Optimal solar collectors defocusing based on maximum temperature

This paper presents a preliminar study to defocus solar collectors when the fluid output temperature is greater than the maximum temperature defined by the fluid manufacturer. The proposed defocusing technique is based on a Mixed Logical Dynamical (MLD) model used by a Practical Nonlinear Model Predictive Controller (PNMPC). The MLD model is used to predict the effect of the defocusing on the output temperature and based on this predictions the PNMPC calculates the optimal control decision solving a Mixed-Integer Quadratic Programming (MIQP). For illustrating the operability of the proposed algorithm a simulation in a study case compounded by a loop with four collectors is performed and the controller performance is analyzed.