Impact of sun patch and three dimensional heat transfers descriptions on the accuracy of a building’s thermal behavior prediction
Résumé
A thermal transient numerical model (M3D) which considers the three-dimensional heat transfer through the envelope of a room and the sun patch through a window has been developed and validated in a recent paper. The use of a refined spatial and temporal discretization allows considering more precise interactions between the sun patch projection with the structure and quick time perturbations in the stresses. This is particularly necessary for highly insulated and low energy consumption buildings. In this new paper, M3D is subsequently transformed to simpler configurations, close to classical modelling thermal building simulation software that neglects the sun patch and the 3D heat transfer, in order to quantify the main contributions of this model. A first configuration is to consider one-dimensional heat conduction for the envelope and the transmitted solar radiation is only projected onto the floor (M1D). A second configuration considers also one-dimensional heat conduction but the transmitted beam radiation falls on each wall or floor that is impacted (M1D,sp). Comparison between experimental data and numerical results of these three models shows, as expected, that M1D and M1D,sp are less accurate than M3D. This is particularly true when wanting to evaluate surface temperature distributions or heating power evolution in winter.