Master planning of an area or region is an ideal opportunity to provide solar access. Planning for solar access at the largest scale can very simplify the design for natural light at the building scale.
Solar envelopes are three dimensional design tools used to maximize the buildable volume on particular site, while preserving access to sunlight for close by buildings. The basic elements used to design a solar envelope are: latitude, size, orientation and topography of the site; times of day solar access is desired and impact of shading on the site.
Planning for solar access includes more than direct solar access and shading. Urban planning e appropriate building orientation (typically elongated on the east-west axis) and thereby facilitate use of direct sunlight, shading and sunlight reflected from nearby ground and buildings.
Building orientation facilitates the use of natural light in buildings. Building orientation is critical for shading and redirecting sunlight, but less for non-directional daylight.
Long axis running North-South
Buildings oriented with the long axis running-north south usually have greatest exposure to the morning sun. The east and west facades receive more light during the summer than during the winter. Because of low -angle sunlight orientations it is hard to shade direct sunlight without also blocking the view. Openings on the east and west sides of buildings are less preferred for illumination, especially side lighting. However, toplighting with this orientation can give the best constancy of daylighting through the day.
Long axis running East-West
Buildings oriented with the long axis running east-west usually have greatest exposure to southern sunlight. This is generally the preferred building orientation. High summer sun has greatest impact on the roof and horizontal surfaces. The north-south faces are the easiest to shade, often by a simple device. The effects of the orientation are greatest at the northern latitudes where sun angle is lower. The higher-angle sunlight entering the openings on the north and south facades illuminates the horizontal surfaces well.
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Book: Architectural Lighting by M. David Egan and Victor W. Olgyay