Geothermal Heat Pumps

AbstractGeothermal heat pump (GHP) technologies utilize the underground environment as a heat source/sink to provide space cooling and heating. From a thermodynamic perspective, the operating cost of the GHP system is much lower than that of the air source heat pump because the underground environment experiences less temperature fluctuation compared to the ambient air temperature swing. Geothermal heat pumps, which may use various underground sources, have been basically grouped into three categories: groundwater heat pump, surface water heat pump, and ground‐coupled heat pump.The basic concepts and various options of the GHP systems that include groundwater heat pump, surface water heat pump, and ground coupled heat pump have been described in this chapter. The brief history of the GHP system has been addressed in terms of its research development and engineering applications. In addition, the advantages and limitations of each type of GHP systems have been summarized respectively. This chapter has also focused on the description of the design strategy or guidelines for these systems, especially for the vertical GCHP system that is considered to be the most widely used type of GHP throughout the world. Finally, various hybrid GCHP systems and some novel technologies have been comprehensively reviewed in order to further broaden and strengthen the applicability of the GHP systems.This chapter provides some design recommendations for various GHP systems, which can assist design engineers in determining what type of system is most suitable for the given location and in designing an optimal GHP system with lowest operating cost and capital cost.