Cycle analysis of gas turbine--fuel cell cycle hybrid micro generation system

Hybrid systems, which are based on a micro gas turbine ([micro]GT) and a solid oxide fuel cell (SOFC), are expected to achieve much higher efficiency than traditional [micro]GT's. In this paper, the effects of cycle design parameters on the performance and feasibility of a [micro]GT-SOFC hybrid system of 30 kW power output are investigated. It is confirmed that the hybrid system is much superior to a recuperated gas turbine in terms of its power generation efficiency and aptitude for small distributed generation. General design strategy is found that less direct fuel input to a combustor as well as higher recuperator effectiveness leads to higher generation efficiency, while higher steam-carbon ratio moderates requirements for the material strength. The best possible conceptual design of a 30-kW [micro]GT-SOFC hybrid system is shown to give power generation efficiency over 65% (lower heating value). [DOI: 10.1115/1.1787505]