Analysis And Optimization Of Operation Characteristics Of Advanced Adiabatic Compressed Air Energy Storage System

Conventional energies are confronting exhaustion and the utilization process of them causes pollution,which make that a heap of countries endeavor to exploit renewable energies,such as wind energy,solar energy and tidal energy etc,to relieve the tension situation of conventional energies.The electricity from renewable energies is instable,which may bring a series of safety problems for power grid.Hence,the phenomena of wind curtailment and solar curtailment go so pervasive.Electrical energy storage technology emerges in the appropriate background and is the efficient way to solve the above problem.Meanwhile,advanced adiabatic compressed air energy storage?AA-CAES?technology eliminates consuming fossil fuels,avoids the emission of pollutants,so appeals to the extensive attention.The deep study on AA-CAES system is propitious for grasping the operation characteristics of it,which can provide the worthwhile reference for the design,operation and optimization of it.So that,the problems of wind curtailment and solar curtailment can be solved better,the utilization rate of renewable energies is improved,and economic loss is lowered.This paper erects thermodynamic model of AA-CAES system and mathematical models of all components,and adopts the method of simulation c alculation.Firstly,four combination operation strategies are proposed,based on air,carbon dioxide,constant temperature air storage chamber,and constant wall-temperature air storage chamber.Thermodynamic performance differences of them are compared with each other and the effects of three key parameters are analyzed.Next,four operation scenarios of system are proposed according to the characteristics of compressor train and expander train.Similarly,thermodynamic performance diversities of them are compared,and sensitivity analysis and multi-objective optimization are carried out.The conclusions have been got as follows.?1?The research on different working mediums and air storage chambers finds that under the same operation parameters,energy storage efficiency of the second strategy is the highest,and energy storage density of the first strategy is the biggest.?2?After conducting key parameters analysis,it shows that for the four strategies,energy storage efficiencies all decrease,and ener gy storage densities all increase when initial temperature of working medium augments.The effect of initial pressure of working medium on two performance indexes is just contrary to the one of initial temperature of working medium.As heat exchanger effectiveness increases,the variations of energy storage efficiencies are different,and energy storage densities all augment.?3?For the four operation scenarios,energy storage efficiency of the fourth scenario is the highest,and energy storage density of the second scenario is the biggest,when basic parameters are identical.Sensitivity analysis shows that their energy storage efficiencies all exist the highest values,and energy storage densities all increase with heat exchanger effectiveness.The lower ambient temperature is beneficial to improving energy storage efficiencies and energy storage densities.The higher ambient pressure is able to increase energy storage efficiencies,but may decrease energy storage densities.?4?Under the given basic parameters,after carrying out multi-objective optimization,it gets that the optimal energy storage efficiencies of four scenarios are respectively 62.758%,65.380%,64.572%,and 67.247%,and the optimal energy storage densities of them are separately 1.103×10⁷,1.150×10⁷,1.071×10⁷,and 1.116×10⁷ J·m^-3.