Irnie Azlin Zakaria

The increased demand for efficient renewable solar energy has presented a substantial thermal management challenge for solar photovoltaic thermal (PVT) panels. Since temperature variations majorly affect solar panel efficiency, alternative choices for advanced cooling systems are desperately needed to guarantee better performance. Nanofluids are nanosized particles dispersed in a base fluid that has superior thermal conductivity properties to increase heat transfer performance. This research investigates the effect of an alumina-silica (Al₂O₃:SiO₂) hybrid nanofluid with a volume concentration of 0.5% in water as an alternative coolant in a serpentine channel. The study investigated three various mixing ratios, ranging from 10:90, 50:50, to 30:70 (Al₂O₃:SiO₂) in water with velocity inlet variations (0.0272 – 0.1360 m/s) upon application of 1000 W/m2 heat flux, to mimic the actual implementation of solar PVT. The impact of these hybrid nanofluids on heat transfer performance and pressure drop effect was investigated using computational fluid dynamics (CFD) simulations with Ansys Fluent software. The solar PVT panel temperature was reduced with the adoption of hybrid nanofluids by 0.2% to 0.3% as compared to the base fluid. The heat transfer increment for the 10:90 ratio is 10.2% and 16.9% as the flow rate increases. However, the pressure drop increased in the range of 9.36 Pa to 88.43 Pa and 11.37 Pa to 101.57 Pa for 10:90 and 30:70 respectively as compared to the base fluid. Therefore, hybrid nanofluids feasibility as a cooling fluid for solar PV panel thermal management need to be further reviewed.

Continuous need for the optimum conversion efficiency of polymer electrolyte membrane fuel cell (PEMFC) operation has triggered varieties of advancements, namely in the thermal management engineering scope. Excellent heat dissipation is correlated with higher performance of a fuel cell, thus increasing its conversion efficiency. This study reveals the potential advancement in thermal engineering of a fuel cell cooling system with respect to nanofluid technology. Nanofluids are seen as a potential evolution of nanotechnology hybridization with the fuel cell serving as a cooling medium. The available literature on the thermophysical properties of potential nanofluids, especially on the electrical conductivity property, has been discussed. The lack of electrical conductivity data for various nanofluids in open literature was another challenge in the application of nanofluids in fuel cells. Unlike in any other thermal management system, a nanofluid in a fuel cell is dealt with using a thermoelectrically active environment. The main challenge in nanofluid adoption in fuel cells was the formulation of a suitable nanofluid coolant with heat transfer enhancement, as compared to its base fluid, but still complying with the strict limits of electrical conductivity as low as 2 mS/cm and several other restrictions discussed by the researchers. It is concluded that a nanofluid in PEMFC is advantageous in terms of both heat transfer and simplification of the cooling system through radiator size reduction and potential elimination of the deionizer as compared to the current PEMFC cooling system. However, there are challenges that need to be well addressed, especially in the electrical conductivity requirement