A new window installation doesn’t just keep the elements out and transmit light and heat—it generates power too. NEXT Energy Technologies recently installed its first commercial facade powered by its transparent organic photovoltaic (OPV) coatings on its own headquarters building in Santa Barbara, California.
The installation—which features six transparent photovoltaic windows, each measuring 40 by 60 inches—showcases how the windows are able to remain transparent while feeding power back to the building through cables hidden in the framing system.
NEXT’s headquarters installation is the next step toward commercializing the technology for wider use. The company previously installed 22 glass panels on the south facade of the Olive Building at Patagonia’s corporate headquarters in Ventura, California, as part of a balustrade; this most recent installation takes the technology a step further by utilizing it in a conventional window that also serves as a weather barrier in addition to a source of energy.
How Energy-Generating Windows Are Made
The windows start with a piece of new glass. A series of coatings are applied to create the organic photovoltaic layer. At the same time laser scribing processes create a series of fine, microns-wide channels, which enable the solar cells to generate power, explained Daniel Emmett, CEO of NEXT Energy Technologies.
“If you’re up close to it, within 2 to 3 feet, you can see those lines, but from a normal viewing distance, you can’t see the lines,” Emmett said. “It’s indistinguishable from a standard low-e coating.”
Next, bus bars around the edge are installed to channel the generated electricity up and out of the window through a junction box. A polyisobutylene (PIB) edge seal keeps out moisture and oxygen. The unit is then laminated to another piece of glass, making it ready for installation.
The windows were fabricated with low-e coated inboard lites and spacers by Viracon, while Walters & Wolf designed, supplied, and installed the framing system as part of the facade integration.
The technology is uniquely suited to windows because of its scalability, Emmett said. “The nature of the glass industry is variable sizes at scale—you’re almost never repeating the same size from project to project,” he said. “For people who are doing things like integrating silicon wafers, taking a commodity technology and applying it to glass, the challenge they have is getting those wafers sized each time you have a new size of glass. It’s hard to scale that kind of operation, both from a manufacturing standpoint and a cost and process control standpoint. Our technology is designed to coat directly onto commercial glass.”
Implications for Future Facades
Larger installations will validate the market demand for the product and the scalability of the process, Emmett said. The company is looking at partnering with glass manufacturers in the future to scale the product further, with the ultimate goal of having energy generation become the new standard for windows.
“Most window applications would take advantage of the native infrastructure in the building to generate additional power at the point of where it’s needed. We can feed that into a battery bank or into the grid itself at the building where we can offset the lighting system, reduce the heat gain load in the building, and help improve the efficiency of the building,” Emmett said. “We would love for this to become the new low-e coating in a building.”
