ENCAPSULATION OF PHASE CHANGE MATERIAL-MAGNETITE (Fe3O4) COMPOSITE IN NOVEL COPPER TUBE CONFIGURATION (VERTICAL AND HORIZONTAL) FOR THERMAL STORAGE APPLICATION

This study aimed to investigate phase change materials (PCMs), particularly focusing on paraffin-magnetite (Fe<sub>3</sub>O<sub>4</sub>) composites as a thermal energy storage medium. The paraffin-magnetite composite was homogenized using sonication and stirred in an ultrasonic bath for 30 min at 80°C with a frequency of 37 kHz. This process was chosen to ensure uniform dispersion and prevent nanoparticle precipitation. X-ray diffraction characterization results showed that the magnetite and paraffin phases were crystalline and monoclinic semi-crystalline, respectively. The addition of magnetite particles in PCMs increased the magnetization saturation to 34.96 emu/g (45 vol.% of magnetite particles). Differential scanning calorimetry revealed that the addition of 15 vol.% magnetite nanoparticles to the composite led to a minimal decrease in latent heat, with a latent heat efficiency of 67.50%. Thermogravimetric analysis results showed that the PCM is stable due to thermal degradation that occurs at 154.3. Thermal analysis of differential scanning calorimetry (DSC) and thermal conductivity suggested that a suitable PCMs sample to be used as a thermal storage medium is PCM-15. The sample has latent heat and thermal conductivity values of 105.66 kJ/kg and 0.35 W/m K, respectively. A novel copper tube configuration for PCMs encapsulation in concrete can improve thermal storage capability.