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.

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.

scholarly journals Dynamic Compression and Thermo-Physical Properties of Some Wood Particles in South Western Nigeria

2017 ◽  
Vol 60 (2) ◽  
pp. 79-84
Author(s):  
Mathew Adefusika Adekoya ◽  
Sunday Samuel Oluyamo ◽  
Olawale Ramon Bello
Keyword(s):  
Heat Capacity ◽  
Physical Properties ◽  
Specific Heat ◽  
Specific Heat Capacity ◽  
Dynamic Compression ◽  
Dependent Model ◽  
Specific Heat Capacities ◽  
Temperature Dependent Model ◽  
Thermal Diffusivities ◽  
Thermo Physical Properties

This study examines the dynamic compression and thermo-physical properties of some woodparticles obtained from Akure, south local government area, Ondo State, South Western Nigeria. Thesewood particles are of the species of Celtis zenkeri and Celtis philippensis of the Ulmaceae family. Thesamples were possessed into different particle sizes (300, 600 and 850 µm) and subjected to variedcompacting pressures (2.6-3.0 MPa). The density and specific heat capacity of the wood samples weredetermined using weighing displacement methods and temperature dependent model while the thermaldiffusivity was estimated from other thermal properties. The results revealed significant variation in thevalues of the specific heat capacity as a result of change in pressure for all the wood samples considered.The density of wood samples lies between 4.51×102 -7.32×102 kg/m3 and the specific heat capacity valuesobtained for the samples fall within the range of 1.28×103-1.33×103 J/kg/K. It was also noted that thethermal diffusivity obtained falls within the range of 1.37×10-7-2.10×10-7 m2/s for the wood materialsconsidered. However, the values of the densities, specific heat capacities and thermal diffusivities of thesamples were found to change as the compacting pressure increased due to decreased in porosity. Theimplication of the study is that the mate

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

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.

Study of Specific Heat Capacity Enhancement of Molten Salt Nanomaterials for Solar Thermal Energy Storage (TES)

2012 ◽  
Author(s):  
Hongjoo Yang ◽  
Debjyoti Banerjee
Keyword(s):  
Heat Capacity ◽  
Energy Storage ◽  
Specific Heat ◽  
Molten Salt ◽  
Specific Heat Capacity ◽  
Power Plants ◽  
Eutectic Mixture ◽  
Solar Power Plants ◽  
Solvent Molecules ◽  
Compressed Layer

The overall thermal efficiency of solar power plants is highly sensitive to the operating characteristics of the Thermal Energy Storage (TES) devices. Enhancing the operating temperature of TES is imperative for enhancing the thermal efficacy of solar power plants. However, material property limitations for high temperature operation severely limit the choice of materials for TES. Molten salts and their eutectics are promising candidates for high temperature operation of TES. To enhance the thermal and operational efficiency of TES, the thermo-physical properties such as the specific heat capacity and thermal conductivity of the materials need to be maximized. The specific heat capacity (Cp) of molten salt is relatively smaller than other conventional TES materials. Recent studies have shown that addition of nanoparticles to molten salts can significantly enhance their specific heat capacity. Several transport and energy storage mechanisms have been proposed to account for these enhancements. Primarily, the layering of solvent molecules due to inter-molecular forces (due to competition between adhesive and cohesive forces) is observed at solid-liquid interface, leading to the formation of a more dense or “compressed layer” of solvent molecules on the dispersed nanoparticles. The formation and existence of the compressed layer has been demonstrated experimentally and from numerical predictions (e.g., Molecular Dynamics/ MD models). To verify the enhancement of specific heat capacity of molten salt nanofluids, the influence of compressed layer has been explored in this study. This implies that for the same amount (or concentration) of nanoparticle, the ratio of surface/volume of the individual nanoparticles can change significantly depending on the nanoparticles size and shape — which in turn can affect the mass fraction of the compressed layer formed on the surface of the nanoparticles. In this study, the specific heat capacity of the molten salt nanomaterials was investigated for: (a) silica nanoparticles in eutectic mixture of alkali chloride salt eutectics, and (b) silica nanoparticles in an eutectic mixture of alkali carbonate salts eutectics. The effect of the particle size distribution was considered in this study and it was observed that smaller nanoparticles contribute a larger proportion to the observed specific heat capacity enhancements. The size of distribution of the nanoparticles in the molten salt mixture/ nanomaterial (nanocomposites and nanofluids) was measured by using Scanning Electron Microscopy (SEM), and subsequently the actual number of nanoparticles (as a function of size) that were dispersed in molten salt fluid was calculated. The specific heat capacity of molten salt nanomaterial was calculated using a classical mixing model and by accounting for the contribution from the compressed layer in the mixture.

scholarly journals Investigation on Thermo-physical Properties of L-Valinium Picrate Single Crystal for Modern Applications

2021 ◽  
Author(s):  
M Manivannan ◽  
S. Balachandar ◽  
M. Jose ◽  
S A Martin Britto Dhas
Keyword(s):  
Heat Capacity ◽  
Thermal Diffusivity ◽  
Physical Properties ◽  
Single Crystal ◽  
Specific Heat ◽  
Specific Heat Capacity ◽  
Thermal Effusivity ◽  
X Ray Diffraction ◽  
X Ray ◽  
Thermo Physical Properties

Abstract Good quality L-valinium picrate single crystal was grown by slow evaporation technique. The lattice parameters of the crystal were measured by single crystal X-ray diffraction analysis. The High resolution X-ray diffraction study reveals good crystalline perfection of the grown crystals. The thermal diffusivity and specific heat capacity were experimentally measured using photoacoustic technique and standard DSC technique, respectively. The thermo physical properties such as thermal conductivity, thermal diffusivity, specific heat capacity, volumetric specific heat capacity, and thermal effusivity of LVP are reported for the first time at ambient temperature.

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.

scholarly journals The influence of utrafine-grained state on thermo-physical properties of Zr-1 wt.% Nb and Ti-45 wt.% Nb alloys and processes of dissipation and accumulation of energy during deformation

2020 ◽  
pp. 28-35
Author(s):  
E.V. Legostaeva ◽  
◽  
Yu.P. Sharkeev ◽  
O.A. Belyavskaya ◽  
V.P. Vavilov ◽  
...  
Keyword(s):  
Thermal Conductivity ◽  
Plastic Deformation ◽  
Heat Capacity ◽  
Physical Properties ◽  
Specific Heat ◽  
Specific Heat Capacity ◽  
Coarse Grained ◽  
Ultrafine Grained ◽  
Substructural Hardening ◽  
Thermo Physical Properties

The results of studying the thermal conductivity and specific heat capacity of Zr-1 wt.% Nb and Ti-45 wt.% Nb in coarse-grained and ultrafine-grained states are presented. The influence of the utrafine-grained state on the thermo physical properties and the processes of dissipation and accumulation energy during deformation of the alloys are estimated. It is shown that formation of the ultrafine-grained state in the Zr-1 wt.% Nb alloy by abc -pressing and subsequent rolling leads to a decrease in its thermal conductivity and specific heat capacity by 10 and 20%, respectively, due to substructural hardening under severe plastic deformation. It is found that thermal conductivity and specific heat capacity of the ultrafine Ti-45 wt.% Nb alloy increase by 7.5 and 5%, respectively, due to dispersion hardening of the ω phase by nanoparticles and formation of a new α phase. It is established that the ultrafine-grained structure has a significant influence on the regularities of the dissipation and accumulation energy during plastic deformation, which in turn depend on their thermo-physical characteristics and on the structural and phase state.

Enhanced Specific Heat Capacity of Molten Salts Using Organic Nanoparticles

2011 ◽  
Author(s):  
Byeongnam Jo ◽  
Debjyoti Banerjee
Keyword(s):  
Heat Capacity ◽  
Physical Properties ◽  
Specific Heat ◽  
Specific Heat Capacity ◽  
Organic Nanoparticles ◽  
Energy Applications ◽  
Energy Demands ◽  
Liquid Phases ◽  
Graphite Nanoparticles ◽  
Thermo Physical Properties

In this study we explore the material properties of carbonate salt eutectics that melt at high temperatures (exceeding 480 °C). These salt eutectics demonstrated anomalous enhancement in the specific heat capacity in both solid and liquid phases — when mixed with carious organic nanoparticles such as carbon nanotubes (CNT) and graphite nanoparticles. Theses experimental measurements are compared with previous reports in the literature for exploring the effect of the synthesis protocol on the resulting thermo-physical properties of these nanomaterials. The enhancement of the thermo-physical properties on mixing with nanoparticles is of significant interest in reducing the cost of thermal energy storage (TES) devices and systems. TES can be utilized for levelizing peaks in cyclical energy demands (or duties) that is typical of renewable energy applications where the input energy source may be intermittent (e.g., solar thermal); as well as in geothermal and nuclear energy applications.

scholarly journals A review on thermo-physical properties of bio, non-bio and hybrid nanofluids

2019 ◽  
Vol 13 (4) ◽  
pp. 5875-5904
Author(s):  
James Lau Tze Chen ◽  
Ahmed N. Oumer ◽  
Azizuddin A. A.
Keyword(s):  
Thermal Conductivity ◽  
Heat Capacity ◽  
Physical Properties ◽  
Specific Heat ◽  
Specific Heat Capacity ◽  
Material Type ◽  
Low Viscosity ◽  
Water Based ◽  
Influential Parameters ◽  
Thermo Physical Properties

The pressure drop and thermal performance of various nanofluids can be affected by their thermo-physical properties. However, there are many different parameters that need to be considered when determining the thermo-physical properties of nanofluids. This paper highlights a detail reviews on the thermo-physical properties of nanofluids with different material type and effect of some process parameters (such as material type, temperature and concentration) on the thermo-physical properties of nanofluids. Four thermo-physical properties mainly density, viscosity, thermal conductivity and specific heat capacity from different literatures were summarized, discussed and presented. The lowest viscosity value of nanofluids in literature was mango bark water-based nanofluid (0.81cP). On the other hand, the maximum thermal conductivity value of nanofluids in the literature was GNP-Ag water-based nanofluid (0.69W/mK). The density and specific heat capacity are strongly dependent on the material type. Meanwhile, the viscosity and thermal conductivity are greatly affected by temperature and concentration. The most influential parameters on thermo-physical properties of nanofluids are material type followed by temperature. Most of the literatures confirmed bio nanofluids have low viscosity value and hybrid have high thermal conductivity values.

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