Development and evaluation of an integrated polymer electrolyte membrane fuel cell test system using exergy analysis

Abstract

This study focuses on a high-power fuel cell test system. The test system integrates hydrogen circulation and recovery preheating, and it uses a condenser to collect the water produced by the stack to realize the integrated gas–heat–water utilization of the system. A complete thermodynamic model of the system is established, and the performance of the system is evaluated using exergy analysis. The avoidable and unavoidable exergy destruction distribution of each auxiliary element in the system as well as the net power, parasitic power, and energy and exergy efficiencies of the system are determined. The results show that the fuel cell stack, bubble humidifiers, exhaust gas discharge, and water-cooled heat exchanger are the locations with the largest exergy losses. Also the stack dominates the avoidable exergy destruction loss (95.7%). Improving the performance of the fuel cell stack is the key to the optimization of the PEMFC system. In addition, the system performance under different operating temperatures, pressures, and inlet gas relative humidity is analyzed. The results show that the net power, energy, and exergy efficiencies of the system reach maximum values of 97.8 kW, 48.1%, and 45.0%, respectively, when the system is operating at 1 A cm⁻² with a stack temperature, pressure, and inlet relative humidity of approximately 348.15 K, 3 bar, and 60%, respectively. To ensure a good state of the system performance, the operating pressure of the fuel cell test system should be kept at a high level, and the operating temperature and relative humidity of the inlet gas should be kept at low levels. The analysis of this system provides a new direction for the performance improvement of fuel cell test systems.