Out of the Vault

We've been going through the Vault's files of clippings and brochures at the North Adams Public Library and were interested to discover that more than 25 years ago, a local agency was exploring the idea of using geothermal heat from the Hoosac Tunnel to provide heat for certain locations in the city!

Library personnel have a particular interest in that form of energy, because geothermal wells were installed during the library's recent expansion and renovation to heat and cool the building. The library is certified as a LEED Green Building, and our interest in alternative energy solutions was piqued by the discovery.

During construction of the tunnel, workers often complained of the heat, and some of the deaths that occurred were attributed to it. That may have been the impetus to explore the geothermal potential of the tunnel more than 100 years later.

According to an article that ran on Aug. 19, 1981, in the Springfield Union, the tunnel reaches 1,900 feet below the surface at its deepest point. Since temperatures rise one degree per 100 feet of depth, theoretically the temperature boost would be around 19 degrees.

So here's the story, assembled from the

found article plus further research in The North Adams Transcript:

In 1981, Housing Now of Pittsfield, provider of low-cost housing in Central and Northern Berkshire, received a $7,720 federal grant to determine whether the extra heat that was such a problem during the construction of the Hoosac Tunnel could be harnessed and used to heat various sites on the eastern end of town, such as Drury and McCann high schools.

Housing Now awarded a research contract to West Stockbridge Enterprises to do a study of the tunnel as a heat source. The Transcript quoted engineering assistant Peter Mikitis as saying that if enough thermal heat was stored in the rock walls of the tunnel, heat pumps could be used to pipe the warmth to the nearby buildings. The study was to take three to six months.

Since the library's geothermal installation was the first in town, we presumed that the study had shown that the geothermal potential was insufficient to be worth the cost, but we could not find an article reporting on the study's results.

Finally our researchers went to the federal Department of Energy site and found the final report, which was dated June 10, 1982. The report states:

The Tunnel

* Is a poor source of geothermal heat. The maximum extractable energy is only 2,200 million BTU (20,000 gallons of oil) at 58 (degrees) F.

* Is a poor heat storage facility. The rock conductivity is so high that 75 percent of the heat injected would escape into the mountain before it could be recaptured for use.

District Heating

* A low temperature system, with individual heat pumps for temperature boost, could be economically attractive if a low cost fuel ... or cost effective seasonal heat storage were available.

The library uses photovoltaic (energy converted from sunlight) panels to power the heat pumps. They were not sufficiently developed in 1981 to be used. Might it be economically feasible with today's energy prices and availability of photovoltaics to capture the tunnel's heat?

It will be interesting to see if anyone pursues this question.

Katharine C. Westwood is special collections librarian at the North Adams Public Library. The library provides its Out of the Vault column on a continuing basis for the Transcript.