Experimental study on the mass transfer permeability of hollow fiber membranes for a humidifier in a proton exchange membrane fuel cell

Abstract

A membrane humidifier is a device used to increase proton conductivity in a fuel cell system, enhancing the performance and longevity of the fuel cell. In this study, a hollow fiber membrane is tested under various operating conditions to determine the membrane humidifier performance by estimating the amount of water vapor through the membrane. The results show that the mass transfer rate increases with increasing temperature, flow rate, and relative humidity while it decreases with pressure and membrane thickness. Particularly, temperature affects the mass transfer rate the most. When the temperature is increased from 50°C to 80°C, the performance improves by approximately 4.5 times. In contrast, the flow rate affects it the least; an approximately 2.5 times increase in the flow rate results in a 16% improvement in performance. Furthermore, the counterflow consistently exhibits greater efficiency than the co-flow. Moreover, the water vapor permeability through the membrane is assessed. The membrane permeability increases with decreasing membrane thickness and pressure and increasing temperature and inlet relative humidity. The findings indicate that 1°C rise in temperature leads to an increase of approximately 5% in permeability and approximately 19% increase in pressure, resulting in an approximately 15% decrease in permeability.