A transient optical-thermal model with dynamic matrix controller for solar central receivers

Maintaining the temperature distribution in solar central receivers below critical material limits is important to avoid premature failure or reduced cycle life of the receiver. For highly concentrated solar tower systems, any transients in the incoming energy will be amplified and are likely to have a significant impact on its operation. This paper demonstrates the dynamic performance of a closed-loop aiming strategy to maintain the receiver's operation when undergoing transients in solar radiation without exceeding the temperature constraints caused by thermal stresses and material corrosion considerations. A Gemasolar-like solar receiver sub-system is modelled in a detailed fashion but with simplifications to minimise computational time. The proposed aiming strategy using a modified Dynamic Matrix Control (DMC) algorithm is implemented in the model, and partially shading of heliostat field is simulated using the biomimetic approach for modelling cloud passage. The simulation performed shows the robustness of the aiming strategy to appropriately handle the incident flux transients on the solar external receiver caused by different intermittent cloud passage characteristics. The techniques implemented in this paper can be a useful tool in the design phase to anticipate consequences for the receiver when subject to regular or subtle DNI transients.