Effect of expanded graphite and carbon nanotubes on the thermal performance of stearic acid phase change materials

Cheng, Xiaomin; Li, Ge; Yu, Guo; Li, Yuanyuan; Han, Jiaqiang

doi:10.1007/s10853-017-1350-9

Cited by 46 publications

(11 citation statements)

References 24 publications

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“…Moreover, absolute thermal diffusivities of fGnPs/PEG400 are twice superior than those of those paraffin nanoparticle composites [ 66 ]. Lower absolute thermal diffusivities than these here reported were also reported for expanded graphite/stearic acid and carbon nanotubes/stearic acid NePCMs by Cheng et al [ 67 ]. Finally, results in thermal diffusivity also show a potential use for the proposed NePCMs in distinctive thermal management applications.…”

Section: Resultssupporting

confidence: 73%

PEG 400-Based Phase Change Materials Nano-Enhanced with Functionalized Graphene Nanoplatelets

et al. 2017

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This study presents new Nano-enhanced Phase Change Materials, NePCMs, formulated as dispersions of functionalized graphene nanoplatelets in a poly(ethylene glycol) with a mass-average molecular mass of 400 g·mol−1 for possible use in Thermal Energy Storage. Morphology, functionalization, purity, molecular mass and thermal stability of the graphene nanomaterial and/or the poly(ethylene glycol) were characterized. Design parameters of NePCMs were defined on the basis of a temporal stability study of nanoplatelet dispersions using dynamic light scattering. Influence of graphene loading on solid-liquid phase change transition temperature, latent heat of fusion, isobaric heat capacity, thermal conductivity, density, isobaric thermal expansivity, thermal diffusivity and dynamic viscosity were also investigated for designed dispersions. Graphene nanoplatelet loading leads to thermal conductivity enhancements up to 23% while the crystallization temperature reduces up to in 4 K. Finally, the heat storage capacities of base fluid and new designed NePCMs were examined by means of the thermophysical properties through Stefan and Rayleigh numbers. Functionalized graphene nanoplatelets leads to a slight increase in the Stefan number.

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Section: Resultssupporting

confidence: 73%

PEG 400-Based Phase Change Materials Nano-Enhanced with Functionalized Graphene Nanoplatelets

et al. 2017

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“…The composite PCMs were prepared via melt blending. The increasing of carbon nanometerials content from 1 to 9% thermal conductivity increased [10]. Based on the literature described above, thermal conductivity and thermal stability of the composite PCMs considerably enhance with addition carbon nanomaterial.…”

Section: Introductionmentioning

confidence: 70%

“…However, stearic acid tends to leakage when melting. Leakage is an important problem for PCMs, which limits theirs usage area [10]. Several preparation techniques have been used to overcome this problem such as encapsulation,photopolymerization [11], embedding like metal particles and fatty alcohol into PCMs [12].…”

Section: Introductionmentioning

confidence: 99%

Preparation of Stearic Acid/Graphene oxide Based Form-Stable Composite Phase Change Materials

Oktay

2018

Marmara Fen Bilimleri Dergisi

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Composite phase change materials (PCM) of stearic acid/graphene oxide were prepared by thiol-alkyne click coupling reaction.Stearic acid was firstly modified with propargyl to introduce thiol-yneclickable sites. Different amounts of graphene oxide were added to thiol-alkyne clickable formulation. To evaluate phase change properties of PCMs differential scanning calorimeter (DSC) was used. Thermal stability and degradation profiles of PCMs were investigated. The structural characterization of stearic propargyl ester and PCMs was performed by ATR-FTIR spectroscopy. The addition of graphene oxide increased the maximum weigh loss temperature from 328 to 351 ˚C with respect to the base formulation. Moreover, the crosslinking of stearic acid prevented the leakage of PCMs. Keywords: Phase change materials, thiol-yne click, graphene oxide ÖzStearik asit-grafen oksit kompozit faz değişim malzemeleri (PCM) tiyol-alkin klik kapanma reaksiyonu ile hazırlandı. Öncelikle stearik asit tiyol-yne klik gruplarının bağlanması amacıyla modifiye edildi. Farklı miktarlarda grafen oksit tiyol-klik formülasyonuna eklendi. PCM'lerin faz değişim özelliklerini incelemek için diferansiyel taramalı kalorimetre (DSC) kullanıldı. PCM'lerin termal kararlılık ve bozunma profil incelendi. Stearik propargyl esteri ve PCM'lerin yapısal karakterizasyonu ATR-FTIR spektroskopisi ile gerçekleştirildi. Grafen oksit eklenmesiyle baz formülasyona göre maksimum kütle kaybı sıcaklığı 328 dan 351 ˚C ye yükseldi. Aynı zamanda stearik propargyl çapraz bağlanmasıyla PCM'lerin akma problem engellendi.

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“…The author summarized that the EG fillers are more significant for thermal conductivity improvement however storage capacity is slightly decreased. Cheng et al [9] studied and compared the thermal conductivity and thermal performance of SA/EG and SA/CNTs (carbon nanotubes) in low temperature storage system. The result indicated that thermal conductivity of SA/EG was greatly higher than SA/CNTs and EG was more improvable for thermal performance of S.A. Dinker et al [10] performed the thermal conductivity of SA by mixing the different mass ratios of expanded graphite for low temperature TES.…”

Section: Introductionmentioning

confidence: 99%

The Effect of Expanded Graphite on the Charging Time of Stearic Acid Phase Change Material in a Hot Water Tank

Sett

Mon

2021

AEJ

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The present work is to investigate the thermal conductivity of the phase change material (PCM) of stearic acid (SA) by using the supporting material of expanded graphite (EG). The EG is used with the mass ratio of 10%, 15% and 20%. SA is commercial grade and the EG is formed by thermal method using natural graphite powder and crystalline zinc nitrate. The composite materials of (SA/10% EG, SA/15% EG and SA/20% EG) are prepared by direct impregnation method. Thermal conductivity of pure SA and composite PCMs are investigated by laboratory apparatus of heat transfer base unit TD1002. The thermal conductivity of the SA/10%EG composite PCM has been improved to 0.64 W/mK from that of SA (0.28 W/mK) with the percentage enhancement of 129%. To verify the morphology of the materials, scanning electron microscopy (SEM) analysis is utilized. The results show that the EG is formed in multilayers with pores in which stearic acid is well absorbed. The charging characteristics of pure SA, SA/10% EG and SA/15% EG for low temperature latent heat storage (LHS) system are studied experimentally. The system is applied for domestic water heating. The PCM is filled in a 33 mm diameter cylindrical copper tube and placed in hot water storage tank. The water is filled in tank from the top section through the distributor to uniform entry. The phase change phenomena of the PCMs are measured by inserting thermocouples at two layers of PCM tube. The result shows that the melting time decreases with the increasing mass ratio of expanded graphite in composite PCM. Although the melting time of both layers are nearly the same at the experiment of composite PCMs, the lower layer takes longer time than upper layer for pure PCM. The charging time is decreased by 67% for SA/10%EG and 79% for SA/15% EG composite PCM from that value of pure SA.

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Effect of expanded graphite and carbon nanotubes on the thermal performance of stearic acid phase change materials

Cited by 46 publications

References 24 publications

PEG 400-Based Phase Change Materials Nano-Enhanced with Functionalized Graphene Nanoplatelets

PEG 400-Based Phase Change Materials Nano-Enhanced with Functionalized Graphene Nanoplatelets

Preparation of Stearic Acid/Graphene oxide Based Form-Stable Composite Phase Change Materials

The Effect of Expanded Graphite on the Charging Time of Stearic Acid Phase Change Material in a Hot Water Tank

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