An Innovative Co-Axial Spiral Borehole Heat Exchanger Dynamic Model

Abstract

A dynamic model of a ground source heat pump (GSHP) system is a very useful tool in order to optimize its operation. It might reproduce the thermal behaviour of each component of the system both on a short-term and a long-term basis, as well as the effect that the borehole heat exchanger (BHE) has in the surrounding ground. Hence, it is possible to use this model to develop proper control strategies in order to increase the global system s efficiency as much as possible. In this work, the approach used for the recently developed B2G dynamic model has been extended to a different configuration than the standard U-tube BHE. The new configuration is a novel co-axial spiral BHE designed in the framework of the GEOT CH project (Geothermal Technology for conomic Cooling and Heating), a HORIZON 2020 European project. The model has been validated against experimental data from a real borehole located in Houten, Netherlands. The results show that the B2G approach applied to this specific configuration produces a model that can accurately predict the short-term behaviour of the BHE.