Deep underground wells on the University of Maine Farmingon campus take advantage of the constant temperature of the earth to moderate the temperature of water used to heat and cool buildings. The Fitness and Recreation Center has 3 geothermal wells for the swimming pool and the Education Center has 42 wells. Renovations and future construction of buildings on campus may also take advantage of this valuable sustainable resource.
The Education Center uses no fossil fuels to generate heat. A ground source heat pump system (sometimes called geothermal) of 42 wells at a depth of 357 feet below the earth’s surface maintain water in a closed loop of pipes at a constant 51°F. These pipes converge three to a manifold before entering the building into the pump room, located behind the classroom on the lower level of the building. Large electric heat pumps with compressors work on the same principles as a refrigerator to transfer heat as follows:
In the winter, chilled water is pumped through the ground loop which warms it up to nearly 51°F, the ground temperature. The 51°F water goes to the heat pumps which chill the water as they transfer heat to the room air or to other components of the heating system. The chilled water returns to the pump room. The cycle repeats.
In the summer, heated water is pumped through the ground loop transferring heat to the earth, water cools to near 51°F. 51°F water goes to heat pumps which absorb heat from the room air and transfer heat to the water, raising its temperature to above 51°F. Warmed water returns to pump room. Cycle repeats.
Four large heat pumps heat and cool the building. A small heat pump controls the radiant heating in the student lounge flooring. Small local heat pumps in classrooms and offices heat or cool air as it enters those spaces. A heat pump in the rooftop air exchanger treats fresh air that enters the building, and also treats air that leaves the building.