A simplified outdoor shading assessment method (OSAM) to identify outdoor shading requirements over the year within an urban context

Abstract

This study proposes a novel way of using and presenting calculations of outdoor thermal comfort, to analyze the requirements of outdoor shading; by showing whether shading would be beneficial, harmful or ineffective – in a specified urban context – for every hour of the year. The simplified Outdoor Shading Assessment Method (OSAM) aims to assist in the early stages of outdoor shading analysis, acting as a decision-support tool regarding the type, application period, design and efficiency aspects of the shade required. The study uses the Universal Thermal Climate Index (UTCI) for thermal comfort evaluation, calculated through the Ladybug-tools (LBT 1.6). The method has been tested for the climate of Cairo against field measurements, revealing a strong correlation (R2 = 0.9267) for the UTCI. It also revealed potential overestimation in the Mean Radiant Temperature (MRT) simulation by newer versions of the LBT. Two climate examples, hot and temperate, are explored through two orientations and urban geometries, demonstrating varying outdoor shading requirements. For the E-W and N-S canyons (H/W = 1.3), Cairo's hot climate shows high shade benefit for at least 2 h per day for 171 and 250 days respectively, compared to 26 and 45 days for London's temperate climate.