Performance enhancement of high-power proton exchange membrane fuel cell system using wet compression under variable fogging strategies

Intake air wet compression in the hydrogen fuel cell systems effectively decreases the compression work and controls the air temperature as well as saturation, thus reducing the need for external cooling and humidification to improve the system performance. To further enhance the performances of the high-power proton exchange membrane fuel cell (PEMFC) system, the impacts of intake air fogging strategies of wet compression on the PEMFC system are investigated. Results indicated that the intake air pressure ratio, power per unit increases of pressure ratio, outlet temperature, and relative humidity can be significantly improved by employing a high fogging ratio and small water droplet diameter. Benefiting from the wet compression and proper fogging strategy, the air temperature at the compressor outlet can be much lower and consequently reduce the heat exchanger loads, seeing the compactness of the heat exchanger enhanced by up to 13.84%. The results also indicated that wet compression with the appropriate fogging method can improve the relative humidity of the compressed air by more than 32 %, which contributes to the compactness of the humidifier as well. The systematic energy analysis finally showed that the overall system output performance can be up to 4.51 %.