To Investigate Thermal Conductivity of Phase Change Material by Incorporating Surfactants

Abstract

Phase change materials (PCMs) store or release heat during their phase transition. Their low thermal conductivity affects the performance of the latent heat energy storage system. This study aimed to investigate the thermal conductivity of PCMs by mixing surfactants. Surfactants with varying weights of sodium stearate (SS), gum arabic (GA), and sodium stearoyl lactylate (SSL) were mixed with paraffin wax. The charging and discharging rate of pure paraffin wax was compared to surfactant-mixed paraffin wax. Pure paraffin wax peaked at 66.76 °C. SSL’s highest temperature was 68.3 °C at the critical micelle concentration (CMC) (the concentration of surfactants above which micelles form) and 69 °C above the CMC. GA reached 70 °C at the CMC and 71 °C above the CMC. Sodium stearate (SS) reached 72.12 °C at the CMC and 73.8 °C above the CMC. The melting time test revealed that a reduced melting time resulted in the higher heat conductivity of paraffin. When compared to the melting times of pure paraffin, those of composite PCM containing SSL (>CMC), GA (>CMC), and SS (>CMC) decreased by 6.12%, 14.28%, and 22.44%, respectively. The results show that a concentration above the critical micelle concentration of sodium stearate leads to the best results compared to other samples. Surfactants form micelle, which acted as the conducting medium inside the paraffin wax. Thus, paraffin wax’s thermal conductivity was boosted, and the study’s goal was met.