by Jbs012710 a3 — February 1, 2010—Researchers at the U.S. Department of Energy’s National Renewable Energy Laboratory (NREL) are working on the high-tech equivalent of putting sunglasses on buildings with a new generation of insulated “dynamic windows” that change color to modulate interior temperatures and lighting.
Electrochomic windows have been available for more than two decades, but they have not become widely available or commercially successful. Among contemporary designs, NREL has verified the performance of one technology developed by Sage Electrochromics. Today’s dynamic windows cost up to $1,000 per square meter of glass, but Sage predicts its technology will drop in price by as much as 70 percent over the next five years as performance improves, volume increases, and production becomes more efficient.
Although electrochromic windows add yet another powered device to a modern building, they should save far more energy than they consume, says NREL. Powering 1,500 square feet of color-changing glass (about 100 windows) would reportedly require less power than a 75 watt light bulb, and would reduce construction, HVAC and lighting costs as well.
NREL researchers also are investigating ways to rapidly make electrochromic films on cheaper, flexible plastic substrates instead of glass. This will allow development of so-called “roll to roll” (R2R) processing methods similar to those currently used to print newspapers. An electrochromic device made of flexible materials could be retrofit to existing windows, says NREL research scientist Robert Tenent.
