A novel trigeneration system based on solid oxide fuel cell-gas turbine integrated with compressed air and thermal energy storage concepts: Energy, exergy, and life cycle approaches

Abstract

Energy storage technologies are considered as an available solution to improve the reliability of conventional energy systems as well as responding to the peak load. This paper offers a novel integrated system with remarkable potential to provide users’ electricity, heating, and cooling demand for small-scale distributed generation applications. The main objective of this research is improving thermodynamic efficiency as well as mitigating emissions of the conventional solid oxide fuel cell-gas turbine (SOFC-GT) hybrid system with the option of peak-shaving. A compressed air energy storage and thermal energy storage are employed to store the surplus power and recover the waste heat of the prime mover, respectively. The proposed system operates with a round-trip efficiency of 76.8 % and exergy efficiency of 46 % under the design condition: 8 h of off-peak period with 97.5 kW power demand and 8 h of peak period with 305.6 kW power demand; 113.4 kW cooling capacity; 37.4 m3 hot water production. Furthermore, the evaluation of environmental impacts indicates that GHG emissions are low at 0.27 kgCO2e/kWh. Also, the life cycle assessment shows that well-to-production GHG emissions of the proposed integrated system during a round-trip of operation are 1890 kgCO2e which is 6.6 % lower than the conventional SOFC-GT.