Conference article

Solar thermal power plants collect available solar energy in a usable form at a temperature range which is adapted to the irradiation levels and seasonal variations. Solar energy can be collected only when the irradiation is high enough to produce the required temperatures. During the operation, a trade-off of the temperature and the flow is needed to achieve a good level for the collected power. The storage is needed to keep the heat supply during the nights and heavy cloudy periods. Efficient operation requires a fast start-up and reliable operation in cloudy conditions without unnecessary shutdowns and start-ups. Fast and well damped linguistic equation (LE) controllers have been tested in Spain at a collector field, which uses parabolic-trough collectors to supply thermal energy in form of hot oil to an electricity generation system or a multi-effect desalination plant. Control is achieved by means of varying the flow pumped through the pipes in the field during the operation. The LE controllers extend the operation to varying cloudy conditions in a smart way. Varying irradiation and energy demand during the daytime can be smoothly handled in the LE control system with predefined model-based adaptation techniques. The system activates special features when needed to facilitate smooth operation. The intelligent state indicators react well to the changing operating conditions and can be used in smart working point control to further improve the operation in connection with the other energy sources.

Solar energy; intelligent control; nonlinear systems; adaptation; optimisation; linguistic; equations; modelling; simulation