Abandoned mine shafts beneath campus, long perceived as an unusable relic of an industrial past, have a new purpose in the quest for alternative energy sources.
Marywood University and Greenman-Pedersen, Inc., an engineering and construction services firm, recently repurposed abandoned coal mines underneath campus into a source of geothermal energy for the Center for Architectural Studies. A highly efficient and environmentally friendly practice, using mine shafts as a source of geothermal energy can minimize or eliminate the need for fossil-fired heating systems. At the same time, geothermal energy systems help reduce greenhouse gas emissions, make use of local resources, don't pollute the environment, reduce operating costs, and don't require a lot of construction and development.
Ground-coupled geothermal systems use the constant temperature of the earth's crust to exchange energy for heating and cooling applications. Marywood's project uses flooded underground mine shafts for this purpose. Geothermal systems can be open or closed. Open systems extract ground water from a well and use that water to meet cooling or heating needs. Closed loop systems include numerous borings or horizontal trenches with long lengths of piping that are completely buried to exchange heat with the earth. Both systems have been used in countless sustainable initiatives, reducing their carbon footprint.
Marywood University uses an open geothermal system that utilizes two wells to extract the energy from the earth. The Center for Architectural Studies uses a direct cooling application. The water extracted from the earth is cold enough to cool the space without any compressorized air conditioning equipment, eliminating the need for refrigerant-driven, energy-consuming equipment. The Center uses the cooling capacity in the geothermal system to serve chilled beams in the large, open studio areas. Water (with a temperature of 58°F to 60°F) is circulated through long, ceiling-mounted chilled beams, providing the necessary cooling capacity to meet the space needs. Chilled beams require no electrical energy to operate and are silent; they simply rely on natural convection (the cool air "dropping") from the beams along the ceiling to the occupied areas below.
Marywood's new geothermal system, completed during the summer, serves a portion of the cooling needs of the Center for Architectural Studies. The system can be expanded and will be utilized in Phase II of the Center's construction, in an effort to continue the University's commitment to sustainability and environmental stewardship.
Graph- How an Open Geothermal System Works: The production well contains a submersible pump, similar to a traditional potable water well pump, to extract water from the flooded mine and pipe it to the surface. The water is then piped to a heat exchanger to extract heat to the building system. The heat exchanger cools the water circulated in the building system, while at the same time preventing the raw mine water from mixing with the building water circulation system. After passing through the heat exchanger, the mine water is returned to the recharge well, which ends in the same mine shaft as the production well. All water extracted from the production well is returned to the recharge well.
To read media coverage of Marywood University's new geo-thermal system, go to:
Scranton Times- Nov. 15:
Pocono Record- Nov. 17
Scranton Times- Nov. 19:
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