Cellulose nanofiber grafting and aluminum nitride deposition on the surface of expanded graphite to improve the thermal conductivity and mechanical properties of phase change material composites

2021 ◽  
pp. 109526
Author(s):  
Wondu Lee ◽  
Jooheon Kim
Keyword(s):  
Mechanical Properties ◽  
Thermal Conductivity ◽  
Aluminum Nitride ◽  
Phase Change ◽  
Phase Change Material ◽  
Expanded Graphite ◽  
Cellulose Nanofiber ◽  
Change Material

Effect of the Additive on Thermal Conductivity of the Phase Change Material

2011 ◽  
Vol 399-401 ◽  
pp. 1302-1306 ◽  
Author(s):  
Wei Hua Li ◽  
Jin Feng Mao ◽  
Li Jun Wang ◽  
Lu Yan Sui
Keyword(s):  
Thermal Conductivity ◽  
Phase Change ◽  
Phase Change Material ◽  
Sodium Acetate ◽  
Heat Storage ◽  
Expanded Graphite ◽  
Sodium Acetate Trihydrate ◽  
Acetate Trihydrate ◽  
Composite Phase Change Material ◽  
Change Material

The aim of the paper is to analyze the effect of the additives on thermal conductivity of the phase change material. The experiment about heat storage and heat release performance of the composite phase change material which uses sodium acetate trihydrate as host material is studied. The effect of the expanded graphite on the composite phase change material is investigated. The results show that: expanded graphite which can be dispersed evenly in the composite phase change material, the thermal stability is well, significantly improve the thermal conductivity of the composite phase change material.

scholarly journals Preparation of SA–PA–LA/EG/CF CPCM and Its Application in Battery Thermal Management

Nanomaterials ◽  
2021 ◽  
Vol 11 (8) ◽  
pp. 1902
Author(s):  
Ziqiang Liu ◽  
Juhua Huang ◽  
Ming Cao ◽  
Yafang Zhang ◽  
Jin Hu ◽  
...  
Keyword(s):  
Mechanical Properties ◽  
Thermal Conductivity ◽  
Phase Change ◽  
Phase Change Material ◽  
Thermal Management ◽  
Double Layer ◽  
Temperature Control ◽  
Single Layer ◽  
Mass Ratio ◽  
Change Material

To improve the heat dissipation efficiency of batteries, the eutectic mass ratios of each component in the ternary low-melting phase change material (PCM), consisting of stearic acid (SA), palmitic acid (PA), and lauric acid (LA), was explored in this study. Subsequently, based on the principle of high thermal conductivity and low leakage, SA–PA–LA/expanded graphite (EG)/carbon fiber (CF) composite phase change material (CPCM) was prepared. A novel double-layer CPCM, with different melting points, was designed for the battery-temperature control test. Lastly, the thermal management performance of non-CPCM, single-layer CPCM, and double-layer CPCM was compared via multi-condition charge and discharge experiments. When the mass ratio of SA to PA is close to 8:2, better eutectic state is achieved, whereas the eutectic mass ratio of the components of SA–PA–LA in ternary PCM is 29.6:7.4:63. SA–PA–LA/EG/CF CPCM formed by physical adsorption has better mechanical properties, thermal stability, and faster heat storage and heat release rate than PCM. When the CF content in SA–PA–LA/EG/CF CPCM is 5%, and the mass ratio of SA–PA–LA to EG is 91:9, the resulting SA–PA–LA/EG/CF CPCM has lower leakage rate and better thermal conductivity. The temperature control effect of single-layer paraffin wax (PW)/EG/CF CPCM is evident when compared to the no-CPCM condition. However, the double-layer CPCM (PW/EG/CF and SA–PA–LA/EG/CF CPCM) can further reduce the temperature rise of the battery, effectively control the temperature and temperature difference, and primarily maintain the battery in a lower temperature range during usage. After adding an aluminum honeycomb to the double-layer CPCM, the double-layer CPCM exhibited better thermal conductivity and mechanical properties. Moreover, the structure showed better battery temperature control performance, while meeting the temperature control requirements during the charging and discharging cycles of the battery.

scholarly journals THE EFFECT OF EXPANDED GRAPHITE ON THE CHARGING TIME OF STEARIC ACID PHASE CHANGE MATERIAL IN A HOT WATER TANK

2021 ◽  
Vol 11 (2) ◽  
pp. 14-24
Author(s):  
Khin Yu Sett ◽  
Mi Sandar Mon
Keyword(s):  
Thermal Conductivity ◽  
Stearic Acid ◽  
Phase Change ◽  
Phase Change Material ◽  
Expanded Graphite ◽  
Hot Water ◽  
Melting Time ◽  
Mass Ratio ◽  
Charging Time ◽  
Change Material

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.

scholarly journals Experimental Study of an Enhanced Phase Change Material of Paraffin/Expanded Graphite/Nano-Metal Particles for a Personal Cooling System

Materials ◽  
2020 ◽  
Vol 13 (4) ◽  
pp. 980
Author(s):  
Chuyuan Ma ◽  
Ying Zhang ◽  
Xianfeng Chen ◽  
Xiande Song ◽  
Kaixuan Tang
Keyword(s):  
Thermal Conductivity ◽  
Phase Change ◽  
Phase Change Material ◽  
Heat Storage ◽  
Cooling System ◽  
Expanded Graphite ◽  
Nano Particles ◽  
Metal Particles ◽  
Personal Cooling ◽  
Change Material

A composite phase change material (PCM) was prepared by incorporating paraffin (PA) with expanded graphite (EG) and nano-metal particles to improve the thermal conductivity and reduce the leakage performance of PA once it melts and, consequently, develop a more efficient PCM for a personal phase change cooling system. A series of experiments was carried out by a scanning electron microscope, a differential scanning calorimeter, a hot-disk thermal analyzer, and leakage tests on the composite PCM with various mass fractions of EG and metals (i.e., Cu, Al, Ni, and Fe). Through comprehensive consideration of the thermal conductivity, leakage, and homogeneity, a composite PCM with the optimal proportion (PA-EG11%-Cu1.9%) was screened out. Its thermal conductivity was significantly improved nine times, while the phase change enthalpy showed a minimal decrease. In addition, the relationships of the composite PCM with its temperature and density were systematically investigated. The experimental results are important for determining the proper package density of PCM for application into a personal cooling system because its weight is crucial for the system design and benefits the performance comparison of various PCMs prepared under various conditions. Lastly, the heat storage efficiency of the PA–EG–Cu material was investigated using heat storage tests. Cooling performance clearly improved compared to the PCM without nano-particles added.

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