This project will install geo-exchange bore fields, which act as a thermal “piggy bank.” The bore fields will receive heat from campus buildings during the summer and store it in the ground. During the winter, the same bores and rock around them will serve as a heat source for campus buildings.
How Geo-Exchange Works
Geo-exchange is part of a closed-loop system in which water is recirculated inside piping within deep bores in the earth. On the Princeton’s Central Campus the bores are 850 feet deep; in the Meadows Neighborhood on the Lakeside Development site in West Windsor, the bores are 600 feet deep. The piping is then surrounded by grout. The water circulating in the pipes never comes in direct contact with subterranean water sources or rock. The heat is transferred via conduction.
The new geo-exchange facilities, which began operation in 2023, will contribute significantly to reducing the University’s reliance on fossil fuels over time, using electrically driven heating and cooling heat pumps that eventually will be powered by carbon-free electricity from renewables, such as solar PV or wind. Geo-Exchange allows us to capture and re-use heat later, during the winter, instead of rejecting it via cooling towers.
After 250 years of using carbon-based heating technologies, Princeton is moving to a new hot-water energy system driven by electric heat pumps, thermal storage and geo-exchange — one of the first in the nation to combine these technologies at this scale.
As Princeton undertakes an ambitious new building plan, it is using this once-in-a generation opportunity to lay the foundation to meet its net-zero carbon emissions goals. A cornerstone of our Sustainability Action Plan involves innovative energy facilities based on geo-exchange. A large-scale system combining geo-exchange technology and thermal capture is a critical component in Princeton’s goal to achieve carbon neutrality by 2046.
Path to Net-Zero
Check out the other projects that will enable us to begin converting from steam to hot water, conserve energy, increase our efficiencies, and decrease our carbon footprint and reliance on fossil fuels: