[Objective] To investigate the detailed impact and mechanisms of molten salt energy storage systems on the unit’s overall performance of classical industrial steam-supply combined heat and power (CHP) units, this have studied optimizes and reconfigures existing molten salt heat release processes to further identify opportunities for improving system energy efficiency and operational economics. 

[Methods] This study comprehensively investigates various different CHP unit configurations that integrate molten salt thermal storage. Building upon typical molten salt heat release schemes, an improved design was proposed to further enhance energy efficiency: the molten salt was used to preheat boiler feedwater to 315 ℃ and replace some of the high -pressure heaters, reducing partial steam extraction from the high-pressure and medium-pressure cylinders, then returning to the unit to perform work to increase the power output of the unit while maintaining the original steam supply method. Additionally, waste heat of the e xtracted steam from steam generation was recovered to achieve higher thermal -to-mechanical conversion efficiency and improved overall unit performance. Taking a 350 MW supercritical extraction -heating 2 CHP unit from typical region as an example , this study combines the unit ’s heat balance diagram with precise modeling using EBSILON Professional modeling software to conduct comparative analyses of thermodynamic performance, including energy efficiency and flow rates. This revealed the mechanisms by which the improved scheme enhances the performance of the case unit compared to the original typical scheme; Based on actual spot electricity market conditions, a comparative analysis was conducted on peak -shaving capacity, thermal performance, and economic performance under typical daily conditions for both schemes. 

[Results] The results have indicated that the improved scheme could further enhance the system ’s available heat through the molten salt ’s simultaneous heat storage and the release mode, while synergistically optimizing the molten salt heat release process to enhance the coupled system’s heat release efficiency and cycle thermal efficiency. Under peak load conditions, the improved scheme achieves a peak capacity of 39.7 MW, an increase of nearly 11 MW compared to the typical scheme; its equivalent round-trip efficiency and thermal efficiency reach 86.5% and 40.0%, respectively, representing significant improvements over the typical scheme; Under typical daily electricity spot market conditions, the improved scheme’s annual operating revenue can reach 20.949 million yuan, with a static payback period of 5.2 years—both significantly outperforming the typical scheme. 

[Conclusion] The findings of this study provide theoretical justification and case -based suppor t for the efficient and flexible operation of retrofitted combined heat and power (CHP) units.