| Title | Groundwater heat pump and free cooling systems for urban heat island mitigation: A case study in the City of Québec, Canada |
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| Authors | Victoria Lee, Jasmin Raymond, Christine Rivard, Félix-Antoine Comeau, Juliet Newson |
| Year | 2026 |
| Conference | World Geothermal Congress |
| Keywords | |
| Abstract | This study explored the potential of open-loop geothermal systems, specifically groundwater heat pumps (GWHP) and aquifer thermal energy storage (ATES), to replace conventional air-conditioning, which releases significant heat into the atmosphere. Despite these systems’ potential to reduce the urban heat island (UHI) effect, the benefits of free cooling without a heat pump remain largely unknown. Our objective was to assess the performance and thermal impact of geothermal cooling solutions in mitigating the UHI effect. To do this, we selected a sandy aquifer located beneath the City of Québec (Québec Province, Canada). Fieldwork was carried out to characterize subsurface properties and numerical models using FEFLOW were developed to simulate various scenarios comparing GWHP and ATES systems, both with and without free cooling. Simulation results indicate that ATES systems slightly outperform GWHPs, benefiting from better abstraction temperatures because of the stored thermal energy. Both systems demonstrated significantly better performance during cooling periods than heating periods. Moreover, 100% free cooling achieved a high seasonal performance factor of 19.13 during cooling, while maintaining a solid performance in heating mode. Furthermore, its thermal impact on the aquifer was lower than that of heat pump-based scenarios, highlighting the potential of free cooling to improve efficiency while minimizing subsurface disturbances. These findings offer valuable guidance for decision-makers seeking sustainable cooling strategies, particularly in regions with similar hydrogeological and cold, humid continental climate. |