The impact of employing carbon nanotube and Fe3O4 nanoparticles along with intermediate boiling fluid to improve the discharge rate of phase change material

Abstract

Despite the fact that solid–liquid phase change materials (PCMs) have various applications in thermal energy storage systems, the low solidification rate of PCMs, which is due to the low thermal conductivity has limited the range of applications of PCMs. One of the methods of increasing the solidification rate of PCMs is using a boiling fluid as an intermediary between the solid–liquid PCM and the condenser to prevent the direct contact between the phase change material and the condenser tubes, this method is also known as the intermediate boiling fluid (IBF) method. The IBF method has been shown to significantly increase the solidification rate (2 orders of magnitude). In this study, the effect of nanoparticles addition on the solidification rate of PCM in the IBF method is investigated. Paraffin and acetone are used as the solid–liquid PCM and the IBF, respectively. Hence, Carbon nanotubes (CNT) and Fe3O4 as carbon-based and metallic nanoparticles, respectively, are dispersed in the acetone at three different concentrations of 1 wt%, 2 wt%, and 4 wt%. The results revealed that, compared to the case without using nanoparticles, the addition of Fe3O4 nanoparticles at concentrations of 1 wt%, 2 wt%, and 4 wt% decreases the total solidification time by 4%, 16%, and 20%, respectively. Likewise, the addition of CNT nanoparticles at the same concentrations decreased the total solidification time by 16%, 28%, and 36%, respectively. Furthermore, the addition of Fe3O4 and CNT at 4 wt% reduces the solidification start time by 20% and 30%, respectively.