An efficient finite volume model for shallow geothermal systems—Part II: Verification, validation and grid convergence

This part of the series of two papers presents the computational capability of the finite volume model, described in Part I, to simulate three-dimensional heat transfer processes in multiple borehole heat exchangers embedded in a multi-layer soil mass. Geothermal problems which require very fine grids, of the order of millions of finite volumes, can be simulated using coarse grids, of the order of few to tens of thousands elements. Accordingly, significant reduction of CPU time is gained, rendering the model suitable for utilization in engineering practice. A verification example comparing the computational results with an analytical solution of a benchmark case is given. A validation example comparing computed results with measured results is presented. Furthermore, numerical examples are presented describing the possible utilization of the model for research works and design.

► Capability of the FV model of Part I, to simulate 3D boreholes in multi-layer soil. ► Comparing the computational results with an analytical solution of a benchmark case. ► A validation example comparing computed results with measured results is presented. ► Geothermal problems are simulated using coarse grids of few to tens thousands cells. ► Numerical examples show significant reduction of CPU time, suitable for engineering.