ENERGY EFFICIENCY:

Oak Ridge puts retrofitted buildings to the test

In the wooded hills outside Knoxville, Tenn., researchers are bringing back a small but expensive slice of the '80s.

Scientists at Oak Ridge National Laboratory are using a couple of newly constructed buildings -- a two-story brick-clad office building and a metal warehouse -- to see how energy conservation might be improved. They were built to the requirements of decades-old building codes.

As part of the lab's Building Technologies Research and Integration Center, these architectural antiques will become test beds for new approaches to retrofitting buildings so they waste less energy.

Currently, buildings lead to 40 percent of carbon emissions in the United States, consuming 73 percent of the nation's electricity and 34 percent of the natural gas, according to Oak Ridge scientists. If there's any hope of chipping away at America's greenhouse gas emissions, energy-efficient buildings will have to be a huge part of the solution.

The White House seems to agree. Under Executive Order 13514, not only will the federal government have to cut emissions 28 percent by 2020, government buildings designed after 2020 have to be net zero energy users by 2030.

In the private sector, programs like the U.S. Green Building Council's Leadership in Energy and Environmental Design certifications are pushing developers to opt for low-flush toilets, tighter insulation and low-energy lighting in new construction so landlords and tenants can avail themselves of tax breaks and green bragging rights.

But what about the homes, offices and factories already built?

"As you look out the window in any city, the vast majority of buildings that will be standing there in 2020 and 2030 are already there," explained Clay Nesler, vice president for global energy and sustainability at Johnson Controls Building Efficiency. This means the bulk of efficiency gains will have to come from retrofitting old buildings rather than constructing new ones. However, upgrading these survivors from the bygone era of cheap electricity and fuel is a daunting and costly endeavor for many building operators.

That's where the Oak Ridge test site comes in. The sparsely occupied vintage, '80s-inspired buildings are flexible research platforms designed to mimic the small spaces, less than 50,000 square feet, that make up 95 percent of America's commercial buildings, according to Diana Hun, a building envelopes researcher at Oak Ridge. With an actual building, scientists can figure out what kinds of upgrades are practically useful and cost-effective without having to interrupt a bustling office or an active warehouse. These buildings can be tweaked to test whatever scenarios they can concoct.

Shortage of parts for drafty buildings

Getting these buildings running was challenge of its own. There are no thrift shops or consignment stores that sell 20-year-old insulation or archaic ventilation systems. New building codes pushed most of these products off the market, even though they persist in many homes and workplaces around the country, Hun lamented.

Pointing to a window inside the office test building, Hun noted that it is double-paned, even though surveys showed most offices still have single-pane windows. However, it lacks the insulating glazing that is becoming more popular in newer buildings. "It's the worst of what's available," she said.

Both the 40-by-60-foot metal warehouse and the 40-by-40-foot brick office are peppered with sensors, detecting heat, light, air pressure and moisture at 15-second intervals. Over the coming year, researchers will use the information to establish a base line of how these buildings respond to different seasons.

Mahabir Bhandari, a building equipment scientist at Oak Ridge, demonstrated an infrared camera he uses to detect thermal breaches, looking at the screen for shocks of cold blue air leaking into the warm, orange indoor space.

Despite all this effort to create relics, the Oak Ridge researchers are hardly nostalgic for drafty, leaky, outdated construction methods. With robust measurements, Bhandari said, researchers could develop better models of how buildings will respond to upgrades and retrofits, helping landlords learn how much energy they are losing and how much they could save by filling in the cracks.

In nearby buildings, researchers can test each retrofit component individually. Using hotboxes, climate simulators, blowers and pressure chambers, engineers can put asphalt shingles, aluminum siding and fiberglass insulation through a lifetime of use, measuring how much they degrade and calculating how cost-effective it can be to upgrade.

Human behavior: a crucial factor

Validating energy performance is critical to building upgrades and retrofits. Operators want to be sure they earn back their investment. "It's one thing to estimate the savings; it's totally another thing to measure, verify and implement those savings," Nesler said.

Nesler highlighted how Johnson Controls developed and implemented retrofits in the Empire State Building. Working with groups like the Rocky Mountain Institute, the team came up with dozens of ways to save energy in the 82-year-old skyscraper but quickly found there were trade-offs. "If we were to implement everything, it would be hideously expensive," Nesler said.

Through surveys and simulations, engineers came up with a $20 million plan to bring the Empire State Building into the 21st century, targeting improvements like insulation and cutting heating loads. Last year, Johnson Controls announced it beat its energy savings targets for the building by 5 percent, saving $2.4 million. This required extensive monitoring and tracking, deploying one of the world's largest wireless sensor networks to make sure the new lights, windows and walls were paying off.

However, the most crucial factor in improving building efficiency may end up being the one that is hardest to model: human behavior. A tight building envelope doesn't mean much if the doors are always propped open or if the heat is cranked up too high. Hun said she hopes to improve her assessments with real-world data on how people actually use their spaces.

After collecting base-line data, Oak Ridge researchers will partner with companies to test their upgrade strategies and see which ones get results as well as how things like insulation and dynamically controlled heating, ventilation and air conditioning systems work together.

Eventually, these retro buildings could draw aging town houses, industrial parks and commercial plazas back to the future, walking the planet back from the brink of more serious climate change to adaptation that building owners can afford.

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