scholarly journals Silver microsphere doping porous-carbon inspired shape-stable phase change material with excellent thermal properties: preparation, optimization, and mechanism

2020 ◽  
Vol 10 (1) ◽  
Author(s):  
Junwei Zhang ◽  
Yan Chen ◽  
Zeguang Nie ◽  
Zhengshou Chen ◽  
Junkai Gao
Keyword(s):  
Thermal Conductivity ◽  
Phase Change ◽  
Phase Change Material ◽  
Porous Carbon ◽  
Phase Change Materials ◽  
Agricultural Waste ◽  
Raw Material ◽  
Stable Phase ◽  
Cotton Stalk ◽  
Change Material

AbstractIn this study, silver microspheres (SMS) were introduced into cotton stalk porous-carbon (CSP) to prepare silver microsphere doping porous-carbon (SMS-CSP), and then SMS-CSP was used as the matrix of polyethylene glycol (PEG) to synthesize shape-stable phase change material of PEG/SMS-CSP. It was found that the introduction of SMS into CSP could not only greatly improve the loading capacity of the porous-carbon for PEG, but also could increase the thermal conductivity of PEG/SMS-CSP. Additionally, the method of introducing SMS into porous-carbon had the advantages of environmental protection and simple operation. Moreover, the raw material of cotton stalk is a kind of agricultural waste, which has the merits of wide source, low price and easy to obtain. Furthermore, in the preparation of cotton stalk porous-carbon, with the increase of pyrolysis temperature the thermal conductivity of PEG/SMS-CSP could be enhanced significantly. The mechanism about the enhancement of thermal conductivity was clarified, which could provide more basic theory for the study about the thermal conductivity of shape-stable phase change materials (ss-PCMs) based on porous-carbon.

scholarly journals Shape-stabilized phase change material with highly thermal conductive matrix developed by one-step pyrolysis method

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Shibin Wu ◽  
Yan Chen ◽  
Zhenshou Chen ◽  
Jiaqi Wang ◽  
Miaomiao Cai ◽  
...  
Keyword(s):  
Thermal Conductivity ◽  
Thermal Properties ◽  
Phase Change ◽  
Phase Change Material ◽  
Wheat Bran ◽  
Porous Carbon ◽  
Agricultural Waste ◽  
Study Results ◽  
One Step ◽  
Change Material

AbstractMetal microspheres doping porous carbon (MMPC), which was prepared using in-situ pyrolysis reduction strategy, could enhance the thermal conductivity of shape-stabilized phase change material (ss-PCM) prepared by MMPC as the matrix. However, in previous studies that were reported, the preparation of MMPC needed to synthesize porous carbon by pyrolysis firstly, and then porous carbon adsorbed metal ions was pyrolyzed again to obtain MMPC, which was tedious and energy-prodigal. In this study, a one-step pyrolysis strategy was developed for the synthesis of MMPC through the pyrolyzation of wheat bran adsorbed copper ions, and the copper microspheres doping wheat bran biochar (CMS-WBB) was prepared. The CMS-WBB was taken as the supporter of stearic acid (SA) to synthesize the ss-PCM of SA/CMS-WBB. The study results about the thermal properties of SA/CMS-WBB demonstrated that the introduction of copper microspheres could not only improve the thermal conductivity of SA/CMS-WBB, but also could increase the SA loading amount of wheat bran biochar. More importantly, the CMS-WBB could be obtained by only one-step pyrolysis, which greatly simplified the preparation process and saved energy consumption. Furthermore, the raw material of wheat bran is a kind of agricultural waste, which is abundant, cheap and easy to obtain. Hence, the SA/CMS-WBB synthesized in this study had huge potentialities in thermal management applications, and a simplified method for improving the thermal properties of ss-PCMs was provided.

scholarly journals The Effect of Hydroxylated Multi-Walled Carbon Nanotubes on the Properties of Peg-Cacl2 Form-Stable Phase Change Materials

Energies ◽  
2021 ◽  
Vol 14 (5) ◽  
pp. 1403
Author(s):  
Lingyu Zheng ◽  
Xuelai Zhang ◽  
Weisan Hua ◽  
Xinfeng Wu ◽  
Fa Mao
Keyword(s):  
Thermal Conductivity ◽  
Carbon Nanotubes ◽  
Phase Change ◽  
Phase Change Material ◽  
Phase Change Materials ◽  
Interfacial Thermal Resistance ◽  
Stable Phase ◽  
Multi Walled Carbon Nanotubes ◽  
Walled Carbon Nanotubes ◽  
Change Material

Calcium ions can react with polyethylene glycol (PEG) to form a form-stable phase change material, but the low thermal conductivity hinders its practical application. In this paper, hydroxylated multi-walled carbon nanotubes (MWCNTs) with different mass are introduced into PEG1500·CaCl2 form-stable phase change material to prepare a new type of energy storage material. Carbon nanotubes increased the mean free path (MFP) of phonons and effectively reduced the interfacial thermal resistance between pure PEG and PEG1500·CaCl2 3D skeleton structure. Thermal conductivity was significant improved after increasing MWCNTs mass, while the latent heat decreases. At 1.5 wt%, composite material shows the highest phase change temperature of 42 °C, and its thermal conductivity is 291.30% higher than pure PEG1500·CaCl2. This article can provide some suggestions for the preparation and application of high thermal conductivity form-stable phase change materials.

scholarly journals Enhancement of heat transfer in phase change material using graphite-paraffin composites

2018 ◽  
Vol 172 ◽  
pp. 02001
Author(s):  
R Sathiyaraj. ◽  
R Rakesh. ◽  
N Mithran. ◽  
M Venkatesan.
Keyword(s):  
Thermal Conductivity ◽  
Energy Storage ◽  
Phase Change ◽  
Phase Change Material ◽  
Phase Change Materials ◽  
Thermal Environment ◽  
Graphite Powder ◽  
Energy Storage Materials ◽  
Melting Period ◽  
Change Material

Phase change materials (PCMs) are energy storage materials which can be used for maintaining a controlled thermal environment for various applications in earth and space. PCMs are used in advanced technologies in aerospace cooling applications like heat exchangers and heat pipes for re-entry vehicles and spacecraft. Paraffin is a phase change material (PCM) commonly used for energy storage-related applications. Paraffin wax exhibits slow thermal response due to low thermal conductivity value (~0.2 W/m K for most paraffin waxes). In the present work, an attempt is made to fabricate a composite PCM using graphite powder. Such a composite material has enhanced thermal conductivity along with reduced melting period which are desirable properties of a PCM during solid to liquid phase change process. The reduction in melting period is indicated by the difference in change in temperature measured by the thermocouples during a specified time. The temperature variation and solid-liquid interface formation during the melting process are experimentally studied. The results showed that composite graphite powder with paraffin can improve the total phase transition time.

The Investigation of Phase Change Emulsion (PCE): Fabrication, Thermal Conductivity and Utilization of Nanoparticles

2013 ◽  
Vol 860-863 ◽  
pp. 862-866 ◽  
Author(s):  
Yi Fei Zheng ◽  
Zhong Zhu Qiu ◽  
Jie Chen
Keyword(s):  
Heat Transfer ◽  
Thermal Conductivity ◽  
Energy Storage ◽  
Phase Change ◽  
Phase Change Material ◽  
Phase Change Materials ◽  
Heat Storage ◽  
Change Material

Phase change materials in the form of emulsion (PCE) is a category of novel phase change fluid used as heat storage and transfer media. It plays an important role in commercially viable applications (energy storage, particularly).The emulsion is made of microparticles of a phase change wax (a kind of paraffin or mixture ) as a phase change material (PCM), mixed paraffin directly with water. This paper presents information on the different PCM emulsions by different researchers. It gives the method of preparation of the PCE, and makes a special effort to investigate the heat transfer phenomena and the method of enhancing the thermal conductivity of the emulsion.

Preparation and thermal properties of shape-stabilized composite phase change materials based on polyethylene glycol and porous carbon prepared from potato

RSC Advances ◽  
2016 ◽  
Vol 6 (19) ◽  
pp. 15821-15830 ◽  
Author(s):  
Bo Tan ◽  
Zhaohui Huang ◽  
Zhaoyu Yin ◽  
Xin Min ◽  
Yan'gai Liu ◽  
...  
Keyword(s):  
Thermal Properties ◽  
Polyethylene Glycol ◽  
Phase Change ◽  
Phase Change Material ◽  
Porous Carbon ◽  
Phase Change Materials ◽  
Composite Phase Change Materials ◽  
Composite Phase Change Material ◽  
Change Material

A shape-stabilized composite phase change material comprising PEG and porous carbon was prepared by absorbing PEG into porous carbon.

scholarly journals Analysis on the Improvement of Thermal Performance of Phase Change Material Ba (OH)2·8H2O

Energies ◽  
2021 ◽  
Vol 14 (22) ◽  
pp. 7761
Author(s):  
Xiaohui Lu ◽  
Xiaoxue Luo ◽  
Shibo Cao ◽  
Changzhen Zou
Keyword(s):  
Phase Change ◽  
Phase Change Material ◽  
Latent Heat ◽  
Large Scale ◽  
Phase Change Materials ◽  
Graphite Powder ◽  
Stable Phase ◽  
Heat Conducting ◽  
Supercooling Degree ◽  
Change Material

Benefitting from the characteristics of a high latent heat capacity and stable phase change behavior, phase change materials have widely received concerns in the field of thermodynamic management. Ba(OH)2·8H2O is an ideal phase change material (PCM) in the mid-to-low temperature range, but its large-scale application is still limited by severe supercooling during the nucleation process. In this paper, the experimental analysis and comparison are performed via an Edisonian approach, where Ba(OH)2·8H2O is adopted as an original substrate; BaCO3, CaCl2, NaCl, KH2PO4, and NaOH are selected as nucleating agents; and graphite is used as a heat-conducting agent. The results show that Ba(OH)2·8H2O containing 1.2% BaCO3 and 0.2% graphite powder has the best performance. Compared with pure Ba(OH)2·8H2O, the supercooling degree is reduced to less than 1 °C, the phase change latent heat duration is extended, and the thermal conductivity is significantly improved. Therefore, this study not only provides a reference for the application of Ba(OH)2·8H2O, but can also be used as a guidance for other material modifications.

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