Influence of thermal transport properties of NEPCM for cool thermal energy storage system

Abstract

The present work deals with thermal energy storage behavior of the nano-enhanced phase change materials (NEPCMs) for building space cooling application. The NEPCMs have been prepared using Deionized (DI) water as the base phase change material (PCM) and multi-walled carbon nanotubes (MWCNTs) as nanomaterial with mass concentration of 0.25%, 0.5%, and 0.75%. For better stability of additive materials in the base PCM, sodium dodecyl-benzene sulfonate (SDBS) has been chosen as an additive element. The sub-cooling of the DI water has been completely eliminated for a mass concentration of 0.75% of MWCNT. The differential scanning calorimetry(DSC) analysis has been conducted to measure the phase transition properties of NEPCMs. The enhancements of 12.8% and 14.13% in latent heat values for charging and discharging processes, respectively, were observed for maximum mass concentration. It has also been observed that the onset temperature for charging is reduced from − 12.8 to − 9.7 °C for NEPCM with maximum concentration. The maximum thermal conductivity (k) augmentation of 23% (solid phase) and 11.2% (liquid phase) has been achieved by the NEPCM having a mass concentration of 0.75% MWCNT at − 10 °C and 15 °C, respectively. According to the study results the reductions in total charging times are 28% and 19% with the NEPCM holding a mass concentration of 0.75% MWCNT for − 8 °C and − 6 °C heat transfer fluid (HTF) temperatures, respectively. The environmental pollution remediation can be achieved by the reduction in energy input to the chiller by minimizing the total time taken for the charging the PCM.