Q. How is the geometrical relation between Earth and the Sun relevant to Building design?
A. For many design purposes, the position of the Sun on a given date at a given time has to be known. This enables the building designer to predict which faces of the building would be sunlit, and hence receive direct radiation; to calculate the shadow cast around the building, the patches on sunlight on floors walls, etc. The knowledge of altitude and the azimuth of the Sun enable the designer to predict the intensity of solar radiation for a specified space and time coordinates. This influences building size, volumetric proportions, orientation, fenestration details, shading devices, ventilation, building materials, etc.