A project is underway to bring sustainable geothermal technology to UConn. As part of the Campus Masterplan and funded by Next Generation Connecticut funds, the South Campus Infrastructure Project includes clean, renewable infrastructure that will extend deep underground to heat and cool the new South Campus Residence Hall.
Elizabeth Craun, Director of Major Projects at University Planning, Design, and Construction, has a background in geotechnical and environmental engineering and is especially excited about this project.
Craun explains that geothermal heat exchange is a well-established renewable energy technology that came into widespread use in the 1970s during the fuel crisis, but largely fell out of use after petroleum prices dropped. Geothermal technologies are seeing a resurgence now with the need to meet emissions reduction goals. The type of geothermal system that will be implemented at UConn is called ground loop heat exchange, which Craun says is similar to air source heat pumps like the ones commonly used in homes, but more efficient.
“A ground loop heat exchanger allows us to utilize the natural geothermal gradient of the ground, where the further you go down, the more stable the temperature is,” she says. “The subsurface temperature is generally cooler than ambient temperatures in the summer and warmer in the winter and geothermal systems utilize that to efficiently exchange heat. You can also store the heat that you exhaust during the summer in the ground and extract it in the winter.”
The system design includes the installation of 78 wells drilled to a depth of 750 feet deep into the bedrock located under the S Lot parking area on the south side of campus. The piping from the wells will be returned to an existing chiller building that will be expanded to accommodate the new sustainable infrastructure. After construction, the area will be returned to parking once the geothermal system installation is complete, preventing the loss of usable space.
Drilling for the geothermal boreholes began at the end of December. Craun says though they have done pre-project studies, several variables can impact the system’s performance. For the first few years, the geothermal system is in use, data will be collected, and operational adjustments made as needed to optimize the efficiency of the system and assess its performance.
The geothermal project is tied to the new, nearly 650-bed suite-style South Campus Residence Hall and Dining Hall, and Craun says there is capacity left for potential future sustainable infrastructure.
“This project takes the existing South Campus chiller plant that was built in the 1990s, which is a seasonal plant and primarily serves the existing residence halls in the cooling season and makes it a year-round facility by adding heating capacity with ground loop heat exchange from the new wells,” Craun says. “The project provides capacity for additional equipment to facilitate future projects or existing building connections in the South Campus district.”
This design will double the size of the chiller plant to provide room for upgraded and new equipment associated with the well field, and will also continue to provide chilled water for cooling and other uses to the surrounding buildings.
Though some geothermal systems can expand to service many buildings at once via a network of distribution pipes and pumps, called district energy, this geothermal system will primarily service the new residence hall at this time.
“Our system is cooling dominant, and it is different from other institutional and commercial district energy systems, which are connected to new or existing buildings and provide both heat and cooling to them,” Craun says. “Our geothermal system cannot fully heat the current buildings that are attached to the South Campus chiller plant, but it will be able to cool them. The expanded South Campus chiller plant is designed to be able to cool the existing residence halls in the area, cool the new residence hall, and heat the new residence hall. “
With the new system, the South Campus Residence Hall’s indoor temperature ranges will not be different from those experienced with conventional heating and cooling. As is the case with most geothermal systems outside of temperate areas, it will utilize “peak shaving,” meaning that it is sized to accommodate typical seasonal conditions but has supplementary sources of climate control built in for exceptionally hot or cold days, which typically happen only a few times a year. In this project, conventionally fueled chillers will remain in use in the chiller plant, and the new residence hall will be connected to cogeneration-produced steam from UConn’s Central Utility Plant.
Craun says the new residence hall and dining hall are on track to open as planned for the 2024 fall semester. Due to unavoidable supply chain issues, the geothermal system is not anticipated to come online until 2025. However, the temporary connection to the steam system means there will be no delay in the residence hall opening.
“We experienced some extraordinary market disruptions from COVID with electrical equipment, exacerbated by extreme heatwave conditions that other parts of the country experienced last summer, which caused a drive to fast-track electrical transmission, distribution, and service projects of all sizes,” Craun says. “As a result, the electrical equipment that we need to upgrade the chiller plant has a very long lead time. Unfortunately, the delay is unavoidable and it’s based on market conditions and on broader climate issues that are happening throughout the country.”
Craun say it’s good to have operational redundancy and maintenance backup to keep housing reliably available for students. “It is a little disappointing that we’ll be operating with steam heat for the first year, but we must bring the residence hall online for the UConn community. I like to compare this to a plug-in hybrid vehicle where you can do 99% of your day-to-day driving on the battery, but when you go on a longer trip, you put gas in it. The goals for the South Campus residential hall are that we will be able to heat it on all but the most extraordinarily cold of days solely with the geothermal system, and to meet all the other hot and cold water needs of the building.”
In the meantime, Craun says they anticipate the well drilling to be audible and potentially a little disruptive to the surrounding buildings, and staff and faculty in the area are already experiencing a loss of employee parking as portions of S lost are being closed to accommodate the geothermal system drilling.
“It’s going to be a little bit stressful at times for some members of the campus community,” she says. “At University Planning, Design, and Construction, we work with our contractors to minimize impacts to the community and to proactively communicate impacts including road closures, detours, impacts on facilities, and noise.”
The parking in S Lot will return after construction, fully restored and with infrastructure beneath it to help UConn work toward the goal of carbon neutrality by 2030.