From the Ground Up

The first geothermal heating and cooling unit on campus is slated to begin operating soon
Grant Garven with students on campus
Grant Garven discusses data gathering and measurements during his Groundwater Field Lab in October. One of the wells he uses will double as the source of geothermal energy. Photo: Alonso Nichols
January 12, 2012

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Four years ago, Grant Garven started building an outdoor laboratory so his geology students could directly learn about groundwater and the surrounding soil and rocks. He used start-up funds given to new faculty and had a dozen observation wells dug around the Medford/Somerville campus. The students got firsthand experience with drilling wells, sampling water, taking measurements and collecting hydrogeologic data at various depths.

Now Garven, a professor of geology in the School of Arts and Sciences and adjunct professor of civil and environmental engineering, is working with the Tufts Facilities Services Department to transform one of the his 700-foot-deep observation wells into a geothermal well, using the steady temperature of the Earth to heat and cool a classroom in nearby Lane Hall.

Using the Earth for cooling or heating is not a new idea. The early pioneers, Garven says, would dig cellars in the ground to store butter, meat, eggs and milk at cool temperatures. Nowadays, geothermal wells, hundreds of feet deep, are being used to help cool and heat homes and offices. According to the Union of Concerned Scientists, there are more than 600,000 wells in the United States with new installations occurring at a rate of about 60,000 a year.

As the cost of fossil fuels keeps rising, the notion of using the Earth as a cheaper and more efficient source of energy is growing in popularity, and universities are joining in. The National Wildlife Federation released a report in February that said that more than 160 colleges and universities in 42 states use some form of geothermal energy.

While the air can be a nippy 25 degrees Fahrenheit in January in New England, the groundwater temperature is constant, staying in the mid-50s F. The trick is to use that steady, moderate temperature to bring warmth in the winter and take away the heat in the summer by using a heat pump.

Electricity powers the pump to circulate refrigerant through an underground pipe, where it absorbs the Earth’s heat in cold weather and brings it inside the building. In the summer, the system works in reverse. The heat pump transfers excess heat back to the Earth where it dissipates underground.

A Well-placed Investment

Betsy Isenstein, the university’s energy manager, says the goal, at least at this point, is to learn about the technology and any operational challenges. “We’re not trying to achieve a payback on this project, but we think we will be able to in the future. The more we learn about how to install, operate and maintain this small system now, the better we will be able to apply the technology in the future to save money and reduce carbon emissions.”

Bob Burns, director of facilities services, said the project will be funded by his department. “Since the investment in the well has already been made, we thought we’d piggyback off that and install the heat pump to provide tempered air to a classroom. We hope the students will learn from this, too.”

Students work on one of the observation wells on campus under Grant Garven’s direction. Photo: Alonso NicholsWhile it’s too soon to tell, says Burns, it’s possible the university could construct more geothermal wells on campus to warm and cool buildings. According to the National Wildlife Federation study, the nation’s 4,100 colleges and universities spend more than $20 billion each year on energy, or $5 million per campus on average.

Using geothermal energy could collectively save between $2 billion and $7 billion in energy costs and reduce the nation’s carbon footprint by up to 1 percent a year, the study says. There’s a tradeoff, though, says Burns. The energy savings have to be weighed against the cost of drilling wells and installing the piping and heat pumps.

With a deep well already dug across the road from Lane Hall, the work will involve connecting the well to the building and then installing a heat pump inside. A trench has already been dug, and plans called for a heat pump to be worked on over the winter break.

Isenstein says the facilities department will determine how well the system works, while giving personnel a chance to become familiar with the technology.

Garven, meanwhile, plans to use the energy project as yet another laboratory for his students. A computer monitor will be installed to register the temperature of the water going in and out. Instead of just learning about theory, he says, students will see firsthand the fundamentals of geothermal energy.

“It’s important for the next generation of geology and geotechnical engineering students at Tufts to become familiar with this rapidly expanding technology,” he says. “This is good for the planet, and the technology is there. Why not use it?”

Marjorie Howard can be reached at marjorie.howard@tufts.edu.

 

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