A team from the School of Engineering is working to solve the problem of thermal short circuiting.
The University of New Mexico is investigating more efficient, long-term, and dependable methods of collecting heat from the Earth for geothermal energy.
The Department of Energy has announced a $12 million investment in seven research projects aimed at improving geothermal systems (EGS). The money will be distributed to a UNM team directed by John Stormont, a professor in the Department of Civil, Construction, and Environmental Engineering. Nick Carroll (UNM), Mahmoud Reda Taha (UNM), Pania Newell (University of Utah), and Stephen Bauer (UNM) make up the UNM team (Sandia National Laboratories).
“A major component of our goal to grow and diversify America’s clean energy market is tapping into geothermal energy, a clean and reliable energy source beneath our feet that is available in all corners of the country,” said U.S. Secretary of Energy Jennifer M. Granholm. “The ground-breaking ideas we expect from the selected national laboratory and university research teams will help America achieve a clean energy economy while creating good-paying jobs and strengthening America’s energy workforce,” said the president.
Researchers from Cornell University, Lawrence Berkeley National Laboratory, Missouri University of Science and Technology, Montana State University, Oklahoma State University, and Pennsylvania State University were also sponsored by the DOE, in addition to the UNM team.
Geothermal energy is a cost-effective and long-term energy source. The Earth generates its own heat naturally. Water may be injected into a heated rock to generate geothermal energy. The water is subsequently heated and converted into steam energy by this rock.
“It would be fantastic if we could drill a hole and use the hot water or steam from the well to generate energy.” “However, there are relatively few resources like that available,” Stormont added. “The concept behind enhanced geothermal is to identify a naturally hot rock with cracks. We pump cold water into the rock through two wells drilled from the surface, allowing the water to run through the cracks and absorb heat. The heated water is then collected in a second well, pushed to the surface, and utilized to generate power.”
Geothermal energy will be an important source of energy for the globe if improved geothermal systems are correctly implemented. Geothermal energy, being a renewable energy source, will not have the same negative environmental impact as fossil fuels.
The DOE money will go toward developing EGS technology and procedures. This involves the creation of novel materials that may be injected into rock cracks to increase heat energy extraction from the rock.
“Creating a good circulation pattern for the water that you inject and having it travel through the rock in a predictable and efficient fashion that absorbs the heat from the granite is the main issue here,” Stormont said.
The pace at which water runs through the rock is affected by fracture size. When water is introduced into the rock, larger cracks absorb more water, causing the rock to cool more quickly around specific larger fractures. As the cracks cool, they enlarge and absorb even more water, resulting in thermal short circuiting, a flaw in the EGS’ efficiency and dependability.
He stated, “We’re looking on techniques to manage or alter fractures that contribute to thermal short circuiting.” “We’re utilizing microcapsules to transport things inside the fractures,” says the researcher. After the capsules disintegrate, the ingredients combine to produce a porous polymer material.”
Water flow in bigger fractures is restricted by the polymer material adhering to the rock inside the fracture. Water may still flow through the crack since the material is porous, albeit at a slower pace. Scientists can produce a more varied network of cracks by restricting waterflow in the larger fissures, increasing the interior surface area of the rock, maximizing water heating time, improving efficiency, and reducing rock cooling time.
“Instead of forcing water through one fracture, you can force it through twenty cracks, giving you twenty times the surface area and extending the life of your resource,” Stormont said.
Overcoming thermal short circuiting is a critical step in ensuring that EGS is a cost-effective energy source.
“The capacity to adjust fracture permeability and therefore minimize thermal short-circuiting tackles one of the most significant difficulties that EGS must overcome to be economically viable,” Stormont added.
