District Geothermal Heating and Cooling with Underground Thermal Energy Storage for Extreme Cold Climates

The objective of this effort is to utilize existing geothermal district heating and cooling (GDHC) technology, combined with underground thermal energy storage (UTES), to enhance thermal energy resilience in installations located in cold regions. The goal is to develop a system that achieves cost savings while supporting resilience for installations in extremely cold climates. GDHC systems integrate diverse energy loads to optimize overall system efficiency and can be supplemented with other renewable energy sources. Unlike traditional heating and cooling systems, which operate linearly by delivering hot or cold temperatures from a producer to a consumer, GDHC systems enable the reuse of rejected hot or cold temperatures, enhancing energy efficiency. In cold climates with unbalanced heating and cooling loads, prolonged energy extraction from the shallow subsurface can lead to a decline in available thermal energy, reducing operational efficiency over time. Integrating UTES can mitigate this degradation in subsurface energy reserves and improve the overall efficiency of GDHC systems. While similar configurations have been successfully demonstrated in temperate climates - for example, the ESTCP-funded UTES at the Marine Corps Logistics Base in Albany, GA - and individual components have been validated in cold climates, a comprehensive, holistic demonstration in cold climates has yet to be conducted. Our effort focuses on adapting and optimizing the design, management, and operation of GDHC systems specifically for heating-dominant cold climates. To demonstrate the efficiency of such a system in extreme cold temperatures, we conducted a model demonstration for an optimized GDHC-UTES system in Fairbanks, AK.