Concentrating solar power plants direct solar radiation to concentrate its thermal energy, which is then transformed first into kinetic energy, then into mechanical energy and then into electrical energy. According to the explanations given by AB Services, leader in energy solutions, solar radiation is composed of several ranges of radiation, including certain ionising radiation such as gamma rays, X-rays, ultraviolet radiation and, of course, visible light. Visible light, which illuminates us during the day, is also used by photovoltaic solar panels to produce electricity.
Explanation of the concept of albedo
Thermal radiation, mainly concentrated in infrared rays, heats the elements that absorb this radiation, such as sea water, soil or even humans. However, the amount of heat radiation absorbed depends on the reflectivity of the surface (albedo). A black surface has almost no albedo, so it absorbs most of the thermal energy. This is why solar thermal panels are black. A white surface has the highest albedo and absorbs only a small part of the thermal energy like snow.
For AB Services, an expert in solar energy, a mirror has an almost perfect albedo that reflects almost all the radiation and depending on its orientation, you can send this radiation wherever you want. To give an example, the zebra also uses the albedo through these stripes, because they send more or less light if they are black or white, which disturbs the vision of some insects and thus prevents them from landing on the animal. Albedo is also used in concentrating solar power plants to direct and concentrate solar radiation on a specific point in order to recover thermal energy.
Types of solar power plants
There are two types of concentrating solar power plants. The first type and the linear concentrating solar power plant. Composed of mirrors in the form of a parabolic cylinder allowing the solar radiation to be concentrated on its axis where there is a black absorber tube in which a heat-transfer fluid circulates. Usually synthetic oil that will heat up to a temperature of around 400 degrees. It is then sent to a steam generator to transfer its heat to another fluid such as water. This water will vaporize and the steam goes to turbines to transform the kinetic energy into mechanical energy. The rotation of the turbines then generates electrical energy.
It is important to know that all the parabolic cylindrical mirrors follow the movement of the sun. For maximum efficiency, as AB Services points out, a variant of this type of power plant exists with Fresnel mirrors, which are slightly curved mirrors that are much cheaper to produce than parabolic trough mirrors. Another type of power plant concentrates solar radiation on a single focal point and is small in size. It is therefore called a concentrating solar power plant by focal point or solar tower. This is because the focal point and in most cases the top of a tower receives the solar radiation thanks to mirrors located all around it.
