Thermal response of composite building envelopes accounting for thermal radiation

Abstract

Thermal loads for an occupied zone depend on several different factors of which heat transfer through the walls of a zone is of interest in this study. Multiple modes of heat transfer, along with transient boundary conditions, create a transient heat transfer problem. The governing equation for heat transfer through the walls is the one-dimensional transient heat conduction equation with associated initial and boundary conditions. A model based on the finite-volume method is developed to solve numerically the transient heat conduction equation. The model provides the temperature profile of a composite wall with multiple homogeneous layers, time varying solar flux and outdoor temperature, and thermal radiation. Results for heat fluxes from the model are shown to be in agreement with those of analytical methods. Results for six walls of a zone with radiant exchange of energy between the interior surfaces of the zone are presented.