Investigation of thermal energy storage properties of a microencapsulated phase change material using response surface experimental design methodology

Abstract

The response surface experimental design methodology was used to investigate thermal energy storage properties of the microencapsulated phase change material (MicroPCM). The capric acid and oleic acid mixture in the presence of hexadecane were encapsulated with styrene-divinylbenzene copolymer shell by emulsion polymerization technique. Response surface design experiments were conducted to determine the effect of three factors, namely, the shell:core ratio, emulsification time and crosslinker percentage at three distinctly different levels. Main effects and interaction effects of the factors on the latent heat of melting (ΔHm), the amount of produced MicroPCM and the encapsulation ratio were examined using statistical methods. The regression models were derived fully fit the experimental data. According to the statistical analysis results, the most significant effect on the thermal energy storage capacity, the amount of MicroPCM and the encapsulation ratio was attributed to the shell:core ratio. The properties of optimal MicroPCM were investigated by Differential Scanning Calorimetry (DSC), Thermogravimetric Analysis (TGA), Scanning Electron Microscopy (SEM) and Fourier Transform Infrared Spectroscopy (FT-IR). The analysis results demonstrated that optimal MicroPCM with its latent heat of fusion value (123 J/g) and encapsulation ratio (85.85%) can be accepted as a good candidate for thermal energy storage applications.