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.

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.

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.

Setting for the Application of Phase Change Paraffin in Block Masonry

2013 ◽  
Vol 448-453 ◽  
pp. 1308-1311
Author(s):  
Feng Jiang ◽  
Yong Le Hou ◽  
Yong Lin Hu ◽  
Wei Dong Zhu ◽  
Qing Hua Wang
Keyword(s):  
Phase Change ◽  
Phase Change Material ◽  
Latent Heat ◽  
Phase Change Materials ◽  
Liquid Paraffin ◽  
Change Temperature ◽  
Composite Phase Change Material ◽  
Heat Preservation ◽  
Solid Liquid ◽  
Change Material

This paper studies the insulation properties of masonry filling paraffin composite phase change material. With high density polyethylene (HDPE) as wrapping materials and solid-liquid mixing paraffin as phase change materials, solid-liquid mixed paraffin phase change material with different amount of admixture is prepared, and the problem of flowing after paraffin phase change is then solved. The phase change temperature and the phase change latent heat of composite phase change material with different amount of admixture are tested. The results showed that the composite material with 30% of 52 # solid paraffin, 70% of liquid paraffin, 70% of HDPE coating performs best as to the phase transition temperature and latent heat. On this basis, This paper studies the composite phase change wall with phase change materials 0%, 33%, 66% and100%. Results show that the composite phase change material wall’s heat preservation performance has significantly improved. the temperature fluctuation range of internal and external wall surface is 4.2 °C lower than unfilled wall.

Preparation and Characterization of a Form-Stable Phase Change Materials Composed by UF, Paraffin and Expanded Perlite

2011 ◽  
Vol 347-353 ◽  
pp. 4109-4113
Author(s):  
Kun Xu ◽  
Shi Rong Liu ◽  
Zhong Bin Ni ◽  
Ming Qing Chen ◽  
Ming Fu Mao
Keyword(s):  
Phase Change ◽  
Phase Change Material ◽  
Phase Change Materials ◽  
Urea Formaldehyde ◽  
Vacuum Impregnation ◽  
Stable Phase ◽  
Expanded Perlite ◽  
Ft Ir ◽  
Dsc Method ◽  
Change Material

A kind of form stable phase change material (PCM) based on expanded perlite, paraffin, urea formaldehyde hybrids is prepared by using vacuum-impregnation process. This kind of form stable PCM is made of paraffin as a dispersed phase change material and expanded perlite as a supporting material, and urea-formaldehyde resins as membrane materials to be applied to the porous surface of expanded perlite(EP). The structure of urea-formaldehyde resins(UF) being prepared is characterized by Fourier Transform Infrared Spectrophotometer(FT-IR). Hybrids’ thermal stability, latentheat and morphology are characterized by the thermogravimetry analysis(TGA), differential scanning calorimeter(DSC) Method and scanning electronic microscope(SEM), respectively. The FT-IR and SEM curves show that urea-formaldehyde resins have already been formed. The TGA analysis indicates that the form-stable phase change material has very good thermostability under working atmosphere. The application of DSC not only studies the appropriate curing time of UF，but also indicates that the form-stable PCM that has been prepared has more stable thermal energy storage performance than the traditional one.

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.

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