Abstract
Soil thermal properties are significant parameters affecting heat transfer between ground and buildings. This paper is dedicated to the study of seasonal heat storage in shallow geothermal installations in unsaturated soils for which hydrothermal properties such as degree of saturation and thermal conductivity vary with time throughout the profile. In the model, a semi-analytical model which estimates time-spatial thermal conductivity is coupled with a 2D cylindrical heat transfer modeling using finite difference method. We apply a time-spatial dependent boundary condition at far field of soil region. Finally, we perform the modeling of a Borehole Heat Exchanger (BHE) for in in-situ soils in Alsace region in France. Generally, we can observe that a thermal equilibrium stage can be reached after several heating and cooling cycles.
