Fabrication of Silica-Covered Erythritol Microcapsules for Thermal Storage

Abstract

Thermal storage techniques that use phase-change materials have recently attracted increased attention. Erythritol, a kind of sugar alcohol and a phase change material, is viable for thermal storage and has both higher thermal storage capacity and phase-change temperature than those of its widely used counterpart, n-alkane. Micro-encapsulation of these phase-change materials results in an increase of both the surface area per unit volume and the transportability of the particles in the form of a slurry or emulsion. In this study we developed silica-covered erythritol microcapsules. These microcapsules are obtained by sol-gel reaction of tetraethoxysilane (TEOS) which yields silica by sol-gel process at interface between the erythritol particle and a TEOS solution. Most of the microcapsules had sizes of less than 50 μm with the average size being 24.1 μm. Moreover, silica-covered erythritol microcapsules could stably store waste heat at ordinary temperatures and pressures, and with the aid of physical stimuli, use this stored heat. Therefore, these microcapsules are potentially viable for use in circulating heat carriers and sources, and have significant potential for the effective utilization of energy.