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Glass Technology Could Revolutionize ‘Green’ Design
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Image of smart glass going from transparent to opaque at the touch of a button
Several types of smart glass go from transparent to opaque at the touch of a button; new research shows that the use of smart glass in architecture and transportation projects is set to increase dramatically. Wikimedia Commons/Sebastian Terfloth

The development and increasing availability of “smart” glass technology could bring significant changes to the design of structures and transportation.

August 27, 2013—As prices drop and supplies grow, so-called “smart” glass has the potential to redefine how architects and engineers design the exterior of buildings to meet sustainability criteria, according to a report released last week by the London office of Navigant Research, Smart Glass: Electrochromic, Suspended Particle, and Thermochromic Technologies for Architectural and Transportation Applications: Global Market Analysis and Forecasts. The firm’s energy-performance projections indicate that smart glass will see significant gains over typical high-efficiency, low-emissivity glass within the next decade, and adoption levels will grow as prices for the new technology drop and supplies increase.

There are three types of smart glass, which can be used in both the construction and transportation fields: electrochromic, suspended particle, and thermochromic.

“Usually what people are referring to when they refer to smart glass is actually electrochromic glass,” says Eric Bloom, a senior research analyst for Navigant Research in London and a coauthor of the study. “When a charge is applied to the glass it changes opacity, so it can go from pretty much totally clear to pretty much totally dark just by changing the voltage being applied.” The charge changes the opacity of the glass by moving lithium ions between two layers of film sandwiched between two layers of glass.

Electrochromic glass offers the highest performance of each of the three types of smart glass, at a typical cost of $45 to $70 per square foot, Bloom says.

Suspended particle glass typically costs about 20 percent more than electrochromic glass and works as it sounds, according to Bloom. Suspended particles located between two panes of glass are controlled through the application of a very low voltage. When the charge is applied, the particles reorient themselves to either let light through or block it.

Thermochromic glass—which has been around for some time, and is the concept behind the ubiquitous color-changing glasses popularized in the 1980s and 1990s—typically costs approximately $30 to 45 dollars per square foot, he says. By comparison, low-emissivity glass typically costs between $5 and $15 per square foot.

“So comparing it, $5 to $15 a square foot versus $45 to $70 a square foot—it’s quite a jump,” Bloom says. “But, having said that, the costs are coming down pretty rapidly.” As manufacturing processes scale up over the next decade, Bloom predicts that the costs of smart glass will drop by approximately 40 percent. In the last two years alone, he points out, the market has effectively transitioned from “science projects to reality,” which is the first step in moving away from research and development toward full-scale production.

As prices decline and supply grows, the report predicts that 80 to 85 percent of the market for smart glass will come from architectural uses in new construction, while the remainder will be come from the luxury automotive industry and naval applications. Overall, the volume of flat glass used in construction and other applications represents 75 billion sq ft per annum and is currently valued at roughly $35 billion globally, according to the report. The advent of smart glass thus has the potential to have an enormous impact as it is adopted by the construction industry.

The volume of smart glass produced is forecast to grow from approximately 1.4 million sq ft in 2013 to approximately 929 million sq ft by 2022, according to the report. 

 Graph depicting the volume smart glass being sold globally 

The volume of smart glass sold globally is expected to grow
dramatically, from a very low volume this year to up to just over
2.7 million m2 by 2022. Navigant Research

“When it comes down to it, electrochromic is going to be the real winner here,” despite its high initial cost, Bloom says, because it is slightly easier to control and cheaper to buy than suspended particle, Bloom says. Thermochromic glass changes opacity when it is exposed to ultraviolet light, making it unsuitable for construction because building occupants cannot control the exterior glass opacity, he says.

Because smart glass can control the amount of light that enters a space, it can reduce overall energy consumption within a building, Bloom says. Controls for the glass can be integrated into a building’s mechanical system, automating the system and removing the individual human element from the technology’s use. “We see a lot of museums taking interest in smart glass as a way to silently and unobtrusively create the right lighting environment inside an art gallery without the need to move around blinds or take other measures,” Bloom says.

The technology has the potential to completely revolutionize architectural design as well because it enables a design team to do away with external fins or louvers to provide shading as a sustainable design element. With variable shading provided by the glass itself, energy consumption can be reduced while daylight is maximized, and the load on a building’s heating, ventilation and air conditioning system can be reduced, Bloom points out. “There’s a possibility that the air-conditioning capacity can actually be decreased, so you’re spending less money on the cooling equipment, replacing a larger chiller with a smaller one,” he says.

The technology makes glass an active element in green design for the first time, Bloom notes. However, while the benefits of being an early adopter of smart glass technology are tangible, especially for new construction, there are downsides, especially uncertainties about long-term performance. “A lot of building owners are still looking at technologies and saying, ‘I really like this, and I’m even willing to pay for it, but I don’t want to have to replace all my windows in five years because the technology is starting to degrade’,” Bloom says. “So that’s another major issue—and partially, that’s only going to be solved through time, just because you do need the sort of reassurance from a product that’s been out on the market for ten years and is still working just as well as it did on day one.”

Bloom anticipates that the first three to four years of adoption will be driven by what he calls the “cool factor” of the technology. “Smart glass, like many green building technologies, is something that does enhance the interior environment and does add value to the building, beyond its straight-up energy savings,” he says. “So it’s something that people will opt for, and won’t necessarily apply really stringent return-on-investment criteria [to], in some cases.”

Additionally, for such buildings as museums and art galleries in which controlling natural daylight is a high priority, the use of smart glass will be seen as more necessary than it would to, perhaps, a conventional office building owner, at least in the beginning, he says.


 

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