Outer Building Surface Profile as an Effective Parameter in Optimizing Building Energy Efficiency in Egypt’s Climatic Regions

Building envelope plays a crucial role in buildings energy efficiency. This study examines the influence of the outer building surface’s self-shading features, such as surface roughness and grooves, along with solar absorptance, on building energy consumption. The study aligns with the Egyptian energy code's guidelines for solar absorptance across various orientations and climatic zones. The study utilizes energy simulations to evaluate both the individual and combined effects of these parameters on energy savings for the eight climatic regions in Egypt. The results demonstrate that increasing grooves and surface roughness texture can yield sensible energy savings, beside its economic efficiency comparing to thermal insulations. The grooving represents the highest energy savings feature that can reach from 40% to 60%, followed by increased surface roughness ranging from 7% to 10%, while reduced solar absorptance has the least impact in the north orientation only by 5%. The combined effect of increasing surface roughness and adding grooves with different solar absorptance levels shows that energy consumption rates generally decrease with increased outer surface shading. Specifically, low absorptance surfaces with 60% grooving achieved energy savings between 39.1% and 40.9% in Eltor and Siwa, while medium absorptance surfaces saved between 35.4% and 38%. High absorptance surfaces showed savings from 13.6% to 38.5% in certain orientations, with the highest energy consumption observed in west-facing orientations. The study concludes an optimization process that categorizes the energy savings of all tested cases, providing insights that could integrate with the Egyptian energy code to further optimize energy consumption in buildings.