Model-Based Performance Optimization of Thermal Management System of Proton Exchange Membrane Fuel Cell

Abstract

As a promising new power source, the proton exchange membrane fuel cell (PEMFC) has attracted extensive attention. The PEMFC engine produces a large amount of waste heat during operation. The excessive temperature will reduce the efficiency and lifespan of PEMFC engine and even cause irreversible damage if not taken away in time. The thermal management system of the PEMFC plays a critical role in efficiency optimization, longevity and operational safety. To solve the problem of high heat production in the operation of the PEMFC, two approaches are proposed to improve the heat dissipation performance of the radiators in thermal management systems. Three kinds of nanofluids with excellent electrical and thermal conductivity–Al2O3, SiO2 and ZnO– are employed as the cooling medium. The radiator parameters are optimized to improve the heat transfer capability. A typical 1D thermal management system and an isotropic 3D porous medium model replacing the wavy fin are constructed to reveal the effects of the nanofluid and the parameters of the radiator performance and the thermal management system. The results show that all three kinds of nanofluids can effectively improve the heat transfer capacity of the coolant, among which the comprehensive performance of the Al2O3 nanofluid is best. When the mass flow rate is 0.04 kg/s and the concentration is 0.5 vol%, the amount of heat transfer of the Al2O3 nanofluid increases by 12.7% when compared with pure water. Under the same conditions, it can reduce the frontal area of the radiator by 12%. For the radiator, appropriate reduction of the fin pitch and wavy length and increase of wave amplitude can effectively improve the spread of heat. The use of fin parameters with higher heat dissipation power results in lower coolant temperatures at the inlet and outlet of the stack. The performance of the radiator is predicted by the two model-based approaches described above which provide a reliable theoretical basis for the optimization of the thermal management system and the matching of the components.