Second-surface silvered glass solar mirrors of very high reflectance

Guillaume P. Butel, Blake M. Coughenour, H. Angus MacLeod, Cheryl E. Kennedy, Blain H. Olbert, J. Roger P. Angel

Research output: Chapter in Book/Report/Conference proceedingConference contribution

7 Scopus citations

Abstract

This paper reports methods developed to maximize the overall reflectance second-surface silvered glass. The reflectance at shorter wavelengths is increased with the aid of a dielectric enhancing layer between the silver and the glass, while at longer wavelengths it is enhanced by use of glass with negligible iron content. The calculated enhancement of reflectance, compared to unenhanced silver on standard low-iron float glass, corresponds to a 4.4% increase in reflectance averaged across the full solar spectrum, appropriate for CSP, and 2.7% for CPV systems using triple junction cells. An experimental reflector incorporating these improvements, of drawn crown glass and a silvered second-surface with dielectric boost, was measured at NREL to have 95.4% solar weighted reflectance. For comparison, non-enhanced, wetsilvered reflectors of the same 4 mm thickness show reflectance ranging from 91.6 - 94.6%, depending on iron content. A potential drawback of using iron-free drawn glass is reduced concentration in high concentration systems because of the inherent surface errors. This effect is largely mitigated for glass shaped by slumping into a concave mold, rather than by bending.

Original languageEnglish (US)
Title of host publicationHigh and Low Concentrator Systems for Solar Electric Applications VI
DOIs
StatePublished - Oct 11 2011
EventHigh and Low Concentrator Systems for Solar Electric Applications VI - San Diego, CA, United States
Duration: Aug 22 2011Aug 24 2011

Publication series

NameProceedings of SPIE - The International Society for Optical Engineering
Volume8108
ISSN (Print)0277-786X

Other

OtherHigh and Low Concentrator Systems for Solar Electric Applications VI
CountryUnited States
CitySan Diego, CA
Period8/22/118/24/11

Keywords

  • CPV
  • CSP
  • Concentrating
  • High reflectance
  • Mirror
  • Reflector
  • Silver
  • Solar
  • Thin film

ASJC Scopus subject areas

  • Electronic, Optical and Magnetic Materials
  • Condensed Matter Physics
  • Computer Science Applications
  • Applied Mathematics
  • Electrical and Electronic Engineering

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  • Cite this

    Butel, G. P., Coughenour, B. M., MacLeod, H. A., Kennedy, C. E., Olbert, B. H., & Angel, J. R. P. (2011). Second-surface silvered glass solar mirrors of very high reflectance. In High and Low Concentrator Systems for Solar Electric Applications VI [81080L] (Proceedings of SPIE - The International Society for Optical Engineering; Vol. 8108). https://doi.org/10.1117/12.894373