Open-source Simulation Study for Direct Use Geothermal Systems

Abstract

Simulation of Direct Use Geothermal Systems can provide guidance for geothermal resource assessment, where the energy production, geothermal system’s lifetime and heat recovery ratio are used as performance indicators. The energy recovery ratio within the expected influence area is a function of a geothermal system’s lifetime. In this work we present reference examples on the design of a DUGS simulation model using the open-source software Delft Advanced Research Terra Simulation (DARTS). The DARTS platform enables accurate and efficient sensitivity and uncertainty analysis. We identify an optimal cartesian grid resolution to forecast the real thermal response of a 3D homogeneous model in a computationally efficient way for a typical reservoir domain and discharge rate. Subsequently, we identify the optimal number of confining layers ensuring a sufficient heat recharge without boundary layer interactions that remains computationally efficient. The models with optimal resolution and number of confining layers are used to define the influenced reservoir volumes within a 3D domain and to calculate the energy recovery factor. The optimal parametrization and computational efficiency of the open-source DARTS platform is used as a basis for research on project feasibility, risk management, and system optimization.