Mechanical Modal Phenomena of a Ganged Heliostat

Ganged-heliostats have the potential for large cost reductions with enhanced solar collector field optimization. Unlike typical heliostats that require dual axis tracking actuators and a base or foundation, ganged-heliostats can share actuation and a support structure. This membership greatly reduces system infrastructure and installation costs. However, concentrating solar power (CSP) heliostats are subjected to wind-induced loads, vibration, and gravity-induced deformations. These effects could impact performance and reliability of these structures, where despite the many advantages for the utility of ganged heliostats, modal limitations exist from wind perturbations. In this investigation, an introductory multiphysics finite element analysis (FEA) model was developed using SolidWorks Simulation software to validate experimental measurements of a novel small-scale ganged heliostat system, parametrically under varying azimuth rotations, facet pitch levels, and cable tension levels. The ganged heliostat design featured a number of mirrors resting on two guide wires which were tensioned and rotated to align with any given target. Experimentally, several standard modal tests were conducted on the ganged heliostat, which was designed to operate under a number of orientations, where for this investigation two scenarios were selected to be representative of an operational heliostat. The heliostat was oriented at a 0° (face up) and 45° orientations for the modal test configurations. The modal tests were computationally validated in good agreement with the experiments to within 2.8% and 6.3% error for 0° and 45° orientations respectively.