Conventional and advanced exergy analyses of a vehicular proton exchange membrane fuel cell power system

Abstract

Vehicles powered by proton exchange membrane fuel cell have received lots of attention due to various merits. A comprehensive proton exchange membrane fuel cell power system with parallel-arranged heat recovery strategy for reactants preheating is proposed and investigated. Thermodynamic model of the system is established and is validated rigorously. In order to minimize system total exergy destruction, an acceptable interval of stream separation ratio for the parallel-arranged heat exchangers in this system varies from 0.01-0.90. Conventional and advanced exergy analyses of the system are presented. Real improvement potential of the proposed system is quantified: 46.42% of the total exergy destruction is avoidable, and the improvement priority orders are given: PEMFC stack >WP>AC>R>CHE>AHE>HC. It is found that a strong interaction exists in the system since 84% of the total exergy destruction is exogenous. Interactions of each component with the remaining components are analyzed. 87.97% of the exergy destruction in the stack is exogenous, which indicates that the improvement of auxiliary components will be effective to improve the system. This paper could provide directions for further improvement on the efficiency of this system and deeper understandings of interactions between the components.