Study on the tracking error and focused spot trajectory characteristics of the dish concentrator under the azimuth axis tilt error

Abstract

The dish concentrator is an indispensable optical device for solar dish/stirling power system, which requires accurate tracking sun’s position. However, both the foundation settlement caused by long-term service and installation error can cause the support column tilt, thus destroying the vertical relationship between the column axis (i.e. azimuth axis) and ground plane resulting tracking errors. In this paper, a tracking error model of dish concentrator with elevation–azimuth dual-axis tracking considering column tilt is developed, the radial error angle θ1 and circumferential error angle φ1 are used to describe column tilt angle and tilt direction. The concentrator tracking error and focused spot position under column tilt error are analyzed using several dimensional evaluation indexes for the whole year, every day and every moment, and are verified by a novel virtual experiment of the concentrator tracking and optical simulation. When θ1 is constant, the tracking performance is worst throughout the year at φ1 of 90° and 270°, while the influence of column tilt can be effectively reduced at φ1 of 0° or 180°. The maximum daily tracking error can reach 1.91∼3.49 mrad in whole year at θ1=0.1° and φ1 in 0°∼360°, so θ1 should be controlled within 0.1°.