Parametric Study on the Effect of Addition of Copper, Iron, Titanium & Zinc Oxides on the Heat of Fusion and Thermal Conductivity of Palmitic Acid-Stearic Acid Mixture
Author : Villanueva, Pamela B.
Major Adviser : Bautista, Ramer P.
Committee Members : Bambase Jr., Manolito E.; Migo-Sumagang, Maria Victoria P.
Year : 2017
Month : December
Type : Thesis
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This study involved the preparation of phase change material with metal oxide additives prepared using the direct-synthesis method by mixing 60:40% palmitic acid-stearic acid (PA-SA) mixture with cupric oxide (CuO), ferric oxide (Fe₂O₃), titanium dioxide (TiO₂), and zinc oxide (ZnO). CuO, Fe₂O₃, TiO₂, and ZnO were dispersed into mass concentrations of 2.0% and 8.0%, and the PA-SA/metal oxide composites were subjected to 56°C and 60°C starting temperatures. The effects of varying metal oxides, concentrations, and starting temperatures on the heat of fusion and thermal conductivity of palmitic acid-stearic acid mixture were evaluated using T-history method. It was found that only the metal oxide concentration has a significant effect on both heat of fusion and thermal conductivity. However, the effect was found to be negative. The parameter combination with highest thermal conductivity and heat of fusion was PA-SA with 2.0% CuO at 56°C, at 0.345 W/m-K and 170 580 J/kg; the lowest was with 8.0% TiO₂ at 56°C, at 0.151 W/m-K and 24 834 J/kg. The results were highly attributed to the size of the particles used and other consequent result of the particle size such as particle agglomeration. Increased particle size of metal oxide caused poor suspension and combination performance, which decreased the surface-to-volume ratio of particles via agglomeration and settling, thereby decreasing the heat transfer area. It was recommended that further studies explore the use of metal oxide additives in the nano-scale.
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