Sustainable operation of large geothermal heat pump systems by regeneration with solar, environmental and waste heat

Geothermal heat pumps with borehole heat exchangers (BHE) can contribute significantly to the future energy supply based on renewable resources. They can sustainably supply space heating, hot water and air-conditioning due to their energy efficiency. The “Geo-Resume” research project aims to analyze the actual behavior of existing borehole heat exchanger fields during operation and the technical and economical potentials for their optimization. For this purpose, metrological investigations will be carried out, the results of which will be evaluated and generalized by means of models.
Within the scope of the project, we will develop basic principles for the sustainably efficient operation of large BHE fields. The goal is to improve the evaluation basis for planning, approval and operation of BHE fields and to provide concepts that enable sustainable and performance-optimized operation – e.g. by means of thermal regeneration. For this purpose, a status quo analysis of realized plants is carried out on the basis of a monitoring campaign. By means of modeling and simulation, the energy transports between the plant and the geological subsurface will be rationalized and evaluated. The models are validated on the basis of the monitored plants and thus provide a reliable basis for the evaluation of instrumental and procedural measures, which leads to the optimization of geothermal plants. The main focus here lies on measures for thermal regeneration.
The goals are:

• Developing an appropriate monitoring system and a procedure for the status quo analysis of the subsurface
• Providing information for licensing practice and a generalizable economic-technical evaluation of the measures as a decision-making aid
• dPreparing a planning tool for new plants with regeneration or for the operational optimization of existing plants.