Numerical simulation of geothermal energy from dry hot rocks with gravity heat pipe

Abstract

Dry-hot rock is a kind of new geothermal energy with abundant energy storage. At present, the extraction of dry-hot rock geothermal energy is mainly through artificial fracturing of the rock mass by injecting water as a working fluid. The heat energy is extracted with water as a heat-carrying medium.This paper combines super-long gravity heat pipe with dry-hot rock, and buries carbon dioxide in dry-hot rock as artificial heat storage. Then, the feasibility of extracting geothermal energy from dry-hot rock by 2500m super-long gravity heat pipe is studied by numerical simulation.The artificial heat storage of carbon dioxide dry-hot rock is equivalent to porous continuous medium model. The temperature field distribution, pressure field distribution and velocity field distribution were simulated by Fluent software to analyze the evaporation and condensation process of liquid refrigerants in heat pipes at different times.Through numerical simulation, it is concluded that water vapor at 80℃ can be obtained at the outlet of overlength gravity heat pipe, and the flow rate of water vapor is about 2m/s. The scheme of extracting dry-hot rock heat energy by overlength gravity heat pipe is feasible.