A solar thermal collector is a solar collector designed to absorb sunlight and collect heat. The term applies to solar water heater panels, but may also be used to refer to more complex installations, such as solar parabolas, solar troughs, and solar towers, as well as simple installations such as solar air heaters. More complex collectors are commonly used in solar power plants, where solar heat is used to generate electricity by heating water to produce steam, which drives a turbine connected to a generator. Simple collectors are typically used for supplemental heating in residential and commercial buildings. A collector is a device that converts solar radiation into a more usable and storable form of energy. Solar energy is in the form of electromagnetic radiation, ranging from long (infrared) wavelengths to short (ultraviolet) wavelengths. The amount of solar energy that strikes the Earth's surface depends on the surface's location and orientation, as well as weather conditions, but it averages approximately 1,000 watts per square meter under clear skies with a surface directly perpendicular to the sun's rays.
