Advanced Glazing and Window Technologies

Brandon Tinianov, chief technology officer, Serious Materials, Sunnyvale, Calif., discussed Advanced Glazing and Window Technologies at the BETEC Symposium, Dec. 10, at the Washington Convention Center.

“The way I see it, there are three generations of windows: high thermal insulation, dynamic glazings and BIPVs. At present, we’re seeing some high thermal insulation; dynamic glazing will probably come in five years; and BIPVs in the next 10 years,” he said.

A high thermal insulation window has multiple layers: sustainable foam, proprietary triple reverse seal; lites of glass; inert gas fill; suspended film; a high-strength, low conductivity fiberglass frame; and wet glazing triple-fin weather stripping. “There are more available surfaces to work with when there are so many layers: the low-E coating can be tuned; the gas, the spacer, the glass, everything can be played with to improve the performance of the window,” Tinianov said. High-performance frames can be aluminum or vinyl, but fiberglass is being used more and more.

Dynamic glazing can actively change its physical properties, such as visual transmission, thermal/infrared transmission, or both, Tinianov said. It changes properties via electrical/user control, environmental conditions, or both. A good example is electrochromic glass from Sage Electrochromics, Faribault, Minn. Benefits of dynamic glazing include dynamic daylight control and reduction in HVAC loads; concerns include high cost, and somewhat hazy “clear” mode.

There are different kinds of dynamic glazing, Tinianov said:
--Passive dynamic glazing offers dynamic daylight control, reduced HVAC load, lower installed cost ($20/sq ft), and use as retrofit. However, concerns include: availability, unwanted activation, service life, and spotty visual field.
--Hybrid dynamic glazing switches on per environmental conditions, and off with voltage. It is similar in cost to electrochromic.
--IR specific passive glazing offers low cost, pure passive, no controls, no change to Tvis and is available as a retrofit solution. But the product is at least three to five years away from being available in the market.

BIPVs, a third generation of high-performance glazing, only produce 100 watts per square meter. “It’s an interesting product, but not compelling right now,” Tinianov said.