GT2003-38774 INTER-LABORATORY DYNAMIC MODELING OF A CARBONATE FUEL CELL FOR HYBRID APPLICATION Internal resistance of the fuel cell

ABSTRACT A detailed comparison of dynamic models developed for carbonate fuel cells used in hybrid fuel cell gas turbine systems is presented. The two models are nearly similar in that both treat the bulk behavior of the system (e.g., through lumped or one-dimensional solutions of the fundamental equations. However, both models are implemented independently by different research groups using disparate simulation software programs. As a test case for the comparison, a generic molten carbonate hybrid fuel cell gas turbine system is identified. Such comparison-work benefits all parties by ensuring sub-mo del reliability prior to integration into a complete hybrid system model. Detailed results for the carbonate fuel cell models are presented. For a generic planar design, voltage and current behavior are shown following step changes in load resistance and fuel flow. The time scales for thermal dynamic response are much greater than those required for the initial electrochemical dynamic response as is expected. These results provide understanding of some of the operational characteristics of fuel cells and indicate the complexity of the dynamic response of fuel cell hybrid components. The results from the two models are not identical, but compare sufficiently well to provide confidence in each of the model's reliability, enabling them to be integrated for hybrid system simulation. Results from the integrated simulations will provide guidance on future hybrid technology development needs. NOMENCLATUR