Thermophysical properties of n-tetradecane@polystyrene-silica composite nanoencapsulated phase change material slurry for cold energy storage

Based on the synthesis of n-tetradecane@polystyrene-silica (Tet@PS-SiO2) composite nanoencapsulated phase change material (NEPCM), a novel composite NEPCM slurry for cold energy storage was prepared by dispersing NEPCM into base fluid. The thermal performances of the Tet@PS-SiO2 NEPCM were measured by differential scanning calorimetry (DSC) and thermogravimetric analyzer (TG). The thermophysical properties of the NEPCM slurry including morphology, particle size, specific heat capacity, thermal conductivity, viscosity and mechanical stability were investigated systematically. The results showed that the Tet@PS-SiO2 NEPCM had a melting latent heat of 83.38 kJ kg−1 and excellent thermal stability. Transmission electron microscope (TEM) images displayed that the synthesized nanocapsules had regular spherical core-shell structure, and particle size analysis of NEPCM dispersed in slurry showed the mean particle size of Tet@PS-SiO2 NEPCM was 151.3 nm. Moreover, the Tet@PS-SiO2 slurry had a high specific heat capacity and obtained an enhancement 8.4% in thermal conductivity by the grafting of SiO2 on the PS shell. In addition, the slurry showed an acceptable viscosity and excellent mechanical stability. Those results indicate the Tet@PS-SiO2 slurry can be considered as an up-and coming latent heat fluid for cold energy storage.