Chenzhen Liu

Preparation and characterization of sodium thiosulfate pentahydrate/silica microencapsulated phase change material for thermal energy storage

Microencapsulated phase change materials (MicroPCM) were successfully fabricated by encapsulation of sodium thiosulfate pentahydrate (SoTP) as core with silica shell using sol–gel method. The chemical structure, phase analysis, surface morphology, thermal properties and thermal stability of the MicroPCM were tested using X-ray diffraction instrument (XRD), X-ray photoelectron spectroscopy (XPS), energy dispersive X-ray spectroscopy (EDX), Fourier-transform infrared spectroscopy (FTIR), scanning electron microscopy (SEM), transmission electron microscopy (TEM), differential scanning calorimetry (DSC) and thermogravimetric analyzer (TG), respectively. The effects of core/shell mass ratio, concentration of emulsifier and stirring rate on the morphology of MicroPCM were studied. In addition, the core/shell mass ratio impact on the latent heat, thermal stability and supercooling of MicroPCM were also tested. The results indicates that the MicroPCM have relatively spherical shape. The encapsulation ratio of MicroPCM decrease with the decrease of SoTP mass percentage. The thermal properties and supercooling degree have been greatly improved. The highest encapsulation ratio of the MicroPCM is 94.65%. The thermal conductivity of SoTP is improved from 0.6035 to 0.7718 W (m k)−1 after the encapsulation of SoTP with silica. Depending on all results, it can be concludes that the prepared SoTP/silica MicroPCM have great potential for being used in thermal energy storage applications.

Synthesis and Characterization of Microencapsulated Phase Change Material of Magnesium Sulfate Heptahydrate/Urea Resin via Emulsion Polymerization Method

In this study, Microencapsulated phase change material (MicroPCM) was successfully synthesized by emulsion polymerization method, using magnesium sulfate heptahydrate (MSH) as core material and urea resin (UR) as shell material. The surface morphology of the MicroPCM was tested by scanning electron microscopy (SEM) and optical microscope (OM). The thermal property and particle size were investigated by differential scanning calorimetry (DSC) and laser particle size analyzer (LPA), respectively. The chemical structure of microcapsule was analyzed by Fourier-transform infrared spectroscopy (FTIR).Copyright

Experimental study on the phase change and thermal properties of paraffin/carbon materials based thermal energy storage materials

ABSTRACT In order to enhance the thermal energy storage efficiency of phase change materials, in this paper, expanded graphite (EG), multi-layer graphene nanoplatelet (MGN), graphite powder (GP) and multi-walled carbon nanotube (MWCNT) as the effective heat transfer promoters in different mass fraction (0.1, 0.5, 1.0, 1.5 and 2.5 wt.%) were added into the paraffin. The chemical properties, latent heat capacities, thermal conductivities and heat storage performances of paraffin and the composites were investigated. The results showed that the addition of EG, MGN, GP and MWCNT could increase the thermal conductivity of paraffin. At 20 °C, the thermal conductivity of the paraffin was increased by 61.04%, 51.2%, 12.18% and 10.22% with 2.5 wt.% EG, MGN, GP and MWCNT, respectively. In addition, with the same mass fraction, the heat storage and release time of the composite were 56.03% and 54.26%, respectively, shorter than that of paraffin when the additive was EG.