A solar thermal collector is intended to collect heat energy from the sun. The most simple type of solar thermal collector is known alternatively as a solar hot water panel, but they can also be used to heat the air directly as an energy-saving heating solution.
These collectors constrast with a traditional solar panel in that they generate heat rather than electricity. Solar Thermal collectors can and oftern are used to generate electricity, but the electricity production is indirect. The solar thermal collector is used to heat water, which is in turn turned to steam. That steam drives a turbine, converting radiation energy from the sun to mechanical energy in the turbine, which in turn generates electricity.
Solar Thermal Collectors come in many varieties: Flat Plate, Direct Air, Evacuated tube, and Asphalt (also known as buried solar installations).
Flat plate collectors are the most common type of solar thermal collector, and are consist of a simple setup that uses natural convection to drive heated water where it is needed - typically a small hot water tank or a pool. Flat plate collectors are comprised of a flat collector surface on top of an insulated and weather-resistant structure. This structure houses the water to be heated, which abosrbs energy from the collection surface and drives heated water up through integrated pipes to the intended destination. Direct Air solar collectors, by contrast, simply heat the air directly beneath the absorbing structure. They are also used as pre-heaters for traditional HVAC installations.
Evacuated Tub collectors are similar to flat plate collectors, but absorb heat at the pipe level. The pipes are typically coated with an outer layer of glass and copper, and inner pipes transfer heated water out of the system.
Asphalt collectors are buried into existing asphault pathing or structures. Integrating such systems as roads, playgrounds, or athletic courts are prepared is cheaper than installing stand-alone panels. Because asphalt surfaces better retain heat than the air, these installations are typically much more efficient than direct-air installations.
Electricity-generating solar thermal collectors come in three distinct varieties: Power Tower, Parabolic Dish, and Pyramid.
These solar thermal collectors all work by concentrating sunlight to obtain very high energy levels in a very small area. This is typically used for electricity generation.