Integration Research And Performance Analysis Of Compressed Ari Energy Storage System Coupled With Electric Heating

In recent years,the realistic need for the transformation of energy structure to green and low-carbon has boosted the vigorous development of renewable energy.However,due to the volatility and intermittence of renewable energy power generation,it has an adverse impact on the security and stability of the power grid in the process of grid connected operation,and then the phenomenon of "abandoning wind and power" is widespread.In this context,energy storage technology is considered to be an effective way to ensure the safety of renewable energy grid connection.Compared with other energy storage technologies,the compressed air energy storage（CAES）system,as a technical means to realize large-scale energy storage,has the advantage of economy and reliability.However,at present,compressor components can only use the low-frequency and high-amplitude parts of wind power,but cannot absorb the highfrequency and low-amplitude parts of wind power.Coupling the CAES with the electrical heating（CH-CAES）is a new way to solve the above problems and increase the utilization rate of fluctuating wind power.Based on this idea,this paper has carried out the following research:Firstly,a CH-CAES-KC system integrated with CH-CAES and Kalina cycle is proposed in this paper.The system performance under basic conditions and the effect of key parameters on system performance are studied by constructing the mathematical model of the system and conducting thermodynamic analysis.The results show that the compressor unit and the electric heater consume 12322 k W and 7006 k W energy respectively in the process of energy storage.Compared with the CAES system without integrated electric heater,CH-CAES system can consume an additional 57%of high-frequency and low-amplitude wind power,reducing the wind abandoning rate.Secondly,a CH-CAES-ESK system integrated with the back-pressure jet Kalina cycle（ESK）is proposed in this paper to solve some shortcomings in Kalina cycle.The performance of the system under basic conditions and its variation with key parameters are studied through thermodynamic analysis.Subsequently,conventional and advanced exergy analysis is performed on CH-CAES-ESK system to reveal the interaction between system components and the real energy saving potential.Finally,this paper studies the thermoeconomic performance of CH-CAES-ESK system and takes the round-trip efficiency and investment cost rate per output power as objective functions to perform multi-objective optimization,which determines the optimal operating conditions of the system.The results show that compared with CH-CAES system,the round-trip efficiency of CH-CAES-ESK system is improved by 4.95%,indicating that ESK cycle has a good performance in recovering the waste heat of the system and realizing the cascade utilization of energy.On the other hand,the parameter analysis shows that increasing the charging pressure while keeping the charge–discharge pressure ratio unchanged can not only improve the round-trip efficiency of CH-CAESESK system,but also conducive to reduce the volume of air cavern volume.Increasing the charging pressure and turbine efficiency,reducing the pinch temperature of cooler and reheater can improve the round-trip efficiency of the system.Increasing the charging pressure and reducing the compressor efficiency can reduce the investment cost rate per output power of the system.Advanced exergy analysis shows that the CHCAES-ESK system has 2353.17 k W energy saving potential and the interactions among system components is not very strong.Exergy destruction of all the components with the exception of the reheater mainly comes from irreversibility of components themselves in the process of energy transfer or conversion.The results of multiobjective optimization show that the round-trip efficiency and investment cost rate per output power of the CH-CAES-KC system under the optimal operating conditions are52.92% and 0.0873 $/k Wh respectively.