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• Integrate solid oxide fuel cell with supercritical carbon dioxide Brayton cycle and CO 2 capture. • 60.96% of net electrical efficiency and 0.342 kg/kWh reducing CO 2 emission are achievable. • Develop detailed off-design models of components and system. • Investigate three key operating parameters' effects on system performance. • Propose system control strategy to investigate part-load system performance. Solid oxide fuel cell (SOFC) and supercritical carbon dioxide (sCO 2) Brayton cycle are both clean and efficient technologies for energy supply. The present study proposes an innovative SOFC-based system combined with sCO 2 Brayton cycle and CO 2 capture system. The bottoming sCO 2 cycle can improve efficiency of the integrated system by recovering waste heat from the combustion chamber while using oxy-fuel combustor to achieve low-energy CO 2 capture. And the quasi-steady model of the system is developed to evaluate the system design and off-design performances. The simulated results indicate that the net electrical efficiency and reducing CO 2 emission of the system are 60.96% and 0.342 kg/kWh, respectively. The system parametric analysis indicates that the reasonable recirculation ratio, fuel utilization and fuel flow rate are prerequisites for the safe and efficient operation of the integrated system. Based on the analysis, a system control strategy is proposed to satisfy the demand for wide-range load adjustment (30%-100%), while the efficiency of the integrated system is decreased from 60.96% to 50.33% during the load reduction process. [ABSTRACT FROM AUTHOR]

• A co-generation system consisting of Allam cycle and heat pump is proposed. • The latent heat of working fluid in Allam cycle is recovered for space heating. • The proposed system is more efficient and economical with nearly zero emissions. • The proposed system is more suitable for co-generation in cold regions. Allam cycle is known as a promising alternative cycle for power generation, which combines the advantage of both oxygen-enriched combustion technology and supercritical carbon dioxide technology. In this study, an integrated energy system consisting of an Allam cycle and a heat pump is proposed to co-generate power and heat. The heat of carbon dioxide in the compression train of the Allam cycle is recovered by the heat pump system, which is used for space heating. The techno-economic and environmental performances of the co-generation system are analyzed and compared with those of the single systems. The results show that the net electrical efficiency of the Allam cycle is improved by 1.56 %, and the coefficient of performance of the heat pump in the combined system is increased by 42.02 %. The lowest and highest investment-increment payback periods are 0.26 and 5.80 years, which indicates the proposed integrated system is economically feasible. Meanwhile, the sensitivity analysis of key economic parameters is also conducted. Finally, the carbon emission of different generation configurations are compared and the results indicate that the integration of the heat pump with the Allam cycle can effectively reduce system carbon emission. The proposed concept provides a new approach to efficient utilization of the heat from the carbon dioxide mixture cooling process for heat and power generation with nearly zero emission, and it would be a better choice for cold regions. [ABSTRACT FROM AUTHOR]