Preparation and thermal properties of nano-microcapsule and simulation heat storage application

• Published in: Applied thermal engineering 2024-06, Vol.246, p.123018, Article 123018
• Main Authors: Huang, Zhiguo, Sun, Zhigao
• Format: Article
• Language: English
• Subjects: N-docosane; Nano-microcapsule; Phase change material; Thermal energy storage bed; Titanium dioxide
• ISSN: 1359-4311
• DOI: 10.1016/j.applthermaleng.2024.123018

•A method is offered to enhance the encapsulation efficiency of NPCMs.•NPCMs significantly boost the heat transfer surface area.•NPCMs exhibit excellent shell structure and resistance to leakage.•NPCMs have good thermal stability and rapid heat response.•NPCMs enhance the thermal performance in latent heat energy storage systems. The prevention of material leakage and improvement of thermal conductivity are very important for thermal energy storage application. In this work, nano-TiO2@n-docosane microcapsules were synthesized by the fine emulsion interface polymerization method using tetra-n-butyl titanate (TBT). This approach enhances the encapsulation rate and efficiency of phase change microcapsules. The microcapsules formation process was observed using a biological microscope. The diameter of the microcapsules decreased significantly with the increase of stirring rate. The phase transition temperature of the optimal microcapsules is 42.4 °C. The encapsulation rate and efficiency reach up to 90.7% and 91.0%, respectively. The average thermal conductivity of nano-TiO2@n-docosane microcapsules is 215% higher than that of n-docosane. SEM and infrared spectroscopy testing results confirm the successful coating of n-docosane by TiO2. Thermogravimetric analysis presents that TiO2 forms a shell, which reduces the leakage of n-docosane. The melting and solidification processes of n-docosane and nano-TiO2@n-docosane microcapsules were simulated numerically. In comparison to n-docosane, nano-TiO2@n-docosane microcapsules exhibit a 14.89% increase in peak storage power and a 12.47% increase in heat transfer coefficient during charging. Additionally, during discharging, these values rise by 3.23% and 6.46%, respectively. Nano-TiO2@n-docosane microcapsules enhance heat transfer and the charging/discharging process of phase change materials.