Passive solar design
Also found in: Acronyms.
Passive solar design
Involves using nontechnical design methods, site conditions, local climate, sun angle, building massing, orientation, and daylight to save and retain energy within buildings. Unlike technologically advanced active solar counterparts, passive solar buildings do not rely on electrical or mechanical systems, control techniques, or other devices to operate. The two basic passive solar design methods are direct gain and indirect gain.
direct solar gain
A method that relies on the orientation of the building, the location of its openings, the building’s materials and their attributes, the structure’s heat storage capabilities, and its insulation systems. In this method, sunlight is allowed to enter the building through south-facing windows. Light is absorbed directly by the thermal mass, which stores and releases the heat as the building cools.
indirect solar gain
A method that requires a buffer thermal mass between the sun and the living space to be heated, where the thermal mass buffer can be a structure, a wall system, an absorption device, and/or another space. In an indirect gain system, the thermal mass acts as a collector, absorber, and distributor of the solar energy. Thermal distribution is accomplished by conduction. There are three main types of indirect gain systems: thermal storage wall, roof water, and sunrooms.
A system that absorbs and transfers heat from outside to inside during the winter, and from inside to outside during the summer. In order to heat and cool a building effectively during both seasons, the water stored in tanks or pipes, along with additional treatment materials such as antifreeze, must be insulated in reverse order from winter to summer. Used primarily in commercial buildings in low-humidity climates.
A hybrid method of passive solar design, which includes the functions and benefits of both the direct and indirect gain methods. Also called “solar greenhouses” or “solariums,” sunrooms have significant advantages over other indirect gain solutions, especially because of their ability to control the level of heat within a building.
thermal storage wall
Consists of a 10- to 16-inch thick masonry wall placed on the south side of a building where it will receive the most sunlight. Dark-colored, single- or double-glazed windows cover the exterior of the wall to absorb the solar energy, which is stored and then radiated to the living area after the space cools. For other thermal wall systems, the wall thickness varies depending on the material: 10–14 inches for brick, 12–16 inches for concrete, and 8–12 inches for adobe.