The role of roof angle and geographic location on the thermal performance of buildings

This study investigates the impact of roof inclination on heat loss and gain within interior spaces, emphasizes its importance for enhancing building energy efficiency. By employing a systematic methodology to evaluate performance under varying conditions. The optimization of thermal performance is crucial for reducing energy consumption and improving comfort in buildings. The investigation begins by altering the roof angle in multiple configurations, focusing specifically on the southern orientation during winter to maximize daytime heat gain and the northern orientation during summer to minimize heat gain. This analysis is conducted for two distinct geographical locations: Miskolc, Hungary (moderate climate), and Baghdad, Iraq (hot climate). The study is conducted using the Hourly Analysis Program (HAP) to calculate thermal loads, as approved by a carrier company. The results are subsequently verified. The second part of the work contains simulation using ANSYS and comparison to the HAP results. After identifying the optimal roof angles for each location, simulations were performed to analyze the thermal behavior of the most effective models. The results indicate that the heat gain entering the building through the ceiling from the optimum roof is 29.393 W/m², while the heat loss is 24.43 W/m². To further enhance thermal performance, Trombe roofs were implemented. Adjustments to the Trombe roof design, with a height of 0.25 m and width 0.05 m of the channel positioned at 90° parallel to the effective roof surface. These modifications resulted in a 45.78 % reduction in heat gain through the ceiling during summer and a 10.8 % reduction in heat loss during winter. Additionally, the application of glass wool insulation was analyzed. By insulating the northern side in winter and the southern side in summer, heat loss through the ceiling decreased by 14.4 %, while heat gain was reduced by 19.85 %. These findings demonstrate the effectiveness of optimized roof inclination and supplementary thermal strategies in improving energy efficiency across diverse climatic conditions. The novelty of this work lies in its thorough approach to judging optimal roof angles and complementary strategies, providing insights and results that go beyond previous efforts in literature.