A new methodology for numerical simulation of geothermal down-hole heat exchangers

This paper presents a numerical procedure for the simulation of heat and fluid flow in a heat exchange system for exploitation of low enthalpy geothermal reservoirs. The authors employ for the first time the generalised model for the mathematical description of heat and fluid flow through saturated porous media in order to study down-hole heat exchanger, well and aquifer, using a single domain approach. Steady state operation of the system is considered and the results obtained are validated against experimental data collected for a geothermal convector prototype installed in an existing geothermal well on the island of Ischia in southern Italy. The comparison shows that the proposed procedure can be successfully used for the simulation of this type of problems, and represents an excellent tool for down-hole heat exchangers optimization. The results of the present model are employed here to analyse the approximate boundary conditions that were previously developed for the simulation of a simplified aquifer model.