Lessons Learned

By STEPHANIE SIMON for Wall St Journal

GOLDEN, Colo.—When the first employees moved into the Department of Energy’s new research facility here last summer, a whole lot of people were watching—with a whole lot of anxiety.

Planners of the $64 million facility, part of the National Renewable Energy Laboratory, set out to make it the greenest office building in the nation.

But no one was certain the building would perform as efficiently as its designers hoped.

“NREL said from the beginning that this building was part of their lab,” says Richard von Luhrte, president of RNL, the international architectural firm that designed the building—and is still tweaking it.

Eight months into the experiment, the building “is performing according to design,” says Byron Haselden, president of Haselden Construction LLC of Centennial, Colo., builders of the facility. “Whew!” he adds.

The Energy Department hopes lessons learned in this Denver suburb will help guide green-construction practices around the world. Outside experts in efficient construction point out that some of the technology used at NREL is best suited for high-sunlight, low-humidity climates like Colorado and wouldn’t work nearly as well elsewhere. The building also demands a lot from its employees, who must adjust to fluctuating temperatures throughout the day and pop up from their desks to open and shut windows; a work force less dedicated to energy efficiency might rebel.

Still, authorities on green design both inside and outside the NREL project say some valuable do’s and don’ts have emerged from the project so far.

NREL considers one of its best moves its early decision to specify a financial and energy budget for the project. It then put out a call for proposals from design-build teams. By specifying that it wasn’t looking for the lowest bid, but rather for the smartest project, NREL freed the teams to focus on innovation.

On Time, Under Budget

Once the winning team was selected, NREL’s staff worked closely with the architects, engineers and construction managers to model predicted energy savings and revise plans as they went along. The first phase of the project was completed on time and under budget, prompting other government agencies to contact NREL about its strategy, says Jeffrey Baker, the Energy Department’s director of laboratory operations.

Perhaps the building’s most conspicuous energy-saving feature is its “transpired solar collector,” a simple, inexpensive method of heating that’s been used in commercial applications for more than a decade. Sheets of perforated black metal hang on the facility’s south-facing exterior walls and heat up quickly in the intense Denver sun. Air flowing through the holes is warmed and then sucked by a giant fan into the basement. There a maze of concrete blocks traps and stores the warm air for later distribution through the building’s ventilation, supplementing a radiant-pipe heating system.

Transpired solar collectors were jointly developed by the NREL and Conserval Engineering Inc., a renewable-energy engineering firm based in Toronto. After installing the system in Golden, NREL engineers determined that future systems would store just as much heat with fewer concrete blocks.

Another bright spot: creative use of daylight. Thanks to ample Colorado sunshine and the relative narrowness of the facility’s wings—each just 60 feet wide and positioned on an east-west axis—so much sunlight floods into the building that overhead lights are rarely needed.

“In six months, I’ve turned on my overhead light twice, for about 20 minutes,” says Drew Detamore, who runs NREL’s construction planning office.

Between 9 a.m. and 4 p.m., the 222,000-square-foot building has used an average of 30 to 40 kilowatts for lighting, while the engineering standard for a building of this size is about 160 kilowatts, says Shanti Pless, a senior research engineer at NREL.

Such reliance on natural light wouldn’t be as effective in some other parts of the country. Other features of NREL may prove less effective outside Denver as well. A transpired solar collector, for instance, won’t help much where there are frequently gray skies, says David Hewitt, executive director of the New Buildings Institute, a nonprofit based in White Salmon, Wash.

During warm weather, the building also relies heavily on the fact that temperatures here cool off quickly when the sun goes down. Windows are opened at night to flush the building with that crisp night air; the thick concrete walls then trap the cool air inside, keeping offices comfortable long after sunrise. Such efforts would likely backfire in humid Southern cities like Atlanta, Mr. Hewitt says. NREL also achieved substantial energy savings in its data-processing center by using ambient air, rather than mechanically cooled air, on most days to keep the servers from overheating. This wouldn’t work in a city like Phoenix where the temperature routinely tops 100 degrees.

Enlisting Employees

Working at NREL requires some sacrifices. An alert flashes on employees’ laptops when it’s time to adjust the windows nearest them. Central air and heat is generally used only in conference rooms, so temperatures in the rest of the building fluctuate from 68 to 76 degrees.

But NREL supervisors are pleased with how well the staff has adapted to a building that is decidedly quirky. Mr. Detamore, the construction planner, says the staff seems proud to help make the facility efficient. “People really dig it,” he says.

Each cubicle is on a strict energy budget of 55 watts. That means employees get a phone, a laptop and a task light. That’s it.

Combination print-fax-copy machines are centrally located; each is shared by about 50 workers. “It’s been…different,” says Jennifer Daw, a project manager in the building.

Asked what she misses about her old office, Ms. Daw doesn’t hesitate: “My heater. That’s at the top of my list,” she says. “But I drink lots of hot water,” she adds, waiting for the communal microwave to warm a mug of tea. Overall, she says, she finds the new space pleasant.

The Fix List

The architects and engineers aim to correct a few problems in the building, including metal window frames that provide little or no insulation, as they work on a $39 million new wing. The same team is in charge: architects RNL, Haselden Construction, and engineering firm Stantec Inc.

The team is confident it can build the new wing for less than the first two cost—$246 per square foot, down from $259 for the original building.

They are convinced it can be greener, too. They are aiming for a 13% reduction in energy use per square foot through several small but significant tweaks.

Among the fixes: A sheet of fiberglass will be inserted between the two metal layers of each window frame for better insulation. The windows will also be slightly smaller, and some will be triple-pane, for better insulation than the double-glazed windows in the first two wings. Stairwell lights will get daylight monitors, so they won’t go on full force if the stairwell is bright from light flooding in through the windows.

And LED lights will be used throughout, at 10 to 15 watts per fixture—versus 32 watts per fixture for compact fluorescents. That may not seem like much of a saving, but every watt counts in a building where the light bulbs inside vending machines are permanently turned off.

“People ask me, ‘How are you going to feel in 10 years, when someone outperforms this building?’ ” says Mr. Baker, the director of lab operations. “I tell them, ‘We’re going to feel great,’ ” he says. “Because they’ll know where it all started.”


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