Enhancing energy efficiency for buildings in hot-desert climate: CFD investigation of Trombe walls using several thermal fins configuration

•Thermal fins integration significantly boosts Trombe walls' thermal efficiency.•Increasing fin height progressively improves efficiency, especially at low Re.•Optimal thermal efficiency is achieved with 3 fins and a 70° rotation.•Horizontal orientation is more effective with over 5 fins at high Re, while rotation benefits lower Re. This study presents a comprehensive computational fluid dynamics (CFD) analysis of Trombe walls in laminar flow conditions, focusing on the impact of thermal fins. The investigation explores configurations with 3 and 5 fins, considering varying fin heights, numbers, and rotation angles. The Nusselt number, friction factor, heat transfer rate, and thermal efficiency are meticulously examined for Reynolds numbers ranging from 600 to 1600. Results reveal that for configurations with three fins, a rotation angle of 70° yields the highest thermal efficiency, showcasing a notable increase from 32.3 % to 44 % across all Reynolds numbers. In contrast, configurations with five fins exhibit enhanced thermal efficiency when fins are maintained horizontally (90°) at low Reynolds numbers but experience a decline as Reynolds numbers increase. Specifically, the thermal efficiency drops from 62.48 % to 55.5 % for Re = 1400 and from 64.7 % to 58 % for Re = 1600. The study concludes that Trombe walls with three fins should be designed with a 70° rotation angle, while those with five fins should feature horizontally oriented fins for optimal thermal performance. These findings offer valuable insights for the design and optimization of Trombe walls, providing guidance for achieving enhanced energy efficiency in passive heating systems.