Thermo Solar Panel
Solar thermal is a technology designed to harness sunlight for its thermal energy (heat). This heat is often used for heating water used in homes, businesses, swimming pools, and for heating the insides of buildings (space heating).
In order to heat water using sunlight, a solar thermal collector heats a fluid that is pumped through it. As the fluid is pumped through the collector, the fluid becomes heated. The now heated fluid then is pumped out of the collector and through a heat exchanger.
Heat exchangers are usually comprised of copper, and are normally found inside a solar storage tank. This allows the heat in the fluid to be transmitted - or exchanged, hence the name - into the water in the storage tank.
The storage tank is an essential element of any solar thermal system, as it allows all the heat being generated by the solar thermal collector to be stored for use whenever it is needed
These highly effective systems are popular in many parts of the globe, from China to Canada to Zimbabwe. The panels are typically 70%-90% efficient, compared to around 20% efficiency for solar photovoltaic (pv) systems. Solar thermal energy displaces the use of the existing hot water heater and heating equipment, typically displacing either natural gas or electricity.
Medium Temperature Collectors
Medium temperature collectors often refer to solar water heating systems in the form of flat plates or evacuated tube collectors. These collectors are use to collect, store, utilize heat for domestic hot water (such as for showers, laundry, or process applications, among others), for space heating, and for space cooling (using various types of thermally driven cooling systems, such as an absorption chiller. Evacuated Tube Collectors
Evacuated tube collectors (ETC) are very efficient at retaining a large percentage of the heat collected from the sun. Each tube works independently from the others, and is surrounded by a double wall tube of glass. In between the double walls is a deep vacuum, producing sa "thermos" effect which greatly increases it's thermal insulation. This design allows the sunlight to pass through the glass, but allows very little heat to escape.
In many evacuated tube collectors, such as the SPP-30A, heat pipe technology is used. A copper heat pipe is inside the evacuated tube, held in place by thin pieces of metal, called heat transfer fins. The heat pipe is also under a vacuum, which allows the water inside to boil at a much lower temperature.
As the water boils, the vapor rises to the top of the heat pipe, which sits inside the collector's header. Water, or heat transfer fluid (usually a water/glycol mixture) passes through the header, where it comes in contact with the tops of the heat pipes, thus heating up rapidly. It then passes through a heat exchanger, usually part of a storage tank, where the heat is stored for immediate or future use. Flat Plate Collectors
Flat plate collectors are generally comprised of a series of copper pipes in a very well insulated glass box. Sunlight strikes the glass, and the heat is trapped and held inside by heavy insulation. As water or a heat transfer fluid is passed through the collector, the heat trapped from the sun is transferred into the fluid.
This fluid is then heated, and circulated back through a heat exchanger, where the heat is stored for immediate or later use in domestic hot water or space heating systems.