Thermal storage performance of eutectic sugar alcohols applied to buildings and enhancement of crystallization

Abstract

Sugar alcohols are suitable for compact and high-density building thermal energy storage systems because of the high enthalpy, low price, and non-toxicity. But most sugar alcohol materials have severe supercooling characteristic, which limits their application as phase change materials (PCMs) in thermal energy storage systems. In this study, xylitol, sorbitol, erythritol, mannitol and dulcitol were selected as PCMs. Based on the five single sugar alcohols, ten multicomponent eutectic sugar alcohols were obtained which melting temperatures is between 60 °C and 90 °C applied to buildings. The thermal parameters of sugar alcohols were tested by differential scanning calorimetry (DSC), the supercooled eutectic sugar alcohols were stimulated by means of mechanical agitation to accelerate crystallization. The crystallization after excitation was monitored by microscope, and the supercooled crystallization phenomenon of eutectic sugar alcohols was investigated by isothermal phase change tests. The results showed that only three eutectic sugar alcohols could crystallize by stirring, and the melting temperatures of three eutectic sugar alcohols are about 80 °C. After multiple repetitive experiments, three eutectic sugar alcohols still have good crystallization characteristics. The results of the research provide a reference value in practical aspects for the design and selection of phase change materials in buildings.