Data driven design for urban street shading: Validation and application of ladybug tools as a design tool for outdoor thermal comfort

Lightweight shading devices like sails, canopies, and street-scale shelters are a key strategy for urban cooling. Studies indicate that interactions between characteristics such as height, thermal emissivity and color, significantly affect outdoor thermal comfort, and those effects vary considerably with local context and time. However, practical understanding of shading often focuses solely on blocking direct solar radiation. Integrating microclimate simulation into design workflows can optimize shade design by considering all thermal effects. This paper validates two workflows using Ladybug Tools (LBT) for modelling freestanding shade, proposing their design applicability. A novel workflow models shortwave and longwave effects of lightweight shade materials on outdoor thermal comfort, differing from LBT's standard approach by considering shade interactions in longwave radiation exchanges. Simulated mean radiant temperature (MRT) is validated against field measurements and compared across both workflows. Field measurements separate long and shortwave contributions for accurate MRT comparison, revealing LBT's tendency to overestimate shortwave radiation effects. The custom workflow is applied to a design case study in Turin, Italy, evaluating various shade materials and their effects on MRT. Results demonstrate how shade material, height, ground material, and time of day interact to influence cooling effects, emphasizing practical implications for optimizing shade design.