A novel strategy for enhancing the thermal conductivity of shape-stable phase change materials via carbon-based in situ reduction of metal ions

2020 ◽  
Vol 243 ◽  
pp. 118627 ◽  
Author(s):  
Yan Chen ◽  
Han Ding ◽  
Junkai Gao ◽  
Xi Tang ◽  
Yi Liu ◽  
...  
Keyword(s):  
Thermal Conductivity ◽  
Metal Ions ◽  
Phase Change ◽  
Phase Change Materials ◽  
Stable Phase ◽  
In Situ Reduction ◽  
Novel Strategy ◽  
Carbon Based

scholarly journals Thermal and Physical Characterization of PEG Phase Change Materials Enhanced by Carbon-Based Nanoparticles

Nanomaterials ◽  
2020 ◽  
Vol 10 (6) ◽  
pp. 1168 ◽  
Author(s):  
David Cabaleiro ◽  
Samah Hamze ◽  
Jacek Fal ◽  
Marco A. Marcos ◽  
Patrice Estellé ◽  
...  
Keyword(s):  
Thermal Conductivity ◽  
Surface Tension ◽  
Carbon Black ◽  
Phase Change ◽  
Phase Change Materials ◽  
Physical Characterization ◽  
Plastic Behavior ◽  
Diamond Nanopowders ◽  
Carbon Based

This paper presents the preparation and thermal/physical characterization of phase change materials (PCMs) based on poly(ethylene glycol) 400 g·mol−1 and nano-enhanced by either carbon black (CB), a raw graphite/diamond nanomixture (G/D-r), a purified graphite/diamond nanomixture (G/D-p) or nano-Diamond nanopowders with purity grades of 87% or 97% (nD87 and nD97, respectively). Differential scanning calorimetry and oscillatory rheology experiments were used to provide an insight into the thermal and mechanical changes taking place during solid-liquid phase transitions of the carbon-based suspensions. PEG400-based samples loaded with 1.0 wt.% of raw graphite/diamond nanomixture (G/D-r) exhibited the lowest sub-cooling effect (with a reduction of ~2 K regarding neat PEG400). The influences that the type of carbon-based nanoadditive and nanoparticle loading (0.50 and 1.0 wt.%) have on dynamic viscosity, thermal conductivity, density and surface tension were also investigated in the temperature range from 288 to 318 K. Non-linear rheological experiments showed that all dispersions exhibited a non-Newtonian pseudo-plastic behavior, which was more noticeable in the case of carbon black nanofluids at low shear rates. The highest enhancements in thermal conductivity were observed for graphite/diamond nanomixtures (3.3–3.6%), while nano-diamond suspensions showed the largest modifications in density (0.64–0.66%). Reductions in surface tension were measured for the two nano-diamond nanopowders (nD87 and nD97), while slight increases (within experimental uncertainties) were observed for dispersions prepared using the other three carbon-based nanopowders. Finally, a good agreement was observed between the experimental surface tension measurements performed using a Du Noüy ring tensiometer and a drop-shape analyzer.

scholarly journals Preparation and Experimental Evaluation of Phase-Change Characteristics in Carbon-Based Suspensions

Materials ◽  
2018 ◽  
Vol 11 (8) ◽  
pp. 1315 ◽  
Author(s):  
Tun-Ping Teng ◽  
Ting-Chiang Hsiao ◽  
Chun-Chi Chung
Keyword(s):  
Thermal Conductivity ◽  
Contact Angle ◽  
Phase Change ◽  
Phase Change Materials ◽  
Sodium Dodecyl ◽  
Sodium Dodecyl Benzene Sulfonate ◽  
Freezing Temperature ◽  
Combustion Method ◽  
Change Characteristics ◽  
Carbon Based

In this study, micro/nanocarbon-based materials (MNCBMs) were prepared using the high-pressure combustion method (HPCM) with an isoperibol oxygen bomb calorimeter at different oxygen pressures (0.5–3.0 MPa). The prepared MNCBMs were added to water to form carbon-based suspensions (CBSs); sodium dodecyl benzene sulfonate (SDBS) and defoamer were added to the CBSs to enhance their stability. The thermal conductivity, viscosity, density, and contact angle of the CBSs were measured using appropriate instruments to determine their fundamental characteristics. The phase-change characteristics of the CBSs were measured and analyzed using a differential scanning calorimeter (DSC) to evaluate the feasibility of employing them as phase-change materials in ice-storage air-conditioning systems. The results revealed that the maximal change ratios of thermal conductivity, viscosity, density, and contact angle of the samples were −3.15%, 6.25%, 0.23%, and −57.03%, respectively, as compared with the water. The CBS of S5 (oxygen pressure of 2.0 MPa) had the lowest melting temperature and subcooling degree (SD) and the highest freezing temperature in the experiments conducted using the DSC; thus, S5 was determined to be the most suitable CBS for use as a phase-change material of cold energy storage in this study.

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.

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