Two types of heat engines have been considered, and demonstrated for ocean thermal energy conversion(OTEC) Closed-cycle system a working fluid such as ammonia to evaporate into gas by energy from warmer water Similar to the ordinary steam-powered electric generating plant in which water as working fluid Open cycle system where the working fluid is seawater Warm Vacuum Drive Condensed Cold Vapor turbine water water 复旦大学环境科学与工程系 Department of Environmental Science and Engineering, Fudan UniversityTwo types of heat engines have been considered, and demonstrated, for ocean thermal energy conversion(OTEC) Closed-cycle system. A working fluid such as ammonia to evaporate into gas by energy from warmer water Similar to the ordinary steam-powered electric generating plant, in which water as working fluid. Open cycle system where the working fluid is seawater Warm water Vacuum Vapor turbine Cold water Drive Condensed by