A Literature Review on Novel Nitrate Molten Salt for Heat Storage

2021 ◽  
Vol 881 ◽  
pp. 87-94
Author(s):  
Jin Hua Chen
Keyword(s):  
Thermal Stability ◽  
Heat Capacity ◽  
Melting Point ◽  
Specific Heat ◽  
Molten Salt ◽  
Specific Heat Capacity ◽  
Molten Salts ◽  
Heat Storage ◽  
Stability Limit ◽  
Capacity Enhancement

Reducing the melting point, in creasing the thermal stability limit, and enhancing the specific heat capacity of molten salt are the research hotspots in the field of medium and high temperature energy storage in recent years. From the perspectives of the melting point, thermal stability limit, and specific heat capacity of nitrates, we summarize the melting point, thermal stability limit, and specific heat capacity enhancement of molten salts with different compositions and ratios. The melting points of molten salt with different compositions and ratios are compared. Furthermore, the enhancing effect of various nanomaterials on molten salt is elucidated. The application of nitrate molten salt is also summarized to provide a reference for the research and application of novel molten salts. Keywords: Nitrate Molten Salt; Melting Point; Thermal Stability Limit; Specific Heat Capacity; Application

scholarly journals The Effects of Nanoparticles on the Specific Heat Capacity of Molten Salts

2018 ◽  
Vol 5 ◽  
pp. 56-65
Author(s):  
Alexander Foldi ◽  
Duy Khang Simba Nguyen ◽  
Yeong Cherng Yap
Keyword(s):  
Heat Capacity ◽  
Thermal Properties ◽  
Specific Heat ◽  
Molten Salt ◽  
Specific Heat Capacity ◽  
Molten Salts ◽  
Power Plants ◽  
Renewable Energy Sources ◽  
Efficiency Increase ◽  
Solar Power Plants

The desire to increase the efficiency of existing renewable energy sources has been thoroughly researched over the past years. This meta study aimed to investigate existing methods used by previous researchers to increase the Specific Heat Capacity of Molten Salt used for Concentrated Solar Power Plants. Investigations into nanoparticles were explored because of the effect of particle size and concentration can potentially increase the specific heat capacity of the molten salt. Numerous nanoparticles have shown to improve the thermal properties such as Silica (SiO2), Alumina (Al2O3), Titania (TiO2). Our summation was that the addition of nanoparticles into Molten Salts shows an increase in desired thermal properties of the Molten Salts. An efficiency increase of up to 28% was noted in the SHC (Cp) of the Molten Salts when Nanoparticles of 60nm were introduced.

Study on Modification of Hitec Molten Salt and its Properties Tests

2014 ◽  
Vol 1073-1076 ◽  
pp. 66-72
Author(s):  
Wei Zhai ◽  
Guang Ming Liu ◽  
Fei Yu ◽  
Yuan Kui Wang
Keyword(s):  
Thermal Stability ◽  
Phase Transformation ◽  
Melting Point ◽  
Molten Salt ◽  
Latent Heat ◽  
Molten Salts ◽  
Heat Storage ◽  
Heat Of Fusion ◽  
Temperature Heat ◽  
Thermal Stability Of

In this paper, additive A and additive B were added into Hitec molten salts in order to optimize the properties of the molten salt. The melting point, latent heat of phase transformation, specific heat capacity, thermal gravity, and thermal stability of the modified Hitec molten salt was characterized. The results showed that compare to Hitec molten salt the modified Hitec molten salt showed low melting point, proper latent heat of phase transformation, greater heat of fusion, wide using temperature range and other advantages. The modified molten salt had good thermal properties and thermal stability. This modified Hitec molten salt has good application prospect in the aspect of high temperature heat storage/transfer.

Experimental Investigation of Molten Salt Nanofluid for Solar Thermal Energy Application

2011 ◽  
Author(s):  
Donghyun Shin ◽  
Debjyoti Banerjee
Keyword(s):  
Thermal Conductivity ◽  
Heat Capacity ◽  
Specific Heat ◽  
Molten Salt ◽  
Specific Heat Capacity ◽  
Thermal Energy ◽  
Molten Salts ◽  
Solar Power ◽  
Solar Thermal ◽  
Wide Range

The overall efficiency of a Concentrated Solar Power (CSP) system is critically dependent on the thermo-physical properties of the Thermal Energy Storage (TES) components and the Heat Transfer Fluid (HTF). Higher operating temperatures in CSP result in enhanced thermal efficiency of the thermodynamic cycles that are used in harnessing solar energy (e.g., using Rankine cycle or Stirling cycle). Particlularly, high specific heat capacity (Cp) and high thermal conductivity (k) of the HTF and TES materials enable reduction in the size and overall cost of solar power systems. However, only a limited number of materials are compatible for the high operating temperature requirements (exceeding 400°C) envisioned for the next generation of CSP systems. Molten salts have a wide range of melting point (200°C∼500°C) and are thermally stable up to 700°C. However, thermal property values of the molten salts are typically quite low (Cp is typically less than ∼2J/g-K and k is typically less than ∼1 W/m-K). To obviate these issues the molten salts can be doped with nanoparticles — resulting in the synthesis / formation of nanomaterials (nanocomposites and nanofluids). Nanofluids are colloidal suspensions formed by doping with minute concentration of nanoparticles. Nanofluids were reported for anomalous enhancement in their thermal conductivity values. In this study, molten salt-based nanofluids were synthesized by liquid solution method. A differential scanning calorimeter (DSC) was used to measure the specific heat capacity values of the proposed nanofluids. The observed enhancement in specific heat is then compared with predictions from conventional thermodynamic models (e.g. thermal equilibrium model or “simple mixing rule”). Transmission Electron Microscopy (TEM) is used to verify that minimal aggregation of nanoparticles occurred before and after the thermocycling experiments. Thermocycling experiments were conducted for repeated measurements of the specific heat capacity by using multiple freeze-thaw cycles of the nanofluids/ nano-composites, respectively. This study demonstrates the feasibility for using novel nanomaterials as high temperature nanofluids for applications in enhancing the operational efficiencies as well as reducing the cost of electricity produced in solar thermal systems utilizing CSP in combination with TES.

Effect of Dispersion Homogeneity on Specific Heat Capacity Enhancement of Molten Salt Nanomaterials Using Carbon Nanotubes

2014 ◽  
Vol 137 (1) ◽  
Author(s):  
Byeongnam Jo ◽  
Debjyoti Banerjee
Keyword(s):  
Carbon Nanotubes ◽  
Heat Capacity ◽  
Specific Heat ◽  
Molten Salt ◽  
Specific Heat Capacity ◽  
Mass Concentration ◽  
Sodium Dodecyl ◽  
Base Material ◽  
Capacity Enhancement ◽  
Carbonate Salt

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.

Experimental Study of Thermal Performance Enhancement of Molten Salt Nanomaterials

2018 ◽  
Author(s):  
Amirhossein Mostafavi ◽  
Vamsi Kiran Eruvaram ◽  
Donghyun Shin
Keyword(s):  
Heat Capacity ◽  
Specific Heat ◽  
Molten Salt ◽  
Specific Heat Capacity ◽  
Thermal Performance ◽  
Thermal Energy ◽  
Molten Salts ◽  
Elevated Temperatures ◽  
Performance Enhancement ◽  
Heat Transfer Fluid

Concentrating solar power (CSP) plants are one of the main technologies harvesting solar energy indirectly. In CSP systems, solar radiant light is concentrated into a focal receiver, where heat transfer fluid (HTF) as the energy carrier absorbs solar radiation. Thermal energy storage (TES) is the key method to expand operational time of CSP plants. Consequently, thermo-physical properties of the HTF is an important factor in transferring thermal energy. One of the promising chemicals for this purpose is a mixture of molten salts with stable properties at elevated temperatures. However, low thermal properties of molten salts, such as specific heat capacity (cp) around 1.5 kJ/kg°C, constrain thermal performance of CSP systems. Recently, many studies have been conducted to overcome this shortcoming, by adding minute concentration of nanoparticles. In this work, the selected molten salt eutectic is a mixture of LiNO3–NaNO3 by composition of 54:46 mol. % plus dispersing Silicon Dioxide (SiO2) nanoparticles with 10nm particle size. The results from the measured specific heat capacity by modulated differential scanning calorimeter (MDSC) shows a 9% cp enhancement. Moreover, the viscosity of the mixture is measured by a rheometer and the results show that the viscosity of molten salt samples increases by 27% and this may result in increasing the pumping energy of the HTF. Consequently, overall thermal performance of the selected mixture is investigated by figure of merit (FOM) analysis. The interesting results show an enhancement of the thermal storage of this mixture disregard with the viscosity increase effect.

Experimental Study of the Effect of Nanoparticle Concentration on Thermo-Physical Properties of Molten Salt Nanofluids

2019 ◽  
Author(s):  
Hani Tiznobaik ◽  
Donghyun Shin
Keyword(s):  
Heat Capacity ◽  
Physical Properties ◽  
Specific Heat ◽  
Molten Salt ◽  
Specific Heat Capacity ◽  
Molten Salts ◽  
Power Plants ◽  
Nanoparticles Concentration ◽  
Thermo Physical Properties

Abstract Increased in thermo-physical properties of molten salt nanofluids have been reported. These findings makes molten salts nanofluids one of the most promising thermal energy storage media. One of the main application of these types of materials are in concentrated solar power plants. In this study, an investigation is performed on nanofluids specific heat capacity mechanisms in order to provide a reasonable description of the specific heat capacity enhancement of nanofluids. Then, a comprehensive experiments are performed on the effects of nanoparticles concentration on the specific heat capacity and materials characterization of molten salt nanofluids. This study is performed to analyze the optimum amount of nanoparticle and find the way to maximize the effects of nanoparticle on thermophysical properties of molten slat. Different molten salts nanofluids with varying nanoparticles concentration were synthesized. The specific heat capacities of mixtures were measured by a modulated scanning calorimeter. Moreover, the material characterization analyses were performed using scanning electron microscopy to investigate the micro-structural characterization of different nanofluids.

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