Control strategy effect on storage performance for packed-bed thermal energy storage

Abstract

Energy storage will play an essential role by complementing renewable energy sources, which are central to the decarbonization of the power sector. Sensible thermal energy storage (TES) system through heating materials with high-temperature heat transfer fluid (HTF) is the simplest and most inexpensive TES technology. However, the inherent disadvantage of thermocline degradation makes the packed-bed TES system has several negative consequences. In the present study, a passive thermocline control (TCC) method with a high ratio of height-diameter and an active TCC method by setting an ending charging temperature were proposed. The results showed that the heat transfer between air and solid thermal storage materials was enhanced because of the fast airflow and the long airflow passage of the TES system with the passive TCC method. The utilization factors were about 75%, and thermal energy efficiencies were about 78%–80% under different interval times between charging and discharging. Combined with the active TCC method, the stable discharging duration was 6%–19% longer than just using the passive TCC method.