Progress in Vacuum Glazing Research

Guardian VIG, Guardian Industries' vacuum glazing panel, could roll out commercially by the end of 2009, according to a February 26th article from the Environmental News Network. The Michigan company has been researching the technology since 2000.

'A major promise of vacuum glazing is that it may provide superior insulation value although it can be made thin enough to be inserted in relatively thin frames, for instance as retrofits for existing single-pane window frames,' says Nils Petermann, senior associate, Efficient Windows Collaborative, Washington, D.C. 'If the vacuum pressure is low enough, there would be no conductive or convective heat transfer. And if low-E coatings are used, radiative heat transfer can also be minimised.'

However, vacuum glazing presents a number of engineering problems, Petermann says. 'A major issue is that the outside glass pane can expand or contract due to temperature changes, which is a structural challenge if non-flexible edge seals are used.' Another issue is the maintenance of an airtight seal around the edge, he says. ‘The seal must be maintained to eliminate gaseous conduction by keeping the air density to less than one millionth of its normal value. This seal must remain intact through manufacture, transportation, installation, and weathering.’

Vacuum glazing is marketed in Japan by Nippon Sheet Glass.

In Germany, the R&D project Production Methods for Vacuum Insulating Glass, or ProVIG, also is working on developing vacuum products. In the U.S., researchers at EverSealed Windows Inc., Evergreen, Colorado, are working on a R&D project on vacuum glazing with flexible metal edge seals.

At GPD in June last year in Tampere, Finland, Wolfgang Friedl, head of the after sales department for Germany's Grenzebach Maschinenbau GmbH, said his company was developing a vacuum insulating glass production line. While several companies have vacuum glass products, none have made notable progress into the market, he said.

The Grenzebach line, set to be operational in 2009, would produce VIG with a very low U-value of less than 0.4