Resumen de Development of oil-in-oil phase change emulsions for cold energy storage applications
Adrián Tenorio Alfonso, Antonio Guerrero, Francisco Javier Navarro
As previously reported in the literature [1] the stable dispersion of Phase Change Materials (PCMs) within heat transfer fluids by different emulsifiers, yielding the so-called Phase Change Emulsions (PCEs), has been proven to maintain the PCM energy storage capacity, while promoting their flow and heat performances [2]. Aiming at avoiding the temperaturelimiting incorporation of water as the continuous, this study was intended to formulate oil-in-oil PCEs for cold energy storage applications. Therefore, an essential oil, more specifically D-limonene, polyethylene glycol 400, and surface-modified fumed silica nanoparticles were used as the continuous phase, disperse phase, and emulsifier, respectively. In this research, the addition degree of the emulsifier was optimised within a range from 0.1-4.8 % wt, while establishing a constant continuous phase: disperse phase ratio (9:1). The synthesised PCEs were subjected to a comprehensive characterisation, including thermal analysis (thermal conductivity, differential scanning calorimetry, thermogravimetric analysis), microstructural assessment (laser diffraction, optical microscopy) and rheological evaluation (flow test, temperature ramps). According to the results, oil-in-oil PCEs exhibited fairly stable thermal and microstructural stability. Additionally, the structuring effect of the solid emulsifier was evinced, giving rise to PCEs with promising flow and thermal responses for their application in the storage of cold energy.
