Study on the implementation effects of a district renewable heat utilization system using ground source heat pumps and cogeneration waste-heat
This study investigates the effectiveness of implementing a district renewable heat utilization system that combines ground source heat pumps (GSHPs) with cogeneration (CHP) waste-heat recovery. The target site is a building complex (buildings A–D) within the Faculty of Engineering, Hokkaido University. Annual heating and cooling loads for each building were estimated, and based on these results, a comprehensive system model was developed using a simulation tool developed by our laboratory. This model incorporates multiple GSHP units connected through a shared thermal loop and considers both geothermal exchange and the use of waste-heat from an on-site CHP system. Simulation results showed that incorporating CHP waste-heat into the system enabled a large reduction in the required number of ground heat exchangers (GHEs) while further reducing CO2 emissions. These findings confirm that the combination of GSHPs and CHP waste-heat in a district heating and cooling system can substantially enhance energy efficiency and reduce environmental impact. The study underscores the practical advantage of underground utility tunnels for routing district-loop mains and the benefits of thermal energy sharing among multiple buildings, demonstrating the potential of hybrid renewable heat systems in supporting carbon-neutral goals, especially in cold-climate regions like Hokkaido. This approach is expected to contribute to the advancement of energy management strategies for campuses, industrial zones, and urban communities.