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Heat Pump Goes Down 1,500 Feet New York Building Taps Into Geothermal Energy Of Bedrock

On 64th Street just east of Central Park, limestone and marble mansions owned by Edgar Bronfman Jr., Ivana Trump, Gianni Versace and other notables line a block busy with black Rolls-Royces and stretch limousines.

Now the block is also home to the two deepest holes in the city, each deeper than the World Trade Center is tall.

The holes were drilled 1,500 feet into bedrock this month to tap the stored energy in the rock for an $8 million building being constructed by Theodore Kheel, the labor lawyer, philanthropist and now environmental showman. Until now, the deepest holes in the city’s bedrock were water tunnels, some of which pierce the earth 900 feet under the surface.

The building will rise this year on a 3,500-square-foot lot sold to Kheel by David Geffen, the record and movie producer. It will house half a dozen nonprofit foundations but is also meant to illustrate how energy-saving technology and environmentally sensitive construction methods can pay for themselves, Kheel said.

Water pumped into and out of the holes will flow through pipes in the building, Kheel said, cooling or heating each room to its ideal temperature year-round. This geothermal heat pump will also generate hot water for bathrooms, all with no boiler, no rooftop clutter of fans and cooling towers, almost no air pollution, and only a small monthly electric bill.

Installing the geothermal energy system will cost slightly more than a conventional heating and air-conditioning system, but reduced fuel, electricity and maintenance costs should make up the difference in a few years, Kheel said.

“We’re not going to change the world with one little building,” he said. “But we can set an example. Geothermal will be our best expression of what can be accomplished. It’s beneficial for the environment and will save tremendously on electricity.”

Although this is the first geothermal heat pump in Manhattan, the technology has already been used by businesses and homeowners around the country.

From about 6 feet down to 1,000 feet or more, rock acts like a long-term storage battery for solar energy, remaining at a temperature about 56 degrees - roughly halfway between the hottest and coldest temperatures experienced on the surface, said Carl Orio, president of Water & Energy Systems Corp., in Atkinson, N.H., and the designer of the unit.

The systems vary depending on local conditions, with some consisting of a shallow subterranean loop of piping in which fluid circulates to collect or dump heat. For businesses or homes with plenty of land, one option is to dig many relatively shallow wells.

But in places where square footage is at a premium, like Manhattan, the only option is to go straight down. The depth of the wells was determined by the amount of heating and cooling that the heat pumps must provide, Orio said.

Adrian Tuluca, an architect and energy specialist in Norwalk, Conn., who is running computer models of the project’s costs and benefits, said some advantages are particularly suited to the neighborhood.

Because the block lies in a historic district, no rooftop equipment - like air-conditioning towers and fans - can be visible. But there is none of that with geothermal systems.

“It preserves the visual environment just as much as the ecological environment,” Tuluca said.