Etude du potentiel géothermique au niveau d'un puit de mine abandonnée

Abstract

Abandoned mines in Liege represent a significant potential for low enthalpy geothermal systems. After their closure, mine reservoirs were flooded with groundwater. Mine water exchanges heat with surrounding medium and could be used for heating houses through heat pumps. Before pumping, water temperature should be homogeneous and close to the average temperature between undisturbed temperatures at the upper and the lower parts of the shaft. Numerical simulations have been done thanks to 3D numerical models and with two different heating needs in order to estimate the geothermal potential of the shaft. Sensibility analyses allowed to understand the influence of some parameters (volume flow rate, depth, heating power). Simulation results of water pumping and system heat recovery gave pessimistic results compared to other similar studies. Some hypotheses are proposed to explain those differences as well as some perspectives to improve modelling and to obtain more realistic and accurate results. Finally, whereas capital cost is much higher than the cost of conventional heating systems, operating cost is significantly lower.