Hierarchical control of Multi-Generation solar thermal power plant

This paper reports on the development of a hierarchical control strategy for a multi-generation solar plant. The plant includes a linear Fresnel reflector, an organic Rankine cycle, an absorption chiller, a thermal storage tank, circulation pumps, and valves. The hierarchical control strategy consists of three successive layers in addition to a wireless monitoring system. The first layer is a supervisory control layer which is responsible for selecting the appropriate operating mode of the plant depending on the current state, user demand, and weather data. The second layer is concerned with determining the reference temperature for the maximum yield from the solar field. The third layer is responsible for regulating the solar collector's outlet temperature, cooling, and electricity production. The proposed strategy is implemented in the Matlab®/Simulink environment using the CARNOT toolbox with validated modeling of the main plant's components. The performance of the whole plant is evaluated under different climate conditions. The results show that the proposed control system is feasible over wide operating conditions and is able to drive the linear Fresnel plant close to the optimum operation, while enhancing the stability of the system, and increasing its final energy production.