Taking the Earth’s temperature

Since installing 144 geothermal wells on campus over the past two years, Dr. Curt Elmore, professor of geological engineering, has led a couple of ongoing geothermal research projects.

Since installing 144 geothermal wells on campus over the past two years, Dr. Curt Elmore (center), professor of geological engineering, has led two ongoing geothermal research projects. Photo by Sam O’Keefe

On the surface, it looks like nothing more than a turf-covered soccer field. But the ground beneath Missouri University of Science and Technology’s intramural field houses a complex system of 144 wells, each one 400 feet deep, that supply the campus’s Gale Bullman Building with heating and cooling using geothermal energy.

That well field is also home to two ongoing geothermal research projects led by Dr. Curt Elmore, professor of geological engineering at Missouri S&T. The first project is designed to monitor possible long-term changes in the Earth’s temperature that could result from the operation of a large-scale geothermal system.

With funding from the geological engineering program and in partnership with the physical facilities department, Elmore and his team outfitted one of the wells in the center of Missouri S&T’s intramural field with eight pairs of thermocouples placed every 50 feet to measure temperature at various levels throughout the 400-foot well.

Wires connect the sensors to a small flush mount vault that looks like a water meter you might find in your yard. Nearly every day, Charlie Smith and Jordan Thompson – two students working with Elmore on the project – connect equipment to read the temperature measurements that the sensors recorded. An additional well, drilled 20 feet from the geothermal well field, provides baseline readings for comparison. Thompson, a junior in geological engineering, is working on the project as part of the Opportunities for Undergraduate Research Experiences program (OURE).

Before the geothermal system went live, the researchers collected about six weeks of background temperature data. Once the system was operational, they began to notice a change in the ground temperature.

“We observed that the average temperature did increase over the course of the summer as energy from the building was transferred to the subsurface,” says Smith, a Ph.D. candidate in geological engineering. “We are now observing the cooling of the subsurface as energy is being removed to assist in the heating of the building. We would like to record data during several full heating and cooling cycles to fully see any long-term overall warming or cooling trends.”

Over time, changes in ground temperature could effect the performance of a geothermal energy system, Elmore says.

“A ground source geothermal system works by taking heat from the air and sending it into the ground,” Elmore says. “Or we take heat from the ground and send it into the air. Here, cooling is predominant. If the ground is warmer, it can’t take on as much heat and that could effect the performance of the geothermal system,” he says. “Let’s say you want to chill a bottle of Coke, for example, and you’re used to putting it in cold water for 10 minutes. If your water gets warmer, it will take longer to cool your Coke. If it’s really cold, it will cool faster.”

An expert in groundwater remediation, Elmore is also working on a project to see if geothermal energy could be used in place of electricity to treat water as a part of an innovative desalination process.

“Geothermal energy has the potential to heat and cool water during the treatment process, thus reducing the amount of water wasted and reducing the amount of energy required to treat the water,” Elmore says.

To pilot the project, Elmore is designing a small desalination system that will fit on a utility trailer towed behind a pickup truck.

Elmore is working on the project with Dr. Mostafa Elsharquawy from King Fahd University of Petroleum and Minerals in Saudi Arabia. They hope to build a water treatment facility that uses geothermal energy.

“Saudi Arabia spends millions of dollars every year changing sea water into drinking water,” Elmore says. “Geothermal energy could provide a much more cost-effective treatment system.”

Missouri S&T’s geothermal energy system – one of the most comprehensive in the nation – provides heating and cooling to 17 buildings on campus and chilled water to the majority of campus buildings. Completion of the system allowed S&T to decommission its World War II-era power plant last spring. The system is expected to cut energy usage by 50 percent and reduce the university’s carbon footprint by 25,000 metric tons per year.

By Mary Helen Stoltz

Comments

  1. Milton J Murry says:

    I have personal experience with Geothermal projects in St. Louis and Park Hills, Mo. You should be o.k. with a short term air conditioning cycle on gym. Have you considered heat reclaim off exhaust air from locker room or hot water from showers? Milton J Murry

    • Jim Packard says:

      The design of the HVAC system for Bullman does incorporate heat recovery by directing exhaust air from the locker rooms to the heat recovery portion of the gymnasium make-up air unit. Further energy conservation is achieved by using gymnasium relief air for locker room supply air. A water-to-water heat pump is installed to assist in the production of domestic hot water for showers. Additionally, the Natatorium HVAC dehumidification units and supplemental swimming pool heaters are connected to the geothermal system, and should help balance the annual geothermal load to the well field.

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