Heat transfer by water flow in rock fractures and the application to hot dry rock geothermal systems

The heat transfer coefficient is an important fundamental parameter which is essential for numerical analysis of hot dry geothermal energy extraction systems. An investigation on joint rock-water heat transfer was successfully carried out using a test set-up for hydro-thermo-mechanical experiments on rock samples from the Carnmenellis granite. From an analysis of steady state data collected under the present range of experimental conditions, the convective heat transfer coefficient is found to have values form 5 to 236 W/m[sup 2] [sup o]C for flow velocities from 4.5 to 200 mm/sec. (UK)