Abstract
To enhance the energy efficiency of Ocean Thermal Energy Conversion (OTEC) systems and explore their performance at larger scales, this study integrates a Magnetic Levitation Expander (MLE) into an OTEC system. A 30 kW OTEC-MLE experimental platform was established, and both system-level and component-level performances under various operating conditions were evaluated through comprehensive energy and exergy analyses. The analysis reveals that as the cold source flow rate increases from 100 m3/h to 200 m3/h and the hot source flow rate increases from 125 m3/h to 200 m3/h, the expander’s maximum output power reaches 22.74 kW. Under the optimized operating condition with a hot source flow rate of 175 m3/h and a cold source flow rate of 125 m3/h, the system achieves its peak net power output of 9.66 kW, with an effective power ratio reaching 53.84 %. Further analysis of the impact of working fluid mass flow rate on efficiency characteristics shows that as the mass flow rate increases from 2.15 kg/s to 2.75 kg/s, the isentropic efficiency of the magnetic levitation expander increases, reaching a maximum of 79.81 %. Simultaneously, the system’s thermal efficiency improves to 2.36 %, and the exergy efficiency reaches 58.91 %, with an annual CO2 reduction of 53.76 tCO2e. This work provides theoretical basis and data support for the engineering and commercial application of the OTEC-MLE system.