Sun backward gazing method for measuring optomechanical errors of solar concentrators: experimental results

Area of Science:

• Optomechanical engineering
• Solar energy technology
• Optical metrology

Background:

• Accurate measurement of solar concentrating surfaces is vital for efficient solar energy conversion.
• Existing methods for measuring optomechanical errors can be limited in operational settings.
• Understanding and mitigating errors in solar reflectors is key to maximizing power output.

Purpose of the Study:

• To present the first experimental results of the four cameras backward gazing method for measuring optomechanical errors.
• To digitally reconstruct slope errors of solar concentrating surfaces using simultaneous camera imaging.
• To analyze experimental error sources and propose mitigation strategies for improved measurement accuracy.

Main Methods:

• Utilizing a four-camera backward gazing setup to capture images near the solar receiver.
• Developing and applying new algorithms for reconstructing mirror slope errors from acquired images.
• Conducting experiments on a sun-tracking heliostat at the THEMIS experimental solar tower.

Main Results:

• The four-camera backward gazing method was successfully implemented for the first time.
• The system achieved a canting error measurement accuracy of 0.2 mrad.
• Analysis identified key experimental error sources and potential mitigation techniques.

Conclusions:

• The developed method shows promise for accurate real-time measurement of solar concentrating surfaces.
• Further refinements could lead to an ultimate measurement accuracy of 0.1 mrad.
• This technique offers a valuable tool for optimizing the performance of operational solar power plants.