A simplification of the differential thermal analysis method to determine the latent heat of fusion of phase change materials

1987 ◽  
Vol 20 (12) ◽  
pp. 1601-1605 ◽  
Author(s):  
D Buddhi ◽  
R L Sawhney ◽  
P N Sehgal ◽  
N K Bansal
Author(s):  
Xiaobo Li ◽  
Hengzhi Wang ◽  
Hui Wang ◽  
Sohae Kim ◽  
Keivan Esfarjani ◽  
...  

Inorganic materials and organic salts are usually used as phase change materials (PCMs) for thermal energy storage. Some of these materials have high latent heat of fusion; however one major drawback of these materials is the low thermal conductivity, which limits the rate of charging and discharging process. In this paper, we studied metallic alloys (eutectic alloys or alloys with a narrow melting temperature range) as phase-change materials, which have both high thermal conductivity and high latent heat of fusion. A formula was presented from entropy change to predict the latent heat of fusion of metallic alloys. We found that the latent heat of fusion of alloys can be expressed from three different contributions: the latent heat from each element, the sensible heat, and the mixing entropy. From the theory we also showed that latent heat of fusion could be greatly increased by maximizing the entropy of mixing, which can be realized by introduce more elements in the alloys, i.e., form ternary alloys by adding elements to binary alloys. This idea is demonstrated by the synthesis and measurement of the binary alloy 87.8Al-12.2Si (at%) and ternary alloy 45Al-40Si-15Fe (at%). The metallic alloy is synthesized by hot pressing method. The latent heat of fusion of 45Al-40Si-15Fe (at%) is about 865 kJ/kg with melting temperature from 830 °C to 890 °C from the differential scanning calorimetry (DSC) measurement, comparing with 554.9 kJ/kg and 578.3 °C for the binary alloy 87.8Al-12.2Si (at%). From the binary to the ternary alloy, the contribution to the latent heat from mixing entropy increases by 17%.


2019 ◽  
Vol 140 (4) ◽  
pp. 1825-1836 ◽  
Author(s):  
Carlos González-Rivera ◽  
Anthony Harrup ◽  
Carla Aguilar ◽  
Adrián M. Amaro-Villeda ◽  
Marco A. Ramírez-Argáez

Author(s):  
Ivan K. Garkushin ◽  
Inna N Samsonova ◽  
Tatiana V. Gubanova

Phase equilibria of quaternary system LiF-LiVO3-NaBr-NaVO3 were studied with differential thermal analysis method. The temperature and composition of eutectic point was determined: Е 458 ºС: 11.2% LiF, 57.2% LiVO3, 16% NaBr, 15.6% LiVO3.


Author(s):  
Pau Gimenez-Gavarrell ◽  
Vincent D. Romanin ◽  
Sonia Fereres

Thermal Energy Storage (TES) can improve the efficient and economical use of available resources associated with renewable energies. The choice of Phase Change Materials (PCM) for TES applications is particularly attractive, since PCMs provide high energy storage densities, low costs, and allow energy storage at constant temperatures during the melting/solidification process. However, most commonly used PCMs have low thermal conductivity values, typically less than 1 W/mK. This leads to insufficient heat exchange rates in many applications, where power is as important as the amount of energy stored. Previous studies have shown that adding nanoparticles to molten salts can enhance the thermal conductivity and heat capacity, thus improving performance in TES systems. This study analyzes how adding nanoparticles to ionic liquids/solids affects the latent heat of fusion and melting temperature, critical characteristics of many thermal management systems. An important aspect of nanoparticle suspension preparation is the synthesis method, both from the point of view of scalability and effect on thermophysical properties. Several nanoparticle suspensions are synthesized with carbon nanotubes (CNT) and salt or ionic liquid base materials, using different synthesis methods and sonication times. The melting point and latent heat of fusion are measured for the base materials and nanoparticle suspensions using a Differential Scanning Calorimeter (DSC). The change in latent heat and melting temperature of the nanofluid with respect to the base fluid is shown to be present but not substantial. Possible explanations for the modification of thermal properties with respect to the base fluid are discussed.


2017 ◽  
Vol 73 (2) ◽  
pp. I_1201-I_1206
Author(s):  
Hiroki TAKATA ◽  
Yuki MORIMOTO ◽  
Narong TOUCH ◽  
Shinya NAKASHITA ◽  
Tadashi HIBINO

2019 ◽  
Vol 1151 ◽  
pp. 29-33 ◽  
Author(s):  
Karen Acurio ◽  
Andrés Chico-Proano ◽  
Javier Martínez-Gómez ◽  
Marco Orozco

In this study, the use of spent diatomite, an industrial waste in the palm oil production process, was evaluated as a support material for phase change materials (PCMs). Calcination tests of the diatomite were carried out at different temperatures (400, 550 and 700 °C) and times (1 and 2 h). For the PCMs preparation, the organic phase, mixtures of palm oil and commercial stearic acid esters, were impregnated on calcined diatomite under vacuum. Differential scanning calorimetry (DSC) analyses were performed in order to select the PCM with the highest latent heat of fusion and a range of phase change temperature corresponding to the thermal comfort range. DSC, TGA and FT-IR analyses were performed before and after the application of 360 thermal cycles to establish the thermal and chemical reliability of the PCM. It was found that 700 °C and 1 h are the best conditions of the calcination process, and the PCM consisting in 100 % methyl esters of commercial stearic acid presented the highest value of latent heat of fusion (34.67 J/g) and a phase change temperature range of 16.4 to 33.5 °C. After the thermal cycles, the results show that the prepared PCMs has thermal and chemical stability.


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