Shallow geothermal systems – geophysical support for geothermal planning maps

摘要

Shallow geothermal energy using ground heat exchangers is an effective technique to producernheat from (renewable) electrical energy. The geological surveys are concerned with ground heat exchangersrnmainly due to two reasons: a) efficiency of the geothermal system, b) groundwater protection: ground heatrnexchanger can penetrate groundwater protective layers leading to pathways for potentially contaminated surfacernwaters into the aquifer. Underground information, especially on thermal conductivity, is required for the properrndesign of the Ground Heat Exchangers (GHE).Therefore, plannig maps showing the effective thermal conductivityrnor the specific thermal power of the ground for defined GHE lengths are provided by the geological surveys.rnThese maps are based on drilling results. In areas with low coverage of drillings geophysical data can be usedrnto fill the data gaps. An approach to use geotechnical techniques for an assessment of thermal conductivities isrndemonstrated and discussed for an area in Northern Schleswig-Holstein.