Research on Enhancing Thermal Conductivity of Phase Change Microcapsules with Nano-Copper

Abstract

The unique ability of phase change materials (PCMs) to store and release heat makes their integration into building materials promising for reducing energy consumption and enhancing sustainability. In this paper, this study investigates a novel high thermal conductivity microcapsule as a thermal storage PCM. Polyethylene acrylate (EA) is chosen as the capsule shell, while a eutectic mixture of decanoic acid (CA) and lauric acid (LA) serves as the core material. The analysis results indicate that as the shell-to-core ratio decreases, the microcapsule size increases, and both the thermal conductivity and thermal diffusivity gradually decrease. Meanwhile, the latent heat capacity of MEPCM increases. When the shell-to-core ratio is 1:1.5, the melting latent heat and solidification latent heat are 81.85 J/g and 88.68 J/g, respectively. Nano-copper doping enhances the material's thermal conductivity and thermal diffusivity by 47.5% and 50%, respectively, leading to a 20.3% improvement in heat storage efficiency. After 200 cycling test, the material maintains good thermal reliability and chemical stability. And mortar-based composite materials containing microcapsules were prepared. It was found that the mortar composite materials containing microcapsules exhibited minimal influence from heating and cooling, with those containing nano-copper microcapsules demonstrating superior thermal response speed. This method of doping and modifying MEPCM with nano-copper holds promise in effectively reducing the impact of temperature fluctuations on the internal comfort of buildings, improving energy utilization efficiency, and providing reliable solutions for temperature-sensitive applications.

Keywords: Poly(ethylacrylate), Capric acid and Lauric acid, Phase change material, Thermal conductivity, Thermal energy storage, Microcapsule