MRL Triangle District

GEOptimize completed a district GSHP feasibility study in 2023 for the Montana Rail Link (MRL) Triangle redevelopment site in Missoula, Montana. The 11.4-acre brownfield site is planned for a mixed-use redevelopment consisting of approximately 14 residential, commercial, and retail buildings totaling roughly 386,500 square feet of conditioned space. The study evaluated the technical, economic, and environmental feasibility of a fifth-generation district geothermal energy system integrated with rooftop solar photovoltaic (PV) to support site-wide electrification and long-term decarbonization.

The feasibility assessment included development of 8760-hour building energy models using Trane TRACE™ 3D+ and simulation of the integrated district energy system using TRNSYS to optimize system sizing, loop temperatures, flow rates, and long-term thermal balance. Multiple geothermal source configurations were evaluated, including vertical closed-loop borefields and optional groundwater heat exchange. The study also assessed conventional all-electric baseline HVAC configurations for comparison and examined modular system phasing strategies to align capital investment with redevelopment timelines.

The recommended system concept utilized a shared ambient thermal loop supporting energy transfer between buildings, enabling modular, phased expansion as redevelopment progressed. The preferred geothermal source consisted primarily of vertical closed-loop boreholes, with provisions for potential future integration of groundwater heat exchange depending on site conditions. Capital cost estimates, energy savings projections, greenhouse gas emissions reductions, and long-term system performance metrics were developed to support investment decision-making.