Performance analysis and exergoeconomic assessment of a proton exchange membrane compressor for electrochemical hydrogen storage

Abstract

Electrochemical hydrogen compression (EHC) is a promising alternative to conventional compressors for hydrogen storage at high pressure, because it has a simple structure, low cost of hydrogen delivery, and high efficiency. In this study, the performance of an EHC is evaluated using a three-dimensional numerical model and finite volume method. The results of numerical analysis for a single cell of EHC are extended to a full stack of EHC. In addition, exergy and exergoeconomic analyses are carried out based on the numerical data. The effects of operating temperature, pressure, and gas diffusion layer (GDL) thickness on the energy and exergy efficiencies and the exergy cost of hydrogen are examined. The motivation of this study is to examine the performance of the EHC at different working conditions and also to determine the exergy cost of hydrogen. The results reveal that the energy and exergy efficiency of EHC stack improve by almost 3.1% when operating temperature increases from 363 K to 393 K and the exergy cost of hydrogen decreases by 0.5% at current density of 5000 A m−2. It is concluded that energy and exergy efficiency of EHC stack decrease by 25% and 5.4% when the cathode pressure increases from 1 bar to 30 bar, respectively. Moreover, it is realized that the GDL thickness has a considerable effect on the EHC performance. The exergy cost of hydrogen decreases by 53% when the GDL thickness decreases from 0.5 mm to 0.2 mm at current density of 5000 A m−2.