Quasi-stationarity of thermal processes

With the aim of developing a new methodology of thermal investigations of heat-insulating structures and materials, the features of quasi-stationary heat conduction in a flat wall under varying ambient conditions have been considered. The quasi-stationary approximation errors and the applicability criteria of stationary relations between the thermal parameters of the medium imposing restrictions on the rate of change in boundary temperatures have been determined. The possibility of using nonstationary states and stable conditions in thermal diagnostics of exterior walls has been shown.