Troy, NY District Geothermal System

GEOptimize Inc provided district energy system modeling for the Troy Urban Thermal Energy Network (UTEN) pilot in downtown Troy, New York. The system was designed to serve approximately 350,000 ft² across six mixed-use buildings from a central geothermal borefield located in Riverfront Park and owned and operated by the Troy Local Development Corporation.

Individual 8760 load profiles for each building were incorporated into a TRNSYS model to simulate the performance of the ambient loop, ground heat exchanger (GHX), and building-side heat pump systems. Initial borefield sizing was established using GLD and refined through transient simulation. The modeled system included an ambient loop distribution network with building isolation heat exchangers and a borefield of 196 vertical boreholes approximately 650 ft deep based on local ground conditions.

The aggregated district load was strongly heating dominant, which would have resulted in long-term ground temperature decline if operated without supplemental heat injection. Unbalanced operation showed the average GHX temperature decreasing significantly over the system lifecycle, with heat pump entering fluid temperatures falling below acceptable limits. To maintain thermal balance, a heat injection strategy using air-source heat pumps was developed. Simulation results determined the required annual heat injection and identified optimal operation during mild outdoor air conditions, maintaining stable loop temperatures and acceptable heat pump performance across all connected buildings. The analysis also demonstrated that a dry fluid cooler could provide a lower-cost alternative for load balancing with high seasonal efficiency. Nature article seen here.