Numerical modeling of heat storage in soils

In this paper we present a numerical model for the simulation of non-isothermal air flow and corresponding heat transport in the unsaturated soil zone. The governing equations for non-isothermal gas flow and related heat transport are derived. The thermo-hydraulic (TH) coupling is additionally due to material properties, such as density, viscosity, heat diffusivity, which depends on the primary variables air pressure and temperature. A finite element model is developed for the solution of the resulting initial-boundary-value-problem. The numerical model is verified against analytical solutions for simplified problems. Finally, a case study for heat storage in soils is conducted.