Supercritical flow and heat transfer of SCO2 in geothermal reservoir under non-Darcy?s law combined with power generation from hot dry rock

Hot dry rock is one of the huge reserves of clean energy sources, and enhanced geothermal system is the effective utilization. Darcy's law is widely employed to describe the fluid flow in geothermal reservoirs. However, when Darcy's law is applied to describe supercritical flow in geothermal reservoir, there will be the deviation of temperature and pressure because of the high sensitivity of thermal physical properties. To compare Darcy's law with non-Darcy's law, Darcy's law is replaced by the non-Darcy' law to establish the coupled numerical model. The results show that there is little difference for the temperature distribution of geothermal reservoir between the two assumptions. The pressure drops of geothermal reservoirs with different mass flow rates have a signif-icant impact on power generation through the heat loss in production well. The heat preservation in production well is indispensability when the flow rate is small. Through the comparison between the two assumptions of Richardson number and Prandtl number, the buoyancy effect under non-Darcy's law is more significant than that of Darcy's law. When power generation, net work output, payback period and exergy efficiency are considered, mass flow rate of 50 kg/s is the optimal in EGS under the actual engineering conditions.