Optimizing Hollow Block Roof Design: A Numerical Investigation of Coupled Heat Transfer under Solar Radiation
: The complex interplay of heat transfer mechanisms, namely conduction, natural convection, and radiation, within hollow block roofs exposed to solar irradiation gives rise to an inherently nonlinear thermal exchange problem. A key yet insufficiently explored question is the extent to which this nonlinearity governs the macroscopic thermal behavior of roofing systems. In this study, a computational investigation is conducted on two roof configurations incorporating five hollow block geometries representative of common construction practices in hot climatic regions. The objective is to identify the optimal design capable of minimizing heat losses and thereby enhancing the overall thermal performance of buildings. The outer roof surfaces are subjected to terrestrial solar radiation and convective exchange with the outdoor environment, whereas the inner surfaces interact with indoor ambient conditions. The governing partial differential equations and associated boundary conditions are discretized using the finite volume method in conjunction with the SIMPLE algorithm. Particular attention is devoted to examining the effects of solar radiation intensity, solid wall thermal conductivity, and cavity aspect ratio on fluid flow characteristics and heat transfer across the roof structures. The results highlight the critical importance of incorporating solar radiation effects into roof design.