Fabrication and characterization of capric–lauric–palmitic acid/electrospun SiO2 nanofibers composite as form-stable phase change material for thermal energy storage/retrieval

Abstract

Through combining a eutectic mixture of capric–lauric–palmitic acid (CA–LA–PA) as phase change material (PCM) and SiO2 nanofibers as supporting material, a novel form-stable PCM based composite was fabricated and studied for thermal energy storage and retrieval. Specifically, the SiO2 nanofibers, prepared via electrospinning followed by a high temperature annealing process, were used to absorb and/or support the PCM consisted of CA–LA–PA eutectic mixture. The structure, morphology and thermal property of prepared CA–LA–PA eutectic mixture, electrospun SiO2 nanofibers and composite PCM were characterized by Fourier transfer infrared (FT-IR) spectra, Scanning electron microscopy (SEM) and Differential scanning calorimeter (DSC), respectively. The results showed the electrospun SiO2 nanofibers were successfully fabricated with high porosity which is capable of absorbing a large amount of PCM; and the CA–LA–PA was uniformly absorbed into porous framework of SiO2 nanofibers. In addition, the phase transition temperatures of CA–LA–PA eutectic mixture were lower than those of individual fatty acids. The melting and crystallization temperatures and heat enthalpies of composite PCM were 21.7 and 6.4°C, and 100.9 and 96.5kJ/kg, respectively; indicating that the composite PCM possessed appropriate phase transition temperatures and high latent heat. Thermal cycling test results showed that there were no noticeable variations on the phase transition temperatures and heat enthalpies after 50 thermal cycles; revealing that the prepared form-stable composite PCM is promising for thermal energy storage/retrieval due to the good thermal reliability and stability.