Thermodynamic analysis of a novel adsorption-type trans-critical compressed carbon dioxide energy storage system

Abstract

Compressed CO2 energy storage technology is a feasible resolution to stabilize the fluctuation of renewable energy output and has significant development prospects. The main challenge currently facing is how to achieve high-density storage of low-pressure CO2. To get rid of the engineering application limitations caused by low-pressure CO2 liquefaction storage and large-scale cave storage, a new type of adsorption trans-critical compressed CO2 energy storage system is proposed in this paper. Using Fe-MOR(0.25) as an adsorbent, the storage density of CO2 can reach 390.94 kg/m3 at 298 K and 0.1 MPa. The thermodynamic simulation is carried out based on the first and second laws of thermodynamics. The results demonstrate that the system round trip efficiency, exergy efficiency, and energy storage density under the design conditions are 66.68 %, 67.79 %, and 12.11 kWh/m3, respectively. The results of sensitivity analysis indicate that the storage pressure and storage temperature of the high-pressure tank have compound effects on the system, and they are the key parameters affecting the performance of the system. Releasing pressure at critical points can cause abrupt changes in system performance. Heat exchanger effectiveness, compressor, and turbine isentropic efficiency improvements positively affect the system performance.