Lab Develops New 'Super Window'
A new type of window is on the horizon, according to The Department of Energy’s Lawrence Berkeley National Laboratory, in California.
Scientists are working on bringing to market what they have dubbed a “thin triple super window,” and note that the design is at least twice as insulating as 99 percent of windows on the market today.
“Our approach is to attack the problem from two sides: to develop both ‘market pull’ and ‘technology push’ forces,” said Berkeley Lab researcher Steve Selkowitz, one of the inventors of the super window concept.
“We are working with manufacturers to assist them with their technology challenges while also working with Energy Star, supply-chain companies and utilities, which can offer rebates and incentives for consumer purchase. Our role is to be a catalyst in facilitating technological innovation and an evangelist in promoting DOE’s energy-efficiency mission.”
The popular double-glazed windows consist of two layers of glass, a layer of low-emissivity coating and argon gas in between the glass layers. The lab’s latest innovation inserts a third layer of thin glass in between the two layers of double-glazed windows, adds a second low-e coating and replaces the argon gas with krypton gas, which the lab says is more insulating.
In addition to the new “formula,” the design is the same width and same weight of double-glazed windows, putting it a notch about the triple-glazed windows that are currently available, the lab says, because it avoids having to redesign the window sash and frame.
The team notes that it is one step closer to its goal of getting windows to outperform insulated walls in terms of energy performance.
“A single layer of glass has an R-value, which is its resistance to heat conduction, of R1; double glazing is R2, and the low-e double is R4,” said researcher Charlie Curcija. “Our thin triple glazing is R8 to R10, or about twice as good as the best low-e double glazing today.”
The lab noted that the initial design was developed 20 years ago, but only recently has technology been widely available to make the thin layer of glass an affordable and viable option.
“The thin glass is 0.7 millimeters thick,” Curcija said. “Twenty years ago we couldn’t find any companies that could make thin glass sheets in volume. Now the flat-screen TV industry has pushed the glass industry to create precisely the glass we need for windows, and at a price the window market can afford.”
The lab is also working on making different windows for different climates, and will be sifting through its database of 5,000 glazings and coatings to get optimal selections for each market.
Scientists say they are working with both Andersen Corporation, the largest window and door manufacturer in the country, and Alpen High Performance Products, which specializes in energy-efficient doors and windows, for large-scale manufacture.