Experimental investigation of solidification and melting characteristics of composite PCMs for building heating application

Highlights: • Composite PCMs possess higher thermal conductivity than their base PCM. • Other thermophysical properties of PCMs were not affected much by nanoparticles. • CuO based composite PCM showed the largest increase in thermal conductivity. • CuO based composite PCM has greatest potential in accelerating melt/freezing process. - Abstract: This paper investigates the thermal energy storage behaviours of the newly prepared composites as phase change materials (PCMs) for building heating application. The composite PCMs have been prepared with lauric acid (LA) and stearic acid (SA) mixture as base material and TiO₂, ZnO and CuO nanoparticles as supporting materials. The proportion of LA/SA mixture for the preparation of composite PCMs has been estimated as 70:30 by weight. TiO₂, ZnO and CuO nanoparticles with 1.0 wt% mass fraction have been dispersed in the base material, individually. For ensuring the better stability of the supporting materials in the base material, sodium dodecylbenzene sulfonate (SDBS) has been preferred as the capping agent. The surface morphology of the as synthesized nanoparticles has been studied by SEM (scanning electron microscope). The phase change temperatures and latent heats of the composite PCMs have been evaluated by DSC (differential scanning calorimetry) measurements. Thermal stability of the composite PCMs has been determined by TGA. The increase in thermal conductivity for composite PCMs with mass fraction of 1.0 wt% TiO₂, ZnO and CuO nanoparticles has been estimated as 34.85%, 46.97% and 62.12%, respectively while comparing to base material. The experimental results have proved that time savings of composite PCM with CuO nanoparticles for melting and solidification processes are greater while comparing to the composite PCMs with TiO₂, ZnO nanoparticles and base material. Thus, composite PCM with CuO nanoparticles could be suggested as the potential candidate for building heating applications