Un GIS tool per il controllo della radiazione solare in aree urbane diversamente edificate

Daylighting is an important issue for urban energy planning affecting the configuration of urban space, occupant comfort (visual and thermal) and energy use inside building. The reflected natural light from the ground (streets, open spaces and urban texture in general) to the surrounding buildings is an important source of interior lighting. Natural light coming from the sky and the sun is considered as the best lighting source for optimal colour rendering and visual perception. Its quality is the essential light source mostly closed to human visual response. Moreover, natural light use can reduce electricity demand and the related cooling load due to artificial lighting. Consequently urban form plays a significant role in daylighting design. This paper investigates the energy consumptions due to different building configurations and daylighting performance and shading effect due to nearby obstructions through good grid pattern and building passive solar design. Then a software tool, based on Geographical Information Systems (GIS) technologies, for the calculation of the shadows distribution in different built up urban areas, is provided. This tool takes into account different climate conditions and the hourly variation of the sun position with respect to different oriented and inclined building façades for the evaluation of the shadows distribution and form due to different building configurations.