Effect of Hole Configuration on Heat Transfer through a Hollow Block Subjected to Solar Flux

Abstract

In this paper, some effort is provided to optimize the geometry of a concrete hollow brick (used in the construction of building roofs) in order to increase the related thermal resistance, thereby reducing energy consumption. The analysis is conducted for three different configurations of the hollow concrete bricks. Coupling of conduction, natural convection and thermal radiation phenomena is considered. Moreover, the flows are assumed to be laminar and two-dimensional for the whole range of parameters examined. The conservation equations are solved by a finite difference method based on the control volumes approach and the SIMPLE algorithm for velocity-pressure coupling. The results show that the aspect ratio affects neither the nature of the fluid flow nor the number of convective cells. However, the extension of the circulation cells increases with this parameter. Moreover, the cavities with a large aspect ratio lead to significant reductions in the heat transfer through the hollow block, these reductions reaching approximately 14%.