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Installation of thermal solar energy

Solar power plant
Thermoelectric

Solar Concentrators. Types and Operation

Solar concentrators. Types and operation

A solar concentrator is a system for concentrating solar energy. This technique's primary use is in thermal solar energy, but you can also see photovoltaics (PV) uses.

It is a crucial element in concentrated solar power (CSP energy).

Its operation works on exploiting the sun rays' reflection in a large area through reflective surfaces. It is usually a design of aligned mirrors. The goal is to focus them on a receiver of contained size.

In solar power plants, this thermal energy is used to generate steam that drives steam turbines. In this way, the radiation is converted into mechanical energy using a heat engine. Then, it drives a generator to get electrical energy.

Compared to classic flat solar collectors, concentrated solar power has the following advantages:

  • High energy efficiency. Convection and radiation losses are directly proportional to the receiver area.

  • Economic. Construction costs move primarily on reflective surfaces and relative pointing devices.

The concentration ratio theoretically is around 46,000.

What Are the Types of Solar Concentrators?

There are two types of concentrators that allow maximizing the work of the solar plant:

  • Cylindrical parabolic solar concentrators (2D hubs). These parabolic trough concentrators have a unique curvature. This system gets average temperatures between 200-300 degrees Celsius.

  • The paraboloid revolution solar concentrators that have a double bend (3D hubs). These systems allow temperatures even higher than 3200 kelvin.

  • Concentrator photovoltaics uses lenses or curved mirrors to focus sunlight onto small, highly efficient solar cells.

Why Is Useful in Tracking the Sun?

One of these systems' difficulties is ensuring that solar radiation strikes parallel to the axis throughout the day.

Once a solar concentrator works, a tracking system for the sun's apparent movement (guided by a control system) is needed. They are commonly using dual axis.

We can be guaranteed the sun's monitoring with a tracking system applied directly to the concentrator in small solar concentrators.

Defects of the parabolic surface crop up in large solar concentrators. These flaws affect the conduct of these energy systems. In these cases, they use one or more flat mirrors called heliostats.

What Are the Uses of Solar Concentrators?

The most common use is the generation of electricity. However, there are also other techniques to harness thermal energy directly.

1. Generation of Electricity

Electricity generation is the most widely used application of solar concentrators. There are two techniques to achieve the goal:

  1. Generate steam and power steam turbines.

  2. Through a Stirling engine connected to an electric generator.

Sometimes this technique is also used to power PV cells. So they are photovoltaic solar energy installations.

2. Solar Ovens

Using small 3D hubs, you can make solar ovens. The hub can be between 80 cm and 2 meters. A “stove” is placed in the focal area where the container with the contents to be prepared rests.

3. Industrial Uses

Solar concentrators make it possible to take advantage of solar energy in multiple industrial uses.

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Published: May 13, 2015
Last review: June 3, 2020