Advanced adiabatic compressed air energy storage systems dynamic modelling: Impact of the heat storage device

Advanced Adiabatic Compressed Air Energy Storage (AACAES) is a technology for storing energy in thermomechanical form. This technology involves several equipment such as compressors, turbines, heat storage capacities, air coolers, caverns, etc. During charging or discharging, the heat storage and especially the cavern will induce transient behavior of operating points, notably temperature, pressure, and volume flow. In contrast, the optimal use of turbomachinery requires it to be as stationary as possible. AACAES technology therefore requires transient modelling to optimize its design. This paper presents a modular and adaptable numerical tool capable of simulating the dynamic behavior of different thermomechanical storage systems. This tool is then applied to an AACAES system to analyze the impact of various configurations on the variability of volume flow. The aim is to optimize Round Trip Efficiency (RTE) while limiting the maximum variation in volume flow. First, the effect of the size of fixed-bed Thermal Energy Storage (TES) is analyzed. Then, we analyze the behavior of the system with heat management based on a heat exchanger and a heat transfer fluid. In addition, the effect of adding pressure control at the cavern inlet/outlet on the two previous variants is studied.