Bridgehampton School Kicks Off Geothermal Construction with Test Loop

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Garrett Carnino of the American Well & Pump Company answers questions from a group of Bridgehampton School students and faculty as he describes a pumping and monitoring device that is being used to test the geothermal conductivity of the earth in a test well that was dug by the company in the field behind the Bridgehampton School. Michael Heller photo

By Christine Sampson

Construction on the Bridgehampton School’s geothermal heating and cooling system got under way last week with the installation of an underground test loop behind the school that will be monitored over the coming weeks to provide critical information about conditions on the campus.

According to Robert Hauser, assistant superintendent for finance and facilities, crews first drilled down 350 feet to install a loop consisting of two parallel, one-inch plastic pipes connected by a U-bend at the bottom. They returned later in the week to begin monitoring the temperature of the water flowing through the pipe. This will be one of 100 such loops that will eventually be installed underground to heat and cool the school as part of the geothermal project.

Bridgehampton voters recently green-lighted the project by approving the district’s use of a reserve fund to pay for it. The geothermal system’s final cost has not been determined yet, but it has been estimated between $500,000 and $600,000.

“I’m learning every day,” Mr. Hauser said. “It will be interesting to see the data that will come out of the test loop. I’m sure it won’t be just the temperature of the water — we’ll see how it will play a role engineering wise, construction wise, in the new project.”

Mr. Hauser isn’t the only one learning. Three teachers brought their classes out to witness the engineers begin reading the test results and explain what a geothermal system is. Among them was speech pathologist Aleaze Hodgens, whose third, fourth and fifth graders were the youngest to witness the action.

“They asked excellent questions while they were out there. ‘How deep is the hole?’ ‘What’s that goop on the ground?’” Ms. Hodgens said. “Very basic questions on a very complex subject, which lets me understand that my students are engaged, that they are thinking about what the engineers said.”

“Plus,” she continued, “the engineers were wearing hard hats and digging in holes, and who doesn’t want to do that in third, fourth and fifth grade? That’s so cool. The students feel like they’re part of the process now, which is great.”

As for the test loop itself, the data are very promising, according to John Rhyner, vice president for geothermal services with P.W. Grosser Consulting Inc., the Bohemia-based firm managing the process.

An illustration of how the closed-loop geothermal system works. Chris Lester illustration

The numbers “look good,” he said. “They are exactly what we anticipated as far as the thermal properties of the ground that the system is going to be tapping into. The starting temperature, the natural ground temperature, is 54 degrees Fahrenheit, and that’s nice and cool. That’s good for cooling and you can even pull heat out of that, too, with the use of geothermal heat pumps.”

Mr. Rhyner explained the system works by circulating water that may be treated with an antifreeze-like additive through a series of closed pipes — identical to the test loop — that will be installed underground behind the school, and which will conduct heat from the ground into a system of pumps inside the school building. In the winter, that heat will be pumped into the school to warm the building to about 75 degrees, and in the summer, the pumps will draw heat out of the building and into the underground pipe system, where the heat will naturally be transferred to the ground surrounding the system. The pumps operate on electricity. The athletic field behind the school will be restored once the system is completed.

Mr. Rhyner said the water in this type of system, known as a closed-loop system, does not come into contact with drinking water — a key aspect in a region that is very focused on water quality these days. It differs from another type of geothermal system, an open-loop system, which does interface with groundwater. The Hampton Library in Bridgehampton at one point built an open-loop geothermal system, but it broke down in 2013 when too much iron from the earth clogged the system, and the library replaced it with a more traditional heating and cooling system in 2014.

“You’re on a barrier island and your groundwater resource is not infinite,” Mr. Rhyner said. “This has no effect on the groundwater quality or quantity or flow. It just relies on conductive movement of heat between the water you circulate in the pipes and the ground.”

He said several thousand homes, businesses and other buildings on Long Island currently use geothermal systems, including Hewlett High School in Hewlett, Adelphi University in Garden City and the Long Island Aquarium in Riverhead.

“Schools are going to be around forever. These systems are more expensive than a conventional heating and cooling system, but they save a lot of energy,” Mr. Rhyner said. “It’s as much as 40 to 50 percent lower annual energy costs compared to conventional systems, so the cost to construct these systems gets paid back over a relatively quick period of time. There are no emissions of combustion from fossil fuels. It’s the most environmentally friendly, benign system for heating and cooling.”

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