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Electrochromic Glazing Offers Intelligent Controls - View Glass - Facility Management Product Release
View Glass combines electrochromic glazing with intelligent controls to provide windows that tint to prevent glare and excessive heat load while maximizing daylight.
Electrochromic glazing relies on a thin film coating to darken glass in response to an electric current. Multiple thin layers of metal oxide form the electrochromic ceramic coating on the inside of the glass. A few volts of electricity cause ions to move between layers, which in turn cause the glass to darken or lighten. “Now you’ve just turned what used to be a static building material into a device,” says Erich Klawuhn, vice president of product. That device can be controlled and connected to other devices on the Internet of Things.
“What we’re really trying to do is improve the occupant well-being and experience,” says Klawuhn.
The View Glass product is controlled by an algorithm that makes three key decisions to determine the level of tinting. One is the position of the sun relative to the window, which is calculated by geometry based on the location and orientation of each window and the known position of the sun at a given time. If the algorithm shows that there will be glare at that time, the algorithm darkens the window.
The second decision involves the amount of solar energy coming through the glass. If the solar gain exceeds a specific amount, determined by the facility manager, the window darkens.
Third, once any glare and solar gain have been addressed, the window allows in as much daylight as possible.
The algorithm goes through a loop every three minutes for every piece of glass.
An outside sensor detects cloud, so that the tinting can be adjusted to account for overcast skies. A recent software upgrade improves the ability to detect clouds in low light conditions, like dawn. In addition, occupants can override the algorithm using an app on a mobile device.
The View Glass product can be integrated with the building automation system using BACnet. The BAS can override the algorithm based on factors like demand response or whether a space is unoccupied. Windows can be addressed individually or zoned.
The system can be monitored remotely to watch for abnormal behavior or errors. “Even glass breakage can be detected,” Klawuhn says.
The software can be reconfigured as the building changes over time. It can also be reprogrammed to reflect occupant preferences.
The company produces glass in 5 foot by 10 foot sheets that are fully switchable, which Klawuhn says are the unobstructed glass size in the industry.
Although there is a 30 to 50 percent first cost premium compared to low-e glass, the View Glass product can reduce peak load, making it possible to specify a smaller HVAC system based on energy models. And there’s not need for blinds or building shading devices. When those factors are taken into consideration, says Klawuhn, the premium typically either disappears or falls to something that has a payback of five years or less based on energy and maintenance savings.
In the nearly three years since the company started shipping product, View Glass has complete more than 150 projects, ranging from small storefronts to entire facades. Renovations account for roughly 40 percent of the company’s projects, Klawuhn says.
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