Volume 19: Sustainable Energy Solutions for a Post-COVID Recovery towards a Better Future: Part II

Numerical Simulation of Enhanced Geothermal System Power Generation Performance Qiang Zhu, Lide Su, Jiansheng Wang, Jintao Niu

Abstract

Enhanced geothermal system can efficiently extract heat, while Organic Rankine Cycle system can generate electricity with heat extracted by Enhanced geothermal system. A combination of underground heat extraction and ground power generation systems is proposed in present work. The underground heat extraction system consists of an enhanced geothermal system coupled with hydraulic-thermal horizontal wells with five disc-shaped fractures. The ground power generation system is comprised of the basic Organic Rankine Cycle system, and R245FA is used as the working fluid. The performance of combined system is numerically investigated. The results show that with the increase of geothermal fluid flow rate, the geothermal fluid outlet temperature decreases more rapidly and the reservoir life is exhausted earlier. Case 7 (geothermal fluid flow rate of 50kg/s and injection temperature of 40℃) can obtain the maximum power generation performance, with net output work and heat absorption of 13.3 MW and 13.4%, respectively. It’s also found that the geothermal fluid flow rate has a greater impact on the power generation performance compared that on the geothermal fluid injection temperature.

Keywords Renewable energy resources, enhanced geothermal system, organic Rankine cycle, energy systems for power generation