Design of near-surface energy geostructures

Energy geostructures (thermo-active elements) are an up-coming technique for the thermal utilisation of the ground. Currently, the energy pile is the most known and used energy geostructure in Europe and all over the world. Nevertheless, plane geostructures such as basement or retaining walls have a large energy potential due to their large contact area to the ground. However, no suitable calculation approaches exists for the design of plane energy geostructures. The chair of geotechnical engineering (RWTH Aachen University) in cooperation with Geophysica Beratungsgesellschaft mbH (Aachen) developed an appropriate calculation approach. This approach, which is based on thermal resistances, was implemented in the finite difference code SHEMAT-Suite. So it is possible to consider all important factors and their interaction. The new model was used for an extensive parameter study. As a result, the flow rate in the heat exchanging system, the ground temperature, the groundwater flow, the pipe arrangement in the structural element and the structure of the element were identified as the decisive parameters.