Investigation of heat capacity and viscosity enhancements of binary carbonate salt mixture with SiO2 nanoparticles

The specific heat capacity of a carbonate salt eutectic-based carbon nanotube nanomaterial was measured in present study. Differential scanning calorimeter (DSC) was used to measure the specific heat capacity of the nanomaterials. The specific heat capacity value in liquid phase was compared with that of a pure eutectic. A carbonate salt eutectic was used as a base material, which consists of lithium carbonate and potassium carbonate by 62:38 molar ratio. Multiwalled carbon nanotubes (CNT) at 1% mass concentration were dispersed in the molten salt eutectic. In order to find an appropriate surfactant for synthesizing molten salt nanomaterials, three surfactants, sodium dodecyl benzene sulfonate (SDBS), sodium dodecyl sulfate (SDS), and gum arabic (GA), at 1% mass concentration with respect to the salt eutectic were added. In preparation of dehydrated nanomaterials, water was evaporated by heating vials on a hot plate. Three different temperature conditions (120, 140, and 160 °C) were employed to investigate the effect of dispersion homogeneity of the nanotubes in the base material on the specific heat capacity of the nanomaterials. It is expected that the amount of agglomerated nanotubes decreases with increase of evaporation temperature (shorter elapsed time for evaporation). The results showed that the specific heat capacity of the nanomaterials was enhanced up to 21% in liquid phase. Additionally, it was found that the specific heat capacity enhancement of the nanomaterials, which contained SDS, was more sensitive to the evaporation time. Also, it can be decided that GA is the most appropriate to disperse CNT into the aqueous salt solution. Finally, CNT dispersion was confirmed with scanning electron microscope (SEM) images for pre-DSC and post-DSC samples. Furthermore, theoretical predictions of the specific heat capacity were compared with the experimental results obtained in present study.

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Nanoparticle Dispersions on Ternary Nitrate Salts for Heat Transfer Fluid Applications in Solar Thermal Power

Journal of Heat Transfer ◽

10.1115/1.4030903 ◽

2016 ◽

Vol 138 (5) ◽

Cited By ~ 5

Author(s):

Ramaprasath Devaradjane ◽

Donghyun Shin

Keyword(s):

Heat Transfer ◽

Heat Capacity ◽

Thermal Power ◽

Heat Transfer Fluid ◽

Salt Mixture ◽

Step Method ◽

Sio2 Nanoparticle ◽

Nanoparticle Dispersions ◽

The Cost ◽

Measure Heat Capacity

In this study, we report enhancement in heat capacity of SiO2 nanoparticle dispersions in a molten ternary nitrate salt (NaNO3, KNO3, and Ca(NO3)2) to obtain an effective heat transfer fluid (HTF)/thermal energy storage (TES) for concentrated solar power (CSP) application. The enhanced heat capacity of the molten salt mixture is expected to greatly increase thermal storage density of HTF/TES, and thus the cost of electricity produced by CSP plant can be significantly reduced. A custom two-step method was used to synthesize SiO2 nanoparticle/ternary salt mixture. The nanoparticle concentration of the mixture was fixed at 1% by weight for comparison with the previous studies. A modulated differential scanning calorimeter (MDSC) was employed to measure heat capacity of the mixture, and it was found to be enhanced by ∼19% compared to the pure ternary salt.

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In Situ Synthesis of Alumina Nanoparticles in a Binary Carbonate Salt Eutectic for Enhancing Heat Capacity

Nanomaterials ◽

10.3390/nano10112131 ◽

2020 ◽

Vol 10 (11) ◽

pp. 2131

Author(s):

Yousof Nayfeh ◽

Syed Muhammad Mujtaba Rizvi ◽

Baha El Far ◽

Donghyun Shin

Keyword(s):

Thermal Decomposition ◽

Heat Capacity ◽

Electron Microscope ◽

Aluminum Nitrate ◽

Alumina Nanoparticles ◽

Al2o3 Nanoparticles ◽

Aluminum Nitrate Nonahydrate ◽

Nitrate Nonahydrate ◽

Carbonate Salt

A binary carbonate salt eutectic (Li2CO3-K2CO3)-based nanofluid was in situ synthesized by mixing with a precursor material, aluminum nitrate nonahydrate (Al(NO3)3·9H2O). Thermal decomposition of the precursor was successfully carried out to synthesize alumina (Al2O3) nanoparticles at 1 wt.% concentration. A thermogravimetric analysis (TGA) confirmed a complete thermal decomposition of aluminum nitrate nonahydrate to alumina nanoparticles. A transmission electron microscope (TEM) was employed to confirm the size and shape of the in situ formed nanoparticles; the result showed that they are spherical in shape and the average size was 28.7 nm with a standard deviation of 11.7 nm. Electron dispersive X-ray spectroscopy (EDS) confirmed the observed nanoparticles are alumina nanoparticles. A scanning electron microscope (SEM) was employed to study microstructural changes in the salt. A differential scanning calorimeter (DSC) was employed to study the heat capacity of the in situ synthesized nanofluid. The result showed that the heat capacity was enhanced by 21% at 550 °C in comparison with pure carbonate salt eutectic. About 10–11 °C decrease of the onset melting point of the binary carbonate salt eutectic was observed for the in situ synthesized nanofluids.

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A Novel Method for the Synthesis of Binary Molten Salt Nanofluids Adding SiO2 Nanoparticles

10.21203/rs.3.rs-97853/v1 ◽

2020 ◽

Author(s):

Joohyun Seo

Keyword(s):

Heat Capacity ◽

Sample Preparation ◽

Phase Change ◽

Specific Heat ◽

Molten Salt ◽

Specific Heat Capacity ◽

Sio2 Nanoparticles ◽

Bottom Surface ◽

Unexpected Result ◽

Novel Method

Abstract In this study, the new method has been suggested for the synthesis of a binary molten salt eutectic adding nanoparticles (i.e. molten salt nanofluids). Solar salt (i.e. NaNO 3 -KNO 3 , 60:40 by weight) adding 10nm of SiO 2 nanoparticles was prepared to measure the specific heat capacity of molten salt nanofluids by a modulated differential scanning calorimeter (MDSC). In previous studies the sample preparation of a molten salt eutectic follows the same procedure. Each chemical of a molten salt eutectic and nanoparticles is dissolved in an aqueous solution. These homogeneous salts are completely mixed by a sonication. Nano-mixtures are scrapped off the bottom surface of a vial after drying. However, there are complex steps in the process of getting fresh molten salt eutectic nanofluids before MDSC measurements. An unexpected result is able to occur due to phase change (i.e. solid-liquid-solid) at each step and then it has an affect on the specific heat capacity of molten salt nanofluids. A suggested novel method (i.e. Liquid-to-Liquid) can not only prevent unexpected errors (e.g. the possibility of contamination) by phase change in the sample preparation, but also enhance the specific heat capacity of molten salt nanofluids.

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Enhanced Specific Heat Capacity of Molten Salt-Based Carbon Nanotubes Nanomaterials

Journal of Heat Transfer ◽

10.1115/1.4030226 ◽

2015 ◽

Vol 137 (9) ◽

Cited By ~ 28

Author(s):

Byeongnam Jo ◽

Debjyoti Banerjee

Keyword(s):

Heat Capacity ◽

Liquid Phase ◽

Specific Heat ◽

Molten Salt ◽

Specific Heat Capacity ◽

Sodium Dodecyl ◽

Base Material ◽

Molar Ratio ◽

Sem Images ◽

Carbonate Salt

This study aims to investigate the specific heat capacity of a carbonate salt eutectic-based multiwalled carbon nanomaterial (or high temperature nanofluids). The specific heat capacity of the nanomaterials was measured both in solid and liquid phase using a differential scanning calorimetry (DSC). The effect of the carbon nanotube (CNT) concentrations on the specific heat capacity was examined in this study. The carbonate molten salt eutectic with a high melting point around 490 °C, which consists of lithium carbonate of 62% and potassium carbonate of 38% by the molar ratio, was used as a base material. Multiwalled CNTs were dispersed in the carbonate salt eutectic. A surfactant, sodium dodecyl sulfate (SDS) was utilized to obtain homogeneous dispersion of CNT into the eutectic. Four different concentrations (0.1, 0.5, 1, and 5 wt.%) of CNT were employed to explore the specific heat capacity enhancement of the nanomaterials as the concentrations of the nanotubes varies. In result, it was observed that the specific heat capacity was enhanced by doping with the nanotubes in both solid and liquid phase. Additionally, the enhancements in the specific heat capacity were increased with increase of the CNT concentration. In order to check the uniformity of dispersion of the nanotubes in the salt, scanning electron microscopy (SEM) images were obtained for pre-DSC and post-DSC samples. Finally, the specific heat capacity results measured in present study were compared with the theoretical prediction.

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HEAT CAPACITY MEASUREMENTS ON THE DILUTED ISING SYSTEM Cs3CopZn1-pCl5

Le Journal de Physique Colloques ◽

10.1051/jphyscol:19711359 ◽

1971 ◽

Vol 32 (C1) ◽

pp. C1-1008-C1-1009 ◽

Cited By ~ 3

Author(s):

E. LAGENDIJK ◽

W. J. HUISKAMP ◽

P. F. BONGERS

Keyword(s):

Heat Capacity ◽

Ising System ◽

Heat Capacity Measurements

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