Efficiency improvement and Thermo-economic analysis of proton exchange membrane fuel cell system with energy recovery for both air and hydrogen

Abstract

Proton exchange membrane fuel cells (PEMFCs) supplies as one of the promising solutions for carbon neutrality in transportation. However, excessive energy consumption of the auxiliary equipment remains one of the major obstacles in realizing large-scale commercialization. Therefore, in this study, a novel PEMFC system with energy recovery for both air and hydrogen was developed to enhance the energy efficiency. A zero-dimensional thermodynamic model was established to forecast and estimate system's performance. Additionally, the economic analysis considering cost sensitivity was conducted to provide feasibility evidence. The effects of current density, cathode air pressure, and turbo-expander cost on the system's efficiency and economic revenue were investigated. The results showed that the energy recovery effect and economic revenue increase with an increase in current density when the operating temperature constant was kept constant and increase with an increase in cathode air pressure when the current density constant was kept constant. Compared to that of the conventional PEMFC system, the system's efficiency of the novel model increased by 6.27%, corresponding to a current density of 1.21 A/cm2 when the cathode air pressure remains constant at 0.31 MPa. The lower of the cost of the turbo-expanders, the higher of the net revenue. The PEMFC system with turbo-expanders can achieve more revenue at larger current density and cathode air pressure conditions.