Within DGE-ROLLOUT, a test site for high-temperature heat pumps (HTHPs) at the Fraunhofer IEG in Bochum, Germany is planned. Heat source for the HTHP is a seasonal high-temperature mine thermal energy storage (HT-MTES) pilot plant which is currently being implemented within the HEATSTORE (Geothermica) project.
Since the drilling operations in the summer, tests on the mine water of a seasonal high-temperature mine thermal energy storage (HT-MTES) pilot plant were performed. These included water sampling, pump tests, heat injection, and short heat recovery tests. The next steps include further heat injection tests during the next summer in conjunction with the concentrated solar power plant.
The chemical and biological properties of the mine water are compatible with the installation of heat exchangers and pumps that will be used to transfer heat into the mine during the summer and successively extract it during the winter. After the completion of each well, corresponding pump tests revealed elevated conductivity for the production well, and lower conductivity in the injection well, making it necessary to perform considerations on the possible use of the monitory well also for heating operations. A first preliminary heat injection test was successfully performed in December 2020.
The picture shows the used drilling equipment BO.REX.