ANALYZING MUTUAL SHADING AMONG BUILDINGS

A method for evaluating solar rights and shading requirements in an ur ban environment is presented. The method is embedded in a CAD tool dev eloped and adapted for this purpose. With this tool one can analyze th e mutual shading between buildings and other objects like trees. The p urpose of this CAD tool is to allow the designer to plan efficiently t he various functions of spaces among different structures, like buildi ngs, as well as determining the location of the passive and active sol ar collectors. The method is a general one and allows a fast and effic ient calculation of the ratio between insolated and total surface area s of any given examined object that is shaded by other irregular and n onplanar elements. The calculation of this ratio is carried out for al l the months and hours for which either shading or insolation is requi red. The information obtained may serve as hourly input data for any d ynamic simulation model which evaluates the thermal performance of the different external or internal shading systems. For a visual and a qu alitative evaluation of the shadows among buildings, the suggested mod el permits a very realistic representation, in which the light source is defined according to the azimuth and the altitude of the Sun at the particular time of examination. The self shading and brightness of th e different surfaces and the shadows cast by the various elements at t he designated time are then generated and can be evaluated visually. ( C) 1997 Elsevier Science Ltd.