Limits of Application for Simple Analytical Solution to Assess Temperature Plumes in Groundwater

Abstract

Utilization of geothermal energy can meaningful contribute to a reduction of CO2 emission. In a central European perspective, small decentralized systems of shallow geothermal utilizations are increasingly installed and a further increase is expected. Such an intensive utilization of that technology implicates also more attention in regard of sustainability and tolerable ecological consequences (e.g. altered temperature regime in the underground). The guideline „ÖWAV-Regelblatt 207 (2009)”, defines the Austrian state of the art regarding geothermal energy utilization. Therein it is recommended to use a simple, steady state analytical calculation method to assess the impact of geothermal groundwater utilization on the groundwater temperature regime. In this work, the limitations and application range of that simple calculation method are determined. It is shown, that with sufficient know-how, very complex situations (e.g. only few operation months per year, therefore non-steady conditions) can be assessed with sufficient accuracy.