a New Thermal Inertia Model Based on Effusivity

In the framework of the PASCOOL project, theoretical and experimental studies have been performed to improve the quantitative understanding of the presence and distribution of massive building elements for the passive cooling of buildings. A new thermal model, based on effusivity, a parameter that can be analytically derived from the solution of the heat equation for a semi-infinite wall, was developed. The transient thermal response of a variety of building zones to a series of steps in heat gain has been measured for the validation of the thermal inertia models. It was observed that, for each step in gain, the mean surface temperature of the spaces increases proportionally to the square root of time, as predicted by the effusivity model. The results allowed the formulation of simple passive cooling design guidelines for buildings.