passive solar

For the application of passive solar technologies in buildings, see passive solar building design. Passive solar technologies convert sunlight into usable heat, cause air-movement for ventilation or cooling, or store heat for future use, without the assistance of other energy sources. Technologies that use a significant amount of conventional energy to power pumps or fans are classified as active solar technologies. Some passive systems use a very small amount of conventional energy to control dampers, shutters, night insulation, and other devices that enhance solar energy collection, storage, and use.
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