The Effect of Solar Greenhouse Balcony Design on Energy Consumption and Daylight Performance in Tehran’s Residential Buildings

This study examines the impact of balcony design on energy efficiency and daylight performance in residential buildings located in Tehran's hot and arid climate. Balconies function as semi-open shaded spaces during the warm season and transform into greenhouses with enclosures during the cold season, significantly influencing ventilation efficiency and thermal dynamics. To investigate these seasonal effects, simulations were conducted using Rhino 7 and Grasshopper3D, along with plugins such as Ladybug Tools, which incorporate Radiance for daylight analysis and EnergyPlus for energy modeling. A dataset comprising 1,636 balcony models with varying dimensions and window-to-wall ratios (WWR) was analyzed. The results indicate that well-designed balconies, optimized for depth, width, and orientation, can substantially reduce energy consumption while enhancing visual comfort. Optimal designs vary based on orientation: east-west elongated balconies maximize daylight access, square-shaped balconies improve versatility and energy efficiency, and north-south elongated balconies achieve the lowest energy consumption. Balconies shorter than 3 meters in length, approximately 1.5 meters in width, and with a WWR of around 20% effectively balance energy efficiency and natural lighting. These findings provide practical insights for sustainable balcony design, promoting reduced energy consumption and improved occupant comfort.