Dynamic power generation performance of enhanced geothermal system during life cycle in gonghe basin, china

Abstract

Enhanced geothermal systems (EGS) can efficiently generate electricity from hot dry rock (HDR), the temperature of which will decrease during its life cycle. In this paper, the organic Rankine Cycle (ORC) experimental device and dynamic model are established to investigate the dynamic power generation performance with heat source temperature decrease, and the relative installed capacity ratio is defined to investigate the optimal mass flow rate of geothermal fluid. The results show that the temperature decrease of the heat source is detrimental to the power generation performance and energy efficiency of the system, but the isentropic efficiency of the expander increases with the decrease of the heat source temperature. The installed capacity and net power output of ORC is proportional to the mass flow rate of the geothermal fluid, but the life cycle of the EGS is inversely proportional to this. There is a mass flow rate that maximize the total power generation over the life cycle while having a high relative installed capacity ratio.