Design and analysis of a supercritical carbon dioxide and high-temperature heat pump combined energy storage and power generation system
To address the mismatch between electricity supply and demand caused by the intermittency and fluctuation of renewable energy sources,a combined cycle energy storage and power generation system incorporating a closed supercritical carbon dioxide(S-CO2)cycle and a high-temperature heat pump is proposed,which is an innovative exploration of the Carnot battery form.Through energy exchange via molten salt heat storage and water cold storage devices,this system efficiently integrates the heating process of the heat pump cycle with power generation process of the S-CO2 cycle,which achieves a favorable round-trip efficiency for the energy storage power generation system.Simulations are performed to calculate the typical operational parameters and thermodynamic performance of the combined cycle,and to analyze the influence of main parameters of the S-CO2 cycle on the overall efficiency of the system.The results indicate that,increasing the inlet temperature of the expander aids in enhancing the overall cycle efficiency,achieving an optimal electrical-to-electrical efficiency of 62.8％,while reducing the demand for heat storage molten salt.Elevating the inlet gas parameters of the main compressor will lead the system efficiency to reach a peak value,beyond which the overall cycle efficiency no longer increases.The optimal bypass ratio for the main recompressor is 0.35,which allows the system to achieve optimal efficiency.The optimal operating conditions of the S-CO2 cycle system are identified,offering an electrical-to-electrical efficiency that is 7.98％higher than a reversible Brayton system under the same conditions.
万方数据
维普
