Experimental study on microcapsules of Ag doped ZnO nanomaterials enhanced Oleic-Myristic acid eutectic PCM for thermal energy storage

Highlights: • Ag doped ZnO nanomaterials enhanced Oleic-Myristic acid eutectic PCMs were developed. • The synthesized microcapsules have uniform spherical morphology with an average size of 3–5 μm. • The melting and freezing enthalpies of microcapsules are about 75–80 J/g and 75–78 J/g. • Microcapsules with highest weight percentage of Ag doped ZnO nanomaterials showed high thermal conductivity enhancement. -- Abstract: Novel microcapsules of Ag doped ZnO nanomaterials enhanced Oleic-Myristic acid eutectic phase change materials (PCMs) were synthesized by in-situ polymerization process. X-ray diffraction analysis reveals that Ag doped ZnO nanomaterials has a hexagonal wurtzite structure. Nano enhanced composite PCMs are prepared by mixing different weight percentage of nanomaterials with Oleic-Myristic acid eutectic mixture act as core material. Microscopic analysis reveals the formation of uniform spherical structure of Melamine-Formaldehyde shell over the core material with a perfect core-shell structure. Differential scanning calorimetric analysis showed that microencapsulated PCMs (MEPCMs) melts and freezes in the range of 4.37–5.81 °C and 10.84–11.86 °C with the latent heat of 75.39–79.35 J/g and 74.9–77.95 J/g. MEPCMs have better thermal conductivity, stability and reliability determined by thermal conductivity, thermogravimetric and thermal cycling analysis. Based on the results, MEPCMs with Ag doped ZnO nanomaterials could be suggested as the potential core material for low temperature thermal energy storage applications.