Field Verification of Components
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Hand-Held Dectector for Low-e and Spectrally Selective
Coatings
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| Spectrally selective low-emissivity coatings offer the potential to
reduce unwanted solar heat gains in cooling dominated climates by 40% over clear double
glazing and by up to 30% over conventional low-e coatings. Windows employing such coatings
are extremely cost-effective technologies for code compliance or incentive programs (i.e.
Energy Star homes). However, since these technologies are typically not discernible to the
human eye, consumers, builders, utility representatives and others have asked for a simple
hand-held detector to determine what type of coating (if any) is used on a double glazed
window. With DOE and CIEE co-support, LBNL Windows and Daylighting Group researchers
developed a prototype of such a detector. It measures reflectance in the near infrared
portion of the solar spectrum (where the different coating technologies have significantly
different reflectances). The low cost measuring technique uses an infrared light-emitting
diode and phototransistor. The result is displayed by illuminating one of three LEDs
giving a simple indication of whether the window is clear, regular low-e, or spectrally
selective low-e.
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| For more information on component verification contact: Howdy Goudey |
The first generation prototype shown
here was completed in November 1998 .