Electrochromic windows for climate control and privacy
There’s been talk recently on some other environmental technology blogs about electrochromic glass for windows and skylights that has got me very excited. Electrochromic glass has a liquid crystal layer embedded in the glass which darkens as current is applied. This is like having a dimmer switch for your windows, allowing for adjustable daylight levels, increased privacy without curtains, and for reducing solar heat gain.
Since my father is an optometrist, I’ve known about photochromic and electrochromic technology for several years now; and I’m glad to see this technology finally hitting the market for windows. Since this technology is a pane of sandwiched glass, it could be integrated into low-e energy efficient windows, skylights, glass wall partitions, and car windows (for on-demand tinting).
The one drawback to this technology is that it requires electricity to function, something ordinary glass does not. Both Treehugger and EcoGeek commented that this technology would be ideally suited to use integrated thin-film solar panels, Treehugger suggested the Sharp LumiWall system, however at first glance it appears too dark to allow any light transmission through the window or skylight. However, there’s a product I’ve been following for a while that would be ideally suited for use with electrochromic glass: XsunX Powerglass.
The Powerglass panels, shown above, look like normal tinted windows but are capable of producing up to half the power of a conventional opaque PV panel. Other translucent PV panels have visible lines or patterns in them, the Powerglass panels do not.
What I propose is to combine these 2 technologies in layers, with the solar cell layer above the electrochromic layer. That way, the system will continue to provide power to your building or window storage batteries, whether your window is darkened or not. This would provide electrical power for your home, and self-powering dimmable windows, all with the potential to be controlled automatically with sensors or from a control switch.
It’s also possible that in the future the technology will be developed enough to display video or still scenes in the windows, turning them into oversized display terminals. We’ve seen this in science fiction for years, perhaps this is the start of the technology that will allow it to actually happen.