[Objective] In order to raise the energy utilization efficiency of Carnot battery systems and improve the economic performance of waste incineration power plants, a Carnot battery energy storage system coupled with waste incineration power units is proposed. 

[Methods] First, the system integration scheme and equipment configuration are formulated. Second, a thermodynamic simulation model of the coupled system is established on Ebsilon Professional, and the rationality of each subsystem is verified. Finally, the overall performance of the coupled system is comprehensively evaluated from multiple dimensions, including energy analysis, energy flow, exergy efficiency, economic performance, sensitivity analysis and technical feasibility. 

[Results] Energy analysis shows that the coupled system yields a net power output of 15.435 MW and a net power generation efficiency of 33.18%, an increase of 12.69 percentage points compared with the reference unit. The net power generation from the Carnot battery subsystem is 7.135 MW with a round-trip energy efficiency of 118.9%. The prominent efficiency improvement mainly results from the significant enhancement of main steam and reheat steam parameters as well as waste heat recovery from the condenser, which effectively boosts power output and system energy utilization efficiency. Exergy analysis reveals that the overall exergy efficiency of the entire system reaches 31.63%, growing by 12.23 percentage points against the original unit. Such improvement is attributed to reduced extraction loss of the steam turbine and full recovery of waste heat from the condenser. Economic analysis indicates that the dynamic payback period of the coupled system is 7.39 years, and the project net present value (NPV) hits 290.92 million CNY over a 25-year service life. This result verifies the sound economic viability of the coupled system, and considerable economic returns can be expected in the short term. Sensitivity analysis demonstrates that when the curtailed grid electricity supplied to the Carnot battery is less than 6 MW, the total power output and economic benefits of the coupled system rise almost linearly with the increasing input power. Further growth in input power slows the rising rates of power generation and NPV gradually. The maximum NPV of 292.87 million CNY is achieved at an input power of 6.553 MW. 

[Conclusions] In conclusion, the proposed coupled system remarkably improves the power generation efficiency and energy utilization of the waste incineration generating unit. With a reasonable payback period and attractive economic profits, the system boasts outstanding technical feasibility.