Research on Flexible Peak Shaving of Combined Heat and Power Generation Units Assisted by High-Temperature Molten Salt Thermal Energy Storage

To address the mismatch between thermal and electrical loads in coal-fired combined heat and power generation units during heating seasons, and the operational discrepancies between heating/non-heating periods, this study proposes a molten salt thermal energy storage system with a bidirectional heat exchange configuration. During heating seasons, the system operates in “main/reheat steam charging-feedwater discharging” mode to enhance operational flexibility and satisfy district heating demands, and in non-heating seasons, it adopts “main/reheat steam charging-feedwater/condensate cooperative discharging” mode to improve thermal efficiency. Simulation results demonstrate that the bidirectional heat exchange architecture enables flexible switching between charging/discharging modes, achieving a minimum electrical load of 98.76 MW_e (28.2% of turbine heat acceptance (THA) rating) at 90 MW_th heating demand during heating seasons, and 106 MW_e (30.3% THA) with 80% main steam extraction ratio in non-heating seasons. Economic evaluation reveals a 12.3% reduction in capital costs compared to conventional molten salt systems during heating operation. The research validates the effectiveness of bidirectional thermal storage-exchanger configurations in enhancing whole-lifecycle economic performance and energy efficiency, providing technical support for low-carbon transition of thermal power units through operational flexibility improvement and energy cascade utilization optimization.