Determination of Gravity-Induced Deformation of Heliostat Structures Through Irradiance Maps Analyses
Abstract
In this work a method for determining the deformation degree of the structure of a heliostat under gravity loads is presented. This method is based on the comparison between the numerical and experimental flux maps acquired at different times of the day. Numerical flux maps are simulated using matrices of slope errors determined through deflectometry. For each heliostat, its matrix of slope errors is determined for a specific orientation of its structure depending of the heliostat position in the field. If there is no gravity-induced deformation, the experimental flux map acquired at any time of the day should be identical to its corresponding numerical one. On the contrary, if deformation exists, there should be differences between both maps depending of the orientation of the heliostat, i.e., on the time of the day. Quantitative comparison between both maps is carry out statistically with the root mean square deviation and the Pearson correlation coefficient. For this study, the heliostat solar field located at IMDEA Energy, Mostoles, Spain, is used.