| Nowadays,the traditional fossil energy is increasingly scarce and the environmental pollution caused by it is becoming increasingly serious.It has increased the demand for renewable energy in the world,and the new energy technology has been developed rapidly.The installed capacity of wind and solar energy has increased significantly every year.However,affected by seasons and weather,these renewable energy sources have intermittent and fluctuating disadvantages.In order to ensure the safe and stable operation of the grid after the new energy grid connection,some new energy generation has to be abandoned.Energy storage technology is considered to be the key technology to solve the large-scale grid connection of new energy generation and promote the new energy consumption.Compressed air energy storage technology has been widely concerned because of its large scale and high efficiency.In order to further improve the efficiency of compressed air energy storage system,based on the advanced adiabatic compressed air energy storage system,a hybrid energy storage combined cycle power generation system coupled with high temperature heat storage and compressed air energy storage is proposed,and the performance of the system is analyzed.Firstly,the thermal systems of pure regenerative hybrid energy storage power generation system and hybrid energy storage combined cycle power generation system are constructed respectively.Based on the derivation of mathematical models of compressor,intercooler,expander,gas storage chamber,heat exchange device,heat storage device,waste heat boiler and other components,the mathematical models of the whole hybrid energy storage combined cycle power generation and storage system are established and defined The related performance indexes are given.The thermodynamic characteristics of the system in the process of the cycle are obtained through the joint solution of the thermodynamic analysis method,and then the influence of the system component parameters on the system performance is analyzed.The performance analysis of the two systems is carried out respectively,and the changes of system exergy and exergy loss are analyzed.In order to further improve the storage capacity of the system(corresponding to the energy storage density of the system)and improve the efficiency of the high temperature air turbine,an electric boiler heating device will be added to the heat storage device.High temperature and high pressure air generates electricity through a combined cycle unit are composed of air turbine and steam turbine.The composite energy storage combined power generation system is compared with the pure regenerative composite energy storage subsystem,the change of energy storage efficiency is observed,a set of optimal system economic indicators(high energy storage efficiency and high energy storage density)are studied,and a set of original design parameters are determined.The results show that the pure regenerative composite energy storage power generation system can achieve about 64.36% storage efficiency,and the energy storage density is5.38kwh/ The efficiency of the system reaches 67.48%.Under the condition of energy storage density of 5.50 k W·h/m3,the storage efficiency is 63.72% and the exergy efficiency is 66.66%.Then the sensitivity analysis of the key parameters(ambient temperature,maximum working pressure and minimum working pressure)of the system performance is carried out,and the influence of the selected key parameters on the performance indexes of pure regenerative composite energy storage power generation system and composite energy storage combined power generation system is compared.Finally,the Pareto parameters of the two systems are optimized,the influence of the main parameters of the system on the system performance is analyzed,and the optimal values of the storage efficiency and energy density are found,so as to determine the optimal parameters.The results show that compared with the traditional compressed air energy storage system,pure regenerative composite energy storage power generation system and composite energy storage combined power generation system have higher energy storage density and storage efficiency.The results show that the working efficiency of the combined thermal energy storage system is greatly influenced by the working pressure and the output efficiency of the combined thermal energy storage system.In contrast,the influence of ambient temperature,heat exchanger end difference and heat exchanger split coefficient is small.However,the combined energy storage power generation system is also affected by the steam outlet pressure,pressure loss,feed water temperature,steam flow rate,expansion efficiency of steam turbine and end difference of waste heat boiler,and has little effect on the storage efficiency.Therefore,it becomes a secondary factor in the engineering design of composite energy storage combined power generation system.Finally,the Pareto parameter optimization method is used to optimize the system.Taking the storage efficiency and energy density as the objective function,the maximum working pressure and minimum working pressure of the gas storage chamber as the decision variables,Pareto frontier is defined. |
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