07-04-2009, 10:50 PM
Passive solar heating and cooling represents an important strategy for displacing traditional energy sources in buildings. Passive solar techniques make use of the steady supply of solar energy by means of building designs that carefully balance their energy requirements with the building's site and window orientation. The term passive indicates that no additional mechanical equipment is used, other than the normal building elements. In this approach, the building itself or some element of it takes advantage of natural energy characteristics in materials and air created by exposure to the sun. Passive systems are simple, have few moving parts, and require minimal maintenance and require no mechanical systems. All solar gains are brought in through windows. All passive techniques use building elements such as walls, windows, floors and roofs, in addition to exterior building elements and landscaping, to control heat generated by solar radiation. Solar heating designs collect and store thermal energy from direct sunlight. Passive cooling minimizes the effects of solar radiation through shading or generating airflows with convection ventilation. The benefits of using passive solar techniques include simplicity, price and the design elegance of fulfilling one's needs with materials at hand.
As a design approach, passive solar design can take many forms. It can be integrated to greater or lesser degrees in a building. Key considerations regarding passive design are determined by the characteristics of the building site. The most effective designs are based on specific understanding of a building site's wind patterns, terrain, vegetation, solar exposure and other factors often requiring professional architectural services. However, a basic understanding of these issues can have a significant effect on the energy performance of a building.
