All solar power plants (SPPs) are divided into several types:
- tower type
- dish type
- Using photovoltaic modules (photobatteries)
- Using parabolic concentrators
- Balloon solar power plants
- Solar-vacuum power plants
These power plants are based on the principle of producing water vapor using solar radiation. In the center of the station is a tower with a height of 18 to 24 meters (depending on the capacity and some other parameters the height can be more or less), on top of which is a tank with water. This tank is painted black to absorb heat and visible radiation. Also in this tower is a pumping group that delivers water to the tank from the turbine generator, which is outside the tower. There are heliostats located at some distance around the tower.
A heliostat is a mirror of a few square meters, mounted on a pole and connected to a common positioning system. That is, depending on the position of the sun, the mirror will change its orientation in space. The main and most difficult task is to position all the mirrors of the station so that at any time all the reflected rays from them hit the tank. In clear sunny weather the temperature in the tank can reach 700 °C0. These temperatures are used in most conventional thermal power plants, so standard turbines are used to generate power. In fact, relatively high efficiency (about 20%) and high capacities can be obtained at plants of this type.
This type of SPP uses the principle of obtaining electric power, similar to that of the tower SPP, but there are differences in the design of the station itself. The station consists of separate modules. The module consists of a support, on which the trussed structure of the receiver and reflector is attached. The receiver is located approximately in the area of concentration of reflected sunlight. The reflector consists of mirrors in a plate-like shape (hence the name), radially arranged on the truss. The diameters of these mirrors are up to 2 meters[source unreported 2197 days] and the number of mirrors is several tens[source unreported 2197 days] (depending on the power of the module). Such stations can consist of one module (stand-alone) or several dozen (working in parallel with the network).
SES of this type are currently very common, because in general SES consists of a large number of separate modules (photobatteries) of different capacities and output parameters. These SPSs are widely used for power supply of both small and large objects (private cottages, resorts, sanatoriums, industrial buildings, etc.). Photovoltaic modules and arrays produce direct current electricity. They can be connected either in series or in parallel electric device to an inverter, to produce any desired combination of voltage and current. Photobatteries can be installed almost anywhere, from the roof and facade of a building to designated areas. Installed capacity also varies widely, from supplying individual pumps to powering cities.
The principle of operation of these SPPs consists in heating the coolant to the parameters, suitable for use in a turbine generator.
DES design: a long parabolocylindrical mirror is installed on the trussed structure, and in the focus of the parabola a tube is installed, through which the coolant (most often oil [source not shown 2197 days]) flows. After passing all the way, the coolant heats up and in the heat exchangers gives the heat to water, which turns into steam and goes to the turbine generator.
These are the parabolic concentrator SPSs, which have a Stirling engine in the focus. There are designs of Stirling motors that directly convert piston vibrations into electrical energy, without using a crank mechanism. This makes it possible to achieve high energy conversion efficiency. The efficiency of such power plants reaches 31.25%. Hydrogen or helium is used as the working medium.
Aerostat solar power plants (SPS) are of two types:
- The first: the solar cells are located on the surface of the balloon
- Second: a parabolic, concave metalized film concave with gas pressure is used as a reflector, which serves to concentrate solar energy.
The cost per square meter of which is small compared to solar panels and any reflective surfaces. Located at an altitude of more than 20 km, the balloon is not afraid of shading in cloudy weather and moving with air currents is not subject to wind loads. The upper part is made of transparent film with armoring, in the middle - a parabola of film concentrator made of reinforced metallized film, and in the focus - a thermal converter cooled by a light gas - hydrogen, for a system with water decomposition, or helium in case of a system of remote energy transfer - for example by radio or microwaves. Orientation of the balloon to the sun is done by pumping ballast fluid (water for hydrogen cycle), precise orientation is done by gyroscopes. If necessary, one airship can contain several floating balloon modules.
Often at the various types of solar power plants additional heat exchangers are installed to produce hot water, which is used both for technical needs and for hot water supply and heating. This is the essence of combined SES. It is also possible to install concentrators and photobatteries in parallel in one area, which is also considered a combined SES.
Uses energy of air stream, artificially created by using difference of air temperatures in the surface layer of air, heated by sun rays in the area covered with transparent glass and at some height. They consist of a glass-roofed plot of land and a tall tower with an air turbine with an electric generator at its base. The generated power increases with the temperature difference, which increases with the height of the tower. By using the energy of heated soil can work almost around the clock, which is a serious advantage.