Experimental Evaluation of a Simulated Geothermal Heat Pump System for Potential Large-Scale Space Heating Application at TBRHSC in Severe Cold Climate in Northwestern Ontario, Canada

Abstract

Space heating for buildings and institutional complexes represents a dominant sector of energy consumption and greenhouse gas (GHG) emissions in Canada, a challenge exacerbated by the nation’s cold climate. This is particularly critical in regions like Thunder Bay, where harsh winters and significant heating demands make the building sector a major contributor to local emissions—the residential sector alone accounts for 27% of community GHG output. The geothermal heat pump (GHP), or ground-source heat pump, is a highly efficient technology that leverages the stable thermal energy of the subsurface to provide space conditioning. By using the ground as a heat source in winter and a heat sink in summer, GHPs can reduce heating and cooling energy use by 25–50% compared to conventional systems. This makes them a promising solution for large-scale space heating applications, such as at the Thunder Bay Regional Health Sciences Centre (TBRHSC), a major healthcare facility and one of the city’s largest energy consumers. Despite this potential, there remains a significant gap in region-specific performance data and operational understanding of GHPs in extreme cold climate in Northwestern Ontario. This study addresses that gap through experimental characterization of a lab-scale GHP system using actual subsurface temperature profiles. An extensively instrumented GHP simulator was employed to evaluate system performance across a key range of operating conditions. The experimental results showed that the supply air temperature from the GHP system rises rapidly following system start-up, with each tested condition achieving approximately 90% of its peak value within the first 4 to 5 minutes. A consistent thermal gain of the GHP was observed, where each 5°C increase in entering water temperature yielded an additional 3°C rise in the useful supply air temperature. The temperature gradients plateau after 10 min indicating that the system has achieved a thermal steady state. Progressively increasing the simulated ground-loop water temperature entering the GHP’s evaporator from 5°C to 10°C and then to 15°C resulted in a corresponding rise in supply hot air temperature and an improvement in the GHP system’s coefficient of performance (COP).