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 Al2O3–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.

► The alumina nanofluid with chitosan was produced by two-step synthesis method. ► The k and phase-change properties of alumina nanofluid were examined. ► Adding Al2O3 nanoparticles into water indeed improves the k. ► Adding the chitosan decreases the thermal conductivity of alumina nanofluid. ► The Tcp and hc are 53.4% and 97.8% of those in DW with the optimal combination.