Performance comparison of transcritical cycle and organic Rankine cycle coupled with Chingshui geothermal reservoir

Abstract

The Chingshui geothermal field stands out as the most significant geothermal field in Taiwan. Understanding the sustainability of geothermal energy is important for its long-term use. In the present study, a numerical model Chingshui reservoir based on geological conditions is developed by using a thermal-hydraulic-mechanical (THM) model in the COMSOL to evaluate the depth’s effect of the production well on the different binary cycles. The thermodynamic cycles of two configurations, namely the organic Rankine cycle (ORC) and transcritical Rankine cycle (TRC), are established by using MATLAB and coupled with the Chingshui reservoir through the COMSOL Livelink module. The study focuses on different well depths’ effects on the cycle performance. The results show the system efficiencies of the ORC and TRC under different well depths were 5.77% and 13.76%, and 9.64% and 16.31%, respectively.