Solar collectors
The basic building block of the solar installation is a collector, which is capturing solar energy, transform it into heat and hot water, air, or any other coolant. There are two types of solar collectors - flat and focused. In the flat solar collectors is absorbed without concentration, and in focusing - with concentration, i.e. with increasing density of incoming radiation. The most common type of collectors in low-temperature solar energy collector is a flat solar energy (CSE). His work is based on the principle of "hot box". In order to produce a flat KSE, requires primarily surface, which has a reliable contact with a number of pipes or channels for the movement of heated coolant. Set flat surfaces and pipes (channels) for the coolant forms a single constructive element - absorber. For better absorption of solar energy absorber top surface should be painted black or should have a special absorbing coating. The maximum temperature to which the coolant can be heated in a flat collector, not exceeding 100 oC. Among the principal advantages of a flat CSE compared with collectors of other types is its ability to capture both direct (radiant) and diffuse solar energy and as a consequence - the possibility of permanent installation without the need for tracking the sun.
Absorber flat solar collectors are usually made of metal with high thermal conductivity, namely steel, aluminum and even copper.
With hubs, i.e. optical devices such as mirrors or lenses, achieved increasing flux density of solar energy. This occurs in focusing solar energy collectors, requiring a special mechanism for tracking the sun. Mirrors - flat, parabolic or parabolic-cylinder - made from thin metal sheet or foil or other materials with high reflectivity, lens - made of glass or plastic. Focusing collectors are usually used where high temperatures are required (solar power plants, stoves, kitchens, etc. in heating buildings, they usually are not used.
The need for storage of heat in the solar system due to mismatch in time and on quantitative indicators of solar radiation and heat. The flow of solar energy varies during the day from zero at night to a maximum value on a sunny afternoon. Since the heat load of heating is maximum in December - January, and the amount of solar energy in this period is minimal, to ensure that heat is necessary to capture solar energy more than you need at the moment, and the excess heat stored in batteries.