| dc.description.abstract | This study aims to develop a phase change material (PCM) composite based on paraffin wax
and polyethylene glycol (PEG6000), reinforced with magnetite (Fe3O4) nanoparticles, to
enhance the thermal conductivity of concrete used as a thermal energy storage (TES) material.
Composite fabrications were first carried out with ultrasonication of magnetite (37 kHz for 30
minutes at 80°C). Then, the magnetite varied into 15%, 25%, 35%, and 45% were
encapsulated within vertically and horizontally arranged copper tubes embedded in concrete.
Characterizations included differential scanning calorimetry (DSC), thermogravimetric
analysis (TGA), X-ray diffraction (XRD), scanning electron microscopy with energy-
dispersive X-ray spectroscopy (SEM-EDX), vibrating sample magnetometry (VSM), as well as
thermal conductivity and heat distribution tests were conducted to evaluate the thermal,
physical, and magnetic properties of the composites. Our DSC’s findings indicated a reduction
in the latent heat but improved thermal conductivity with a rise in the magnetite content. The
paraffin–magnetite composite with 35% magnetite achieved an optimal thermal conductivity
of 0.52 W/m·K, while the PEG–magnetite composite reached 0.624 W/m·K. TGA analysis
demonstrated enhanced thermal stability, with degradation temperatures reaching up to
450°C. XRD patterns confirmed the formation of physical composites without the emergence
of new chemical phases, and SEM-EDX analysis revealed a uniform dispersion of Fe particles
within the PCM matrix. VSM analysis indicated superparamagnetic behavior, with maximum
saturation magnetization values of 34.96 emu/g for the paraffin–magnetite composite and
29.84 emu/g for the PEG–magnetite composite. Overall, the incorporation of magnetite
(Fe3O4) effectively enhanced the thermal conductivity, stability, and energy storage capacity
of PCM-embedded concrete. The developed PCM–magnetite composite, encapsulated in
concrete, demonstrates significant potential as an efficient and sustainable passive thermal
energy storage material for energy-saving building applications. | en_US |
