Study Of Double-ejector Ocean Thermal Energy Conversion Cycle

The demand for energy is increasing with the society development day by day.Drnven by the limit reserves of the fossil energy,exploit is under developed of other types of energy.Ocean thermal energy belongs to the renewable energy which is an important potential substitution of the fossil energy.It utilize the different temperature between the surface and deep seawater to generate a pressure difference between the inlet and outlet of the turbine,then work fluid expands and give impetus to turbine to whirl and generate power.Ocean thermal conversion device achieves this process.The performance of the thermodynamic cycle used by the thermoelectric power generation device determines the energy capture efficiency and cost of the thermoelectric power generation device.Therefore,improving the cycle efficiency of a cycle or finding a cycle with higher cycle efficiency is the key technology for using ocean thermal difference energy.A new thermodynamic cycle is proposed in the view of the working condition of the ocean thermal power generation combined with the previous research on the improvement and conclusion of thermodynamic cycle.Ammonia solution was used to reduce the entropy less during the process of the evaluation and condensation,and energy in the liquid working fluid after evaporation can also be recovered throughregeneration process and using of injector to increase the energy utilization of the cycle.After the completion of the cycle construction,based on the first law of thermodynamics and the second law of thermodynamics,the theoretical analysis of the constructed double ejector cycle is carried out,and the mathematical model of the thermal analysis of each device in the cycle is established,and the calculation of cycle thermal efficiency and net output power is compiled.The relationship between thermal efficiency,net output power,turbine inlet pressure,turbine inlet gas temperature,condensing temperature,pumping ratio,base liquid ammonia concentration,and ejector pressure drop is obtained.And the effect comparing was carried out between one and two turbines,and also between one and two ejector to the cycle performance.According to the relationship between thermal efficiency,net output power,turbine inlet pressure,turbine inlet gas temperature,condensing temperature,pumping ratio,base liquid ammonia concentration,and ejector pressure drop,it is known that when the evaporation temperature is 303.15K,the condensation temperature is 279.15K,the evaporation pressure is 650kPa,the base liquid ammonia concentration is 0.78,the pumping ratio is 0.2,and the pressure drop of the first and second ejector is lOkPa,the cycle efficiency can reach its highest value 4.076%,moreover,the turbine output power is relatively stable when the operating conditions of the thermodynamic cycle change,and the output power fluctuation due to the change of the working environment is smaller.Finally,based on the determined state parameters of each state point in the thermal cycle during the optimal working state of the thermodynamic cycle,the test bench for the verification test was designed,and the components required for the test bench were designed and selected.