ENCAPSULATION OF PARAFFIN-METAL OXIDE COMPOSITES IN A NOVEL DESIGN OF FINNED COPPER TUBES (SQUARE CONFIGURATION) FOR THERMAL STORAGE CONCRETE APPLICATION

This research evaluates the effect of adding metal oxide nanoparticles on the performance of encapsulated phase change material (PCM) composite in concrete as a thermal storage. Here we report an experimental method involving the preparation of PCM-based composites, where paraffin acts as the matrix and various metal oxides as the filler. The metal oxides used in the current investigation are Al<sub>2</sub>O<sub>3</sub>, MgO, and TiO<sub>2</sub>. The volume compositions of metal oxide in PCM composites are varied as follows 0, 10, and 20 vol.%. Then, the PCM composites were encapsulated in a novel design of four-fin copper tubes arrangement and installed in concrete. The results of the research show an increase in the thermal conductivity of PCM composite as the composition of metal oxide nanoparticles is increased. The thermal conductivity increases from 0.261 W/m K (100% paraffin) to 0.473, 0.466, and 0.406 W/m K (PCM with 20 vol.% of Al<sub>2</sub>O<sub>3</sub>, MgO, and TiO<sub>2</sub>), respectively. The decrease in latent heat of PCM composite occurred by adding the metal oxides. The value reductions are from 156.53 J/g (100% paraffin) to 84.28, 62.58, and 66.69 J/g (PCM with 20 vol.% of Al<sub>2</sub>O<sub>3</sub>, MgO, and TiO<sub>2</sub>), respectively. The melting temperature in the samples suggested a range of 57.68-59.17°. The performance test of the concrete proposed that the addition of PCM composite in the encapsulation tubes improves the temperature distribution and can be applied as thermal storage.