Microencapsulated phase change materials: Facile preparation and application in building energy conservation

Abstract

An experimental thermal storage gypsum-matrix model with performance of low density and thermal energy conservation was produced by the incorporation of traditional buildings materials and microencapsulated phase change materials. Here, the microencapsulated phase change materials (PCM@CMC-CS) were designed and synthesized based on the paraffin wax, chitosan (CS) and carboxymethyl cellulose (CMC), paraffin wax was used as PCM to store and release latent heat through solid-liquid phase change, CS and CMC were rapidly combined together to form the shell of capsules through electrostatic interaction between groups in order to prevent the leakage of melted PCM. They were added directly in hydrogel form at the mixing stage of gypsum-matrix model production, the presence of water and PCMs in the hydrogel particles would be play an important role on the holes structure and energy storage performance of model respectively. The chemical structure, thermal properties and morphology of PCM@CMC-CS were characterized by fourier transform infrared spectroscopy (FT-IR), differential scanning calorimeter (DSC) and scanning electron microscope (SEM), finding that raw materials CS and CMC were well combined together to form a complete sphere, encapsulating the paraffin wax. The maximum phase change enthalpy and phase change temperature of sample was about 110 J/g and 57 °C. The results of the application experiment of the gypsum-matrix models with the prepared PCM@CMC-CS 2 showed that they had an improved capacity of thermal inertia as well as lower inner temperatures when compared with conventional gypsum models without PCMs. The maximum temperature inside the gypsum-matrix model containing PCM@CMC-CS 2 hydrogels particles was only 63 °C, far below that of pure gypsum-matrix model prepared with nothing. At the same time, PCM@CMC-CS 2 particles also played a very important role in the experiment of photothermal conversion. This work not only introduced an interesting way to prepare PCM composites with the characteristic of simple, low cost, safe, and environmentally friendly, and further extended the potential of PCM composites in the application of building energy efficiency, but also lay the experimental foundation for the development of more high performance thermal energy conservation gypsum boards.