Energetic and Exergetic Insights into Geothermal Sourced ORC and Supercritical CO2 Systems

This study investigates the thermodynamic performance of two power-generation systems driven by a geothermal heat resource. The first configuration is an organic Rankine cycle (ORC) employing cyclopentane, R152a, and R1233zd as working fluids, while the second utilizes a supercritical carbon dioxide (s-CO2) Rankine cycle. Detailed energy and exergy analyses for each working fluid were carried out using the EBSILON® Professional simulation. Among the ORC fluids, cyclopentane demonstrated the most favorable performance. In the ORC system, thermal and exergy efficiencies reached up to 29.58% and 70.51%, respectively. However, in the s-CO2 Rankine cycle, thermal and exergy efficiencies were found to be 20.29% and 47.77%, respectively. Also, it was determined that the ORC and s-CO2 Rankine were economically viable for investment, with payback periods of 4.2 years and 2.26 years, respectively.