A Design Methodology For Improving Outdoor Thermal Comfort In The Urban Space

Abstract

Improvement of outdoor thermal comfort is essential for achieving a livable and functional urban space and creating a thermally comfortable environment, so designers must think about developing solutions for landscape and urban design. The main problem is that urban developments in Egypt often overlook green design strategies, leading to an outdoor thermal discomfort environment for users. This paper introduces a simulation workflow utilizing the grasshopper interface with honeybee and ladybug plugins to determine the correlation between optimal tree shading ratios and the changing dimension proportions of a hypothetical central courtyard within the Cairo region. The Cassia nodosa tree model with maximum foliage (Seasonal leaf factor 1.0) has been simulated for a typical summer week from July 24th to July 30th to assess the impact of this correlation on outdoor thermal comfort. The simulation results indicate that the optimal tree shading percentage correlates with varying courtyard dimension proportions, keeping the height constant. This correlation leads to an optimum reduction in Mean Radiant Temperature (MRT) and Universal Thermal Climate Index (UTCI) values, as well as an enhancement in Outdoor Thermal Comfort Percentage (OTCP%) for the square-shaped hypothetical courtyards. Accordingly, a curve graph represents the correlation between the courtyard dimension proportions and the corresponding optimal tree shading ratio obtained. This curve enables both graphical and mathematical determination of this ratio.