Performance analysis of phase change slurries for closed-loop geothermal system

Abstract

Geothermal energy offers a route to clean power generation with baseload reliability that is unique among renewable sources. Current geothermal energy systems employ water, brine, or CO2 as a working fluid and rely on sensible heating to extract energy. In this work, latent heat based phase change slurries (PCSs) are assessed as geo-fluids for use in closed-loop geothermal systems. The PCS property data and its thermal, physical, chemical, and rheological behaviour at reservoir-relevant high-pressure and high-temperature conditions are studied. The experimental data is further used to model the viability of PCS-based closed-loop geothermal. The thermal output performance of PCSs is assessed and optimized in comparison to water. The resulting strategy achieves a 12.5% enhancement in thermal output compared to the water base case. The additional thermal power gain achieved with the PCS motivates further advancement in geo-fluids for geothermal energy systems.