Model and experimental validation of a controllable membrane-type humidifier for fuel cell applications

For temperature and humidity control of fuel cell reactants, a gas humidification apparatus was designed and constructed. We then developed a low-order, control-oriented model of the humidification system thermal dynamics based on first principles. A simple and reproducible methodology is then employed for parameterizing the humidification system model using experimental data. Finally, the system model is experimentally validated under a wide range of operating conditions. It is shown that a physics based estimation of the air- vapor mixture relative humidity leaving the humidifier system (supplied to the fuel cell) is possible using temperature and pressure measurements. This estimation eliminates the need for a bulky and expensive humidity sensor and enables the future application of temperature feedback control for thermal and humidity management of the fuel cell reactants.