Preparation and physical and thermal characterizations of enhanced phase change materials with nanoparticles for energy storage applications

•Preparation, characterization, and thermal cycling of nanocomposite phase change materials is presented.•Product nanocomposites increases density, viscosity, melting, and solidification rates compared with base fluid.•pH of the PCMs reduces with nanoparticle addition, especially for sp24 with the CuO nanoparticles.•Rates melting and solidification of PCM sp24 increase by ∼18.7% and 14.3% respectively when adding 5wt.% CuO NPs.•Rate of melting of sp26 increases by almost 3 times when adding 5.0 wt.% CuO and 5.0 wt.% Al2O3. An experimental investigation is presented on the preparation, and characterization of nanocomposites of the phase change materials (PCM) sp24, sp26 and sp29 with Al2O3 and CuO nanoparticles (NPs). The product samples are characterized and evaluated during melting and solidification cycles. The effects of the nanoparticles in the PCMs are observed from XRD and FTIR results, sedimentation tests, color changes, density, phase change range, pH, viscosity, and rate of solidification and melting during thermal cycles. It is found that the product nanocomposites have increased density and viscosity compared to the base phase change fluids. The rate of melting for sp24 is improved by 18.7% when 5 wt% nanoparticles are used. Its rate of solidification is also improved by 10.5 and 14.3% with 5 wt% Al2O3 and CuO NPs, respectively. The rate of melting increases by almost three times when 5 wt% of Al2O3 and 5 wt% of CuO are added in the same base PCM-sp26 sample. The latter nanocomposite has the best thermal performance in the study, it has an improved rate of melting at optimum melting temperature range ∼22–28 °C suitable for thermal comfort and does not undergo any supercooling.