Stack and system level modeling
The modeling and simulation activities on the stack and system level are pursued in the Electrochemical Systems group. They follow several goals: (1) Development of computationally efficient fuel cell stack models for real-time simulations; (2) Development of models for balance-of-plant components (heat exchangers, humidifiers, blowers, fuel processing units etc.) and compilation of component libraries; (3) Analysis of the interaction between the components in order to assess optimum system design and develop control strategies.
System-level studies are performed in a number of application areas, all of which are characterized by a high complexity and are therefore particularly demanding in simulation and control requirements. Hybrid power plants combining SOFCs with a gas turbine promise high electrical efficiencies (Fig. 1). Because the operating time scales of SOFCs and gas turbines are very different, models are needed to understand the dynamical interaction between these components. Auxiliary power units for airplanes based on either PEFC or SOFC are studied (Fig. 2). A particular feature here are the multiple functionalities of the fuel cell system, including emergency power, water supply, and nitrogen for tank inertization. For portable systems for small-scale power generation (Fig. 3), the interaction between a fuel cell and a storage battery is analysed for reliable operation during both, short transient load changes and long-term power supply.
The stack and system modeling activities are being conducted within the Electrochemical Systems group