Design of an innovative enthalpy wheel based humidification system for polymer electrolyte fuel cell

摘要

Water management plays a crucial role to ensure high performance and to limit degradation of PEFC systems. Thus, a reliable and accurate humidification system is necessary. The most common types, especially membrane humidifiers, are characterized by large pressure drop, affecting compressor power consumption, and make use of special expensive materials. To overcome these problems, many current researches deal with modeling of the heat and mass transfer processes occurring in such humidifiers, in order to find the best compromise between performance and cost. Conversely, in this work a different solution to the humidification requirement is proposed. An innovative low cost and low pressure drop humidification system based on a properly designed enthalpy wheel is presented and discussed. System design and performance evaluation are reported in both nominal and off-design operating conditions. The analysis is carried out by coupling an enthalpy wheel model based on the heat and mass transfer balances with experimental data of a real PEFC-CHP system. Results suggest that the optimal enthalpy wheel is characterized by peculiar geometries and revolution speed. This component, integrated in a suitable humidification system, could represent a low cost and high reliability alternative to conventional technologies. Moreover, the proposed system has potentially a lower energy consumption than conventional ones, thanks to the lower pressure drop.