Shading in Glass

It’s the middle of June in the Phoenix suburb of Scottsdale, Ariz., and the intense desert sun spurs the mercury’s climb to the 108-degree mark and beyond. 

Roger Watson, vice president of sales and marketing for Saint-Gobain Glass Exprover NA, peers out one of two windows in the fluorescent-lit building he’s occupied since moving to Scottsdale three months ago.

“We’re using up all the energy,” Watson says. “Outside, that energy is free and we’re not using it? Why?”

Watson crystallizes the philosophy guiding glassmakers such as Saint-Gobain and energy-conservation organizations around the country that are racing to grow the market for new glazing technologies taking advantage of natural light and conserving energy—what is referred to as “daylighting.”

One of those technologies—IGU shading systems that hermetically seal computer-controlled louvers between a pair of lites—is beginning to be seriously considered for daylighting projects in the U.S. market after years of use in Europe.

“With energy costs going through the roof in the U.S., people understand you have to build very conscientiously,” says Watson, whose company markets a between-lite shading system called Ecklite.

To make such equipment pay off in this country, experts say, will require the re-education of those occupying America’s office buildings.

‘Shady’ European glass comes to the U.S.
Pierre-André de Chalendar, who was named CEO of France’s Saint-Gobain in June, told London’s Financial Times, June 6, that he thinks the $56 billion producer and processor of glass and other building materials stands to expand its business by helping European businesses cut their office building energy costs. One of the most efficient ways to accomplish this, the company has found, is through the installation of Ecklite.

Ecklite IGUs feature a series of motorized aluminum louvers that come in two models: the standard unit with a single set of blinds, and the Ecklite Evolution, which contains standard louvers on the lower two-thirds of the unit, and inverse louvers above. The top blinds reflect daylight up to the ceiling to provide a more diffuse, energy-saving ambient lighting.

The Ecklite equipment, manufactured by Saint-Gobain subsidiary Eckelt Glas GmbH in Austria, is designed to work closely with a building’s intelligent HVAC system. The system controls glare throughout a building, adjusting to the changing position of the sun and weather conditions by tweaking the pitch of the louvers automatically. Saint-Gobain also supplies the software that controls the units.

Low-E coatings and other options are available for the glass, Watson says, declining to quote a price range for the line. “It’s not going to cost any more than regular glass and having mechanical blinds on the inside,” he says.

For the last 10 years, the company has sold Ecklite systems for installation in buildings throughout Germany, Austria and Switzerland, where concern for energy savings is such that “you can’t install glass in Switzerland if it’s not triple glazed,” Watson says. “Europe has been looking at the long term for a long time.”

Saint-Gobain finally cracked the U.S. market for “intelligent glass” in May when it received an order for 56 units from Loyola University’s Chicago campus for inclusion in the top floor of its new information commons building. Watson says Ecklite’s successful incorporation into the four-story, 67,000-square-foot library facility should go a long way toward introducing the use of similar daylighting technology throughout the United States.

There’s no great mystery behind the disparity between the technology’s adoption rates in Europe and the United States, Watson says.

“We have only four or five cities in the whole of Europe that have skyscraper type buildings, so we’re not investing so much,” Watson says. “And [a U.S.] office block may be there for 10 years, so you’re not going to invest that kind of money init.” Most of the European projects that incorporate smart window systems are art galleries, universities and other buildings that tend to stand for decades.

The Loyola project, designed by Solomon Cordwell Buenz in Chicago, is being built by that city’s Pepper Construction, and is slated for completion in November. Trainor Glass Co. in Alsip, Ill., is handling installation of the Ecklite units, which were expected to arrive on site July 4, with installation expected to begin at the end of July.

“What makes this glass nice is it’s an easy install,” says Mike Murphy, senior project manager. The glazier has worked with other integral shading units before where attention had to be paid to the placement of each unit’s control box. The Ecklite units contain their own controllers, he says, “so our field guys are just going to drill a hole in the mullion, drop the wire through, and that’s it.”

The only real challenge so far has been the custom dies Trainor had to have manufactured by U.S. Aluminum to accommodate the 15⁄8-inch wide IGUs, Murphy says. Still, “there shouldn’t be too much leg work later,” he says. “It’s all upfront.”

The human factor
Overall, architects, building developers and owners in the United States are positively inclined toward daylighting systems, according to a March 2003 focus group of 48 individuals sponsored by the Lighting Research Center at Rensselaer Polytechnic Institute in Troy, N.Y. Among other findings, the study revealed that building designers were those most excited by the use of smart shading and other technologies and frequently convinced developers to adopt them.

According to the study, the biggest bars to their adoption were:

“First cost, and second, not being convinced that there is an economic return on investment,” says Russ Leslie, LRC associate director, an architect who also chairs the institute’s graduate programs in lighting.

However, he adds, “the big unknown with saving energy through daylighting is whether the daylight will annoy the people in the building in such a way through glare that they will operate the blinds themselves.” If the occupants are constantly stumbling half-blind down a hallway or having to tweak their computer monitors’ brightness settings, “they’ll disable the system as fast as they can figure out how,” he says.

Poorly configured window control systems that don’t take into account the variations of sunlight from day to day are usually the weakest link, agrees Abby Vogen Horn, director of the Daylighting Collaborative at the Energy Center of Wisconsin in Madison. “People have an amazing way of correcting problems that we haven’t thought of in the design process. I think of how many times we’ve seen paper taped over windows that were supposed to be daylighting.”

The key to getting the most energy benefits out of shaded glass may be finding a way to strike a balance between computer and human controls, suggests a 1998 study by the Windows and Daylighting group at the Lawrence Berkeley National Laboratory in California. In this classic experiment, three scenarios were tried. In the first, participants could manually operate both their office’s window blinds and light switches. In the second, both blinds and switches were controlled by computer. In the third, the computer controlled the blinds while participants could adjust the light switches. Most people preferred the last, semiautomatic setup.

“If you give people a modicum of control, they will accept an automated system,” says Eleanor Lee, a scientist and architect with the Windows and Daylighting group at Lawrence Berkeley lab.

These aren’t just annoying little quirks that building owners can work out on the fly, she emphasizes. “When I’m modeling my system, I will size my HVAC system based on it. If the control system isn’t smart enough, people [in the building] will be unproductive or they’ll complain so much the facility manager will disconnect it.”

As for Watson, he’s still getting used to the intense heat and sunshine of Scottsdale, after having lived in the darker, wetter climes of Vancouver, B.C. in Canada for the last five years.

“I’m looking for a little piece of land here to build a house completely out of glass to show that [daylighting] does work,” he says from his two-window location. “The products are out there, and they work.”