In 1995 Maine Audubon outgrew its headquarters building and nineteenth-century farmhouse building and began constructing s state-of-the-art “green” environmental center that now houses offices, facilities for public programming, a Maine Audubon Nature Store and the Teacher’s Resource Center.
Erecting a large new building on the sanctuary represented a special responsibility. The building had to blend in with the surrounding landscape and structures and use affordable materials that minimize negative impact on the environment, at the same time serving the needs of the staff and public who would use it.
Green building design and construction had come a long way since Maine Audubon constructed its landmark headquarters building at Gilsland Farm in 1976. But there is nothing revolutionary or complicated about the technology or materials used in Gilsland Farm’s environmental center. In fact, they are far simpler, and it is in its simplicity that this building can serve as a realistic model for incorporating green principles in most residential or commercial settings.
In siting, design, materials and construction, the award-winning center is a realization of a green future for indoor environments.
In a modern twist on the traditional post-and-beam style, hollow structural tubing made from recycled steel form the environmental center’s framework. Steel was chosen because it provides the strength to span large interior spaces—a wood frame of comparable size would have required cutting down dozens of rare, large old-growth trees. Also, steel is one of the most widely recycled—and recyclable—materials available. Every pound of steel recycled conserves 5450 Btu of energy, enough to light a 60-watt bulb for 26 hours. The steel used in the center contains up to 75 percent recycled scrap from such everyday items as old cars, appliances and cans.
In keeping with Maine Audubon’s commitment to supporting sustainable forestry, much of the wood in the building came from land that has met the scientific criteria for certification as being “well managed.” The wood for the shingles, the framing lumber and the interior trim was harvested from the country’s largest certified forest in northern and western Maine. Wood typically relegated as scrap was used to make the roof decking and window frames.
Other green materials include the petroleum-free floor covering in the restrooms and kitchen, which is made from a blend of chalk and various plant products. The carpeting will be recycled by its manufacturer into a variety of products, such as the curb stops out in the parking lot.
Whether the ground is buried by snow or carpeted in fields of green, the temperature of the water deep underground remains relatively constant at 45-50 degrees (F). That may seem cold, but there is actually enough heat in this water to keep the environmental center comfortable year-round. The secret lies not in producing heat, but in transferring it.
From the 600-foot well outside the building, groundwater is drawn up into the building’s basement where it passes through a series of three heat pumps, or compressors. The heat pumps operate much like a refrigerator in reverse. Each contains sealed coils containing a refrigerant solution. As the groundwater passes through the coils, the refrigerant absorbs the water’s heat and vaporizes. The now-chilled groundwater returns to the ground, but the vaporized refrigerant passes through a second tank of water, where it condenses, releasing its energy in the form of heat.
With its temperature raised as high as 130 degrees (F), the newly heated water circulates through hundreds of feet of tubing embedded in the concrete floor. The concrete absorbs this heat and radiates even warmth across the floor. During the heating season, the air just above the floor is warmer than air at the ceiling—exactly as it should be, but almost never how it is in most buildings.
A heating system without weather-tight insulation is a waste of effort and energy. Highly efficient nontoxic foam insulation in the walls and insulated panels on the roof provide a tight barrier against air and moisture infiltration and minimize heat loss. Additional benefits come from air-tight windows that allow heat to enter but restrict its escape. And to keep the indoor air from becoming stale and unhealthy without letting all the warmth disappear out an open window, the ventilation system preheats incoming fresh air with warm exhaust air.
The need for artificial light is minimized by the large, south-facing windows and interior glass that allow abundant natural light to reach most of the building for long periods each day. When needed, long-lasting fluorescent bulbs on electronic ballasts provide the artificial lighting. Sensors that detect motion or heat automatically turn lights on or off when people enter or leave a room.
When you visit Gilsland Farm, look for the small green panels in the environmental center that identify and describe specific green features in greater detail.