Location: Sweden Architect: John Robert Nilsson Arkitektkontor

by Bruce Mulliken

Green Energy News

Someday we’ll consider windows as devices, as part of the heating, air conditioning and energy systems in homes and all buildings.

It’s relatively easy to help keep a room cool in warm months or warm in cool months by controlling the amount of light that streams through windows. Closing window blinds, shades, shutters or curtains will keep sunlight from heating a room and its contents. Keeping sunlight out will cut air conditioning costs and reduce associated emissions. Conversely letting the sun shine in, by pulling back the curtains or retracting the shades will help warm a room and the people in it even on the coldest of days. This free natural solar heating cuts energy costs.

One downside of using window coverings to control heat in a room is that the view of the immediate world is hidden. People often pay a premium for what they want to see. Putting that view behind a wall of curtains wastes the investment.

Another downside of covering glass for energy’s sake is that adjusting window coverings often requires human input. Unless the coverings are automated and controlled by an energy management system, someone has to be there to open or close the blinds, shades curtains, or what have you.

Where the view, both in and out, needs to be preserved while attempting to save energy tinted windows can be installed or solar control window films can be applied to existing glass. Solar Gard, a maker of such films, says that their products help buildings consume up to 30 percent less energy for cooling by stabilizing interior temperatures, transforming standard glass into high performance windows.

(Solar Gard, by the way, is making available the results of its environmental product declaration (EPD), which scientifically substantiates that Solar Gard architectural solar control window films have a net positive environmental impact across the globe.)

A net positive environmental impact from the application of solar window films is a good thing, but there’s a downside here as well in terms of human comfort. Window films may be great in the hot months when too much sun is bad thing, but not so great in cold months when a warm solar glow is appreciated. There’s nothing like sitting in the sunny spot on a frigid winter day.

The next technological advancement in utilizing windows to control energy consumption would be the mass adoption of smart windows (or switchable windows) which incorporate glass that will change in opacity from fully transparent to translucent to completely light blocking by the turn of an electronic control. One variation of smart glass is known as electrochromic glass which changes light transmission properties in response to voltage and electricity applied and thus allows users, or some automated energy management system, to control the amount of light and heat passing through the glass.

Though the electrochromic technology is available it’s not widely commercialized for use in buildings.

That is set to change.

Global building materials maker Saint- Gobain and SAGE Electrochromics are teaming up to build the world’s first large-scale plant to produce electrochromic glass, SAGE’s specialty.

In a statement the companies say, “Saint-Gobain Glass and SAGE will build the world’s first large-scale electrochromic glass plant in Faribault, Minnesota (United States). The project which started in November 2010 will cost about 135 million US dollars. It will act as the spearhead for electrochromic technology worldwide. The new plant will have an annual production capacity of more than 370, 000 square meters (4 million square feet) of electrochromic glass with sizes ranging up to 1.5 x 3.5 meters (5 x 10 feet), much larger than currently available in the market. The plant is scheduled to begin production starting in mid-2012. Leveraging the resultant economies of scale, this innovative glass will be sold at an affordable price.”

Both companies will market the glass under their own brand names. Sage will use SageGlass (R), Saint Gobain the QUANTUM GLASS(tm) brand in Europe.

Installing smart windows will require an electrical connection. Once this wiring is in place new possibilities will certainly arise using some technologies already available and others that are in the development stage. Powered windows that open or close automatically for security’s sake or for ventilation could become common; so will automated window coverings for insulation and privacy. Further down the line, and now in early the development stage, are solar photovoltaic windows that will be a new power source for the house even if it’s only to provide electricity for the operation of the window itself.

Wired windows as heat and cooling devices. They’re on the way.

Links:

Solar Gard’s Environmental Product Declaration (EPD)
http://www.solargard.com/energy

Saint-Gobain
http://www.saint-gobain.com

Quantum Glass
http://www.quantumglass.com

SAGE Electrochromics
http://www.sage-ec.com

Credit to: www.green-energy-news.com/