Triumph Over Tragedy
Demolished Iowa high school rebuilds with geothermal after an EF-5 Tornado destroys its campus.
Sunday, February 28, 2010
By Randy Happel
On May 26, 2008, the small, rural town of Parkersburg, IA, (population 1,900) was nearly leveled by an enormous EF-5 tornado—the most devastating twister to strike the Hawkeye State in decades. Packing winds estimated by the National Weather Service in excess of 250 miles per hour, the storm unleashed a 43-mile-long path of destruction spanning three counties. But it was Parkersburg that took the biggest hit—eight people killed, 282 homes demolished, and another 400 heavily damaged—23 businesses lost including City Hall, the town’s only grocery store, and the Aplington–Parkersburg High School.
Rebuilding Renewable
Despite the horrendous destruction, there was never a question that the resilient folks of community located in northeast Iowa would rebuild. By sunrise the day following, fleets of equipment had arrived on the scene, and cleanup was underway. The same day, school administrators met to begin laying the groundwork for rebuilding the school.
Shortly thereafter, architects were commissioned to submit bids for rebuilding the school. Design specifications were to include two noteworthy features: a geothermal heating/cooling system and a lower-level storm shelter—just as a precaution.
Superintendent Jon Thompson says the decision to go geothermal made sense on several fronts. He and the five other committee members who led the rebuilding planning process researched as many options as possible, given the short timeframe.
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Photo: Two Rivers Marketing
Despite the destruction, the community focused on the opportunities the rebuilding provided. |
“We conducted energy audits, plus, we visited with other schools in our area that have had success with it geothermal,” says Thompson. “It quickly became evident that geothermal was the way to go. A geothermal system was the most economical and cost-efficient for the majority of the new building.”
Although Thompson admits installing geothermal costs more up front than a conventional system, the monthly savings in reduced energy bills over time will help free up money for things more directly related to education—such as new textbooks, computers, and teachers.
“Schools have different pots of money to pay for different types of things,” explains Thompson. “Installing a geothermal field costs more initially, but it’s money that comes from a separate pot, not from school operating funds. We were also able to receive assistance from various sources after the tornado to help fund construction. Reducing our monthly utility costs created more dollars from our operational fund to do things like buy textbooks and hire more teachers.”
The committee determined the most efficient route was to combine geothermal with a conventional system that will be used to heat and cool the gym only. Thompson explained the rationale.
“One of the things we discovered is that for large, open spaces, geothermal isn’t as efficient as in areas divided by rooms with lower ceilings,” says Thompson. “I’m not an expert, but it has something to do with the amount of air that has to change over. In the case of the gym, an area that isn’t always occupied, a conventional system was the more cost-effective approach.”
A-One Geothermal, based in Earlham, IA, was selected to install the geothermal system after participating in an extensive bidding process. Founded in 1975, the family-owned business has a long geothermal installation track record. A-One got its start installing water and sewer lines, and then, during the 1990s, expanded services to include fiber optic installations using horizontal directional drilling (HDD).
Over the years, A-One founder and vice president, Dale McNair, had always been intrigued by the geothermal concept, and took the initiative to learn more about it. When the fiber optic market went bust in early 2000, McNair had become a geothermal expert and decided to make it his core business.
“As geothermal became more popular, so did the demand for installers,” says McNair. “It now accounts for over 90% of our business.”
Stay in the Loop(s)
A typical geothermal system features several loops buried underground, either vertically or horizontally. The loops—extending 200 feet or more, depending on the need—are filled with environmentally safe antifreeze and connected to a geothermal heat pump.
During the heating cycle, the system automatically pulls heat from the ground via the antifreeze in the loops and circulates it through the geothermal heat pump, which concentrates the heat and distributes it throughout the structure via ductwork. At the same time, the antifreeze constantly cycles back through the loops, where it reheats, and the process repeats itself.
Often, the first step in the installation process is to complete a conductivity test. Since ground composition varies from site to site, conductivity results help to more accurately project the potential energy storage capacity of a specific formation. This is especially important for larger installation projects.
HDD Preferred
McNair prefers the horizontal directional drilling approach for installing the U-shaped loops, citing a number of advantages. “HDD is a more cost-effective installation method,” says McNair. “It also takes less time and fewer resources than vertical drilling. There is also less ground disturbance and more field installation options. We’ve installed horizontal systems under parking lots, driveways, existing structures, and athletic fields.”
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Photo: Two Rivers Marketing
A-One Geothermal got its start installing water and sewer lines. |
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Photo: Two Rivers Marketing
In order for a geothermal system to operate at peak efficiency, accurately calculating the size of the system, i.e., the number of loops needed, is critical. |
McNair’s fleet of HDD equipment includes four Vermeer models of varying size. His crew used the Vermeer D36x50 Navigator model to install the geothermal field at Parkersburg. The field consists of 58 loops and stretches 420 feet from north to south, installed in “piggyback” formation with one line at a depth of approximately 30 feet, and a second installed directly above at 15 feet. Bentonite grout, a substance that helps maximize conductivity, is pumped into each of the bores as the loops are pulled back through.
The series of loops connect to several 8-inch supply lines that feed to an underground “vault” where the fluid-filled loops transfer the stored energy to the high school. The entire configuration was installed directly underneath the school’s softball field with minimal disruption. The project took eight weeks to complete.
The size and condition of the structure and the capacity of the ground formation to store energy determine the number of loops necessary to support a specific system. The amount of energy generated by each loop will vary by design. McNair explains that in order for a geothermal system to operate at peak efficiency, accurately calculating the size of the system, i.e., the number of loops needed, is critical.
“There is a tendency for most people to think the bigger the system—the more loops—the better,” says McNair. “In reality, nothing could be further from the truth. With geothermal, it’s all about being able to accurately calculate the requirements of the structure and nothing more or less.”
Payback
No one disputes that it costs more up front to install a geothermal system. But there’s also no disputing the energy savings and payback. All systems begin paying for themselves immediately in the form of monthly energy savings, and the additional up-front investment is likely recouped within four to six years, depending on the size of the system. McNair says a conservative estimate for monthly utility cost savings is 50%, while many systems can save up to 70% over the cost of operating a conventional system.
Not unlike the example shared by Superintendent Thompson, whose school can now afford to buy more textbooks and computers with funds that previously would have gone to paying monthly heating bills, the same can be said for any homeowner, business, or nonprofit organization who chooses the geothermal route. And once installed, maintenance is minimal and repairs nearly nonexistent.
Incentives Aplenty
After deciding to go geothermal, Thompson has since learned that a number of residents, who are rebuilding after losing homes in the tornado, are also installing geothermal systems. “In talking with several parents who built new homes, I found a lot of them also installed geothermal,” says Thompson. “Talking with them made me a bit jealous that I didn’t [have a geothermal system] at my home.”
Numerous incentives are available for individuals and businesses that choose the geothermal route. The federal government and most states have sweetened the geothermal installation pot. Uncle Sam offers direct energy-savings tax credits for homeowners who use energy-saving techniques when building a new home. At the state level, incentives, grants, and rebates are available. Even private utility companies are in the game; offering rebates to commercial and residential customers for converting to geothermal systems.
Mortgage companies are also offering rewards. For those who qualify, an Energy Efficient Mortgage, also called an EEM, can increase the purchasing power of buying a geothermal system by allowing the lender to increase the borrower’s income by a dollar amount equal to estimated energy savings.
Author's Bio: Randy Happel is a features writer based in Des Moines, Iowa. |
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