BU Goes to the Center of the Earth
Geothermal system to heat Comm Ave building
By Vicky Waltz
Twelve years ago, the Brookline Historical Society declared the former Fellsway Motor Mart, with its intricate stone arches and large-windowed storefront, the most historic structure along Boston’s Auto Mile, a stretch of road between the BU Bridge and Packard’s Corner that was dominated by more than 100 automobile dealerships in the 1920s. Today the building, at 882 through 888 Commonwealth Ave., which currently houses the Kidney Center, is making history again by becoming Boston University’s first geothermal building.
“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, and we’re very excited to bring such a unique practice to the Charles River Campus.”
Derived from the Greek words geo (Earth) and therme (heat), geothermal energy is literally heat that comes from the Earth. “We’re drilling deep into the ground to harness the Earth’s natural energy,” says Patrick Watson-Hogan, president of ZVI Construction Co., which managed the construction of the project.
Last spring, construction workers drilled a series of six wells 1,500 feet deep — that’s twice as high as the John Hancock building — and 6 inches wide into the land adjacent to the 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 55 degrees, Watson-Hogan explains, and then pumps the water out of the wells and into a heat exchanger. The heat pumps work similarly to a refrigerator, using a compressor to discharge heat.
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, thereby warming the building. In the summer, the heat exchanger absorbs the excess heat from the air, blows the newly cooled air back into the building, and discharges the heat into the Earth. “Think of it as a pool of energy that is constant and not affected by atmospheric temperatures because it’s so far below the Earth’s surface,” Watson-Hogan says.
Geothermal systems are rare — only a handful exist in the Boston area, including one at Trinity Church in Copley Square and another at the Fessenden School in Newton — but the technique dates back to the beginning of the 20th century, when Prince Piero Ginori Conti introduced the first geothermal power generator in 1904, in Italy. The first geothermal power plant in the United States appeared in 1921 at The Geysers Resort Hotel in Northern California. Although the practice languished during the latter half of the 20th century, recent improvements in materials, equipment, and installation procedures have made the system more viable, Watson-Hogan says.
While the initial cost of installing a geothermal system is higher than conventional heating, ventilating, and air conditioning (HVAC) systems, Difabio expects the project to pay for itself within the first seven to nine years. The University opted for geothermal wells over other energy-saving methods, such as solar panels and wind turbines, he says, because “the geothermal system is the most reliable.”
Because they require no dependence on fossil fuels or natural gas, geothermal systems are highly energy-efficient, according to 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.” In fact, he adds, roof gardens are planned in place of the standard HVAC roof equipment.
One drawback of the geothermal process is that the pumps operate on electricity, Difabio says, but they do use less than comparable natural gas and fossil fuel systems.
Most geothermal projects require either building an entirely new structure or redeveloping an existing one from the ground up, Watson-Hogan says. The Fellsway Motor Mart building was an ideal candidate for a geothermal system because it involved the addition of a second and third floor, as well as interior loading space. When completed, the 95,000-square-foot structure will accommodate, along with the Kidney Center, the University’s Center for English Language and Orientation Programs classrooms, the International Programs offices, and several retail shops and restaurants.
This article first appeared in BU Today on January 14, 2009.