Numerical Modeling of Geothermal Use of Mine Water: Challenges and Examples

Geothermal energy, including the geothermal use of mine water, is increasingly important, due to ecological and economical reasons. Numerical flow and heat transport models can help to estimate the efficiency of such facilities. In addition, it is possible to test different configurations. However, the modeling of mine voids is challenging because it is necessary to simultaneously solve the heat transport in the surrounding porous medium and within the mine workings. Different modeling approaches are demonstrated, such as 2-D cross-sections, 2-D models with 1-D elements for the mine workings, and 3-D models. It is shown that numerical simulations can provide sufficient validity for specific modeling goals. However, none of the currently feasible modeling strategies can be seen as a perfect and fully physical solution. Suggestions are given on how to use the different approaches.