Abstract
Utilizing the volume change of phase change materials (PCM) to realize ocean thermal energy-electric energy conversion is a promising method. The PCM-based ocean thermal engine has the potential to solve the energy limitation problem of underwater vehicles. In this paper, detailed numerical and experimental research on the thermoelectric conversion process was conducted. A numerical model was proposed for thermal–mechanical and mechanical–electrical energy conversion process; and an experimental set-up was built for system identification and model validation. The efficiency and power density of the ocean thermoelectric generator under different configuration were analyzed numerically. Finally, a prototype was developed and tested. Results showed that: (1) In deep water area, the optimal pre charging pressure is 10 MPa for achieving maximum power density and this configuration is a compromise among the efficiency, phase change time and weight; (2) In shallow area, to achieve maximum output power, pressure range for power generation should be set to 15-20 MPa, while the motor speed need to be set to 6000 rpm; (3) the total energy conversion efficiency and the power density of the prototype in the lab test was 0.453 % and 21.58 mW/kg, respectively, attaining state-of-the-art performance compared to the current literature.