Heliostat field aiming strategies for solar central receivers

Abstract

This thesis work deals with the development and validation of four optical models for Solar Power Tower technology. The first model accurately computes the solar flux distribution incident on any central receiver reflected by a single heliostat; the novelty relies on the oblique projection of the receiver mesh onto the image plane where an analytic convolution function is evaluated. The second model determines the canting errors in the facets of real heliostats using a deterministic optimization algorithm that minimizes the difference between computed flux maps and experimental images captured on a Lambertian target. The third model extends the basic model to complete fields of heliostats where a symmetric aiming strategy is developed; just a single parameter, novel k factor, is needed to aim all the heliostats. The last aiming model maximizes the output in molten salt receivers while meeting the corrosion and thermal stress constraints; which are translated into allowable flux densities.