Numerical estimation of time lags and decrement factors for wall complexes including Multilayer Thermal Insulation, in two different climatic zones

Abstract

In the current contribution, time lags and decrement factors for a building wall including different Multilayer Thermal Insulation (MTI) configurations have been calculated numerically. For this investigation purpose, a numerical model which can take care of composite walls was developed. The combined conduction, radiation and convection heat transfer equation was solved explicitly via a control volume discretization. In order to investigate the thermal behavior of a wall under certain outdoor climates, meteorological data that served as boundary conditions were applied to the outer surface of this wall. The outdoor air temperatures were averaged over a number of years after been obtained from hourly measurements in both locations under study. Regarding the solar radiation, it was calculated using a clear-sky model during the summer period. The influence of geographic coordinates’ location on the insulating performance of MTI applications was investigated while the wall configurations were supposed to be located in two different climatic zones. The selection of a particular wall configuration involved not only the outdoor climate, but also the whole building characteristics, orientation, etc. The results of the present study are useful for further development in order to conceive and design the optimum MTI configuration, adjusted in specific geographic coordinates and orientations.