution of the outlet water temperature can be divided into the initial, the cold-reduction and the stable phases with the operating time. Moreover, the influence of the injection flow, as well as the thermal conductivity of the anti-seepage layer, on these characteristics is analyzed. During the temperature recovery period in autumn and spring, 79.4% of the heat at the end of summer is stored until the winter, and 78.8% of the cold capacity at the end of winter is stored to the summer. Under the heating condition in winter, the average heat extraction power, when considering the residual summer heat storage, is 1.4 times higher than that without considering the residual heat. Especially, the artificial seepage heat storage is more suitable for the situation that requires both the refrigeration and the heating. It is expected that this work could offer a new idea to develop the geothermal energy.