Thermal conductivity and phase-change properties of aqueous alumina nanofluid

This study uses thermal conductivity and differential scanning calorimeter experiments to explore the thermal conductivity and phase-change properties of alumina (Al₂O₃)-water nanofluid produced using a two-step synthesis method. Deionized water (DW) is used as a control group, and the Al₂O₃-water nanofluid uses chitosan as a dispersant. Nanoparticle morphology and materials were confirmed using transmission electron microscopy (TEM) and X-ray diffraction (XRD), respectively. The results show that adding Al₂O₃ nanoparticles to DW improves DW thermal conductivity, but adding chitosan reduces the thermal conductivity of Al ₂O₃-water nanofluid. Adding the nanoparticles to DW affects the phase-change peak temperature and phase change heat. The optimal combination is 0.1 wt.% chitosan and 0.5 wt.% Al₂O₃ nanoparticles; the charging phase-change peak temperature and latent heat are 53.4% and 97.8% of those in DW, respectively.