Increased Thermal Conductivity of Eicosane-Based Composite Phase Change Materials in the Presence of Graphene Nanoplatelets

2013 ◽  
Vol 27 (7) ◽  
pp. 4041-4047 ◽  
Author(s):  
Xin Fang ◽  
Li-Wu Fan ◽  
Qing Ding ◽  
Xiao Wang ◽  
Xiao-Li Yao ◽  
...  
Keyword(s):  
Thermal Conductivity ◽  
Phase Change ◽  
Phase Change Materials ◽  
Graphene Nanoplatelets ◽  
Composite Phase Change Materials

scholarly journals Thermal Properties of PEG/Graphene Nanoplatelets (GNPs) Composite Phase Change Materials with Enhanced Thermal Conductivity and Photo-Thermal Performance

2018 ◽  
Vol 8 (12) ◽  
pp. 2613 ◽  
Author(s):  
Lihong He ◽  
Hao Wang ◽  
Hongzhou Zhu ◽  
Yu Gu ◽  
Xiaoyan Li ◽  
...  
Keyword(s):  
Thermal Conductivity ◽  
Phase Change ◽  
Energy Conversion ◽  
Phase Change Materials ◽  
Near Infrared ◽  
Graphene Nanoplatelets ◽  
Solar Irradiation ◽  
Blending Method ◽  
Conduction Pathway ◽  
Composite Phase Change Materials

This paper mainly concentrates on the thermal conductivity and photo-thermal conversion performance of polyethylene glycol (PEG)/graphene nanoplatelets (GNPs) composite phase change materials (PCMs). The temperature-assisted solution blending method is used to prepare PCM with different mass fraction of GNPs. According to the scanning electron microscope (SEM), GNPs are evenly distributed in the PEG matrix, forming a thermal conduction pathway. The Fourier transform infrared spectra (FT-IR) and X-ray diffraction (XRD) results show that the composites can still inherit the crystallization structure of PEG, moreover, there are only physical reactions between PEG and GNPs rather than chemical reactions. Differential scanning calorimeter (DSC) and thermal conductivity analysis results indicate that it may be beneficial to add a low loading ration of GNPs to obtain the suitable latent heat as well as enhance the thermal conductivity of composites. To investigate the change in the rheological behavior due to the effect of GNPs, the viscosity of the composites was measured as well. The photo-thermal energy conversion experiment indicates that the PEG/GNPs composites show better performance in photothermal energy conversion, moreover, the Ultraviolet-visible-Near Infrared spectroscopy is applied to illustrate the reasons for the higher absorption efficiency of PEG/GNPs for solar irradiation.

Composite phase change materials improve the photo-thermal effects of cotton fabrics

2020 ◽  
pp. 004051752097561
Author(s):  
Wei Zhang ◽  
Shang Hao ◽  
Jiali Weng ◽  
Yibo Zhang ◽  
Jiming Yao ◽  
...  
Keyword(s):  
Thermal Conductivity ◽  
Surface Temperature ◽  
Ambient Temperature ◽  
Phase Change ◽  
Latent Heat ◽  
Thermal Effects ◽  
Phase Change Materials ◽  
Thermal Storage ◽  
Cotton Fabrics ◽  
Composite Phase Change Materials

We report on the impregnation-based preparation of composite phase change materials (CPCMs) with thermal storage properties, using paraffin wax and multi-walled carbon nanotubes (MWCNTs). We coated the CPCMs on the fabric by scraper coating, then evaluated their shape stability, latent heat, thermal conductivity, thermal storage stability and photo-thermal effects. Results show that CPCMs with 10% acid-oxidized MWCNTs introduce only a small phase leakage when heated at 50℃ for 900 s; their latent heat energy reduces by 16.5%, while their thermal conductivity increases by 131.9% compared to pure paraffin. When exposed to sunlight at an ambient temperature of 12.5℃, the cotton fabrics coated with CPCMs record a 12.8℃ higher surface temperature than the pristine fabric, while their heat dissipation is delayed by 120–180 s. The fabric surface temperature increases to twice the ambient temperature during daytime. Overall, these findings indicate that the coated fabric has excellent thermal stability, affirming its potential as photo-thermal functional material.

scholarly journals Preparation and Thermal Performance Enhancement of Low Temperature Eutectic Composite Phase Change Materials Based on Na2SO4·10H2O

Materials ◽  
2018 ◽  
Vol 11 (11) ◽  
pp. 2230 ◽  
Author(s):  
Pumin Hou ◽  
Jinfeng Mao ◽  
Fei Chen ◽  
Yong Li ◽  
Xian Dong
Keyword(s):  
Thermal Conductivity ◽  
Phase Change ◽  
Thermal Performance ◽  
Phase Change Materials ◽  
Performance Enhancement ◽  
Expanded Graphite ◽  
Nucleating Agent ◽  
Thermal Reliability ◽  
Composite Phase Change Materials ◽  
Mass Fractions

In this paper, a series of Na2SO4·10H2O–KCl eutectic mixtures were prepared by adding different mass fractions of KCl (1 wt.%, 3 wt.%, 5 wt.%, or 7 wt.%) to Na2SO4·10H2O. Polyacrylamide (PAM) was proposed as the thickener, sodium tetraborate decahydrate (STD) was proposed as the nucleating agent, and expanded graphite (EG) was proposed as the high thermal conductivity medium for Na2SO4·10H2O–5 wt.% KCl eutectics. The results showed that in Na2SO4·10H2O–5 wt.% KCl eutectics with 5 wt.% PAM and 5 wt.% STD, almost no phase separation occurred, and the degree of supercooling was reduced to 0.4 °C. The thermal performance of Na2SO4·10H2O–5 wt.% KCl composite phase change materials (CPCMs) with varying contents of EG was explored. The results showed that EG could improve the thermal conductivity effectively and that the mass fraction of EG should be no more than 3%, otherwise the crystallization value and supercooling would deteriorate. The thermal reliability of the Na2SO4·10H2O–5 wt.% KCl eutectic CPCMs containing 5 wt.% PAM, 5 wt.% STD, and 3 wt.% EG was investigated, mainly through the ambient temperature, thermal cycling test, and TGA analysis. The results demonstrated that these CPCMs showed perfect thermal reliability.

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