Browsing by Author "Swart, Benjamin Dawid"
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- ItemA Method for accurate measurement of heliostat mirror orientation(Stellenbosch : Stellenbosch University, 2017-03) Swart, Benjamin Dawid; Treurnicht, J.; Engelbrecht, H. A.; Stellenbosch University. Faculty of Engineering. Dept. of Electrical and Electronic Engineering.ENGLISH ABSTRACT: Heliostat tracking is a critical component of the solar field of concentrating solar power central receiver systems and can be the source of significant losses in power and profit when it lacks the necessary accuracy. The current industry norm seems to be open-loop tracking using an error model for a tracking error of one milliradian, with error model parameters requiring periodic recalibration. In this thesis a method is developed which is able to determine the orientation of all heliostats in the field simultaneously, providing near real-time feedback to the control system, removing the need for recalibration while maintaining an accurate tracking accuracy. The method works by determining the positions of three or more distinct points on the heliostat mirror surface. These points form a plane which is then used to calculate the heliostat normal vector. The performance of the method is analysed and quantified using simulations, and experiments are used to validate the theoretical models. Quantification of the system performance is used to determine the initial feasibility of the method. Results indicate that for the error sources included in the model it is theoretically possible to achieve a tracking error in the order of one milliradian or less. Furthermore, experimental results are found to differ by only 5% from theoretical results. This is promising and merits further investigation into the method as a possible solution to the current heliostat tracking problem.