The Relation between Urban Physical Indicators and Solar Irradiation Availability on Building Envelopes: Using Tehran as a Case Study

Abstract

This chapter investigates the relation between various urban physical indicators and the availability of solar irradiation on building envelopes. For this purpose, 16 urban forms in Tehran (IRAN) are compared to 6 urban physical indicators, including plot ratio, average building height, sky view factor, site coverage, nearest-neighbor ratio, and standard deviation of building height with solar irradiation availability on building envelopes. In this study, CitySim simulations calculate the hourly solar irradiation on each building's surfaces over one year. The influence of urban physical indicators on building envelope solar irradiation was explored using multiple linear regression (least squares). The result shows that the selected urban physical indicators have a good correlation with solar irradiation availability on building envelopes (coefficient of determination = 0.99). According to the results of this study, solar energy gain on building envelopes is mainly influenced by plot ratio and average building height, respectively, and nearest-neighbor ratio and standard deviation of building height have the least effect, respectively. These results can make it easier for urban planners at the early stages of planning and also reduce the time required for solar analysis at the urban scale.