Low intensity heat and mass transfer in the soil adjacent to a heat source/sink occurs in a number of engineering applications. These include earth coupled heat pump coils, underground buildings, insulation, buried pipelines, and waste heat rejection from power plants to extend the growing season. For most soils the thermal conductivity decreases sharply with moisture content; thus, accurate predictions of the thermal performance of a system require an understanding of moisture movement.

This paper summarizes the approaches currently used to analyze low intensity heat and mass transfer in moist soils. Governing conservation equations are given along with models currently used to describe the flow of liquid and vapor due to moisture content and temperature gradients. Experimental comparisons to the models presented are given where available. Examples of the application of models presented are given along with results. An extensive reference list is also provided.

Units: I-P