Influence of Al₂O3-Water Nanofluid Coolant on Thermal Performance of Hydrogen PEM Fuel Cell Stacks

Abstract

Hydrogen polymer electrolyte membrane (PEM) fuel cells are renewable and future sustainable power generation systems that operate with zero emissions. Thermal management in fuel cells is still an important issue that must be addressed to extend their life and the possibility of their widespread commercial use. In this research, a simulation model has been developed and validated using MATLAB to investigate the cooling process and its effect on the PEM fuel cells using nanofluids as coolant. Al2O3 nanoparticles have been used due to their thermal characteristics, chemical stability, and cost-effectiveness compared to other nanoparticles. The Al2O3-H2O nanofluid was used with 0.1 to 0.4 vol % concentration. The results showed that employing nanofluids as coolant increases the temperature difference between the coolant outlet and inlet. Nanoparticles concentration increases, the temperature difference increases. Similarly, the nanoparticles concentration increases, both pressure drop across the cooling channel and pumping power increases. Therefore, employing nanofluids in PEM fuel cells seems an impractical choice for the lower temperature difference criterion at a certain pumping power.

Liquid Cooling Flow Field Design and Thermal Analysis of Proton Exchange Membrane Fuel Cells for Space Applications

“…Typically, the actual fuel cell output current is approximately equal to the theoretical fuel cell output current. Assuming that the two quantities are equal, it is expressed in Equation ( 18) [42].…”

Al2O3–H2O nanofluids for cooling PEM fuel cells: A critical assessment

“…where T � is the volumetric mean temperature of the cooling plate. The Reynolds number is calculated by [12]:…”

“…where 𝜌𝜌 f is the density of either the base fluid or the nanofluid [kg/m 3 ], 𝑢𝑢 is the uniform inlet velocity of the cooling fluid [m/s], 𝐷𝐷 ℎ is the hydraulic diameter of the cooling channel [m], which is calculated as follows [12]:…”

“…where W is the cross-section's side length of the cooling channel, [m]. Finally, the pumping power can be expressed by the following equation [12]:…”

“…For high power generation PEM fuel cell stacks, thermal management is crucial [12,13] since about 58% of the fuel energy is converted to heat [14]. Liquid cooling is preferable to air cooling in high power generation PEM fuel cells due to the high cooling capacity of liquids compared to air.…”