Spectral selectivity of electrochromic windows with color state for all sky conditions

David E. Soule; Ji-Guang Zhang; David K. Benson

doi:10.1117/12.217339

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23 August 1995 Spectral selectivity of electrochromic windows with color state for all-sky conditions

David E. Soule, Ji-Guang Zhang, David K. Benson

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Proceedings Volume 2531, Optical Materials Technology for Energy Efficiency and Solar Energy Conversion XIV; (1995) https://doi.org/10.1117/12.217339
Event: SPIE's 1995 International Symposium on Optical Science, Engineering, and Instrumentation, 1995, San Diego, CA, United States

Abstract

The optical performance of an electrochromic window is found to deviate with window color state and with sky condition from clear to cloudy. A new spectral cloud model ALLSKY1 (Soule) is developed and applied to an electrochromic window recently developed at NREL (Zhang and Benson). A comparison in spectral selectivity also is made between the electrochromic window and spectrally selective standard windows. Two series of double- glazed window sections, including the electrochromic window with color state and a series of standard windows with spectral selectivity, were measured for transmittance and reflectance (300 - 2500 nm). A new near-infrared blocking factor, that depends strongly on sky conditions, is developed for warm-climate window applications with cooling load reduction. The color shifts of both the incident daylight spectra from clear to cloudy and the electrochromic window with color state are studied with a chromaticity analysis (CIE 1931 2 degrees). Computed daylight correlated color temperatures show a wide range, with values of 5660 K for clear global irradiation, 6210 K for clouds, and 13,250 K for a zenith blue sky. Chromatic trajectories with color state for transmitted radiation extend further toward the blue to 8180 K for the global and 28,990 K for the zenith sky irradiation.

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David E. Soule, Ji-Guang Zhang, and David K. Benson "Spectral selectivity of electrochromic windows with color state for all-sky conditions", Proc. SPIE 2531, Optical Materials Technology for Energy Efficiency and Solar Energy Conversion XIV, (23 August 1995); https://doi.org/10.1117/12.217339

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