Layout design and performance evaluation of hydrogen-fueled solid oxide fuel cell power generation system

Abstract

This study aims to design different layouts of hydrogen-fueled solid oxide fuel cell (SOFC) power generation systems and evaluate their performance differences from a thermodynamic perspective. According to the location of the afterburner and the heat transfer sequence of the gases, the system is divided into three groups of configurations, which are subdivided into 11 layouts. A comparative study is conducted to select the optimal system layout. To simulate the SOFC power generation system, a mathematical model of the SOFC stack and an iterative solution algorithm are developed to better fit the actual operation of the entire system. A single standard evaluation is conducted on the different system layouts from the perspectives of electric power output, total energy efficiency, and temperature uniformity between the SOFC anode and cathode inlet gases. Significant differences are found between these system layouts under two operating modes, fixed gas utilization and fixed gas flow, and each layout has its own advantages and disadvantages under various standards. To further evaluate the system performance, various indicators are normalised, and a comprehensive multi-indicator evaluation method is established. The results show that under high-current conditions at fixed gas utilization, the layout of direct combustion of the SOFC off-gases followed by the preheating of the anode and then the cathode inlet gases exhibit the optimal comprehensive performance. In the fixed gas flow operating mode, where each system reaches the peak power, the layout of the cathode and anode off-gases preheating their respective inlet gases before combustion exhibits the best overall performance.