Calibration of a finite element model of a borehole thermal energy storage in FEFLOW: model and numerical considerations

Abstract

We present operational data from a Borehole Thermal Energy Storage (BTES), and develop and calibrate a numerical temperature model of the thermal storage. Operational data from the initial 310 days form the basis for calibrating a 3D finite element model of the BTES. The model is subsequently validated by comparing temperature predictions for the following 200 days of operation to corresponding recorded measurements. We discuss modelling considerations and numerical issues encountered when attempting to calibrate and run a full finite element model for the BTES using the commercial software FEFLOW and present differences in predictions based on a simple thermal response test (TRT) versus the full finite element model.