Comprehensive analysis of polysulfone membrane humidifier in hydrogen fuel cell vehicles: Experimental and theoretical approaches

This study performed a comprehensive experimental and theoretical analysis of a shell-and-tube type gas-to-gas humidifier module in a 95 kW class hydrogen fuel cell vehicle. The humidifier module features a polysulfone hollow fiber membrane characterized by its hydrophilic and non-fluorinated properties. Experimental investigations were conducted to understand the impacts of the inlet temperature, relative humidity, and temperature differences on heat and mass transfer rates, and the approach dew point temperature (ADT). The results showed that the ADT increased from 12.42 to 15.89 degrees C with a temperature difference of 15 degrees C between the shell and tube inlet sides, as the flow rate increased from 1000 to 3400 L/min, with the highest performance observed at lower flow rates. Simultaneously, a detailed theoretical model was developed, incorporating a new dual-mode sorption approach that accounts for temperature dependency within the solution-diffusion mechanism across the membrane. The developed model was in good agreement with the experimental results, with a relative error of less than 5 %. Furthermore, the dynamic model accurately predicts the response of the humidifier module to step changes in feed flow rates, simulating load variations in the fuel cell vehicle. This provides valuable insights into the humidifier's adaptability and responsiveness, which are crucial for optimizing its performance under various operating conditions.