Tailoring nano-enhanced phase change material emulsions for efficient thermal energy storage: A thermophysical investigation

Thermal energy storage (TES) is a key technology in the pursuit of cleaner energy production that enables the more efficient use of renewable energy sources and reduces reliance on fossil fuels. Phase change material emulsions (PCMEs) are studied as TES and transportation mediums. A stable PCME with n-hexadecane (HXD) as a dispersed phase and deionized water as base fluid was successfully fabricated using sodium dodecyl sulfate as a surfactant. Functionalized multi-walled carbon nanotubes (F-MWCNT) were incorporated into the emulsion as an additive to reduce supercooling and enhance thermal conductivity (TC). The prepared emulsions were analyzed in terms of droplet size distribution, phase change properties, stability, TC, and viscosity. The surfactant significantly improved the PCME stability and prevented phase separation. The average droplet size and zeta potential for PCME without nano additive were 166.9–202.2 nm and −67.56 mV, respectively, whereas for PCME with F-MWCNT, 183.41–188.73 nm and −49.53 mV, respectively. The latent heat increased as the concentration of the dispersed phase PCM was higher. The underlying mechanism for the TC enhancement of 22.9 % with the addition of F-MWCNT was investigated. The findings suggest that the developed PCME with F-MWCNT is a promising candidate for TES applications, offering efficient energy management and enhanced thermal performance.