Future for self-tinting windows looks rosy

Summary:Sage Electrochromics receives $72 million in federal funding for smart windows. Their high-tech glass dims and brightens automatically and could be a clear choice for green buildings.

The U.S. Department of Energy has granted $72 million to Sage Electrochromics to build a manufacturing plant for their smart windows.

The Minnesota company is producing glass that tints to reduce solar heat and glare.

According to the Lawrence Berkeley National Laboratory, SageGlass could possibly cut cooling costs for commercial buildings by 20 percent. The electrochromic-glazed panes might also lessen lighting expenses up to 60 percent.

These windows aren't akin to the eyeglasses that shift from spectacles to sunglasses in response to changing light.

Owners have complete control over them. They tint them by flipping a switch or by programming them to dim at certain times of the day. A low-voltage electric current passes through the glass, coloring it from clear to a blueish hue.

Currently, the glass transitions between two shades, but the company hopes to offer intermediate levels in the future.

Layered atop the SageGlass are five metal oxide coatings: Two transparent-conductor layers surround an electrochromic layer, an ion conductor, and an electrode counter.

The window darkens as lithium ions and associated electrons transfer from the counter electrode to the electrochromic layer. When the current switches off, the ions and electrons return to their previous layers, and the glass becomes clear.

The combined width of the coatings is less than one-fiftieth of a human hair.


In addition to energy savings, electrochromic windows could reduces a building's need for cooling equipment by 25 percent. Sage Electrochromics also says its product helps protect furniture and textiles from fading due to ultra-violet and visible light exposure.

Video from EngineeringTV.com

[via EcoSeed]

This post was originally published on Smartplanet.com

Topics: Innovation


Contributing Editor Melissa Mahony has written for Scientific American Mind, Audubon Magazine, Plenty Magazine and LiveScience. Formerly, she was an editor at Wildlife Conservation magazine. She holds degrees from Boston College and New York University's Science, Health, and Environmental Reporting Program. She is based in New York.... Full Bio

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