Science: Keeping Warm, Boston Style

A building that generates heat from people and machines

Nature, says the second law of thermodynamics, never gives you anything for nothing. Now some engineers in Boston have come close to defying that unbreakable rule. They have produced a building that heats itself without a furnace or conventional fuel and remains warm even during such blustery periods as the recent cold spell, when Boston temperatures plunged to 0°F. The building performs this scientific magic by a cunning engineering stratagem: it recaptures the waste heat of its own machinery, everything from computers to coffeemakers, as well as of the 2,000 people who will eventually work inside it.

Situated in Boston's theater district, the unusual self-heating structure will open formally at the end of this month, when local temperatures typically hover at 20° or 30°F. Still, the designers of the ingenious heating system, Henry Eggert and Howard McKew of Shooshanian Engineering Associates of Boston, are confident that teeth will not chatter nor pipes freeze. Indeed, they insist, the eight-story, 880,000-sq.-ft., redbrick Transportation Building will stay a comfortable 72°F all year round.

The state-owned structure's basic secret: three swimming-pool-size, 250,000-gal. concrete water tanks resting in the basement. Like giant thermos bottles, these insulated containers can store heat, which can be tapped at will. In daytime, when the building's population is at its peak and office machinery is working full blast, the air in the central core of the building rapidly warms up. (The human body in a 72°F room gives off 250 B.T.U.s per hour, about equal to the heat from a 75-watt light bulb.) This hot air is propelled through a labyrinth of ducts by ventilating fans. Some is mixed with cool air from outside and pumped back into the center of the building to provide fresh air; some is circulated past pipes carrying cooler water from the basement. During this encounter, the water from the basement is initially heated by 10°. Its temperature is raised further by large refrigerator-type compressors called heat pumps, which can add or remove large quantities of heat.

In winter the pumps hike the water's temperature to an optimal 105°. Some of this freshly warmed water is immediately sent off to the building's naturally cooler, outside offices, where it passes through heating coils that warm the air. The heated water can be stored in the tanks for re-circulation through the building at night or on weekends, when the building's population is low and very little machinery is operating. In summer the system works in reverse, with the heat pumps acting as air " conditioners. Rather than being stored in the basement for later use, heat picked up in the building's inner recesses is directed to 5 two cooling towers on the roof, which dissipate the heat into the atmosphere. In all seasons, the building gets a boost from rooftop solar collectors, which are arrays of black-painted pipes that absorb the energy of the sun's rays and provide most of the building's hot water for washrooms.