Thermodynamic performance study of a novel cogeneration system combining solid oxide fuel cell, gas turbine, organic Rankine cycle with compressed air energy storage

Energy storage becomes increasingly significant for addressing imbalance of grid supply and demand. In this paper, a new cogeneration system based on combined compressed air energy storage (CAES), solid oxide fuel cell (SOFC), gas turbine (GT) and organic Rankine cycle (ORC) is proposed. SOFC-GT system replaces GT combustor of traditional CAES, and SOFC-GT can operate with high efficiency at peak time. At the same time, ORC is employed to recover the exhaust from GT. Especially, in the new system, the surplus electricity is utilized to compress air, thus eliminating power consumption of air compressor in conventional SOFC-GT. Additionally, the system can also provide heat and power for small-scale distributed generation application users. The combined system is simulated based on Aspen plus and embedded Fortran. The energy, exergy analysis and parametric sensitivity analysis are used to evaluate the system performance. The results revealed that the round-trip efficiency, exergetic round-trip efficiency and discharging electrical efficiency are 76.07%, 61.78% and 72.39%, respectively. Compared with an integrated SOFC-GT-ORC system without energy storage, the electrical efficiency of the new system increases by 17.07%. Overall, the combined system can achieve high efficiencies, which can provide important theoretical guidance for efficient energy utilization.

Automated summary

This paper proposes a new cogeneration system using a combination of various technologies to address the imbalance of grid supply and demand, optimizing system efficiency. Simulation results show that the combined system has excellent performance and improved electrical efficiency.