Enhancing Geothermal Enthalpy Extraction Using Quantum Nanofluids: Overcoming the Thermal Conductivity Limit of Aqueous Brines

Geothermal energy systems are fundamentally constrained by the thermal transportproperties of conventional working fluids, primarily water and saline brines. While subsur-face reservoirs are capable of delivering heat at rates governed by rock thermal conductivity,overall system performance is bottlenecked by the intrinsically low thermal conductivityof fluids. This paper proposes the use of quantum nanofluids—aqueous fluids doped withgraphene- and carbon-nanotube-based nanoparticles—as an engineered solution to this lim-itation. By leveraging ballistic phonon transport, nanoparticle percolation networks, andinterfacial liquid layering, nanofluids exhibit anomalous thermal conductivity enhancementsbeyond classical diffusion-based predictions. We analyze the underlying physical mecha-nisms, assess system-level performance impacts in Advanced and Enhanced GeothermalSystems, and evaluate economic and environmental implications, with particular focus onlow-enthalpy geothermal deployment.