Local model predictive controller in a solar desalination plant collector field

This paper proposes a new predictive control strategy for a distributed collector field of a solar desalination plant. The main purpose of the controller is to manipulate the water flow rate to maintain constant the outlet-inlet temperature gradient in the collectors in spite of disturbances. The controller is based on a filtered Smith predictor generalized predictive control algorithm and a simple procedure to update the linear model used in the predictor as well as the tuning parameters, in such a way that non-linear optimization is avoided. The controller copes with the process non-linearities, constraints, dead time and plant-model mismatch obtaining the desirable performance both, in the reference tracking and in the rejection of strong irradiance disturbances. Simulations and real experimental tests in AQUASOL desalination plant solar field are presented to show the advantages of the proposed controller.