Growing numbers of building owners, developers, designers and energy consultants have begun to see the light – or varying levels of it. Study after study indicate the market for “smart windows” – meaning glazing systems that leverage voltage, light or heat to regulate solar heat gain and optics – are demonstrating significant growth.
Among them, electrochromic systems are seriously shaking up the market.
Electro-what? Simply put, electrochromic window systems consist of a dual-pane units that pass a low-voltage across a microscopically-thin on a nano-layer of metal oxide coating on the outer pane’s interior, with charged lithium ions moving between glass layers, striking electrochromic material and altering the tint of the glass. Voltage to initiate transitions is miniscule, with 100 windows requiring the same amount of power as a single75-watt light bulb. In the case of Milipitas, CA-based View, Inc. (View’s Director of Product Management, Deepak Shivaprasad, spoke at the BuiltWorlds Summit earlier this month), colors transition to one of four opacities ranging, from clear to a translucent blue, often with no additional voltage required once the designated tint is achieved.
Occupants continue to enjoy daylighting, with reduced glare and no degradation in views, while owners and operators benefit from lower energy costs.
Here’s where things get interesting: Systems operate intuitively. Changing opacities for View’s Dynamic Glass technology rely on roof-mounted sensors to monitor sunlight and cloud coverage, in addition to an intelligent platform that monitors astronomical data, latitude and longitude, building orientation, time of day and architectural features to calculate the precise location of the sun and corresponding amounts of light and solar radiation striking the building at a given moment. Further, the system collects web feeds from multiple weather services to predict future conditions. Resulting calculations occur every three minutes, with glazing modifications initiated in accordance with prevailing conditions, according to View Vice President, Product Management, Erich Klawuhn. “The system can block more than 90% of solar radiation, achieving up to 20% reduction in HVAC energy consumption and 23% production in peak loads,” he said.
The system is programmed to respond in accordance with designated zones within a building, accounting for window numbers, size and placement, workstation locations and allowable heatloads. Although window opacity alters automatically, occupants can manually control – or override – given space conditions with a mobile app or one of a series of wall-mounted controllers, Klawuhn said.
Dynamic Glass can be integrated into building management systems, communicating with interior lighting and cooling so that all perform in unison, thereby conserving energy and maximizing comfort.
In some respects, electrochromics go where few smart windows have gone before. Liquid crystal-based systems, for instance, are more ideally suited for interior than exterior glazing systems and typically require continuous high-voltage current in both transparent and translucent modes. Meantime, photochromic systems may be more appropriate for eyeware than applications involving windows, according to Klawuhn. Although suitable for exteriors, thermochromic technology is triggered by temperature and doesn’t perform as well during winter months, resulting in glare. “It isn’t a full solution,” Klawuhn said.
Like other smart glass systems , electrochromics isn’t new – in fact the concept dates back to the 1960s – but View’s product required time to literally grow into its role as an exterior building component. Prior to launching Dynamic Glass in 2012, View was tasked with with scaling up 2-in.-by-2-in. glass modules to dimensions of 5 feet by 10 feet, as well as developing a cost model that resulted in a reasonable payback for clients.
There’s no denying electrochromic systems come at a premium relative to standard glass curtain wall – up to 40% to 50% in the case of Dynamic Glass. However, electrochromic systems eliminate requirements for interior blinds or exterior shades, simplify maintenance and, according to studies, improve worker productivity, Klawuhn noted. They additionally facilitate downsizing of HVAC components in the form of reduced cooling tons, fan, shaft & duct size, chiller terminal units, diffusers, pumps and water circulation.
In all, resulting savings can yield payback times of five years or less, as occurred with a south- and west-facing glass atrium spanning the height of the five-story, 223,000-sq-ft Method Olive Branch Hospital, in Olive Branch, MS. During the design phase, project team members considered tinted glass and a motorized shading system for the atrium prior to selecting Dynamic Glass. In all, the 2,100-sq.-ft. installation reduced HVAC system capacity by 35%, translating into immediate cost reductions of $22,000. The approach since has saved Method $2,000 annually in energy costs.
DPR Construction, a sustainabilty-oriented general contractor and CM, confronted a similar dilemma in renovations to an existing building in San Francisco designated to serve as firm headquarters. By harnessing solar energy and incorporating energy-efficient systems and materials, the objective was to create San Francisco’s first net-zero building, meaning a facility that consumed no more energy than it generated. At issue was a central 720-sq-ft skylight with the potential to cause glare and significant solar heat gains. Prior to renovations, the facility consumed an average of 10,500kw hours per month. Along with other innovative systems, including installation of Dynamic Glass for the skylight, dramatically energy costs plummeted from $1,800 per month to $20 per month. “View Dynamic Glass is one of the critical elements modulating the amount of light entering the building and controlling heat gain,” Ted Van Der Linden, DPR’s director of sustainable design, noted in a statement. As with the Method Hospital facility,
“Further, DPR was able to downsize HVAC components for related areas,” Klawuhn added.Investors know a smart technology when they see one. In 2015, View raised raised $150 million from The New Zealand Super Fund in a late-stage Series F round. To date, the enterprise has raised more than $600 million. In April, it was awarded a contract to supply all glazing – some 66,000 square feet in all – for the redevelopment of Terminal 1 in San Francisco. The project is the culmination of a strategy that initially targeted modest skylights in occupied buildings, typically for enterprises eager to adopt new technologies, even if they required a longer return on investment, Klawuhn recalled.
Although View has hundreds of projects under its belt, it’s worth noting that a competitor of similar might, SageGlass, likewise supplies similarly functioning system. Among other initiatives, SageGlass if focusing on electrochromic units with varying geometries and colors, in addition to installations that deploy panes of different hues collectively create imagery, such as snowman atop a glazed rotunda skylight at Mall of America in Bloomington, MN.
Together, View, SageGlass and a handful of others are forging a clearer path to ever-smarter windows.