Pickering-stabilized oil-in-oil emulsions with enhanced cold-storage capability

The growing global demand for energy, particularly in cold applications such as refrigeration, air conditioning, and cold chain logistics, necessitates the development of efficient Thermal Energy Storage (TES) solutions. Phase Change Emulsions (PCEs) have emerged as promising materials for cold TES systems due to their enhanced thermal energy storage capacity, low pumping power requirements, and improved heat transfer properties. However, conventional water-based PCEs face limitations in low-temperature applications due to freezing-induced destabilization. This study explores the development and optimization of anhydrous PCEs for cold TES applications by formulating emulsions with D-Limonene as the continuous phase, polyethylene glycol 400 as the Phase Change Material, and surface-modified silica nanoparticles as the stabilizing agent. The impact of varying PEG400 volumetric fractions on the emulsions’ thermal, microstructural, and rheological properties was systematically assessed. Results revealed that increasing PEG400 content led to larger mean Sauter diameters, forming denser crystalline structures. Formulations with PEG400 fractions above 15 vol% exhibited enhanced thermal stability and energy storage capacity. However, a catastrophic phase inversion occurred beyond 52.4% PEG400. Moreover, the PEG400 concentration significantly influenced the performance of the PCEs, enhancing their cold-energy thermal storage capacity. This study highlights the potential of anhydrous PCEs as efficient materials for cold energy storage, promoting sustainable cooling technologies.