The study on heat transfer case of pile foundation ground heat exchangers

The paper explains the significance of pile foundation ground heat exchangers (GHEs) and interprets how to get this kind of GHEs, describes several heat transfer models including line heat source, hollow cylindrical heat source and solid cylindrical heat source. And then chooses the most suitable one for pile foundation GHEs after pointing out the deficiencies and shortcomings of other models. The relevant analytical solutions on temperature response are obtained based on pure conduction case and the heat exchange process is analyzed carefully. Some factors that have influences on heat transfer case are taken into consideration. Afterwards reveals that the performance of pile foundation GHEs is excellent especially in the initial period then changes with the time, and the heat exchange efficiency between pile foundation GHEs and borehole GHEs is compared. At last, authors illustrates that the economic effect is obvious if the pile foundation GHEs are applied fully.