A novel analytical solution for the system performance evaluation of advanced adiabatic compressed air energy storage suitable for variable process configuration and parameter

Abstract

System performance metrics such as compression power, expansion power, and system efficiency are key indicators for assessing the scale of advanced adiabatic compressed air energy storage (AA-CAES). Analytical solutions offer a method to evaluate system performance. However, existing solutions often assume identical compression and expansion stages, equal compression and expansion ratios, and the use of only dry air. This study proposes a steady-state analytical solution consisting of seven equations and fourteen independent parameters without relying on these assumptions. The solution is applied to both ideal and practical conditions, taking material temperature limits into account. The findings indicate that under ideal conditions, a single-stage process achieves the highest system efficiency, whereas a multistage process reduces efficiency. Additionally, compression power is affected by $T_{1c,\mathrm{out}}$, and expansion power is affected by both $T_{1c,\mathrm{out}}$ and $T_{1\mathrm{ex},\mathrm{out}}$. The higher value of $T_{1c,\mathrm{out}}$, the higher value of the expansion power. The highest system efficiency of 68.15 % occurs when $T_{1c,\mathrm{out}}$ equals to 245 °C for a three-stage process. Compared with ideal conditions, the performance differs when $T_{1c,\mathrm{out}}$ is higher than the upper-temperature limit of the thermal medium under practical conditions. This study broadens the application of analytical solutions to processes with varying stages, compression and expansion ratios, and the use of both dry and humid air. The solution offers fast calculation speed and high accuracy, making it a valuable tool for engineers in the design and optimization of AA-CAES.