On Humidity Transport by Using Porous Media (Effect of Treatment and Property of Materials on Transport Performance)

摘要

The exhaust gas of fuel cell vehicles is environmentally clean water or water vapor. In addition, fuel cell vehicles are more efficient compared to other 'clean vehicles', such as the electric vehicle. Therefore, fuel cell vehicles are expected as a viable means of transportation in the 21st century. Fuel cell systems generally consist of a fuel and air supply unit, a humidifier, cooling device, and the fuel cell itself. The degree of ionic conduction in an electrolyte film in the fuel cell is affected by humidity; some humidity is necessary to maintain ionic conduction. Investigations into the influence of humidity on the performance of fuel cells, and methods for humidifying have been conducted [1-2]. From a space-saving point of view, it is desirable to recover and reuse the moisture of exhaust gas, and this can be achieved using the supply air. Based on previous studies of dehumidification and gas separation, one possible method for the recovery of the moisture of exhaust gas is to use a porous plate [3]. To date, there have been many studies on the heat and mass transfer in porous media [4-5], however; they have been mainly theoretical, with relatively few experimental studies having been performed. The objective of this paper is to evaluate the factors that influence moisture and heat transfer from moist air to dry air through porous media having very small pores. The initial investigation was focused on clarifying the factors that influence the movement of moisture between constant-temperature water vapor and dry air, through a porous media plate.