Resolving performance contradictions in ORC and alternative power cycles: Systematic analysis of five technologies with time-adjusted economic insights

This study conducts a comprehensive analysis of five thermodynamic cycles: subcritical Organic Rankine Cycle (ORC), supercritical ORC, trilateral cycle (TLC), zeotropic mixture ORC, and Kalina cycle, for electricity generation from heat sources between 100 °C and 300 °C. While existing literature shows contradictory findings about relative cycle performance, this study provides a direct comparison of all five cycles under identical conditions. Also, it applies the Chemical Engineering Plant Cost Index (CEPCI) to standardize component costs from different time periods, revealing that traditional cost calculations significantly underestimate current costs by up to 2.76 times. Furthermore, it addresses working fluid selection challenges for zeotropic mixtures by examining R245fa drop-in replacements. The results reveal distinct optimal applications for each technology: the TLC achieves highest power output (7.96–212.95 kW) and lowest LCOE (0.09–0.83 USD/kW.hr) but requires specialized equipment; the Kalina cycle shows superior efficiency at moderate temperatures and offers zero GWP but demands complex safety protocols; the zeotropic mixture ORC emerges as a practical solution between 200 and 250 °C, offering balanced performance with lower investment costs; the subcritical ORC provides simpler design; while the supercritical ORC achieves high performance but faces system complexity challenges.