Single-walled carbon nanotube for shape stabilization and enhanced phase change heat transfer of polyethylene glycol phase change material

Abstract

In order to simultaneously stabilize the shape and enhance the heat transfer efficiency of a typical polyethylene glycol (PEG) phase change material (PCM), a family of novel nanocomposites consisting of single-walled carbon nanotubes (SWCNs) and PEG was tailor-made via a facile impregnation method. The effects of SWCNs loadings ranging from 2% to 10% on the chemical structure, thermal performance and heat transfer enhancement of PEG were investigated experimentally. The fabricated nanocomposite exhibits high adsorption of PEG as high as 98% and can completely preserve its original shape without any PEG leakage even when subjected to a 400 melt-freeze cycle. The maximum adsorption of PEG is the highest value in literature up to now. The melting point of PEG/SWCNs nanocomposite shifts to a lower temperature while the freezing point shifts to a higher temperature while compared to the pure PEG, resulting in a substantial reduction of the supercooling degree. Above all, the thermal conductivity was found to increase with SWCN loadings whether in solid or liquid state. In detail, only with a small SWCN loading of 4%, a dramatically high, 375% enhancement is obtained in the solid state and a relatively high enhancement of 121% is achieved in the liquid state.