That windowpane in your office will soon become valuable for more than the view. Newly developed electrochromic "smart" glass can cloud up for privacy, block the sun's rays to cool you down, or absorb them to power the place. Scientists say the glass will soon enable your office windows to turn into multitouch screens for PowerPoint presentations or videoconferences.
Green glass: Electrochromic glass draws its properties from a thin transparent glaze. Sage Electrochromics, based in Faribault, Minn., already manufactures panes that can change colors. The glass is lined with five layers of ceramic coating that, taken together, are less than 1/50th the thickness of a human hair. When a tiny voltage is applied, lithium ions and associated electrons pass across the layers, darkening the glass. Reverse the polarity, and the glass clears. This can reduce peak energy demand in a commercial building by 20% to 30%, according to a study by Lawrence Berkeley National Laboratory. The potential savings have attracted public and private investment that will soon bring down the cost of manufacturing, which could lead to new uses and applications for the technology.