Geothermal project completed

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Pond pumps out savings on garrison energy bill

U.S. Army Human Resources Comand PAO
Fort Knox is now saving $10,000 on its monthly energy bill, thanks to an innovative geothermal pond placed in front of the Human Resources Command complex by the Army Corps Engineers.
The project was submitted for Army Energy Conservation Investment Program funding and was deemed worthy after detailed review.
The Lt. Gen. Maude Complex represents approximately 12 percent of the entire electric bill for the post. Out of that 12 percent, Building 6434-4—the facility’s information-technology, or IT, building—represents almost 8 percent of the whole bill, said Robert “R.J.” Dyrdek, a certified energy manager who is the energy program manager at the Fort Knox Directorate of Public Works.
Located at the corner of Spearhead Division Avenue and North Huron, the pond generates considerable energy savings for the Lt. Gen. Maude Complex.
The twist is, this geothermal-pond system isn’t designed to warm in winter and cool in summer like the geothermal well fields used by most of the post using GT technology. HRC’s system is designed to cool in summer and in winter.
One geothermal manhole was installed near the Building 4 (6434-4) dock during construction of the Lt. Gen. Maude Complex under the base realignment and closure, or BRAC, congressional mandate.
“There was not sufficient funding to install a full geothermal HVAC system during the construction of the Maude complex, but the HVAC system was set up to be able to connect to a geothermal well field in the future,” said Pat Walsh, director of Public Works on Fort Knox.
However, after observing the existing system’s operation for about two years, engineers found out that the large interior spaces needed cooling all of the time, said Jason Volz, the project’s energy engineer. Volz is a measurement and verification engineer with Harshaw Trane, who manages operation of Fort Knox HVAC systems.
“If there’s a room on the interior that doesn’t have an exterior wall, there’s nowhere for the heat to escape,” Volz said.
In smaller buildings, excess heat would normally be conducted out the exterior walls. However, in a large facility like the Maude Complex (the largest office building in Kentucky at nearly 900,000 square feet), the interior space “outnumbers” the exterior walls so sufficient heat cannot be conducted through the exterior walls into the outside air, making it a cooling-dominated load.
The Fort Knox energy program manager put it another way.
“Building 4 needs air conditioning all year ’round. During the winter the excess heat from Building 4 almost completely heats the other five buildings in the complex (6434-1/2/3/5/6),” Dyrdek said. “Adding the pond allows us to take advantage of the cooling effects of a fountain and the effect of a deep-water pond—a very good application of this type of technology.  It will mainly help with the heavy air-conditioning load of Building 4.”
People, computers and lights all produce heat, Volz said.
“Because those loads are there all year ’round, we needed to efficiently dissipate that heat. That’s where the pond heat-exchanger comes into play,” he said.
The pond’s heat-exchanger is located at the bottom of the pond under at least 10 feet of water.
The large-projects leader at Harshaw Trane, Glen Thomas, compared the pond’s heat-exchanger to the radiator of a car. Thomas is the project manager, responsible for the delivery of the project and coordination of Trane efforts with Fort Knox DPW, Nolin Rural Electric Cooperative and the Corps of Engineers design and contracting teams.
“A car radiator takes the heat (of your engine) and dumps it into the air. We’re taking the heat (of the Lt. Gen. Maude Complex) and dumping it into the pond,” Thomas said. “The pond fountain is kind of like the fan in a car radiator: It injects the water into the air, and the heat that was in the water goes into the atmosphere.”
It’s a closed system so none of the water that goes to and from the pond through hydronic piping actually intermingles with the pond water.
“Air (in the Lt. Gen. Maude Complex’s air-conditioning and ventilation systems) transfers its heat to the building heat pumps’ refrigerant systems. The refrigerant systems transfer their heat to the building’s heat-pump water-loop system. The heat-pump water-loop system circulates water throughout the building to the building heat-pump units (absorbs heat), then to the pond heat-exchanger system (releases the heat). The pond transfers its heat to the air through the fountain,” Thomas said. “It started with air, and it ended with air: The water is in between.”
The project wasn’t without its problems, though.
“We dug some test holes prior to excavation so we had a pretty good idea that we would encounter rock and at what elevation so we were somewhat prepared,” said Mike Kersey, superintendent with Phillips Brothers Construction. “We had to change our operations to get the rock out—between 8,000 and 10,000 cubic yards of rock—and dirt on top of that.”
Despite the problems with excavating the rock using heavy construction machinery, favorable weather conditions allowed the project to be finished months before its March 2013 deadline.