Virtual family brings energy savings to ‘net zero’ house in Gaithersburg


A. Hunter Fanney, project leader of an experiment by the National Institute of Standards and Technology, explains how the agency’s three-bedroom house is used to study how a residence can produce as much energy as it uses. (Dan Gross/The Gazette)
September 26, 2012

At 6 a.m., an alarm clock wakes a Gaithersburg mother. She turns on the kitchen lights as her husband steps into the shower. Breakfast goes into the microwave for exactly 2 minutes.

The couple’s two children, ages 8 and 14, wake at 6:30 a.m., without fail, every weekday morning.

Virtual families — as this one is — tend to be punctual. Mother, father and children are “residents” of the National Institute of Standards and Technology’s newest laboratory, an experimental three-bedroom, three-bath house that is intended to generate as much energy as its virtual family uses.

Hundreds of devices simulate the family’s energy use while solar panels and geothermal systems generate energy. The 2,700-square-foot structure sits on NIST’s campus in Gaithersburg.

“The house looks pretty normal, except for the wires,” said A. Hunter Fanney, chief of NIST’s energy and environment division.

NIST, a federal agency, built the test facility to experiment with alternative energy and high-efficiency designs and materials. The goal of the experiment is to show that such a house can fit into a typical suburban neighborhood, spokeswoman Jennifer Huergo said.

By the end of a year, the family’s energy costs should even out, or become “ net zero,” Fanney said.

“Some months we’re actually using more energy than we’re producing, and some months we produce more energy than we consume,” he said.

The control center is in the house’s detached garage. In the house, appliances receive commands to turn on and off at specific times through the day, simulating the average American family’s energy use. The test facility cost about $2.5 million to build, according to the NIST.

The television, microwave, coffee maker, can opener and every other device with a plug run on a timed script. The coffee maker runs in the mornings; the television runs in the mornings and evenings. Water usage works the same way, Fanney said.

“At, say, [6:15 a.m.], a computer in the garage triggers valves that are in the basement. And that triggers the shower flow,” he said.

Each room has a heat generator and humidifier to replicate the home’s four residents. When Parent A “moves” from the kitchen to the living room, the Parent A heat generator in the kitchen switches off, while the one in the living room switches on.

“We actually control what time they get up, when they turn the lights on, when they take their showers,” Fanney said.

Because appliances also generate heat, they have similar devices that switch on and off when the virtual family is using them.

“They don’t actually open the refrigerator, but they put a device inside that simulates heat, as though they were opening it,” Huergo said.

NIST electrical engineer Farhad Omar and his team produced the script that runs the home’s energy-consuming devices. In his lab on the NIST campus, a few mouse clicks turned on a microwave and a hair dryer for one minute each.

“We’re trying to simulate occupancy and behavior as closely as we can,” Omar said.

The home’s energy usage totals are vital to the net-zero calculation.

The home also employs multiple devices to conserve and recycle energy.

Geothermal loops, installed in the outside walls and floors, “extract heat from earth, rather than the air, in order to heat and cool your home,” Fanney said.

Although the home has many windows, he said, the walls are built to reduce energy loss and keep the home at a comfortable temperature.

“This home is the tightest-built home that the U.S. Department of Energy has ever made,” he said.

The home was built with stimulus funds from the American Recovery and Reinvestment Act, which required everything in the home to be made from U.S.-made supplies. Everything except one device, which was made in Canada, can be bought commercially and used in a typical residence, Fanney said.

“What we’re trying to do is show that this can be done relatively simply,” he said.

In Frederick, a community of similar net-zero homes are already on the market. The homes use energy-conscious devices, such as geothermal loops, solar panels and Energy Star appliances, states the developer, Nexus EnergyHomes, on the North Pointe community’s Web site.

“We started well before [NIST] did,” Nexus Executive Vice President Mike Murphy said. The North Pointe community has 15 occupied net-zero residences, with 12 more under construction.

But when a real family moves into a net-zero home, Murphy said, it’s up to them to be energy-conscious.

“It’s the occupant’s responsibility to achieve net-zero; it’s the builder’s responsibility to build a home that is net-zero capable,” he said.

In North Pointe, residents brag about their energy bills, with some only paying in the single digits, Murphy said.

“They’re aggressively seeking energy efficiency the same way they expect them from their homes,” he said.

The Department of Energy is funding net-zero projects nationwide through its Building America program. The program aims to bridge the gap between research and commercial innovation for homes and businesses, according to its Web site.

After NIST installs the final pieces of laboratory technology in the Gaithersburg house, it will be sealed for one year while data is collected. Huergo said the home will probably be finished within the next few months.

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