Outdoor Thermal Comfort Evaluation in Commercial Settings of Delhi: Towards Green Building Strategies

The thermal comfort of outdoor open spaces plays a crucial role in supporting various urban activities. This study examines how the geometry of vertical urban surfaces influences outdoor thermal conditions in Delhi's existing built environment. Two district centers with distinct vertical surface configurations and high pedestrian activity were selected for analysis. Micro-meteorological measurements was conducted to assess subjective thermal comfort and validate Envi-met 5.1.1 simulation outputs. Key thermal indices, including Tmrt and PET, were analyzed concerning geometrical parameters such as H/W, SVF, and the orientation of vertical surfaces. The study focused on Delhi's extreme summer conditions and revealed that even minor variations in vertical surface geometry significantly impact thermal comfort within short distances. Findings emphasize the importance of shading and wind velocity in enhancing outdoor comfort levels. Shading reduced Tmrt by up to 13.7°C and 27°C, while increased wind velocity lowered PET by 10.82°C and 11°C. Additionally, factors such as H/W ratio, vertical surface orientation, and spatial relationships between adjacent surfaces are critical considerations for the future design of outdoor spaces in Delhi.