Conventional and advanced exergy analysis of a novel SOFC-MGT hybrid power system coupled with external solar methane hydrogen production process

Abstract

The world is facing energy shortages. One of the ways to reduce energy usage in energy systems is to introduce renewable energy to complement fossil fuels, and the other way is to reduce exergy destruction to improve efficiency. A novel solid oxide fuel cell – micro gas turbine (SOFC-MGT) hybrid power system coupled with solar thermochemical hydrogen production process is proposed to realize multi-energy complementarity and efficient power generation. Advanced exergy analysis method can reveal the underlying causes of exergy destruction and provide guidance for the optimization potential in energy systems. The proposed system is comprehensively studied using both the conventional and advanced exergy analysis methods. The results indicate that the avoidable exergy destruction accounts for 22.61 % of the total destruction. The system's endogenous exergy destructions are mainly due to the strong irreversibility of the components themselves. Both heat exchanger 3 (HE3) and air compressor (AC) are most affected by other components, while improving the performance of both SOFC and afterburner have the most significant improvement in system efficiency. The endogenous unavoidable exergy destruction of SOFC, MGT, AC and reactor are significant, indicating they should be optimized first, which is distinct from the conventional exergy analysis's findings.