Enhancement in Thermal Property of Phase Change Microcapsule with Modified Carbon Nanotube

2013 ◽  
Vol 856 ◽  
pp. 314-317 ◽  
Author(s):  
Min Li ◽  
Zhi Shen Wu
Keyword(s):  
Thermal Conductivity ◽  
Carbon Nanotubes ◽  
Thermal Stability ◽  
Phase Change ◽  
Stearyl Alcohol ◽  
Analysis Method ◽  
Phase Change Temperature ◽  
Heating And Cooling ◽  
Change Temperature ◽  
Thermal Stability Of

Carbon nanotubes grafted with stearyl alcohol (CNTs-SA) was used to enhance the thermal conductivities of the microcapsules. Differential Scanning Calorimeter (DSC) and thermogravimetry (TG) analysis method are employed to measure thermal properties of the prepared MicroPCM containing the grafted CNTs (MicroPCM/CNTs-SA). The results indicated the phase change temperature and latent heat of MicroPCM/CNTs-SA was 26.2°C and 47.7J/g. An increase in thermal conductivity, thermal stability of MicroPCM/CNTs-SA was observed. After 100 heating and cooling cycles, MicroPCM/CNTs-SA still had better durability and thermal stability.

scholarly journals Latent Heat Storage and Thermal Efficacy of Carboxymethyl Cellulose Carbon Foams Containing Ag, Al, Carbon Nanotubes, and Graphene in a Phase Change Material

Nanomaterials ◽  
2019 ◽  
Vol 9 (2) ◽  
pp. 158 ◽  
Author(s):  
Hong Kim ◽  
Yong-Sun Kim ◽  
Lee Kwac ◽  
Hee Shin ◽  
Sang Lee ◽  
...  
Keyword(s):  
Thermal Conductivity ◽  
Carbon Nanotubes ◽  
Phase Change ◽  
Latent Heat ◽  
Carbon Foam ◽  
Phase Change Temperature ◽  
Carbon Foams ◽  
Change Temperature ◽  
Latent Heat Loss ◽  
Change Material

Carbon foam was prepared from carboxymethyl cellulose (CMC) and Ag, Al and carbon nanotubes (CNTs), and graphene was added to the foam individually, to investigate the enhancement effects on the thermal conductivity. In addition, we used the vacuum method to impregnate erythritol of the phase change material (PCM) into the carbon foam samples to maximize the latent heat and minimize the latent heat loss during thermal cycling. Carbon foams containing Ag (CF-Ag), Al (CF-Al), CNT (CF-CNT) and graphene (CF-G) showed higher thermal conductivity than the carbon foam without any nano thermal conducting materials (CF). From the variations in temperature with time, erythritol added to CF, CF-Ag, CF-Al, CF-CNT, and CF-G was observed to decrease the time required to reach the phase change temperature when compared with pure erythritol. Among them, erythritol added to CF-G had the fastest phase change temperature, and this was related to the fact that this material had the highest thermal conductivity of the carbon foams used in this study. According to differential scanning calorimetry (DSC) analyses, the materials in which erythritol was added (CF, CF-Ag, CF-Al, CF-CNT, and CF-G) showed lower latent heat values than pure erythritol, as a result of their supplementation with carbon foam. However, the latent heat loss of these supplemented materials was less than that of pure erythritol during thermal cycling tests because of capillary and surface tension forces.

scholarly journals Largely enhanced thermal conductivity and thermal stability of ultra high molecular weight polyethylene composites via BN/CNT synergy

RSC Advances ◽  
2019 ◽  
Vol 9 (70) ◽  
pp. 40800-40809
Author(s):  
Yiyou Guo ◽  
Changlin Cao ◽  
Fubin Luo ◽  
Baoquan Huang ◽  
Liren Xiao ◽  
...  
Keyword(s):  
Thermal Conductivity ◽  
Carbon Nanotubes ◽  
Thermal Stability ◽  
Molecular Weight ◽  
Boron Nitride ◽  
Thermal Conduction ◽  
Conduction Path ◽  
Ultra High Molecular Weight ◽  
Thermal Stability Of ◽  
Enhanced Thermal Conductivity

The carbon nanotubes (CNTs) synergistically assist boron nitride microsheets (BNs) to form a more continuous and effective thermal conduction path.

Thermal Stability Experimental Study on Three Types of Organic Binary Phase Change Materials Applied in Thermal Energy Storage System

2018 ◽  
Vol 10 (4) ◽  
Author(s):  
Song Mengjie ◽  
Liao Liyuan ◽  
Niu Fuxin ◽  
Mao Ning ◽  
Liu Shengchun ◽  
...  
Keyword(s):  
Thermal Stability ◽  
Energy Storage ◽  
Phase Change ◽  
Thermal Energy ◽  
Thermal Energy Storage ◽  
Phase Change Materials ◽  
Research Work ◽  
Energy Storage Materials ◽  
Phase Change Temperature ◽  
Change Temperature

Phase change materials (PCMs) are widely applied in recent decades due to their good thermal performance in energy systems. Their applications are mainly limited by the phase change temperature and latent heat. Many publications are reported around the characteristic improvement of binary organic PCMs. The thermal stability study on organic binary PCMs used in thermal energy storage applications becomes fundamental and meaningful. In this study, thermal stability of three types of organic binary PCMs was experimentally investigated, which are frequently used in building and industry applications. To qualitatively investigate the stability of composite PCMs, differential scanning calorimetry (DSC), and Fourier-transform infrared spectroscopy (FT-IR) spectra testing of samples were also conducted. Experimental results showed that the selected composite PCMs, capric acid (CA), and myristic acid (MA), had the best thermal performances, with its phase change temperature unchanged and heat of fusion decreased only 8.88 J/g, or 4.55%, after 2000 thermal cycles. Furthermore, quality ratio of required PCMs as the variation of operation duration was analyzed to quantitatively prepare the materials. The PCMs can successfully operate about 3125 times when prepared as 1.20 times of its calculated value by starting fusion heat. Conclusions of this research work can also be used for guiding the selection and preparation of other energy storage materials.

Study on Phase-Change Temperature and Latent Heat of Organic Phase-Change Nano-Fluid

2010 ◽  
Vol 152-153 ◽  
pp. 1591-1594 ◽  
Author(s):  
Jian You Long
Keyword(s):  
Thermal Conductivity ◽  
Phase Change ◽  
Latent Heat ◽  
Organic Phase ◽  
High Thermal Conductivity ◽  
Phase Change Temperature ◽  
Nano Fluid ◽  
Change Temperature ◽  
Surface Modified

Nano-aluminum, which has high thermal conductivity and good compatibility, was added into paraffin to improve its thermal conductivity. Surface modified technology was adopted and dispersant was used to prepare uniform and stable organic phase-change nano-fluid of paraffin and nano-aluminum. Experiments were conducted to test the phase-change temperature and latent heat of the prepared organic phase-change nano-fluid. Results show that the addition of nano-aluminum has no effect on phase-change temperature, but it changes phase-change latent heat of the prepared organic phase-change nano-fluid. Reduced degree of the latent heat is nearly proportional to the quantity of the added nano-aluminum.

Numerical and experimental investigation on dynamic thermal performance of floor heating system with phase change material for thermal storage

2020 ◽  
pp. 1420326X1990053
Author(s):  
Qunli Zhang ◽  
Zhaosheng Yang ◽  
Gang Wang
Keyword(s):  
Thermal Conductivity ◽  
Numerical Model ◽  
Phase Change ◽  
Thermal Performance ◽  
Heating System ◽  
Indoor Temperature ◽  
Phase Change Temperature ◽  
Fluctuation Range ◽  
Change Temperature ◽  
Floor Heating

The floor heating system with phase change materials (PCMs) for thermal storage is an effective approach to increase the floor thermal capacity and reduce indoor temperature fluctuation range. A two-dimensional numerical model of the floor heating system combined with PCM was developed to investigate its dynamic thermal performance in winter. To verify the reliability of the model, an experimental room was established in Beijing, China. The experiment results agreed well with the modelling results, which demonstrated that the numerical model was reliable. The effects of the phase change temperature, latent heat and thermal conductivity of PCM on the thermal performance of the floor were numerically investigated. The results showed that the phase change temperature and thermal conductivity of PCM had a significant influence on thermal comfort. At the same time, these two thermal physical parameters also played a critical role in improving the utilization rate of PCM. Conversely, the latent heat, in the range of 100 to 200 kJ/kg, had no obvious influence on the thermal performance of the floor. PCM with phase change temperature of 313 K was recommended, which could increase the average indoor temperature by 2.2 K, increase the thermal energy storage ratio by 12% and reduce indoor temperature fluctuation range by 2.2 K.

Preparation and thermal properties of Glauber’s salt-based phase-change materials for Qinghai–Tibet Plateau solar greenhouses

2017 ◽  
Vol 31 (16-19) ◽  
pp. 1744085 ◽  
Author(s):  
Zipeng Jiang ◽  
Shengnian Tie
Keyword(s):  
Thermal Conductivity ◽  
Phase Change ◽  
Latent Heat ◽  
Phase Change Materials ◽  
Tibet Plateau ◽  
Basic Material ◽  
Phase Change Temperature ◽  
Industrial Grade ◽  
Change Temperature ◽  
Qinghai Tibet Plateau

This paper reports the preparation and characterization of eutectic Glauber’s salt-based composite, phase-change materials (G-PCMs). PCMs were prepared using industrial-grade sodium sulfate decahydrate (Na2SO4 ⋅ 10H2O) as the basic material. Other salts were added to obtain the eutectic Glauber’s salt-based PCMs with phase-change temperatures of 25[Formula: see text]C, 15[Formula: see text]C and 10[Formula: see text]C. The modification of the G-PCMs was designed using the same experimental method to select the efficient nucleating, thickening and thermal conductive agents. The results show that borax can be an effective nucleating agent, sodium carboxymethyl cellulose is an excellent thickener and carbon powder is a good thermal conductive agent. The phase-change temperature, latent heat and thermal conductivity of the three different PCMs are 23.9[Formula: see text]C, 15.4[Formula: see text]C and 9.5[Formula: see text]C; 179.6, 129 and 116.2 J/g; and 1.02, 1.10 and 1.23 W/(m K), respectively. These PCMs possess suitable phase-change temperature, high latent heat and good thermal conductivity, and can be used in Qinghai–Tibet Plateau agricultural solar greenhouses.

scholarly journals Thermoelectric Materials for Textile Applications

Molecules ◽  
2021 ◽  
Vol 26 (11) ◽  
pp. 3154
Author(s):  
Kony Chatterjee ◽  
Tushar K. Ghosh
Keyword(s):  
Thermal Conductivity ◽  
Carbon Nanotubes ◽  
Seebeck Coefficient ◽  
Thermoelectric Materials ◽  
Figure Of Merit ◽  
Inorganic Materials ◽  
Peltier Effect ◽  
Electronic Textiles ◽  
Heating And Cooling ◽  
Recent Attention

Since prehistoric times, textiles have served an important role–providing necessary protection and comfort. Recently, the rise of electronic textiles (e-textiles) as part of the larger efforts to develop smart textiles, has paved the way for enhancing textile functionalities including sensing, energy harvesting, and active heating and cooling. Recent attention has focused on the integration of thermoelectric (TE) functionalities into textiles—making fabrics capable of either converting body heating into electricity (Seebeck effect) or conversely using electricity to provide next-to-skin heating/cooling (Peltier effect). Various TE materials have been explored, classified broadly into (i) inorganic, (ii) organic, and (iii) hybrid organic-inorganic. TE figure-of-merit (ZT) is commonly used to correlate Seebeck coefficient, electrical and thermal conductivity. For textiles, it is important to think of appropriate materials not just in terms of ZT, but also whether they are flexible, conformable, and easily processable. Commercial TEs usually compromise rigid, sometimes toxic, inorganic materials such as bismuth and lead. For textiles, organic and hybrid TE materials are more appropriate. Carbon-based TE materials have been especially attractive since graphene and carbon nanotubes have excellent transport properties with easy modifications to create TE materials with high ZT and textile compatibility. This review focuses on flexible TE materials and their integration into textiles.

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