Summary
A gas‐to‐gas membrane humidifier recovers heat and water from the wet hot exhaust gas of a proton electrolyte membrane fuel cell and keeps the inlet feed air of the cell warm and humid. This type of humidifier does not need external water sources, and it is compact and efficient with practical applications in portable devices and automobiles. In the present study, four potential designs of gas‐to‐gas planar membrane humidifiers were introduced, and their characteristic behavior was examined. The simulation results showed that the geometrical design of the humidifier channels could notably influence the efficiency of the device. It was found that a three‐inlet serpentine humidifier could provide the largest water recovery ratio and the heat transfer rate among the proposed designs, with a slight increase in the pressure drop. Hence, the three‐inlet design was selected as the optimal geometrical design of the humidifier. Then, the impacts of design parameters on the characteristic behavior of the three‐channel model were explored. The results show an increase in the outlet (wet side) temperature and relative humidity enhances the water recovery and efficiency of the humidifier. The outcomes of the present research are of practical interest for the design of novel commercial humidifiers.