Energy and Exergy Analysis and Optimization of a Cogeneration System Based on Solid Oxide Fuel Cell for Residential Applications

It is expected that the ordinary heat and power production systems in residential section are substituted by cogeneration systems in near futur due to higher overall efficiency. Between different cogeneration systems, fuel cell based systems are a suitable choice due to high efficiency, high power density, low emission and noise. In this paper a cogeneration system based on solid oxide fuel cell were examined on energy and exergy basis at first, then using optimization algorithms and a choice of three goal function electric power generation, heat production and minimizing waste Exergy, the operation of the system were optimized. The results included the calculating the working parameters of system with three goal functions and show that the most change of flow exergy is in fuel channel of fuel cell stack and most irreversibilities are due to recovery (38%), catalyst burner (37%) and fuel cell (16%). Among the internal components, air compressor is the biggest power consumer, with (14%) of produced power. Optimization results also show that the minimum exergy destruction is in the electricity production approach, thus using a CHP system is more preferable rather than the single system for producing power or heat.