système thermosolaire
- Domaine
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- énergie énergie solaire
- Date
Terme :
- système thermosolaire n. m.
Terme associé :
- système héliothermique n. m.
Traductions
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anglais
Date :Définition
A term generally applied to any means of generating electrical power from solar energy by using the heat produced in a collector to drive a heat engine, such as a stream turbine. This is also known as "thermodynamic conversion" of solar energy. These systems are still at the experimental and pilot-plant stage, but many conceptual designs have been drawn up. In order to achieve reasonable thermodynamic efficiency a high temperature heat input is required and this entails the use of focusing collectors of some kind.
Note :
In simple systems of this type water is passed along a blackened tube at the focus of a paraboidal mirror, converted to steam and passed to a steam turbine. The mirror must be steered to track the sun to achieve good performance, and this can be carried out by a servo motor linked to a temperature or light sensor. Larger-scale solar thermal power systems are envisaged to consist of a large central tower at the focus of an array of heliostats. The array is able to track the sun by virtue of individual steering of the heliostats. Heat transferred from the tower would be used to generate steam to drive a turbogenerator. Such systems can only be considered feasible in regions with high insolation over most of the year and low precipitation from rain and dust. Desert sites, especially in the south-western USA, are considered to be the most primising. Advantages include the absence of air pollution and low running costs. Capital costs, however, would undoubtedly be high as a result of the large mirror surfaces required. Land requirements too are large, which is another factor leading to the choice of desert sites. A major problem with such sites, however, is the provision of cooling water for the turbine since the temperature of heat rejection is critical for the thermodynamic efficiency. The use of open-cycle turbines operating on air has been considered. Thermionic, thermoelectric and thermochemical conversion have also been suggested. Energy storage may be required, either as heat or as electrical power, to provide power in periods of low insolation and at night.
Termes :
- solar thermal power system
- solar-thermal power-system
Terme associé :
- solar-thermal system