Analysis on the transient heat transfer process inside and outside the borehole for a vertical U-tube ground heat exchanger under short-term heat storage

A three-dimensional unsteady model is established to study the heat transfer performance for a vertical U-tube ground heat exchanger (GHE). The transient heat transfer process between the inside and outside of the borehole under short-term heat storage is analyzed. The results indicate that the soil temperature field in the depth direction at the center section is distributed in a “narrow belt shape”. The thermal interference distance of the...