Vacuum Glazing Could Emerge as "Game Changing Technology"
Vacuum glazing as a concept is nothing new. Glass researchers have been investigating the idea for years. Nippon Sheet Glass of Japan started offering a vacuum glazing product in the 1990s. Most window and door manufacturers, however, don't see the available technologies to be commercially viable yet.
Now, at least two companies say the long-discussed concept could become a reality. Guardian Industries., the Michigan-based flat glass manufacturer, and Eversealed Windows Inc., a high-tech start up company based in Iowa, both report they hope to have prototypes of new vacuum glazing products ready this year. They both admit that energy costs will play a key role in when their products might become commercially viable, but they also point out that most experts think energy costs will eventually rise again.
The technology, in which two lites of glass are separated by a vacuum and tiny, nearly-transparent spacers or pillars, is already in limited use. By replacing the air or gas between the panes of glass with a vacuum, you are left with fewer molecules to act as a gateway to pass heat in and out, and therefore far higher insulating values, explains Andy Russo, market development manager with Guardian Industries.
Guardian is currently developing its technology for a partner window seller that Russo says could have a product to market by early- to mid-2010. “We have proven the technological principles, and are in the process of securing funding to upscale,” reports Ken Bettger, Eversealed vice president and chief operating officer. “The next step is to demonstrate our laboratory results on a full-scale size, in a prototype.”
Researchers agree that creating a vacuum between the panes of glass would create R-values far above today's high performance glass packages. “We’re looking at R-10, R-11,” says Russo. “This is a game-changing technology.” Developers could “reasonably shoot for” an R14 rating using Eversealed's vacuum glazing technology, says Bettger.
A vacuum glazing product that can be mass-produced has eluded and frustrated developers for years, however. According to Betger, vacuum glazing concepts have appeared in patent literature for close to 85 years. So why has it taken so long for the technology to reach this stage? Russo says sealing the vacuum has been the most difficult issue to overcome from a manufacturing perspective. “You need an extremely strong vacuum, and any small hole or crack will inevitably get larger,” he continues. “The typical structure may not last.”
“In between the panes, sunlight can also do something to vacuum,” Russo adds. “Any impurities in the glass or the vacuum can degrade your vacuum and must be removed.”
A convergence of technologies, such as flattening out the tubes used to create vacuums in older-style televisions, could be the missing piece, Bettger states. “We’re not trying to suggest something that can’t be done on a large scale, he adds. “Think about micro-computer chips – it’s not beyond high-volume manufacturing.”
Besides creating and maintaining a near-perfect vacuum, any developer must also consider how to separate the panes of glass without having them collapse upon the vacuum area. Russo notes that early prototypes were separated by large, ugly spacers that ruined views and conducted heat, somewhat defeating the purpose of the vacuum. Eversealed describes its spacer system as “little pillars,” but the spacers are the size of a grain of pepper, Bettger points out. “If you put them on a white sheet, you might see them,” Bettger says. “You take a step back, and you can’t.”
Even as these developers say they are close to a prototype vacuum-glazed window, hurdles remain. Eversealed has spent three years developing the prototype, and is currently going into a second year of looking for funding in an economy that is floundering. “There hasn’t been as much of a demand as you would expect, given all the press about green, but most everyone agrees that energy costs are on the way up–that’s what will make this possible,” Bettger says.
“Quite a bit of the green movement is still religious fervor," he adds. "Find ways to make me some real money – that’s what people want to know.”
"People say, ‘Sure, I can up my R-value, but who’s going to pay for it,’” says Guardian's Russo. “We’re seeing a lot of excitement, but you always have people who are skeptical.” The technology could be the answer to proposed Energy Star standards for 2013, which he says will require insulating values for Northern climates that would require either a triple-glazed window or some new technology.
Looking at the future, Bettger says, “It’s going to come down to how much energy goes out the window, and how much does it cost me. Thee second question will be, ‘How long will it last.’ We’re as focused on number two as we are on number one–it doesn’t pay to bring in a great component that doesn’t last long.”