Drilling for Energy
Geothermal system to heat Comm. Ave. building| From Commonwealth | By Vicky Waltz
The redevelopment of 882 through 888 Commonwealth Avenue includes a geothermal heating and cooling system, the first at Boston University. Illustration courtesy of ZVI Construction Co.
It’s not exactly a journey to the center of the Earth, but by drilling deep into the ground, BU plans to harness the Earth’s natural energy to heat one of its Commonwealth Avenue buildings.
Last spring, construction workers drilled a series of six wells 1,500 feet deep — that’s twice the height of the John Hancock building – and 6 inches wide into the land adjacent to the former Fellsway Motor Mart, at 882 through 888 Commonwealth Avenue. The building, which is being renovated, currently houses the Kidney Center. After the project is completed, in June, it will accommodate the University’s Center for English Language and Orientation Programs classrooms, the International Programs offices, and several retail shops and restaurants. And it will be the University’s first geothermal building.
Using well water as a medium, the system draws upon the Earth’s energy to warm the water to a constant temperature of approximately fifty-five degrees, says Patrick Watson-Hogan, president of ZVI Construction Co., which manages the construction of the project. It then pumps the water out of the wells and into a heat exchanger.
During the winter, the heat exchanger uses heat that is transferred from the Earth to the heat pump, which compresses the air to raise its temperature. In the summer, it absorbs excess heat from the air and blows the cooled air back into the building.
Geothermal systems are rare – only a handful exist in the Boston area, including one at Trinity Church and another at a school in Newton — but the technique dates back to the early 1900s. Recent improvements in materials, equipment, and installation procedures have made the system more viable, Watson-Hogan says.
“Geothermal systems make up only about 1 percent of heating and cooling systems throughout the country,” says Michael Difabio, the University’s associate vice president for property acquisition. “As a general rule, we’re always looking into whatever energy-saving methods we can employ in the redevelopment of our buildings.”
While the initial cost of installing a geothermal system is higher than conventional heating, ventilating, and air conditioning systems, Difabio expects the project to pay for itself within the first seven to nine years.
Because they do not depend on fossil fuels or natural gas, geothermal systems are highly energy-efficient, says Watson-Hogan. “And because you’re not burning anything, the maintenance and operation costs are significantly lower, and the process is much cleaner and quieter,” he says. “Your largest piece of equipment is the size of a conference room table, so there’s no need for a boiler room.”