Use of MT3DMS for Heat Transport Simulation of Shallow Geothermal Systems

Abstract

The multi-species transport model MT3DMS is applied to simulate heat transport in shallow confined aquifers. This is done by taking advantage of the mathematical similarities between the description of heat and solute transport. A comprehensive analysis on the applicability of MT3DMS (version 5.2) for heat transport simulation of closed shallow geothermal systems is shown. MT3DMS simulations are compared with results from heat analytical solutions and with those from the established numerical code FEFLOW. Issues regarding the definition of the boundary conditions, as well as the evaluation of the type of the numerical advection solver are investigated. The computed results are examined based on residual errors. The overall agreement of MT3DMS with the analytical solutions and FEFLOW is good. Larger discrepancies are only found close to the heat source, which is due to the inherent differences of the numerical methods used by each code and the boundary conditions required by the analytical solutions. Despite these differences we find that MT3DMS can be successfully applied to simulate heat transport in saturated and confined porous media under the influence of GSHP systems.