In this paper, exergy analysis of a solid oxide fuel cell (SOFC) based cogeneration system for buildings is conducted to investigate the exergetic performance and determine the true locations and magnitudes of the exergy destructions/ losses within the system. First, the thermodynamic properties and chemical gas composition of the inlet and exit of a direct internal reforming, high temperature SOFC are determined using the given input data. Second, an energy analysis is done for the other components of the system to find all the thermodynamic data related to the plant. Third, the system is divided into several control volumes and an exergy analysis is applied to each of them to calculate the exergy destruction rates. The results of this study show that the plant has a fuel utilization efficiency of 68%, whereas its exergetic efficiency is 62%. The component which destructs the most exergy is the SOFC including the combustor which is mainly due to the combustion process and it accounts for the 12.5% of the exergy of the fuel and 40.5% of the total exergy destruction of the system.

Units: SI