Nano-enhancement of phase change material in a shell and multi-PCM-tube heat exchanger

摘要

The fundamental defect of PCMs in discharging process is their low conductivity which results in long solidification time. In this study distribution of a PCM in a multi-tube heat exchanger is conducted numerically to reduce the solidification time. Therefore, the PCM mass is distributed in the inner and outer tubes between which a heat transfer fluid (HTF) passes through. Various volume fractions of copper nanoparticles are added to the PCM and the consequences of the conductivity enhancement is observed. Moreover, the variation of Stefan number (Ste) is considered to evaluate the effect of this parameter on the solidification process. In addition, it is shown that the distribution of the PCM is greatly effective on the heat transfer enhancement. Proper PCM mass distribution leads to 62% reduction in the solidification time. Results also indicates that by increasing the nanoparticles volume fractions to 4% and Ste to 0.45, the solidification time reduces 15% and 26%, respectively in the best case.