Solar power plant
Thermoelectric

High-temperature solar thermal energy

We refer to hight-temperature solar thermal to those collectors who work at temperatures above 500 ° C. They are used for power generation.

The technologies used in hight-temperature solar thermal energy are:

  • Parabolic trough solar collectors
  • Central tower
  • Parabolic dishes or parabolic reflector
  • Linear Fresnel concentrators

Parabolic trough solar collectors

Scheme solar thermal parabolic trough Parabolic trough solar collectors concentrate sunlight using parabolic mirrors in an absorber pipe which passes through the axis of the parabola. Within this absorbing pipe pipe a fluid is heated and can reach temperatures as high as 450 º C.

Depending on the application and the temperature at which you want to achieve a type of fluid or another is used. To a maximum temperature of 200 ° C can be used demineralized water or ethylene glycol as working fluids and for higher temperatures of up to 450 º C synthetic oils are used.

This type of getter concentration should be modifying their position adapting to the sun's position by rotating around the axis parallel to its focal line to take advantage of direct sunlight position.

Solar thermal high termperature with cylindrical solar tasters

 

Solar power tower

Solar thermal high temperature. Diagram of a central tower.Tower systems or central receiver tower consist of a field of heliostats (movable mirrors over 2 axles). The heliostats capture and concentrate the direct sunlight onto a receiver, installed on the top of a central tower.

Operation of the plant is simple, the central solar receiver generates high temperature steam. The steam generated is then used to drive a turbine that produces electricity.

Solar thermal high temperature. Central Tower.

 

Parabolic reflector

Solar thermal high temperature. Outline of a parabolic dish. The parabolic dishes are systems that concentrate solar energy in a point where the solar receiver is located and a Stirling engine or a microturbine that is coupled to an alternator.

The fluid located in the receiver is heated to temperatures above 750 ° C thereby obtaining a certain heat energy. This heat energy generated is used by the Stirling engine or the microturbine to produce electricity.

A Stirling engine is a thermal engine, which means that the energy contribution can be realised through concentrated solar energy. An alternator coupled in a Stirling engine approaches the movement generated by the engine to produce electricity. The electricity generated can be connected to the grid for sale or in most cases can be used for direct consumption.

This technology is still experimental and is still less profitable than tower or parabolic mirrors.

Solar thermal high temperature. Central with parabolic dishes.

Linear Fresnel concentrators

The reflectors lead normal flat mirrors and simulate the curvature of the parabolic mirrors (more expensive) varying the angle of each row with a single axis tracking.

The main advantage of linear Fresnel concentrators system is its simple installation and low cost although the yield is less than the parabolic trough solar collectors.

Solar thermal high temperature. Linear Fresnel receptors.

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References

Last review: May 21, 2015