Erdgasbetriebene Brennstoffzellen-Blockheizkraftwerke im Einfamilienhaus - Simulationsbasierte Entwicklung von Regelstrategien

Micro CHP allow the combined production of electrical and thermal energy in buildings. In this context fuel cells, stirling engines, gas motors and micro gas turbines are considered as technologies with a high potential for energy saving and reduction of pollutants. This contribution presents investigations for grid connected residential fuel cell power plants based on the Polymer Electrolyte Membrane technology PEM and driven with natural gas. The effective ecological and economical benefit of such fuel cell systems in comparison to a conventional energy supply system is determined by the chosen control strategy. Therefore simulation based investigations offer a time efficient development, evaluation and optimization of control strategies, on the other hand detailed descriptions of the system correlations are needed. Due to seasonal effects, investigations of stationary energy supply systems require simulation runs with a time horizon of one year. For this purpose an efficient modeling technique is needed, which is given by the simulation environment ColSim [2], developed at Fraunhofer ISE. The developed fuel cell system library of [1] includes models of a reformer, a PEM fuel cell stack, a power inverter, heat exchangers and peripheral devices. As an example the fuel cell model is compared with measurement data of a stack with an electric power of 1.7 kW. Furthermore a control concept is presented, including the supply guaranty of the building and control circuits for energy and material flow. On this bases new control strategies are developed, which are reducing the primary energy demand and/or the running costs of the energy supply system. The comparison with conventional heat or electric load following operating modes shows especially the influence of the optimized control strategies for the fuel cell system with an electric power of 2 kW.