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TOPHAT™ for the Alignment & Focus of Heliostat Mirror Facets

Theoretical Overlay Photographic Heliostate Alignment Technique

Sandia National Laboratories

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PDF Document PublicationMarket Sheet
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Technology Marketing Summary

The Theoretical Overlay Photographic Heliostat Alignment Technique (TOPHAT) is a unique method which helps to accurately and effectively concentrate solar energy onto a receiver. By utilizing a camera/target fixture placed in front of the heliostat TOPHAT aligns and focuses the mirrors on a heliostat. It uses the photographs taken by cameras on the fixture and comparing the location and size of the target patterns with their predicted theoretical images. Adjustments are made to the facets until the photographic images of the targets match the theoretical images in location and size. The fixture is a flat structure nominally the same dimensions as the heliostat. Cameras are accurately mounted at the center and corners of the fixture. Targets, also mounted on the fixture, are viewed by the cameras in reflection through the facets.


Sandia also holds a similar technology– TOPCAT™- for trough applications.

  • Increased efficiency & accuracy in solar mirror alignment
  • Reduced loss of concentrated solar
  • Increased efficiency in solar energy generation
  • Can be used during heliostat assembly or within the heliostat field
  • Cameras can work during the day or at night
Applications and Industries
  • Energy sustainability
  • Increased efficiency in solar concentration
  • Power production
  • Fuel and chemical production
More Information

Patent pending.

Patents and Patent Applications
ID Number
Title and Abstract
Primary Lab
Patent 8,582,092
Alignment and focus of mirrored facets of a heliostat
Various technologies pertaining to aligning and focusing mirrored facets of a heliostat are described herein. Updating alignment and/or focus of mirrored facets is undertaken through generation of a theoretical image, wherein the theoretical image is indicative of a reflection of the target via the mirrored facets when the mirrored facets are properly aligned. This theoretical image includes reference points that are overlaid on an image of the target as reflected by the mirrored facets of the heliostat. A technician adjusts alignment/focus of a mirrored facet by causing reflected reference markings to become aligned with the reference points in the theoretical image.
Sandia National Laboratories 11/12/2013
Technology Status
Technology IDDevelopment StageAvailabilityPublishedLast Updated
SD#11629Development - It has been demonstrated that the key elements of this technology have been integrated with reasonably realistic supporting elements so technology can be tested in a simulated and operational environment. Available - Various license and partnering options are available. Please contact the Intellectual Property department to discuss. 06/10/201010/31/2016

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