Heat transfer of advanced coolant dispersed with hybrid oxides nanoparticles in PEMFC cooling plates / Saifuddin Khalid @ Chik

Thermal management analysis has always been a major concern in the energy-based sector.
Thermal management in Proton Exchange Membrane Fuel Cell (PEMFC), as one of the
leading green energy converter, is extremely important to ensure efficient heat extraction
from the system. The low operating temperature of PEMFC has been known to reduce the
rate of heat transfer which contribute to large volume space consumption for the cooling
mechanism. The low electrical conductivity requirement of the system also limited the
implementation of the well-established nanofluids as a coolant in PEMFC. This research
aims to study the effect of hybrid nanofluids Al2O3-SiO2 with 0.5% volume concentration
dispersed in base fluid water to heat transfer enhancement in PEMFC. Nine different ratios
of hybrid Al2O3-SiO2 nanofluids were investigated, starting from 10:90 (Al2O3:SiO2) to
90:10. Three thermophysical characteristics affecting heat transfer of fluids were analyzed
namely thermal conductivity, electrical conductivity and dynamic viscosity of each sample.
Correlation between properties was investigated using property enhancement ratio (PER)
of thermo-electrical and thermo-hydraulic of each sample. Investigations made on two
different cooling plates which are Serpentine-type and Distributor-type to obtain Nusselt
number and pumping power requirement through the adoption of hybrid nanofluids in
PEMFC. At the end of the experiment, the most feasible nanofluids ratio and cooling plate
type for PEMFC application was selected. The Al2O3-SiO2 hybrid nanofluids with ratio R1
(10:90) is shown as the most prominent ratio among all samples of Al2O3-SiO2 hybrid
nanofluids. Ratio R1 (10:90) exhibits the highest convective heat transfer coefficient and
Nusselt number but show higher pumping power requirement as compared to the other
ratios. Serpentine-type cooling plate shows the most feasible cooling plate with the highest
convective heat transfer and Nusselt number at all ratios. It also shows a lower value in
pumping power as compared to Distributor-type plate.