Variation of Heliostat Wind Loads in a Radial Field Array Model

Abstract

The design of heliostats throughout a concentrated solar power (CSP) plant are currently of uniform design, however, research into the variation in heliostat wind loading within a radially staggered field array can provide insight into potential material cost savings in heliostat field design. Experimental investigation was carried out on a field array model in the University of Adelaide large wind tunnel. A total of 64 heliostat models of size 0.1 × 0.1 m were radially arranged over four surround rows. Four 3-axis load cells were utilized to analyze field array cases of morning (0700 hours), noon (1200 hours), and evening (1700 hours) configurations. Angle calculations for beam reflection were made for the 21^st March (equinox). Results show mean and peak drag force coefficients reduce with distance into the field for a 1700 hour case due to high upstream blockage. Comparing the downstream drag and lift force coefficients against each test configuration, when heliostats are at steep elevation angles, high flow blockage leads to a reduction of coefficients downstream (0700 hour and 1700 hour cases). When elevation angles are reduced (1200 hours), drag and lift coefficients increase with distance from the central tower in the downstream direction. Results also show the central tower increases load coefficients on downstream heliostats, and therefore should be considered in heliostat wind loading and field design.