Automatical assignment of petrographic parameters for optimized ground-source heat pump

The specific heat extraction capacity of the subsoil depends strongly on the petrographic conditions of the used horizons. Besides the heat conduction of the mineral phase, particularly in granular soils, the specific heat extraction capacity depends on the convective heat transport by groundwater flow. For an optimal configuration of borehole heat exchangers (BHE) and a minimization of investment costs, the knowledge of the conditions of the extracted horizons is essential. In Germany these data are available at the geological Surveys in the form of drilling logs and hydrogeological maps. In this article an automatic analysis of these data is presented. Besides the analysis of archived logs of a whole region an evaluation of a projected extraction-site is possible as well. In combination with the findings of the dimensions of cold plumes around a BHE, also information of the optimal length, number and positions of BHEs can be provided.