What components comprise the system? What are the benefits of the geothermal system? Is a geothermal system good for the environment? Are there existing implementations that demonstrate the success of geothermal in this region? Where will the energy stations and borehole fields be located? How much will the project cost? Will this change the appearance of the Ball State campus or will it change the comfort level inside buildings?
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Jim Lowe, director of engineering and operations, explains the geothermal heat pump system. |
What is a geothermal system and how does it work? A geothermal heat pump system is a heating and cooling system that uses the Earth’s ability to store heat in the ground and water thermal masses. A geothermal heat pump uses the Earth as either a heat source, when operating in heating mode, or a heat sink, when operating in cooling mode.
The ground a few feet below the surface has a very stable temperature throughout the year. Geothermal heat pumps draw that available heat in the winter and sink heat into the ground in the summer. A conventional furnace or boiler produces heat. In contrast, geothermal systems simply transfer heat from one place to another.
Geothermal heat pumps are also known as “ground-source heat pumps.” They are different from common heat pumps in homes where the heat source is the air. Geothermal heat pumps differ from geothermal heating, used in areas where exceptionally high underground temperatures are used to heat indoor spaces.
The switch to geothermal heat will not be detectable. Faculty, staff, and students will notice no difference in temperature in offices and classrooms.
What components comprise the system? The system is comprised of four key components: boreholes, energy stations, hot and cold district loops of water-filled pipes, and building interfaces.
Borehole Fields Borehole fields will be spaced around campus. The fields will be a series of closed pipes that run vertically in the ground. Ball State’s loop will consist of approximately 4,100 boreholes, 400 to 500 feet deep. The boreholes will be 4 to 5 inches in diameter. Pipe pairs in the hole are joined with a U-shaped cross connector at the bottom of the hole, allowing water to circulate through the sealed pipe. The borehole is commonly filled with a grout surrounding the pipe to provide a good thermal connection to the surrounding soil or rock to maximize the transfer of heat.
Ball State’s closed loop system will circulate water. In colder climates, similar systems require the use of an antifreeze such as propylene glycol, denatured alcohol, or methanol. Ball State’s system will not require any antifreeze and will use only fresh water. There is no direct interaction between the water in the system and the Earth, only heat transfer across the pipe.
Energy Stations Energy stations will be the workhorse of the system. They will exchange the heat and dispatch it from where it originates to where it is needed. Two energy stations will each have a closed loop of refrigerant. The refrigerant is pumped through a vapor-compression refrigeration cycle that moves heat from a cooler area to a warmer one. Closed loops with water pass through the chiller and run throughout campus.
Here, the heat pulled from or sunk into the ground will be transferred, or exchanged with two district loops that run throughout campus: a cold water loop (constantly 42 degrees) and a hot water loop (constantly 170 degrees). The direction of transfer depends on the season and whether heat is being pulled from the ground or sunk into it.
District Loops Hot and cold water is routed through campus via two district loops, one for hot water and one for cold water. Much of the piping needed for this system already exists as part of the university’s current heating and cooling system.
Building Interface The district loop will supply buildings’ demand for heating or cooling. The hot and cold pipes pass through heat exchangers (similar to a radiator in a car) and fans blow the correct temperature into buildings or offices as called for by the occupants.
What are the benefits of the geothermal system? Economic Ball State will drill between approximately 4,100 boreholes and construct two energy stations. The system will be American-made and built by U.S. contractors, many of them from Indiana.
The impact of the project will be immediate. Building the system will span more than five years and will create many construction jobs. Manufacturers supplying the project will be able to increase production and keep more workers on the job and out of the unemployment office.
We find history repeating itself. The Ball brothers came to Muncie to reduce costs for their glass business by using “free” energy in the form of natural gas pulled from the ground. Now, the university they founded will save $2 million annually in fuel costs by using a different form of “free” energy pulled from the same ground.
Environmental By taking the current, aging boilers offline, the university will be able to reduce the amount of carbon dioxide it adds to the atmosphere by a substantial amount—nearly 80,000 tons annually. The net result of switching to the geothermal system will allow Ball State to cut its carbon footprint roughly in half.
This project will also debunk the erroneous assumption that alternative energy projects are always too expensive or impractical to be adopted by cost-conscious businesses and consumers. The best ones, like Ball State’s geothermal energy system, are a boon to the economy as well as the environment.
Is a geothermal system good for the environment? By taking the current, aging boilers offline, the university will be able to reduce the amount of carbon dioxide it adds to the atmosphere by a substantial amount—nearly 80,000 tons annually. The net result of switching to the geothermal system will allow Ball State to cut its carbon footprint by nearly half.
There is no direct interaction between the water in the system and the earth, only heat transfer through the pipes. Ball State’s closed loop system will circulate water. In colder climates, similar systems require the use of an antifreeze such as propylene glycol, denatured alcohol, or methanol. Ball State’s system will not require any antifreeze and will use only fresh water.
Implementing a university-wide geothermal system is part of Ball State’s longtime
commitment to sustainability.
Are there existing implementations that demonstrate the success of geothermal in this region? Geothermal technology has been used for decades in residential and commercial applications. For example, One American Square—approximately 1 million square feet—in Indianapolis has been heated and cooled since 1982 with four wells supporting its open loop system. The Galt House in Louisville, Kentucky, also uses open loop geothermal heating and cooling. One American Square is replacing its system with large capacity heat pump chillers similar to those Ball State plans to use.
It’s the scope of the system—including more than 45 buildings over 660 acres—that makes the new Ball State system unique.
The availability of very large capacity heat pump chillers that have come to market in only recent years makes the project possible today. This would not have been possible five or six years ago. The university has consulted the U.S. Department of Energy’s National Renewable Energy Laboratory, Oak Ridge National Laboratory, and the country’s leading firms in this area. Ball State has also received a ringing endorsement from a past president of the American Society of Heating, Refrigeration, and Air-Conditioning Engineers (ASHRAE). ASHRAE sets the national standards for heating and cooling equipment.
Where will the energy stations and borehole fields be located? See the map.
How much will the project cost? The new geothermal system will replace four aging boilers that are nearing the end of their usefulness. Cost for the project is estimated at $65 million to $70 million. University officials anticipate a highly competitive bid process due to the current economic climate that could result in a highly favorable final cost.
Once fully implemented, the project will save the university $2 million in fuel costs annually. Additional cost savings could also be realized due to lower life cycle costs compared to the university’s current system.
Will this change the appearance of the Ball State campus or will it change the comfort level inside buildings? The boreholes will be installed on campus. As part of the project, these spaces will be restored to their original use and beauty. People using the parking lots and recreational fields atop the well fields will not notice they are atop a well field.
See a map of the locations.
Two energy stations will house large-capacity heat pump chillers to move water through the system. One new building will be built. The other will be housed within the current
Central Chilling Plant. The buildings will not be constructed on the well fields. When the project is complete, the four existing boilers will be removed.
Modest changes will be made inside campus buildings, involving mostly upgrades to current systems and installations of new piping for the hot water system which will be connected to the district hot water loop. A newly designed heat exchange interface will be necessary for each building. Upgrades will be made to the electrical distributions systems to ensure reliability.
The switch to geothermal heat will not be detectable. Faculty, staff, and students will notice no difference in temperature in offices and classrooms.