It is expected that residential units may replace traditional heat and power production systems with cogeneration ones. Among the different cogeneration systems, fuel cell based systems are a suitable choice due to their high efficiency, high power density, low emission and low noise. In this paper, a cogeneration system based on solid oxide fuel cells is examined. The system, including the fuel and air compressors, desulphurizer, fuel reformer, fuel cell stack, etc., has been modeled from an energy and exergy viewpoint. An optimization algorithm with three different objective functions, including power production, heat production and the minimum exergy destruction, is applied. Then, the base system is utilized along with photovoltaic and electrolizer as a combined system. The results showed that an OP (Ordinary + Photovoltaic) is the best configuration with emissions reduction in the heat production approach, while OP and OFPE (Ordinary + Fuel cell + Photovoltaic + Electrolizer) configurations are the best configurations with excess energy in power production approach. The conditions of the numerical calculations were selected in accordance with a sample building located in eastern Iran.
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