ABSTRACT
To be sustainable, a city must be energy efficient, and for a city to be energy efficient its buildings must be energy efficient. Because most building energy consumption is for heating, cooling and lighting, all of which are greatly impacted by the sun, buildings and therefore cities must be solar responsive. The orientation of buildings, which is largely a function of the street layout, is the single most important factor in designing with the sun, whereby the energy consumption for heating, cooling and lighting can be reduced by as much as 40 per cent. The best street layout for new cities or developments is oblong city blocks with the long axis running east-west so that most buildings will have only the ideal north and south exposures. The second most important strategy is bulk zoning so that access to the winter sun and year-round daylighting is available for as many buildings as possible. All roofs, walls, streets, parking areas, sidewalks and plazas should be white or of a light colour to significantly reduce the heat island effect and to improve the amount and quality of daylighting. It is vital to design cities and buildings to be solar responsive, but that requires a good understanding of solar geometry. Because of its complexity, solar geometry is best learned with the help of a heliodon, which is also a great tool for learning and testing solar strategies.
