Harness the Power of Solar Energy
A solar thermal collector’s main purpose is to capture solar radiation and convert it into heat. In the center of the solar thermal collector is an absorber, where the conversion of solar radiation to useful heat occurs, making this heat available for use in a solar-heating or solar-cooling system.
The basic types of thermal systems include:
Non-Concentrating thermal systems: the area that intercepts the solar radiation is the same that absorbs the radiation.
Flat Plate Collectors are the most common non-concentrating thermal system. They are identified as the dark flat plate absorber-made of aluminum, steel or copper with black coating with a transparent cover to reduce heat loss as well as insulating backpacking. Sunlight passes through the cover to the absorber which heats up and changes solar energy to heat energy. This energy is transferred to liquid, either antifreeze or water, through a system of piping.
Evacuated Tube Collectors are composed of a series of hollow glass tubes with an absorber coating. Radiation is absorbed and heats transfer fluid located throughout the tubes to a hot water storage tank or space heating system. This type of thermal system is used to heat great volumes of water or increase water to very high temperatures. In comparison, Flate Plate Collectors lose more heat to the environment than Evacuated Tube Collectors. Tube systems have a lower absorber-to-plate-area ratio, making them more efficient.
Parabolic Trough thermal systems are used mostly by Solar thermal power plants. These thermal systems are designed to collect the sun’s radiation through a mirrored trough. The trough reflects direct solar radiation into glass tubes, also known as a receiver or absorber, containing fluid that runs the length of the trough and positioned at focal points on the reflectors. As the fluid passes through the receiver, it becomes very hot as it gets transported to a heat engine where the heat is then converted to electricity. Most Parabolic Trough thermal systems consist of many troughs laid parallel over a large land area, with these troughs changing position based on the daily situation of the sun.