Hybrid Ocean Thermal Energy Conversion System And Exergy Analysis

Ocean thermal energy is a kind of clean and renewable energy, which can be used for generating electricity, seawater desalination, and seawater breed etc. The exploitation of ocean thermal energy not only can alleviate the pressure caused by energy resources consuming and adjust the structure of energy resources in china, but also can be beneficial to environment. There is lack of researches on ocean thermal energy at present in this country, so this paper studies on the integrated ocean thermal energy conversion (OTEC) cycle system. Firstly, the integrated OTEC experimental platform is changed and debugged in this paper. Secondly, a common integrated OTEC system is analyzed in the method of exergy analysis, which shows the relation between exergy losses in every part, energy or exergy efficiency of the system and many factors. Lastly, According to the experimental platform, this paper analyses the problems as follows: (1) The influence of the worm seawater's intake temperature on the exergy losses, exergy and energy efficiency of the system. (2) The influence of the cold seawater's intake temperature on the exergy losses, exergy and energy efficiency of the system. (3) The influence of the working fluid's evaporating temperature on the exergy losses, exergy and energy efficiency of the system. (4) The influence of the working fluid's condensing temperature on the exergy losses, exergy and energy efficiency of the system. It also discusses the relation between different environmental temperatures and the power generation system. On the basis of exergy analysis of a large-scale OTEC system, the results are compared to those from the OTEC experimental system in the article. Some conclusions can be obtained: If the other parameters are fixed, the exergy efficiency of the power generation system will increase when the working fluid's evaporating temperature rises, which will happen in the reduction of the working fluid's condensing temperature or the warm seawater's intake temperature. The major exergy loss takes place in the evaporator in the experimental or the large-scale OTEC system, therefore, the rise of the system's exergy efficiency mainly depends on the deduction of exergy loss associated with the evaporator. Compared to the exergy efficiency of the experimental system, the large-scale system's rises greatly. To make good use of ocean thermal energy, a effective way is to make the system's scale larger. If the other parameters are fixed, the exergy efficiency of the seawater desalination system will decrease when the warm seawater's intake temperature rises, which will also happen in the deduction of the flash temperature. The flash ration is proportional to the flash temperature difference. The research will guide the later optimization of the experimental system, it also prepares for the future exploitation of ocean thermal energy in china in theory.