Current state of the art of geothermal heat pumps as applied to buildings

Abstract

This paper summarizes the current state of the art of geothermal heat pumps as applies to buildings. Geothermal or ground source heat pump (GSHP) systems provide heating, cooling as well as domestic hot water, by the use of the underground or bodies of surface water as heat source or sink. More specifically, a GSHP system comprises a heat pump (usually water-to-water) and a ground source system (ground heat exchanger or groundwater well) in order to provide heating and cooling to the building through a low-temperature heating system and domestic hot water as well. The main concept of a GSHP system is the maximization of the heat pump efficiency i.e. minimization of electricity consumption mostly due to underground temperature which is almost invariant throughout the year. So, it is clear that GSHP systems have contribution to the environmental protection and reduction of greenhouse gas emissions. GSHPs are a mature industry, with a continuous trend of development and due to their increasing energy efficiency due to recent advances of the technology (described in the following chapters) are attractive and are more and more considered as an excellent substitute of conventional heating/cooling sources including air source heat pumps and variable refrigerant volume. Due to these advances in several cases the high efficiency of GSHP compared to the initial capital cost minimizes the need for subsidies.