DYNAMIC RESPONSE OF THE BUILDING ENVELOPE WALLS DUE TO DIURNAL VARIATIONS OF THE OUTSIDE TEMPERATURE

Abstract

In this paper results of numerical simulations that solve the non-steady heat equation are presented, thus
providing the thermal assessment of typical walls composed of multiple layers of homogeneous materials and
subjected to a diurnal variation of the outdoor temperature. The heat flux by conduction is quantified while the
decrement factor and the time lag are estimated and compared to the admittance method results, finding a good
agreement. Numerical results provide detailed information on the heat flux evolution within the walls, which
helps to improve the understanding of complex physical situations associated with multilayer envelopes (and
hence, with the insertion of thermal interfaces), and to determine the boundary conditions effects on the results.
The effects on layers, which use to remain undercover when general analytical methods are applied, are now
showed thus highlighting the importance of the proper choice of material and its localization inside the wall.