Thermodynamic analysis of a low-powered SOFC CHP system

Solid oxide fuel cell systems are a novel concept for combined heat and power (CHP) generation with high total efficiency and low emissions of harmful gases. In order to successfully review the operational processes of such a system, thermodynamic analyses are normally employed. The aim of this paper is to propose a SOFC system topology based on a preselected SOFC and determine the heat transfer rates as well as the overall efficiency of the plant by means of a mathematical model. The results indicate a total system efficiency of 0.628 without evaluating the energy available from the combustion of the remaining anode off-gas (AOG). Analysis of the effects of the steam to carbon (S/C) ratio on the system’s behavior and outcomes is also performed. The analysis reveals that increasing the S/C ratio of the system leads to a decrease in the electrical efficiency, while the total efficiency of the system experiences a slight increase.