More Efficient Heliostat Fields for Tower Solar Plants (HELIOSUN)

Concentrating solar thermal plants should play an important role in the energy transition towards renewable energy sources, since they offer a simple and economical way of storing energy, allowing the generation of electricity to be extended to those moments when there is no solar radiation. direct (at night or on cloudy days). Among the different concentrating solar technologies, the central receiver tower technology is the one that presents the greatest potential for improvement: higher conversion efficiencies when operating at higher temperatures, as well as a greater reduction in costs in its implementation. And among the components of this technology (solar field, receiver, energy storage system and power block), the reduction of costs in the solar field, made up of thousands of heliostats, is the one that would have the greatest impact on reducing costs. of a central receiver plant, since it represents up to 60% of the investment cost for plants with more than 100MWe of nominal power; in addition to also assuming a majority cost in the costs of operation and maintenance of this type of plants.

This project addresses cost reduction from 3 different but complementary points of view. First, an artificial vision system for object recognition is proposed, based on neural networks, which allows closed-loop control of the pointing of the heliostats in the field. The system, which consists of a low-cost camera and processor installed in each of the heliostats, will make it possible to eliminate positioning sensors as well as improve the pointing accuracy of the heliostats in the solar receiver. This strategy contributes to improving the industrialization of heliostats (industry 4.0), in addition to being aligned with the SmartCSP lines promoted by the European Commission. Secondly, a correct measurement of the atmospheric attenuation suffered by the solar radiation concentrated by the heliostats on its way to the solar receiver, with distances greater than 1500m for those solar plants with nominal power greater than 100MWe, will allow, in the first place, , an adequate selection of those locations with the best characteristics for the implantation of tower plants with a central receiver; and, in addition, to optimize the routine operation of the solar plant with real-time measurements of atmospheric attenuation. For this, the proposal intends to work on the generation of a typical year of extinction for the Plataforma Solar de Almería; in addition to generating and validating atmospheric extinction prediction models based on climatic variables. Finally, using the generated models and satellite images, it is intended to build an atmospheric extinction map for Spain, very useful for those companies interested in the development of technology at a national level.

Finally, it is proposed to develop a ray tracing model that allows a more accurate prediction of the behavior of a central receiver tower solar plant considering spectral analysis, as well as including all the experimental results exposed above.

These three approaches will make it possible to improve the operation of the central tower solar plants as a whole, optimizing in particular the operation of the solar receiver and the solar field, increasing the annual electricity generation and therefore the technical and economic efficiency of these systems.

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