Urban Canyon Shading Design in Hot Dry Climate (Low Latitudes)

摘要

Under low latitude conditions, minimization of solar irradiance within the urban environment may often be a desirable criterion in urban design. The dominance of the direct component of the global solar irradiance under clear high sun conditions requires that the street solar access will be small. This can be achieved when the obstruction angle is large (high H/W ratio, H=height, W=width). Solar access to streets can always be decreased by increasing H/W to larger values than those appropriate for temperature latitudes. It is shown in this paper that the street canyon orientation (and not only the aspect ratio) has a considerable effect on the shading which affects the urban microclimate which in turn will affect the environmental performance of buildings. This paper demonstrates that a number of useful relationships exist between the geometry and the microclimate of urban street canyons. They are potentially helpful to assist in the formulation of urban design guidelines governing street dimensions and orientations for use by urban designers.