Thermal performance of PEG-MWCNTs composites as shape-stabilised phase change materials for thermal energy storage

Abstract

The development of phase change materials (PCM) for thermal energy storage is a promising technology. However, the liquid PCM leaks and low thermal conductivity limit the practical PCM applications. This article aims to solve these problems; it presents the preparation and thermal characterisation of PCM enhanced by carbon-based nanoparticles. The polyethene glycol 6000 (PEG 6000) is used as PCM and multi-walled carbon nanotubes (MWCNTs) as a shell matrix and thermal conductivity enhancer. The sample was prepared by the sonification method under vacuum conditions. Fourier transform infra-red spectroscopy (FT-IR) and thermo-gravimetric analysis (TGA) tested the chemical and thermal compatibility of the prepared samples. The storage performances are tested by modulated differential scanning calorimetry characterisation. The nano-enhanced-PCM (NPCM) with 1 wt% MWCNTs showed excellent shape stability without any liquid leakage when the temperature was about 110 °C for 30 minutes. Drying method has a significant effect on the thermal storage capacity of the NPCM. The melting, solidification points and the latent heats of the NPCM were measured as 61.75, 35.50 °C, and 174.24, 167.84 J g⁻¹, respectively. Meanwhile, the specific heat is 2.63 J g⁻¹°C⁻¹ for the solid-state and 2.14 J g⁻¹°C⁻¹ for the liquid-state. The thermal conductivity of pristine PEG was improved by 49%.

Highlights

• PEG-MWCNTs shape-stabilised phase change materials were prepared through ultrasound-assisted vacuum method for efficient thermal energy storage.

• The thermophysical properties and thermal stability of the proposed NPCM has been analysed and discussed.

• The drying method highly influences the phase change temperatures and latent heats of the prepared NPCM.

• PEG adsorption into MWCNTs reached 99 wt% without leakage, and 1 wt% of MWCNTs enhanced the thermal conductivity by 49% and maintained good latent heat of 175 J g⁻¹.

• The developed NPCM is an excellent potential candidate for electronic devices cooling applications.

Keywords:

• Thermal energy storage
• phase change materials (PCM)
• shape-stabilised composite
• polyethylene glycol (PEG)
• multi-walled carbon nanotubes (MWCNTs)

Disclosure statement

No potential conflict of interest was reported by the authors.