Heat transfer in porous media comes in two flavors. As a porous media is made up of a solid matrix filled with a fluid, heat is transported at different rates through the two types of media. If the heat exchange between fluid and matrix occurs practically instantly — on the time scale considered; that is, both temperatures can be assumed to be identical. Thus there is a thermal equilibrium, and the temperature equation defined in porous media domains corresponds to the convection-diffusion equation with thermodynamic properties averaging models to account for both solid matrix and fluid properties. The Heat Transfer in Porous Media Interface provides tools and support for defining an appropriate matrix model.

If the above assumptions cannot be made, meaning that fluid and matrix are not in thermal equilibrium, a two-temperature model is required to simulate heat transfer. The Local Thermal Nonequilibrium Interface provides tools and support for modeling the heat transfer in the solid matrix and the fluid, and the heat exchange between both phases.