Heat transfer mechanisms
Thermal insulation at room temperature. Physical basis

Heat transfer by conduction, convection and radiation through thermal insulators is described by the equations applied to continuous media following the assumption of the fictitious, single continuous medium, which has been adopted for porous media (§ 2, article [ ]).

The associated physical quantities [temperature, velocity and luminance fields, as well as thermophysical parameters (thermal conductivity, heat density, etc.)] are macroscopic averages within the representative elementary volume (VER). In all cases, it is assumed that the conditions of local thermodynamic equilibrium (LTE) are met.

This assumes that the maximum temperature difference inside the VER is much smaller than the temperature...