Case Studies and Lessons Learned in Shallow Resources and Heat Pumps in Germany

Abstract

Geothermal Heat Pumps, or Ground Source Heat Pumps (GSHP), are systems combining a heat pump with a ground heat exchanger (closed loop systems), or fed by ground water from a well (open loop systems). They use the earth as a heat source when operating in heating mode, with a fluid (usually water or a water-antifreeze-mixture) as the media transferring the heat from the earth to the evaporator of the heat pump, utilising that way geothermal energy. In cooling mode, they use the earth as a heat sink. With BHE geothermal heat pumps can offer both heating and cooling at virtually any location, with great flexibility to meet any demands. More than 25 years of R&D focusing on BHE in Europe resulted in a well-established concept of sustainability for this technology, as well as sound design and installation criteria. In recent years, several larger plants for offices or commercial areas have been designed and built in the central region of Germany, and mainly in the Rhein-Main-area. Both systems with borehole heat exchangers (BHE) as well as with shallow geothermal doublets (ground water wells) are operational. New solutions had to be found to adapt the technology to certain site constraints, and innovative components like thermally enhanced grouting material have been used.