Peotro Partal

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.

This work proposes novel biobinders as a more sustainable alternative to traditional bituminous products. They should be able to fully replace petroleum bitumen as binders of aggregates in road asphalts. Colophony resin ester (R), waste cooking oil (O), and cellulosic pulp (CP) were used as the main components of biobinders. Furthermore, the addition of a small amount of a reactive isocyanate-terminated prepolymer (MDI) is required. Binder formulation and processing were assessed by a comprehensive rheological, microstructural, and technological characterization to understand the role of each component in the final material properties. Rosin was a structuring agent, oil acted as a plasticizer, and the cellulosic pulp increased the material's softening point. MDI played a key role as a compatibilizer via urethane/amide linkages between the isocyanate groups of MDI and the OH/COOH groups present in the other three components. As a result, a biobinder formulation was proposed to replace bituminous binders, which was composed of 27.22 wt % oil, 67.76 wt % rosin, 2.02 wt % cellulosic pulp, and 3 wt % MDI. They should be added following the order R > O > MDI > CP and processed at 150 °C. Finally, its potential as an asphalt binder was evaluated according to European and American standards accepted for commercial bituminous products.