Optimal Control of Solar Thermal Plants with Energy Storage

This paper describes and assesses an optimal strategy to control distributed solar collector fields with thermal storage systems, especially during days with partial radiation due to the passage of clouds. The main objective of these control strategies is to maximize the thermal energy stored during different situations in which different parts of the solar field receive different degrees of solar radiation while keeping the net electrical power produced close to its set point. Simulations were carried out using three connected models, one for the solar field (taking into account all of its loops individually), that includes the passage of clouds, another one for the thermal storage system, and finally one for the power cycle. The solar field simulated is a small demonstration plant, in which it is assumed that all the loops have the same characteristics; and the nominal power range of the Rankine cycle is 800-2330kW.