Fort McCoy News September 12, 2014

New housing to feature energy-efficient systems

Fort McCoy's new housing construction will feature energy-efficient technology to provide heating, cooling and hot water.

According to the Directorate of Public Works (DPW) Master Planner Brian Harrie, 42 new homes will include geothermal heat sources that will provide all heat and air conditioning to units. Additionally, domestic hot water will be provided through high-efficiency, instantaneous tank-less natural gas water heaters.

Photo for housing article
Several of the existing 57 homes in Fort McCoy's South Post housing area are shown. A contract to build 42 new homes in this same area was awarded Aug. 1. Construction begins in fall 2014. Photo by Scott T. Sturkol

"The new geothermal units should greatly reduce seasonal heating and cooling costs while providing increased comfort to the Soldier and his or her Family," Harrie said. This would provide geothermal heating and cooling the units, taking all the Army Family housing heating and cooling requirements "off the grid" with this innovative technology.

Geothermal home energy systems use the constant temperature of the earth as the exchange medium instead of the outside air temperature, according to the U.S. Department of Energy (DOE). Though many areas of the U.S., including Wisconsin, can experience seasonal temperature extremes such as high heat in the summer and sub-zero cold in the winter, the ground remains at a relatively constant temperature a few feet below the earth's surface.

Harrie said although the geothermal systems planned for the new housing units are new to Fort McCoy, they will be systems that will be efficient and within construction budget requirements. The planned system for each residence will include one high-efficiency, ground-coupled water-source heat pump unit; two pumps; three or four vertical ground-loop wells (depending on house size); a plate-type energy recovery ventilator; and one inverter compressor providing only the required energy to satisfy space conditions.

"As the system unloads, the energy efficiency increases while maintaining comfort in the space by keeping the temperature closer to the thermostat set point," Harrie said. "Since most of the operating hours are under partial load conditions, the inverter can take advantage of low airflows while operating quietly at reduced energy levels.

"The ground-source heat-pump system and wells are sized to provide the entire heating load to the house, and, therefore, will not have to resort to expensive, inefficient electric heat to get through typical Wisconsin winter cold snaps," Harrie said.

DOE statistics show the system life of geothermal home energy systems are estimated at 25 years for the inside components and more than 50 years for the ground loop. There also are approximately 50,000 geothermal heat pumps installed in the United States each year.

"As these systems get installed and we begin to validate that this truly is a cost saving and energy conserving system, the installation will look at retrofitting similar geothermal units into the other 57 houses in the subdivision," Harrie said.

Tank-less natural gas water heaters can heat water directly without the use of a storage tank. When a hot water tap is turned on, cold water travels through a pipe into the unit. The gas burner then heats the water and delivers a constant supply of hot water.

"We had one of these tank-less heaters installed in one of our housing units as an experiment," said Ross O'Neill, chief of the DPW Housing Division. "It works well and we have not had one complaint about the system."

The DOE states gas-fired, tank-less water heaters produce higher flow rates than electric ones. Also, for homes that use 41 gallons or less of hot water daily, tank-less water heaters can be 24 to 34 percent more energy efficient than conventional storage-tank water heaters. They also can be 8 to 14 percent more energy efficient for homes that use a lot of hot water, which is around 86 gallons per day.

"We are always encouraging all of our residents to be more energy efficient as well," O'Neill said. "The energy efficiency expected in these new homes will help in that effort."

Harrie said as geothermal technologies get used more and more by the Army and at Fort McCoy, the next logical step is evaluating the systems for use in other parts of the installation.

"As our existing 1940s-era wood inventory continues to age, we will need to replace them with larger, commercially constructed facilities," Harrie said.

"It is possible that geothermal could also be incorporated into the design of new buildings, further reducing our dependence on fossil fuels and making Fort McCoy a more self-sustaining and energy-responsible installation well into the future."

For more information about energy conservations efforts at Fort McCoy, call 608-388-8682.

(Information courtesy of DPW.)