The objective of this project is to provide a feasibility study for incorporating industrial loads into a geothermal energy network (G-TEN) at U.S. Army Garrison – Detroit Arsenal (DTA). The study will build off previous work funded by the Department of Energy (DoE) Geothermal Technologies Office (GTO), which produced a preliminary design concept and analysis for a G-TEN serving select administrative facilities at DTA with a payback period as low as six years. This expansion of the original feasibility study will investigate how to optimally incorporate the industrial loads from the various research and development (R&D) facilities at DTA. The R&D facilities have process loads that require significant thermal and electrical energy input, much of which is then rejected to the environment. Instead of wasting that energy, this project will examine methods to provide pre-conditioning to reduce energy input and solutions to capture the waste energy. Those industrial loads are inherently more difficult to incorporate into thermal energy networks (TEN) due to their operating characteristics and requirements and are frequently omitted from similar studies. The project will produce a detailed techno-economic analysis (TEA) of proposed solutions for integrating those industrial loads into the G-TEN and build on the rich collaboration between national labs, industry, academia, and U.S. Army energy professionals launched under the DoE GTO project. 

TEN are complex, dynamic systems where energy flows are highly dependent on operational strategies and environmental conditions. G-TENs add an additional level of complexity with the incorporation of a ground heat exchanger for the geothermal heat pumps providing the heat rejection and extraction from the environment. As such, the modeling tools required for the study will need to be capable of accurately representing that complexity. Modelica and Simulink offer physics-based, component-oriented modeling environments that enable detailed dynamic simulations of thermal, hydraulic, and control systems in an integrated framework, making them ideal for co-simulating control logic and network behavior with high fidelity. EnergyPlus, widely used in the building simulation community, supports detailed modeling of thermal loads, equipment performance, and zone-level interactions, and can be coupled with external control strategies or embedded user-defined optimization frameworks. Solvers like Interior Point OPTimizer will be used to solve optimal control problems or design scenarios, such as determining dispatch schedules for thermal storage or optimizing the operation of centralized heating/cooling under operational constraints. 

The project will provide a preliminary design for a G-TEN at DTA that will provide the installation with multiple benefits: energy and water use reduction and associated cost savings; increased energy security by modernizing the steam-based central heating system; and reduced maintenance, rehabilitation, and repair burden. In addition to those installation-level benefits, the project will also serve as a template for low-temperature geothermal systems and G-TENs that could be expanded to other Department of Defense (DoD) installations across the country, not only in locations with high geothermal activity. The project will demonstrate the feasibility of incorporating industrial loads typically excluded from these systems, furthering the benefits provided by the G-TEN. Additionally, the project will provide financing pathway recommendations to ensure this feasibility study results in secured funding for further design and construction and not simply a concept. G-TENs provide a secure, reliable, and affordable option for serving the energy needs of DoD installations throughout the country by harnessing the energy beneath our feet. (Anticipated Project Completion - 2028)