Parametric study of a membrane energy exchanger based on energy, entropy, and exergy analysis for proton exchange membrane fuel cell application

Document Type : Research Paper

Authors

Department of Mechanical Engineering, Shahid Rajaee Teacher Training University, Tehran, Iran

Abstract

The present work uses the thermodynamic technique to model a membrane energy exchanger (MEE) used for proton exchange membrane fuel cell (PEMFC) application. Governing equations, including a system of three nonlinear coupled equations and several dependent equations, are solved. The present numerical results were compared and validated by an experimental study, indicating a suitable match with a reasonable error. A comprehensive parametric study and sensitivity analysis are conducted in this work based on four efficiency evaluation criteria, including effectiveness, water recovery ratio (WRR), entropy generation, and exergy efficiency. The exergy efficiency, comprises the thermodynamic exergy, chemical exergy, and mechanical exergy. The analyzed parameters include temperature at the wet and dry channel entry, pressure at the wet and dry channel entry, and relative humidity (RH) at the wet and dry channel entry. A to D ratings are assigned to these parameters. When three criteria show positive results by enhancing each parameter, the A rating is assigned to that parameter, representing the optimal efficiency. For example, enhancing the dry channel entry temperature from 306 to 318 K leads to a 30.5% enhancement in WRR, a decrease in DPAT, an 11% improvement in exergy efficiency, and a reduction in entropy generation. Since all four criteria are desirable, enhancing the dry channel entry temperature is rated A and is highly recommended.

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