| With the development of society,traditional energy sources such as oil and coal are depleted,and the impact of energy utilization on the environment has attracted more and more attention.So people turned their attention to renewable energy such as wind,solar and geothermal energy.However,the renewable energy sources such as wind and solar energy have the shortcomings of intermittent and unstable,and the power generated by them also has intermittent and unstable problems.The turbulence caused by the integration of new energy sources has already had a great impact on the safe operation of the system.After a high proportion of new energy is connected to the grid,it will have a profound impact on the shape and operation mechanism of the power system,so the large-scale utilization of renewable energy is limited.The peak-to-valley difference of the power grid is increasingly obvious,which is a big problem in the utilization of electric energy and results in great energy waste.Based on the above problems,energy storage technology emerges as the times require.Energy storage technology cleverly solves the above two problems,which not only makes up for the shortcomings of poor continuity of power supply,unstable power output,which achieves stable output and provides an effective solution for large-scale utilization of renewable energy,but also realizes peak clipping and valley filling,which improves the efficiency,safety and economy of the energy system.Firstly,the related theories of compressed air energy storage technology are introduced,including the working principle of compressed air energy storage technology,the classification of compressed air energy storage system according to different basis and the main components of compressed air energy storage system.Also the mathematical formulas of the main components are used to digitize different components to facilitate a deeper understanding of the compressed air energy storage system.Firstly,the related theories of compressed air energy storage technology are introduced,including the working principle of compressed air energy storage technology,the classification of compressed air energy storage system according to different basis,and the main components of compressed air energy storage system.And the formulas are used to express the working principle of different components,which is convenient for a deeper understanding of the compressed air energy storage system.The static and dynamic models of compressor and expander are established in Aspen Plus and Simulink respectively according to the mathematical formulas.The advantages and disadvantages of dynamic model and static model are compared to highlight the intuitiveness and timeliness of dynamic models.Finally,the dynamic model is selected to model and analyze the entire compressed air energy storage system.Taking the TICC-500 energy storage system as an example to verify the accuracy of established dynamic model,and the simulated parameters of gas storage,compressor and expander parameters were compared with the actual running data.Then the model is used to analyze the influence of thermodynamic parameter changes in the compression system,heat exchange system and expansion system on the efficiency of the CAES system,including total pressure ratio,compression stage,compressor inlet temperature,entropy efficiency of compressor,heat exchanger efficiency after compression stage,initial temperature of heat exchange medium,dry humidity of compressed gas,total pressure ratio of expander,and entropy efficiency of expander.Which are as the foundation for optimizing the compressed air energy storage system and improving the efficiency of CAES system.Finally,a compressed air energy storage system with variable pressure ratio is proposed and a corresponding model is established based on reducing the power consumption of the compressor and increasing the output of the expander.The system is realized by a valve regulating compressor and an expander in series and parallel,and generates different exhaust pressures in different pressure demand stages of the compression process,which can meet the requirements of gas storage,eliminate unnecessary compression process,and save power of compressor.In the expansion phase of the variable pressure ratio operation,the system gradually reduces the series number of the expander according to the gas pressure in the gas storage chamber,so that the system can more fully utilize the stored gas and increase the output power of the expander.In a conclusion,the variable voltage ratio system can effectively improve the system efficiency by reducing the input electric energy and increasing the output electric energy. |
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