Dehumidifying Characteristics of Polymer Electrolyte Dehumidifying Cell and its Application to Air Conditioner

Abstract

Lots of the chlorofluorocarbon (CFC) has been released to atmosphere, resulting that the ozone layer in the stratosphere has been destroyed by the released CFC. Therefore, air conditioners without using CFC have been required to be developed. One of the candidates for such air conditioners is a combined conditioner of the dehumidifying cell by the proton exchange membrane (PEM) and the air cooler by water evaporation. But, we need to understand the operating principle of the dehumidifying cell because the performance of existing dehumidifying cells are not cleared. In this study, first we measured the transmissibility and the electro-osmotic coefficient nd of water vapor through the membrane electrode assembly, the water vapor diffusivity through the diffusion electrode, and the mass transfer coefficient between the flow in channel and the diffusion electrode, as important factors to determine the dehumidifying performance. These factors were adopted in our analysis of the dehumidifying cell performance, where the conservation equations of mass and energy with an equivalent electric circuit of the cell are solved simultaneously. Calculated results can describe well the experimental dehumidifying performance. By using this simulation code we predicted the coefficient of performance (COP) of our novel air conditioner. Calculated COP’s for test cell are as small as 0.10 or 0.21, but could be 4 when we can get the PEM with high nd of 5.