Determining the thermal diffusivity of the ground based on subsoil temperatures. Preliminary results of an experimental geothermal borehole study Q-THERMIE-UNIOVI

• Published in: Geothermics 2015-03, Vol.54, p.35-42
• Main Authors: Arias-Penas, D., Castro-García, M.P., Rey-Ronco, M.A., Alonso-Sánchez, T.
• Format: Article
• Language: English
• Subjects: Borehole; Boreholes; Clusters; Differential equations; Geothermal; Grounds; Mathematical model; Mathematical models; Regular flow of heat through a surface; Sensors; Thermal conductivity; Thermal diffusivity
• ISSN: 0375-6505; 1879-3576
• DOI: 10.1016/j.geothermics.2014.10.006

•We explain a method for determining ground thermal diffusivity.•The method is based on the regular flow of heat through the surface.•We show the theoretical framework of the experimental study.•We have determined ground thermal diffusivity by different methods.•We compare the different results of each of these methods. This article presents the preliminary results of a method for determining ground thermal diffusivity using temperatures recorded at different depths below the surface ground. The theoretical framework is based on the regular flow of heat through the surface, and the experimental framework involves measuring temperatures with sensors placed inside a geothermal borehole. The project has been made possible by the Universidad de Oviedo's Energy, Environment and Climate Change Cluster, and was carried out at their facilities in Gijón (Asturias, Spain). To solve the differential equation, a common model for variations in surface temperature was used to describe the environmental conditions, and the temperatures recorded at various depths with the sensors were compared with the predictions set forth in the theoretical framework. Based on the results obtained so far, the method is believed to show encouraging results although difficulties were encountered in interpretation due to variations in water table level during the period of measurements.