Towards sustainable shallow geothermal systems : combined simulation-optimization of borehole heat exchanger fields under uncertainty

Abstract

The unbalanced performance of borehole heat exchangers (BHEs) causes subsurface thermal anomalies, reducing geothermal system efficiency and posing environmental risks. To address this, a sequential simulation-optimization framework is proposed to dynamically adjust energy demand distribution among BHEs over long-term operation. Optimized operation plans are refined by integrating monitoring data with model-based simulations. In the following, an embedded model calibration strategy utilizes parameter estimation to improve BHE field optimization. The effectiveness of this approach is demonstrated using a synthetic BHE case with various transient groundwater velocity fluctuation patterns. Finally, a Bayesian inference-based stochastic framework is developed to characterize multiple correlated unknown parameters in a BHE field with heterogeneous subsurface settings and groundwater flow, enhancing the reliability of temperature simulations.