Crystallization of PCMs inside an emulsion: Supercooling phenomenon

Heat transfer characteristics during crystallization and melting of the phase change material (PCM) dispersed inside an emulsion are investigated theoretically and experimentally. The dispersed PCMs are hexadecane, octadecane and water. The crystallization and melting processes are not symmetrical because of the supercooling phenomenon induced by the smallness of the emulsion droplet sizes. Nucleation laws are used to simulate the supercooling phenomenon. Energy analysis is carried out to understand the behavior of the emulsion using two paraffins (octadecane and hexadecane). The effects of different parameters such as the mass fraction of PCM and the stabilization temperature on thermal behavior of emulsion are also analyzed.

Cooling process is limited to a temperature Ti and stabilized at this temperature afterwards. When Ti was sufficiently low, the dispersed PCM inside the emulsion crystallized rapidly. When Ti is higher and close to the flat shape of hexadecane, the results are different. Duration of the phase change process inside the emulsion is considerably increased due to higher stabilization temperature.Figure optionsDownload as PowerPoint slideResearch Highlights
► Crystallization and melting of the phase change material dispersed inside an emulsion are investigated theoretically and experimentally.
► Nucleation laws are used to simulate the supercooling phenomenon.
► The emplacement of the PCMs has no effect on the heat transfer inside the emulsion.