Incorporating available micro gas turbines and fuel cell: Matching considerations and performance evaluation

Abstract

The present paper aims to study the performance of the hybrid systems based on the fuel cell stack developed by Siemens-Westinghouse coupled with four different commercially available recuperated micro-turbines. The different systems considered were studied through the development of appropriate simulation models validated with available data. Full and part load performance of those systems are presented and discussed. For the part load operation two control strategies were adopted by maintaining either the SOFC stack temperature or the turbine exit temperature constant. The part load results have shown large variations in SOFC stack and turbine exit temperatures. Those data must be taken into account in order to avoid system malfunctions and to ensure long lifetime. The smaller (among the four considered) the micro-turbine coupled with the Siemens-Westinghouse SOFC generator, the more efficient the corresponding hybrid system. It was also revealed that when the power requirements are low, the designer may choose a larger micro-turbine than the required, as the system operates efficiently also at higher loads than the base and could satisfy peak energy demands.