Project Profile: Next-Generation Low-Cost Reflector

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PPG, under the Baseload CSP FOA, produced a durable first-surface mirror with improved optical performance and geometry design to reduce the unit cost of the reflector subcomponent in a concentrating solar power (CSP) application.

Approach

PPG Industries created an ultra-large, front-surface glass mirror with an inorganic protective hardcoat. This approach worked toward reduced operation and maintenance costs and a lower overall unit cost of the reflector assembly. Moving to a larger-sized glass reflector also reduced manufacturing costs because fewer mirrors are needed. The project aimed to achieve an estimated levelized cost of electricity (LCOE) of less than $0.08/kWh.

ppg_baseload.jpg

Schematic cross section of a first surface mirror.

Innovation

LS3-sized mirrors use only 55%–65% of the available capacity of existing glass coating equipment. PPG pioneered a design that:

  • Represents a size increase of 2.5 times more than current mirrors
  • Uses a first-surface mirror as opposed to a second-surface mirror
  • Adds a proposed alumina hardcoat to eliminate the passage of light through the glass material while also providing durability and anti-soiling properties
  • Achieves a reflectivity of 97%.

Conclusion

  • The design and feasibility of the first surface mirror concept and the potential for durable topcoat were demonstrated. A solar weighted reflectance of 90.6% (+/-0.6) was achieved and a pathway towards 97% identified
  • A potential of 1% reduction in soiling was demonstrated
  • The design and feasibility of the large area mirror reflector assembly was completed. A mirror support structure was designed and analyzed. Estimated material cost and fabrication and installation cost of $51/m2 and $106/m2 were respectively obtained
  • The LCOE computations obtained a cost of $0.122/kWh and a capacity factor of 76.4%
  • Absorption at silver/dielectric interface was identified as a major technical barrier to achieving high reflectance performance

Final Report

McCamy, James W., Kwaku Koram, and Brian F. Kornish. Next-Generation Low-Cost Reflector. No. DE-EE0003586. PPG Industries, Inc-Glass R&D, 2013. DOI: 10.2172/1080364 

Publications, Patents, and Awards

At this time, this project does not have published articles, patents, or awards.

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