The sun provides daily unlimited potential energy. Therefore, humanity is developing ways to use this energy to their advantage. And from solar energy, people learned to produce electricity and heat. The heat is used for space heating and hot water.
The question arises, how solar energy is converted into heat energy? Conversion takes place by means of solar collectors. They differ from the solar cells is that they produce no electricity, namely thermal energy.
Solar collector — is the heart of the thermal solar installation. Collectors are divided into two types:
· Flat.
· Vacuum.
Flat-plate collectors consist of an element that absorbs solar energy, a transparent coating and insulation layer. In turn, the adsorber is connected to a system that conducts heat. For better absorption element is coated with black paint or selective coating. The element itself is made of glass or polycarbonate, the main condition — it is a minimum metal. The back side of the panel securely Insulate. When the heat analysis no water can be heated up to 190 — 210º. Recently, for higher collector efficiency started to use adsorber made of copper.
Vacuum collectors. Collectors of this type resemble conventional flasks. The only difference is that the upper layer from the reservoir is transparent, and the inner layer is coated with an absorbing solar selective coating. The outer and inner tube separates the vacuum layer. Also collectors of this type are widely used heat pipes, which are excellent conductors of heat. The scheme of work of the collector is very simple. At the bottom of the tube and fluid to be heated is converted into steam. Then rushing up tube steam condenses and gives off heat collector. This scheme allows to achieve higher efficiency than the previous embodiment of the collector during operation, even at low temperatures.
Combining the individual collectors can obtain thermal unit. The heat resulting from the coolant flows into the tank and is stored in the accumulator. And then from the battery directly to the water being selected.
Heat supply of solar energy is of two types:
· Single-circuit system, where the heat pipe water is supplied directly from the reservoir;
· Double-circuit system. Here the energy is given to the water circuit by circulating coolant in the collector circuit.
If we make the correct assembly and installation of solar collectors, the heating water can be increased by 50-65%, but in the summer months, solar heating reaches 100%. Therefore we can say that the use of solar collectors with confidence allows completely abandon the traditional methods of water heating with gas and electrics. That in turn makes it possible to implement a nonvolatile property heating and hot water.
