The structure of the library of the developed CAES-TES software toolbox is shown in the below chart. The multi-level classification method has been used. To the first level subdirectory, the first eight categories are classified based on their functions, which belongs to different CAES-TES system components; the last in the first level categories are relevant to the CAES-TES overall system simulation examples/case studies. To the second level subdirectory, the classification is based on the different approaches of mathematical modelling (e.g. modelling for thermodynamic & steady state analysis and modelling for dynamic simulation & control, marked or the functions of machines. The second level subdirectory can be divided into the third level subdirectory and even further. With this multi-level classification method, the massive component modules to CAES-TES systems can be clearly sorted out and the user can easily find and select the desired component models to assemble a required system model for simulation study and other applications.