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The secret to Spacia’s high performance lies in its special structure.
Spacia consists of two sheets of 3mm-thick glass, but it is the 0.2mm-wide evacuated space between the two sheets that differentiates Spacia from conventional double glazing. The vacuum is quite extreme, boasting an air pressure of only about one millionth of an atmosphere.
Heat is generally conveyed through conduction, convection and radiation, and Spacia impedes all of these mechanisms. A special metallic film coating the glass also helps, but it is the vacuum between the sheets of glass that plays the major role in preventing conduction and convection. The effectiveness of vacuums in providing insulation has long been known, but the mass production of evacuated glazing glass proved so problematic that it remained an impossible dream for many years, until NSG finally succeeded in creating Spacia, the world’s first mass-produced evacuated glazing glass.
“Special metal studs of 0.5mm diameter, called microspacers, are placed at uniform intervals between the glass sheets to maintain the space between them,” says Hideo Kawahara, general manager of NSG’s Spacia business section. “They are literally just placed there. If adhesives were used, they might eventually give off gas that would reduce the vacuum. It was laying the microspacers at an acceptable speed at equal distances over a range of pane sizes that proved to be the most difficult task technologically. This was where a lot of makers ran aground. Of course, even once that problem is conquered, creating the vacuum and sealing it off afterwards also presents its own challenges. NSG started development of Spacia in 1994 and succeeded in overcoming all of these hurdles within three years.”
According to Kawahara, those three years of effort resulted in almost 100 patent applications.
NSG’s first target for selling Spacia, making use of its special features, was the home improvement market. Requiring no special sashes or attachments, Spacia could be fitted into existing windows and glass doors, and NSG decided that a rich potential market lay in pushing Spacia’s ability to boost home insulation through replacing existing single pane glass.
“Demand has grown by 20 to 30% every year. We’ve also received enquiries from Europe, where people are particularly conscious of environmental issues,” comments Kawahara. “Our efforts in caring for the environment are of course not limited to the development of green products like Spacia. We also concern ourselves with recycling waste products generated during manufacturing processes, as well as reducing emissions and addressing other issues. At the moment we’re talking with housing companies about the possibilities of recycling window glass from house and building demolition.”
It certainly seems that you really can solve a lot of problems with just a window pane. |
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| NSG's Spacia is the world's first mass-manufactured evacuated double-glazed window pane. Tiny metal studs called microspacers, whose innovation marked a giant milestone in the product’s commercialization, are placed at uniform intervals to maintain the 0.2mm-width evacuated space between the panes. |
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