Stable nano-enhanced phase change material emulsions of natural surfactant and silica nanoparticles for thermal energy storage applications

Abstract

The study investigates the stabilization of n-PCM (nano phase change material) emulsions using natural surfactants combined with silica nanofluid of single step origin at concentrations of 0.5 and 1 wt%. The novelty of study lies in application of natural surfactant used to enhance the emulsification process, ensures a sustainable and non-toxic stabilization method. Silica nanofluid of single step origin was incorporated to improve stability and performance, making these advanced emulsions a practical choice for various industrial applications. The emulsions were characterized through various techniques, including differential scanning calorimetry to assess thermal properties, interfacial tension measurements to evaluate emulsification efficiency, microscopic analysis for droplet distribution, and rheological testing to determine viscosity changes. Corrosion tests were conducted to investigate the protective effects of the stabilizers, while scanning electron microscopy and energy dispersive x-ray spectroscopy provided insight into the structural characteristics and distribution of nanoparticles within the emulsion. The results demonstrated that the addition of 0.5 wt% silica nanofluid significantly improved the stability and thermal characteristics of the n-PCM emulsion without adversely affecting its phase change behavior, with melting point of 21.08 °C, enthalpy of melting 1205.171 J/g, freezing point of 15.46 °C and enthalpy of crystallization 1284.825 J/g. In contrast, the emulsion with 1 wt% silica nanofluid led to alterations in thermal properties and viscosity, suggesting a more complex interaction with the n-PCM matrix. Overall, the study highlights that a lower concentration of silica nanoparticles (0.5 wt%) is preferable for optimizing the stability and thermal performance of n-PCM emulsions, making it a viable approach for applications requiring efficient thermal energy management.