An experimental study for optimizing the energy efficiency of a proton exchange membrane fuel cell with an open-cathode

To develop an operating strategy for maximizing the energy efficiency of open-cathode proton exchange membrane fuel cells (OCPEMFCs), the present study investigates the effect of the fan speed on the stack performance and energy efficiency using a commercially available OCPEMFC system. The temperature, voltage, and current of the stack are monitored, and the energy efficiency is calculated at various stack power levels. The results of the system with a lab-developed controller are compared with the commercial system with a built-in controller. It is found that the fan speed should be minimum to reduce the auxiliary power consumption and that the stack should be efficiently heated to enhance the electrochemical reaction. In addition, it is noticed that the stack performance dramatically drops when the stack temperature is above 75 degrees C, due to the membrane dehydration. Overall, the results show that the stack temperature is an important indicator for controlling the fan speed for optimization of energy efficiency, and for stack powers of 50, 60, 70, and 80 W, the peak values of energy efficiencies are 38.0%, 38.3%, 38.5%, and 38.3% at the duty cycles of 0.2, 0.2, 0.25, and 0.3, respectively, which are 28-38% higher than the commercially available OCPEMFC system. (C) 2021 Hydrogen Energy Publications LLC. Published by Elsevier Ltd. All rights reserved.