Alliant Energy Logo Alliant Energy Geothermal
Alliant Energy Geothermal Home Page


Call 1-800-723-7635, use our Contact Us form or e-mail .

Home  |  About Us  |  Contact Us  |  Sitemap  

What It Is: Geothermal In Action

CNN Science Report - Stockton College

"Colleges have the reputation for being a hot-bed of innovative ideas and at one college in New Jersey an idea is being closely watched. On Science Report, CNN's Brian Jenkins visits a campus that is becoming an environmental model for the country. The geothermal project is of national significance."

Scott Weiner, New Jersey Commission of Environmental Protection and Energy:

"I think if there was one project that people wanted to point at to show the benefits of energy conservation, environmental sensitivity, and what can be accomplished, this project here at Stockton College would be the example."

Brian Jenkins, CNN Science Report:

What is a geothermal heat pump? A geothermal heat pump is an electrically powered device that uses the natural heat storage ability of the earth and its ground water for heating and cooling purposes.

Because of the density and mass of the earth, nearly half the thermal energy reaching the earth from the sun is absorbed; far more than the atmosphere which is thinner and less thermally absorbent. In contrast to the atmosphere, the ground remains at a relatively constant 55 degree temperature throughout the seasons providing a higher temperature source in winter and a cooler sink in summer.

Geothermal technology uses this thermodynamic advantage to provide highly efficient space conditioning. Geothermal heat pumps differ from conventional air source heat pumps in that the geothermal heat pump system uses the earth as both a heat source and a heat sink.

This is accomplished by constructing an underground high-density polyethylene closed-loop piping system that circulates water through a heat exchanger that transfers the temperature of the circulating water to a rooftop geothermal heat pump system.

Stockton's well field was constructed by a company out of Western Pennsylvania and contains 400 wells, each installed to a depth of 425 feet.

Additionally, 18 observation wells equipped with temperature probes and other scientific instrumentation are symmetrically located within and adjacent to the well field. These observation wells will enable the college to carry out long-term scientific studies related to the operational and environmental efficiency of the ground loop system.

The well field is laid out in a grid that contains four segments with each segment consisting of 100 wells. The entire well field covers roughly 3.5 acres of land, which includes all of parking lot plus a tract of land immediately adjacent to the parking lot. A permanent 500-car parking lot will cover the entire well field upon its completion prior to the opening of Stockton's fall semester.

Since ground loops function more efficiently in wetter soil where thermal resistivity is lower, the hydrology of the campus is particularly well suited for installation of the geothermal system.

The college's well field was drilled through three aquifers, three confining beds and two transitional units. The aquifers are from top to bottom the Upper Cohansaq, 80 feet in thickness; the Lower Cohansaq Aquifer, 52 feet in thickness; and the Rio Grande Water-Bearing Zone, 36 feet in thickness. Confining beds, which are for the most part impervious to water, keep the ground water within the aquifer.

Two variable speed 125 horsepower pumps, located in the building under construction, pressurize the primary supply and return system that will be located in the main manifold house. Only water will circulate through the closed loop system, which will be set at least four feet below ground level.

At peak demand, water will flow at a rate of 3,600 gallons per minute. When fully operational, the total amount of water flowing in the entire system will be less than the amount used to fill Stockton's pool, about 100,000 gallons.

A 10-inch secondary supply and return piping system distributes water to and from the pump house to the academic buildings, and ties into a three-inch piping distribution system that delivers the water supply to and from high-efficiency roof top geothermal heat pumps manufactured by the Trane Company.

To reduce energy costs further and, at the same time, provide an independent heating and cooling zone control capacity, the forced air system is equipped with a variable air volume or VAV system. The VAV system is designed to supply the volume of conditioned air to a space that is required to satisfy the appropriate heating or cooling load as well as meet established fresh air requirements.

The VAV unit is installed inside an insulated sheet metal VAV box suspended in ceiling plenums and is equipped to regulate air flow to maintain a zone temperature that is established at set points.

Both the New Jersey Department of Environmental Protection and Energy and the United States Department of Energy have endorsed geothermal heat pumps, forecasting they will supply as much as 2.7 quads of renewable energy annually by the year 2030. A quad is equivalent to a 170 million barrels of oil or one trillion cubic feet of natural gas.

The significant benefits that result from the cooperative public and private sector partnership that have made the college's project possible are numerous:

  1. First, preserve the State's capital investment. By implementing a cost-effective replacement program for the college's originally installed HVAC system that has reached and exceeded its usable life, the State's capital investment will be preserved.

  2. Second, materially reduce energy consumption by installing a geothermal ground-water source heat pump system, which provides an alternative energy resource that will cut electrical energy consumption by one quarter and natural gas consumption by three quarters over existing usage under the current HVAC system. Energy consumption will be reduced dramatically.

  3. Third, strengthen the quality of the environment. By avoidance of gas and electrical energy consumption by installation of the geothermal system, over 2100 tons of environmental pollutants would be removed from the air. Carbon dioxide, the principal contributor to global warming, 2,115 tons; sulfur dioxide, the principal contributor to acid rain, 5.2 tons; nitrogen oxide, a contributor to smog, 13.4 tons; the equivalent of removing annually nearly 450 cars from the roadways.

  4. Fourth, achieve substantial cost-containment savings. By reducing operating, maintenance and energy costs, which are projected to reach $455,000 on an annualized basis, the college has strengthened its fiscal capacity to retain its position as amongst the most affordable senior level colleges in New Jersey.

  5. Fifth, provide a model to demonstrate the application of an alternative energy source. By implementing a replacement project that is technically and economically feasible for adaptation for large facilities throughout the southern New Jersey region, for example, shopping malls, public schools, public housing, Stockton provides a national model that demonstrates the application of an alternative energy source.

  6. And finally, demonstrate public and private-sector partnership. By enabling Atlantic Electric, the college and the Department of Environmental Protection and Energy to work together on the geothermal project, the benefits of public and private sector teamwork will serve as a model for inter-governmental cooperation.

  7. Public and private sector partnerships that promote the public good are a much idealized goal that generate considerable discourse which is only infrequently matched with action.
In this vein, perhaps the most significant benefit that will accrue from Stockton's geothermal project is that it demonstrates that it is possible to accomplish a public and private-sector partnership that works.

Return to Top

About Us Legal | Sitemap | Privacy