Comprehensive characterization of a 30 kW-class ocean thermal energy conversion experimental system with a magnetic levitation expander: A 5E (energy, exergy, economy, environment, and energy level) analysis

Ocean thermal energy conversion utilizes the temperature differential between surface-level warm seawater and deep cold seawater as a renewable method for power production. However, the practical application of ocean thermal energy conversion system faces considerable challenges. This research constructed a 30 kW-class ocean thermal energy conversion experimental system incorporating a magnetic levitation expander. A comprehensive energy, exergy, economy, environment, and energy level analysis framework was established for the first time, and the performance of the system was evaluated through experimental validation. The study defined the key evaluation indices, such as thermal and exergy performance, with a focus on the operational behavior of key system modules such as the expander and heat exchanger. Results indicated that the ocean thermal energy conversion unit achieved peak power generation of 20.81 kW, a maximum net generation ratio of 31%, a maximum exergy efficiency of 53%, and thermal efficiency up to 1.50%. For component analysis, the maximum isentropic efficiency of the magnetic levitation expander was 85.88%. The research work in this paper fills the vacancy of the high-power ocean thermal energy conversion experimental platform with a magnetic levitation expander in experimental research and provides a reference for the efficient utilization of ocean temperature difference energy in the future.