Going Green: Tapping the earth to heat, cool buildings

By U.S. ArmyMarch 19, 2013

Geothermal well drilling
1 / 3 Show Caption + Hide Caption – One of 12 geothermal wells is drilled behind the headquarters building for the U.S. Army Corps of Engineers North Atlantic Division on Fort Hamilton in June 2011. The wells house piping for a closed-loop, water-to-water ground source heat pump system... (Photo Credit: U.S. Army) VIEW ORIGINAL
Variable frequency drive controls
2 / 3 Show Caption + Hide Caption – Four variable frequency drive controls serve as the computers that monitor and adjust the level of compression in the closed-loop, water-to-water ground source heat pump system installed at the headquarters building of the U.S. Army Corps of Engineer... (Photo Credit: U.S. Army) VIEW ORIGINAL
Vertical loop system
3 / 3 Show Caption + Hide Caption – A diagram shows how a closed-loop ground source heat pump system uses pipes buried in the ground to moderate heat. Recently, the U.S. Army Corps of Engineers New York District completed three geothermal projects at Fort Hamilton, New York, including ... (Photo Credit: U.S. Army) VIEW ORIGINAL

Through a series of recently completed geothermal projects at Fort Hamilton, New York, the garrison has reduced energy demand by 300 million BTUs per year, saving the U.S. taxpayer money and reducing greenhouse gas emissions.

The U.S. Army Corps of Engineers New York District project called for the installation of a closed-loop ground source heat pump system at several buildings on the installation. At one of the buildings, the headquarters of the Army Corps' North Atlantic Division, the efficiency occurs because the water used in the buildings' conventional radiator system is either pre-heated or pre-cooled (depending on the season) by the earth. The real technology lies in the loops, where a solution of glycol antifreeze and water is channeled more than 300 feet into the ground where the temperature stays a steady year-round temperature of about 55 degrees Fahrenheit. Here, the temperature of the solution is moderated by compression in the heat pump before coming back up to heat or cool the office space.

"We connected it to the building's existing HVAC (heating, ventilation, and air-conditioning) system," said Michael A. Ortega, New York District project engineer and contracting officer representative. "It uses the earth to reduce the building's heating and cooling demands and, ultimately, saves the government money."

The $2.6 million project was completed by Reva, Inc. in summer 2012 through a contract with the Corps' New York District. The project also included the installation of similar systems at two other buildings at Fort Hamilton. In total, 54 geothermal wells were installed on post.

"In light of the increasingly constrained fiscal environment, it is even more important to find ways to reduce the cost of operating our facilities and executing our missions -- and to help our customers do the same," said Patricia Donohue, sustainability program manager at the North Atlantic Division. "USACE is making smart investments for the future by ensuring that whatever we're doing is sustainable, saving taxpayer dollars."

Across the nation, the U.S. Army Corps of Engineers is investing in sustainability and energy efficiency projects both in new construction and at existing sites. Ultimately, the Corps is working to reduce its greenhouse gas emissions by 23 percent by 2020, which will meet one of its federal sustainability goals.

The New York District's first contract for a geothermal system was in 2004 at Fort Drum at the Wheeler-Sack Army Airfield Complex. Since the success of that project as well as a District project to complete a geothermal system at a Fort Drum child development center, the District has been providing geothermal systems as a primary option for heating and cooling needs in all new construction at Fort Drum, when feasible. Geothermal systems reduce energy costs and reduce the amount of fossil fuels burned, which can be high during the Northeast's cold winters. Although constructing geothermal systems costs roughly 30 percent more than traditional heating and cooling systems, it generally takes three to seven years to recoup the initial cost through savings.

"Geothermal systems an effective way to reduce cost and reduce greenhouse gas emissions, as well as a first step in achieving our federal net zero mandate" said Donohue. "We have found that they work well with smaller footprint, multi-level buildings such as administration buildings and barracks."

The U.S. Army Corps of Engineers strives to protect, sustain, and improve the natural and man-made environment of our nation, and is committed to compliance with applicable environmental and energy statutes, regulations, and Executive Orders. Sustainability is not only part of the Corps' decision processes, but is also part of its culture.

Related Links:


USAG Fort Hamilton

USACE North Atlantic Division

USACE New York District

U.S. Army Corps of Engineers

USACE Sustainability Page