Efficiency improvement of a PEMFC system by applying a turbocharger

A novel proton exchange membrane fuel cell (PEMFC) system that employs a turbocharger to reuse waste energy is proposed. This study is focused on optimal placement of the PEMFC turbocharger, using either the hydrogen feed stream or the stack outlet as the motive force. A one-dimensional isothermal two-phase model for a PEMFC and an isenthalpic model for the turbocharger are developed for system analysis. To find a better energy source, the system efficiency, power generation, and interaction with the balance of plant (BOP) are considered. To evaluate the feasibility of both systems, an exergy analysis is also performed. The results show that the system efficiency is higher when the turbocharger is installed after the hydrogen tank and that the amount of power generation is also larger when the turbocharger is located in the stack outlet. For the exergy analysis, the case for the turbocharger installed after the hydrogen tank shows higher performance. Therefore, it is preferable to install the turbocharger after the hydrogen tank.