-- This project is inactive --
HiTek Services, under the Baseload CSP FOA, conducted fundamental parametric analyses of the optimum heliostat size and developed a novel low-cost heliostat design.
Approach
There were four tasks under this award:
- Develop a means to determine the optimum size range of the heliostat, in terms of the applied forces and moments, manufacturing learning curve effects, O&M, and optical efficiency. The outcome of this task will be a spreadsheet analysis tool for parametrically determining heliostat costs that are appropriately allocated into categories with inputs for a specific design.
- Construct a prototype glass-fiberglass reflector with built-in compressive loads that greatly resist breakage. The outcome of this task will be test results on performance.
- Design a drive unit based on a high-efficiency staged sprocket-chain configuration that has a lower cost and longer life than conventional gear drives. The outcome of this task will be a drive unit that meets the load requirements for the size range predicted by the parametric analysis for the optimum heliostat size.
- Create a low-cost, long-life tracking control subsystem. The outcome of this task will be a prototype control system and performance test data.
A staged-chain drive unit eliminates destructive coupling loads from severe wind conditions and greatly reduces cumulative fatigue damage.
Innovation
This project targets three heliostat sub-components to reduce the overall costs of these systems. Innovative approaches are being applied to develop the following:
- A more break-resistant reflector using glass-fiberglass
- A drive configuration based on sprockets and chains rather than gears
- Lower resolution encoders that provide the necessary precision for a long-life tracking control subsystem.
Conclusion
The single most important accomplishment of Phase I was the development of a generic method to find an optimally sized heliostat. Using cost data from previously published DOE reports, this method showed that the cost-optimal heliostat was much smaller than many in the field had been developing. For the chosen set of inputs, it was shown that a heliostat size of around 10m2 was much closer to a cost minimum than a 148m2 heliostat.
The two most important accomplishments of Phase II were the publications detailing the heliostat sizing work and the development of the autonomous heliostat controller.
Final Report
Kusek, Stephen M. Low Cost Heliostat Development. No DE-EE0003593, 2014. doi:10.2172/1154729.
Publications, Patents, and Awards
- Blackmon, James B. "Parametric determination of heliostat minimum cost per unit area." Solar Energy 97 (2013): 342-349. doi:10.1016/j.solener.2013.08.032
- Blackmon, James B. "Heliostat drive unit design considerations–Site wind load effects on projected fatigue life and safety factor." Solar Energy 105 (2014): 170-180. doi:10.1016/j.solener.2014.02.045
- Blackmon, James B., Allen H. Weber, and Steven R. Chiswell. "Wind gust distribution analysis and potential effects on heliostat service life." Solar Energy 120 (2015): 221-231. doi:10.1016/j.solener.2015.07.014
- Kusek, S., Caraway, M., McFarland, T., Lynn, M., Sahm, A., Boehm, R., & Ayubi, O. "Initial Testing of the HiTek Solar Tracking Monitor." ASME 2012 6th International Conference on Energy Sustainability collocated with the ASME 2012 10th International Conference on Fuel Cell Science, Engineering and Technology. American Society of Mechanical Engineers, 2012. doi:10.1115/ES2012-91204
- Lovegrove, Keith, and Wes Stein, eds. Concentrating solar power technology: principles, developments and applications. Elsevier, 2012. Chapter 17 “Heliostat size optimization for central receiver solar power plants”. Blackmon, J.B.
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