Heliostat vibrations due to wind loading can degrade optical pointing accuracy while fatiguing the structural components. This paper reports the use of structural dynamic measurements for design evaluation and monitoring of heliostat vibrations. A heliostat located at the national solar thermal testing facility (NSTTF) at Sandia National Laboratories in Albuquerque, New Mexico, has been instrumented to measure its modes of vibration, strain and displacements under wind loading. The information gained from these tests will be used to evaluate and improve structural models that predict the motions/deformations of the heliostat due to gravitational and dynamic wind loadings. These deformations can cause optical errors and motions that degrade the performance of the heliostat. The main contributions of this work include: (1) demonstration of the role of structural dynamic tests (also known as modal tests) to provide a characterization of the important dynamics of the heliostat structure as they relate to durability and optical accuracy, (2) the use of structural dynamic tests to provide data to evaluate and improve the accuracy of computer-based design models, and (3) the selection of sensors and data-processing techniques that are appropriate for long-term monitoring of heliostat motions. This work also demonstrates the first measurements of rigid body modes of vibration associated with heliostat drive (azimuth and elevation) mechanisms, which are important structural dynamic response characteristics in dynamic design of heliostats.
Structural Dynamics Testing and Analysis for Design Evaluation and Monitoring of Heliostats
Contributed by the Solar Energy Division of ASME for publication in the JOURNAL OF SOLAR ENERGY ENGINEERING: INCLUDING WIND ENERGY AND BUILDING ENERGY CONSERVATION. Manuscript received June 19, 2012; final manuscript received September 2, 2014; published online October 23, 2014. Assoc. Editor: Markus Eck.
The United States Government retains and the publisher, by accepting the article for publication, acknowledges that the United States Government retains a nonexclusive, paid-up, irrevocable, worldwide license to publish or reproduce the published form of this manuscript, or allow others to do so, for United States Government purposes.
- Views Icon Views
- Share Icon Share
- Cite Icon Cite
- Search Site
Todd Griffith, D., Moya, A. C., Ho, C. K., and Hunter, P. S. (October 23, 2014). "Structural Dynamics Testing and Analysis for Design Evaluation and Monitoring of Heliostats." ASME. J. Sol. Energy Eng. April 2015; 137(2): 021010. https://doi.org/10.1115/1.4028561
Download citation file:
- Ris (Zotero)
- Reference Manager