Investigation into thermal conductivity of palm kernel fibre nanofluids with mixture of ethylene glycol/water as base fluid

Nanofluids have been found to possess enhanced thermo-physical properties such as thermal conductivity, heat capacity, as well as convective heat transfer coefficients compared to conventional heat transfer fluids like water, ethylene glycol and oil. The high level of hazards involved in the use of metallic nanoparticle in nanofluid research is a source of worry since there are reported literatures showing damaging effects of metal oxides to human cells. In this paper, a readily available bio–based Palm kernel nano-fibres (nanoparticle) were produced by first washing the raw fibre material with caustic soda (NaOH) to remove the residue palm oil and sundried for 10 days. The dried palm kernel fibre was ball milled for 24 hours and the resulting nanoscale fibre particles were dispersed into mixtures of water and ethylene glycol (50:50) as base fluid to form palm kernel fibre nanofluid with volume concentrations of 0.1, 0.2, 0.3, 0.4 and 0.5 %. Images of Scanning and transmission electron microscopy revealed a nearly spherical particle shape and a particle size of 100 nm. Thermal conductivity experiments were conducted in temperature range of 10 to 60 °C. Results showed that thermal conductivity of the nanofluid increased with increase in volume concentrations and temperature. An enhancement in thermal conductivity of 16.1 % was recorded for volume concentration of 0.5 %. The Maxwell, Hamilton and Crosser and Wasp models over predicted the thermal conductivity of palm kernel fibre nanofluid.Papers presented to the 12th International Conference on Heat Transfer, Fluid Mechanics and Thermodynamics, Costa de Sol, Spain on 11-13 July 2016

Activated carbon from orange peels as supercapacitor electrode and catalyst support for oxygen reduction reaction in proton exchange membrane fuel cell

Activated carbon is synthesized using orange peel as precursor through chemical activation using H3PO4 and its ability as electrocatalyst support for ORR reaction is examined. The prepared material was subjected to various structural, compositional, morphological and electrochemical studies. For ORR activity, the platinum loaded on activated carbon (Pt/OP-AC) was investigated by cyclic voltammograms (CVs) recorded in N2 and O2 saturated 0.1 M aqueous HClO4. For supercapacitor performance, three electrode systems was tested in aqueous H2SO4 for feasibility determination and showed electrochemical double layer capacitance (EDLC) behaviour which is expected for activated carbon like materials. Electrochemical surface area (ECSA) of the activated carbon from orange peel is measured using CV. The physical properties of the prepared carbon are studied using SEM (scanning electron microscope), XRD (X-ray diffraction), Fourier transform infrared (FT-IR) spectroscopy and Raman spectroscopy. The AC derived from orange peels delivered a high specific capacitance of 275 F g−1 at 10 mV s-1 scan rate. Hence, this study suggested that orange peels may be considered not only as a potential alternative source for synthesizing carbon supported catalyst for fuel cell application but also highlight the production of low-cost carbon for further applications like supercapacitors