Techno-economic assessment of GSHP systems for large-scale sports facilities: an integrated approach via long-term dynamic simulation and soil thermal balance analysis of “Bosco dello Sport” stadium in Venice

Large-scale sports facilities present demanding thermal loads and require carefully engineered HVAC solutions to ensure both performance and long-term sustainability. This thesis develops a techno-economic assessment of a Ground Source Heat Pump (GSHP) system for the “Bosco dello Sport” stadium in Venice and compares its performance with an air-source configuration based on multiple VRF heat pumps. A DesignBuilder/EnergyPlus model is used to simulate two HVAC configurations: the system designed for the project, composed of twelve VRF air-source heat pumps, and an alternative system employing a single large water-to-water GSHP coupled to the borehole field. Preliminary results indicate notable differences in seasonal efficiency due to the different heat sources (ground vs. outdoor air), and the final electrical consumption comparison will consolidate the potential energy savings of the GSHP configuration. The analysis is carried out through an integrated methodology combining whole-building dynamic simulation, ASHRAE-based borefield sizing, and long-term soil thermal modelling. The GSHP borehole field is dimensioned using the Classic ASHRAE Method and validated through the Alternative ASHRAE Method based on g-functions. A detailed 3D groundwater and soil temperature model is developed in FEFLOW to evaluate the 10-year thermal drift of the ground under highly unbalanced annual loads and conditions of nearly stagnant groundwater. Results show that, despite a cooling-dominant imbalance, the predicted long-term temperature rise of the soil remains limited, confirming the technical feasibility of the geothermal solution. Overall, the study highlights the importance of integrating soil thermal balance analysis with multi-year building simulations when assessing GSHP systems for large sports facilities, ensuring reliable design decisions and a robust evaluation of long-term performance.