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The Reflected Target Non-intrusive Assessment (ReTNA) tool measures mirror surface slope and facet canting error for heliostat qualification, R&D, and quality assurance on the heliostat assembly line. It is designed to adopt simple, low-cost equipment such as modular, lightweight printed targets and off-the-shelf cameras.

Project Lead: Devon Kesseli (NREL)

Team: Guangdong Zhu (NREL), Kyle Kattke (Solar Dynamics)

Objectives:

• To develop and validate laboratory optical measurement technology. 
•  To offer the industry a lightweight, low cost, and portable system capable of fast setup and automated measurement. 
•  To enable accurate measurement of slope and facet canting error:
           o  For For heliostats of various geometries
           o  At varied heliostat orientations
           o  With varied loading applied to the heliostat

Approach:

• Using target deflection techniques to accurately measure mirror shape. 
•  Using photogrammetry to reduce the required precision of the setup. 
•  Leveraging advancements in image-processing and computer vision to automate measurement.

Status:

• Completed concept-proof stage, and repeated ReTNA testing on a commercial heliostat. 
•  Built initial ReTNA prototype at NREL, working on second generation system prototype. 
•  In next year, complete further rigorous validation campaigns with research and industry partners and collaborate with industrial partners to demonstrate commercial ReTNA layouts.

OpenCSP is an open-source platform including source code, applications, and data to enable collaborative development for the CSP community, supporting industry, research, and education. 

• OpenCSP_Code – Both foundation classes for building new programs and ready-to-run applications, including Sandia’s SOFAST 2.0 code, all in Python.
  
  
• OpenCSP_Data – Large data sets for research, optical targets for metrology ground truth tests, and test data for OpenCSP_Code.
  
  
• OpenCSP_Mechanical – Includes an interactive CAD tool for designing deflectometry layouts, plus a gallery of CAD models to support collaborative CSP research.
  
  
• OpenCSP_Tools – Non-code tools to aid CSP analysis and understanding.
  
  
• OpenCSP_Documents – Documents supporting OpenCSP and related topics. 

All are provided with an open-source license allowing unlimited use, requiring acknowledgement.

Project Lead: Randy Brost, Ph.D. (Sandia)

Objectives:

• Accelerate transfer of state-of-the-art CSP metrology and analysis tools to industry. 
• Provide a resource for businesses seeking to support CSP development. 
• Enable the code and data to contribute to education. 
• Provide a community collaborative development environment to enable teams to build new advanced CSP applications more quickly, and to speed their deployment.

Approach:

• Establish a strong collaborative code development environment set up to support effective team code development, including automatic testing, document generation, and issue tracking. 
• Provide a large corpus of difficult-to-produce CSP research data. 
• OpenCSP welcomes all to use its resources and contribute to make it even better!

Status:

• As of July 2024, both code and non-code OpenCSP repositories have been operational for months, used by the OpenCSP team. We plan to announce the public opening of OpenCSP at SolarPACES in October 2024. Presentation: “OpenCSP: Collaborative Code and Data For CSP.” 
• OpenCSP web portal is under construction; send inquiries to OpenCSP@sandia.gov.
   
  

Description: The drone-based Non-Intrusive Optical (NIO) Technology developed at NREL allows for in-situ characterization of heliostat optical errors at commercial-scale power tower CSP plants. The method will be validated using data collected from commercial solar fields, including Cerro Dominador and Crescent Dunes and compared against Beam Characterization System (BCS) measurements of tracking error at NREL’s Flatirons campus. Project Lead: Rebecca Mitchell

Project Lead: Rebecca Mitchell

Objectives:

• Update the NIO software so that it is fully automated and reliably produces optical error estimates at high volume 
• Validate the reliability and accuracy of estimates of slope, tracking, and canting error produced by the NIO algorithm through repeatability testing and comparison with BCS data. 
• Perform and comparison test of NIO and BCS measurements at the Flatirons campus

Approach:

• Test and refine the algorithm performance by processing drone image data collected at Crescent Dunes and Cerro Dominador. 
• Install a solar collector and BCS target at NREL’s Flatirons campus. 
•  Perform a comparison study of NIO and BCS measurements of tracking error at the Flatirons campus.  

Status:

• Made significant advancements towards commercialization of the NIO software through streamlining the data architecture and improving the reliability of the automated post-processing of data through testing of collected Cerro Dominador and Crescent Dunes data. 
•  A BCS has been deployed at Flatirons campus and two types of heliostats have been identified for installation at the site. 9 Heliogen heliostats have been delivered on campus and a purchased Heliuss heliostat prototype is being fabricated. 
• An IF1200A hexacopter UAS has been acquired for NIO data collection and test flights were conducted at Flatirons campus.