The University of Michigan is testing a deeper approach to geoexchange technology that could expand the capacity and efficiency of sustainable heating and cooling on campus.
Instead of using conventional water-well drilling rigs, crews are applying oil and gas drilling techniques to install a closed-loop system farther below the surface.
Crews are drilling a test borehole capable of reaching a depth of 1,600 feet — a little over four football fields end to end. That is about twice as deep as conventional geoexchange bores, which typically extend to around 800 feet. Such test bores are a standard step in developing new geoexchange systems, allowing engineers to assess subsurface conditions and performance before full-scale installation. The results will help evaluate the university’s capacity for sustainable heating and cooling.
The test bore is a critical step in validating new technological approaches and verifying performance. Data gathered during the test will inform U-M’s plans to meet ambitious climate action goals, illustrated by the Campus Plan 2050 aspirations to modernize and decarbonize district-scale heating and cooling systems.
“With this project, the University of Michigan is not only investing in renewably powered, highly efficient heating and cooling technologies, but also exploring innovative approaches that could accelerate our long-term energy transition efforts,” said Shana Weber, associate vice president for campus sustainability. “If successful, the approaches we’re testing today are poised to inform similar efforts locally and across the country.”
Unlike traditional fossil-fuel-based heating and cooling, geoexchange systems use ground-sourced heat pumps that rely on Earth’s stable underground temperatures to move heat in and out of buildings. Sealed or “closed-loop” piping transfers heat to the surrounding rock through conduction, with no interaction with groundwater. In the summer, excess heat is stored underground, and in the winter, that stored heat is drawn back up, allowing the heat pumps to operate far more efficiently year-round.
Geoexchange systems tend to provide more heating and cooling per unit of energy input than conventional systems, helping the university reach its efficiency and carbon neutrality goals. The specific performance efficiencies of each geoexchange project are calculated during the design process.
In addition to efficiency, geoexchange systems improve local air quality by reducing reliance on natural gas. They also require far less water than conventional cooling towers, meaning the campuswide transition will deliver significant water savings as more systems come online.
Taking advantage of stable underground temperatures makes geoexchange a highly efficient alternative to conventional heating and cooling and a key technology in the university’s plan to improve local air quality, decrease water usage and eliminate on-campus greenhouse gas emissions (scope 1) by 2040.
The borehole test will allow engineers to measure thermal energy performance at greater depths, which are anticipated to have even greater potential for efficiency. Results are expected late this fall and will help guide decisions about future geoexchange deployment on campus.
“The test well gives us critical data to understand the limits and potential of deeper geoexchange boring technologies to support our long-term carbon neutrality goals. It reflects our role as a living learning laboratory, testing real-world solutions and sharing what we learn,” said Geoff Chatas, executive vice president and chief financial officer.
The terms “geothermal” and “geoexchange” are often used interchangeably, but have different meanings. Geothermal systems generate electricity by tapping Earth’s high temperature and high pressure geologic “hot spots,” typically along tectonic plates. Geoexchange systems, by contrast, are widely applicable and use the stable temperatures of rock layers relatively near the surface to heat and cool buildings. U-M’s systems are closed-loop, meaning water is sealed inside piping and never comes into contact with groundwater.
This test borehole builds on the university’s other recent geoexchange projects, including the Hayward Street system on North Campus (99 borings at 700 feet) and the Ginsberg Building system (eight borings at 535 feet). Both the Central Campus residential development currently under construction, featuring more than 80 borings at a depth of 800 feet, and the Ginsberg Building are pursuing LEED Gold certification, based in part on the role of geoexchange systems.
Together, these projects advance U-M’s work toward large-scale, all-electric campus facilities contemplated as part of Campus Plan 2050. Heating buildings in cold Michigan winters requires significant energy, and cooling needs are becoming more pronounced. Switching to efficient, electric-driven geoexchange systems powered by renewable electricity is a key strategy for reducing the university’s reliance on fossil fuels. By transferring heat from where it is rejected to where it is needed, geoexchange systems are especially effective for a campus with diverse building types and energy demands.
“Sustainability is critically important for our students and campus community,” said Kambiz Khalili, associate vice president of student life. “We strive to design and construct buildings that meet the needs of current and future Wolverines. Partnering across campus units allows our buildings to be at the leading edge of efficiency and sustainability, to meet the moment and encourage others to look to Michigan for solutions.”
The project also reflects U-M’s broader approach to sustainability: embedding innovation into campus planning, research and operations in a way that provides hands-on learning opportunities. Students, faculty and staff have been able to observe this technology in action, seeing firsthand how the university tests and implements advanced energy solutions.
Walbridge, a Michigan-based construction and engineering company, is performing the borehole test in collaboration with CUDD Pressure Control.
