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Abstract

Summary

This study compares the performance of Enhanced Geothermal Systems (EGS) using Supercritical CO (sCO) and water, focusing on how each fluid’s efficiency depends on fracture geometry. While sCO offers many advantages for geothermal applications, the impact of fracture network properties on its performance is not yet fully understood compared to water. Using a fully coupled Thermo-Hydraulic model in COMSOL Multiphysics, the study simulates fluid flow and heat transfer in a 2D EGS domain with three fracture scenarios: discrete fractures, a connected fracture network, and a combination of both. Results show that water is more sensitive to fracture geometry, with greater variations in output temperature and thermal power across different fracture configurations. In contrast, sCO maintains more stable output temperature and thermal power due to its lower dynamic viscosity and higher mobility. The study highlights the importance of optimizing fracture network design differently for water- and sCO-based EGS, given their distinct behaviors within fracture networks.

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/content/papers/10.3997/2214-4609.202522091
2025-09-01
2026-02-08
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