Research And Contrastive Analysis Of Hybrid Ocean Thermal Energy Conversion System

The ocean thermal energy is a kind of greatly important ocean energy, which is renewable, clean and rich in the reserves. At present, the main mode of utilizing the ocean thermal energy is ocean thermal energy conversion (OTEC) system. Combined with the advantage of an open-cycle system and a closed-cycle system, a hybrid OTEC system not only can generate electricity, but also can produce the fresh water. China is rich in ocean thermal energy resources, but there are scarcely researches on OTEC system. Considering the requirements for the renewable energy sources in the future, it is imperative to strengthen the exploitation of the ocean thermal energy.The main purpose of this paper is to study two cycle modes of the hybrid ocean thermal energy conversion systems. Firstly, the operation parameters of the two systems are calculated, including the generating power system and desalination system. Secondly, the components of the systems are designed and their equipment selections are completed. The physical models of the two systems are established. Thirdly, the two systems'heat transfer performance and resistance performance are analyzed and the mathematical models are established. Finally, the simulation programs of the two systems are compiled utilizing Fortran language. On the basis of the simulation results, the operation characteristics and change trends of the two systems are discussed under different working conditions.The performance of system1 and system2 operating under different parameters, such as the temperature of the flash chamber, the evaporation temperature, the condensation temperature and the warm water's flux, are analyzed in detail. The two systems'output parameters under different effective utilizing temperature differences are analyzed contrastively. It can be concluded that under the same work condition, the export work of generator and efficiency of system1 are more than those of the system2, but system1'flash export parameters is higher than system2's. Within the scope of calculation, System2's operation efficiency and the export work of generator are 12%～15% and 5.4%～17.8% higher than those of system1, but the irreversible temperature change of flash chamber of system1 is 4.8%～5.8% higher than system 2's, and at the same time, the flash ratio and fresh water output are 4.9%～6.0% higher. System1 is utilized mainly to produce fresh water, and system2 is used to generate electricity, in which fresh water is byproduct.