Influence of Geometry and Orientation on Flank Insolation of Streets in an Arid Climate City

Abstract

Problem statement: Whilst at the design stage the various aspects of design impact must be taken into account, the incident solar radiation, insolation, is a key to many environmental aspects of street canyons. In this regard, the configuration of an urban street has a decisive role in magnitude of the solar radiation which it receives on its flank. This study aimed the influence of geometry and orientation of urban street canyon on flank insolation in an arid climate city. Approach: This study approached numerical simulation and employs a computational programme to carry out a 2D simulation within Urban Canopy Layer; (UCL). To enhance the resolution, the simulation condition is based upon accumulative hourly insolation on the daily-basis sun movement for the both solstices as the two extreme days of the year. Results: Geometry has an inverse influence on flank insolation and streets approaching deeper canyons would have lower insolation in both summer and winter. The orientation influence on insolation is to be seen with the season. In winter, orientation effect is analogous to geometry impact and higher inclined canyons would have lower insolation on their flank. In summer, increase in orientation causes variation in flank insolation of which the variation trend is not in the same direction. Conclusion: This study showed that both geometry and orientation influence the solar radiation incident on the street flank and therefore ought to be considered in the design stage where the designers can take full advantages. The increase in geometry or orientation towards deeper canyon and higher inclination respectively, yield insolation reduction excluding for the orientation influence in summer that causes insolation variation.