Specific Heat Capacity Enhancement Research Articles

Molecular dynamics study on thermophysical properties of K2CO3 molten salt-based SiO2 nanofluids using Buckingham potential framework

In concentrated solar power (CSP) systems, molten salt plays a vital role as a medium for both storing and transferring heat. This research conducts molecular dynamics (MD) simulations to investigate the thermophysical properties of K2CO3 molten salt-based SiO2 nanofluids within the Buckingham potentialframework. MD results show that the Buckingham potential along with the derived parameters can well reproduce the thermophysical properties of K2CO3 molten salt. At 1.0 wt% of nano-SiO2, the nanofluids achieve a 11.80 % enhancement in specific heat capacity compared with the pure molten salt. The thermal conductivity of molten salt nanofluids is increased as the doping ratio of nano SiO2 is increased. Specifically, when the doping ratio reaches 3.0 wt%, the thermal conductivity is increased by 14.31 % compared with the undoped base salt. It has been found that the enhanced specific heat capacity of nanofluids is primarily resulted from the change in the Coulomb energy due to the addition of the nano-SiO2 and a compression layer surrounding the nanoparticles. Heat flow decomposition of the nanofluid has also shown that its enhanced thermal conductivity is mainly caused by the strengthened nonbonded interactions by adding the nanoparticles.

Development and comparison of multi-walled carbon nanotubes and graphite nanoflakes dispersed solar salt: Structural formation and thermophysical properties

A molten salt energy storage has proven to be a promising candidate for medium and high-temperature thermal energy storage (TES) applications. Improving the thermophysical properties, such as specific heat capacity (Cp) and thermal conductivity (k) is crucial to deciding the charging/discharging characteristics of the energy storage system. In this study, 1 wt% of two variant carbon allotropes, such as multi-walled carbon nanotubes (MWCNTs) and graphite nanoflakes (GNFs), were dispersed in solar salt (i.e., MWCNTs nanosalt and GNFs nanosalt) using wet preparation method. Thermophysical properties of the prepared nanosalts were evaluated using different analytical techniques and compared with pristine solar salt. The specific heat capacity was measured from 50 °C to 350 °C, and the maximum specific heat capacity enhancement in 1 wt% of MWCNTs dispersed solar salt was 18 %. The enhancement in 1 wt% of GNFs dispersed solar salt was 12.5 % at 200 °C (in solid phase). Similarly, in the liquid phase (at 350 °C), MWCNTs dispersed solar salt improves Cp by 6.2 %, while GNFs dispersed solar salt exhibits negligible improvement in Cp. Further, a modified transient plane source (MTPS) technique was used to measure the thermal conductivity of both carbon nanosalts in the solid phase (30–100 °C). The maximum thermal conductivity enhancement observed for MWCNTs dispersed solar salt and GNFs dispersed solar salt was 5.8 % and 11.7 %. Finally, thermogravimetric analysis was conducted to evaluate the thermal stability of the MWCNTs nanosalt and GNFs nanosalt at a maximum temperature of 700 °C, and found that the MWCNTs nanosalt show better thermal stability than the GNFs nanosalt.

Specific Heat Capacity of Solar Salt-Based Nanofluids: Molecular Dynamics Simulation and Experiment.

In this study, a nanofluid composed of molten solar salt (MSS) and 1.0% SiO2 nanoparticles by mass was created and analyzed using differential scanning calorimetry (DSC) to determine its specific heat capacity (SHC). The SHC of the nanofluid was found to be significantly higher than that of pure MSS. The average increase in SHC of the nanofluid with 1.0% SiO2 nanoparticles (NPs) loading was found to be 15.65% compared with pure MSS. The formation of nanostructures after doping with NPs may increase the SHC of molten salt (MS) nanofluids, according to certain published research that included experimental confirmation. Nevertheless, no thorough theoretical or computational studies have been conducted to verify the experimental findings related to MSS nanofluid. Molecular dynamics (MD) simulations were conducted in various simulation boxes for different cases to verify the experimental findings and investigate the mechanism behind the enhancement of SHC caused by the addition of SiO2 NPs in eutectic MSS. The simulations used pure MSS and mixtures containing NaNO3 nanostructures bonded with SiO2 NPs. The highest SHC increase of 25.03% was observed when the simulation box contained 13.71% NaNO3 nanostructures by weight. The incorporation of NaNO3 nanostructures increased the surface area and total surface energy, leading to a positive effect on the SHC of the MSS nanofluid. However, the decrease in the base molten salt's SHC had a slight negative impact on the overall SHC of the MS nanofluid.

Enhancement of quick charging and discharging of tes system by PCM mixed with Al2O3 nano particles for EV

Technology for storing heat energy with small amount of area has been proposed a challenge to the researchers over the past few decades. This would render highly useful for the thermal management system of electric vehicles. The PCM was used as an energy storage system in this work. It offers the chief advantage of higher storage density which is very much expected for both industrial and domestic needs, especially electric vehicles. In this work, the enhancement of specific heat capacity for the provided PCM was improved by embedding alumina nanoparticles into the storage medium. The addition of nanoparticles in the PCM resulted in the increase of heat absorption capacity, a 50% increase in charging time and a 25% reduction in discharging time of the PCM for the volume concentration of 0.833%. The increase of efficiency by 6% during charging and 4% during the discharging processes were observed as the effect of addition of alumina nanoparticle in the system.

Hybrid MWCNT/TiO2 nanoparticles based high-temperature quinary nitrate salt mixture for thermal energy storage applications

This study developed an advanced thermal energy storage (TES) material consisting of a quinary nitrate salt mixture doped with hybrid MWCNT/TiO2 nanoparticles. The structural, morphology, and thermophysical properties of hybrid MWCNT/TiO2 and hybrid MWCNT/TiO2 doped quinary nitrate salt mixture was characterized using differential scanning calorimetry (DSC), thermogravimetric analysis (TGA), laser flash analysis (LFA), viscosity measurement, X-ray diffraction (XRD), Fourier Transform Infrared (FTIR) spectroscopy, Raman spectroscopy and Field environmental scanning electron microscopy and Energy dispersive X-ray (FESEM-EDX) analysis. Furthermore, levelized cost of electricity (LCOE) of concentrated solar power (CSP)-parabolic trough collector (PTC) power plant using the optimized sample as the TES materials were calculated using the “physical trough model” in system advisor model (SAM) software. Based on the result, 0.05 wt% dosage of hybrid MWCNT/TiO2 nanoparticles in the quinary nitrate salt mixture has the most favorable thermophysical properties, with 17.655 % enhancement in average specific heat capacity, 37.769 % enhancement in latent heat, 25.412 % enhancement in average thermal conductivity and 94.77 % decrement in viscosity. Furthermore, SAM simulation studies also showed that the developed TES material could reduce LCOE of the CSP power plant by 1.29 % to 0.1687 USD/kWh. Therefore, in the efforts of replacing the coal-fired electricity generation with the CSP-PTC power plants, it is also possible to achieve a potential annual saving of up to 552 million USD compared to commercial TES materials.

Experimental study on glycerol/aldehyde or ketone binary nanofluids for thermal management

Glycerol is a bio-based low-cost chemical, which has been widely studied in the field of heat conduction because of its wide working temperature range and superior thermopysical. However, high viscosity of glycerol is a prominent problem that limit the application of glycerol. In this work, low viscosity and high thermal conductivity of glycerol nanofluids are prepared under the dual role of nanoparticles, in which nanoparticles work as the nanoadditives enable an enhancement of thermal conductivity and specific heat capacity of nanofluids and the catalyst make a decline of viscosity of nanofluids. The thermal and viscosity properties of the nanofluid were investigated, and the addition of 15% acetylacetone and 2% TiO2 increased the thermal conductivity of the nanofluid to 0.3194 W/m·K, which was 8.12% higher than that of the glycerol. Meanwhile, the viscosity was reduced to 357.4 mPa (30 °C) with 15% acetylacetone and 0.5% TiO2 nanoparticles, which was 47% lower than that of glycerol at the same temperature. Additionally, results of fourier transform infrared spectrometer and proton nuclear magnetic resonance demonstrate that acetal reaction plays an important role in reducing the viscosity of nanofluids, meanwhile, the tests of X-ray diffraction show that nanoparticles can be utilized circularly.

New insights into the heat capacity enhancement of nano-SiO2 doped alkali metal chloride molten salt for thermal energy storage: A molecular dynamics study

Molten salts and their based nanofluids are important media for heat transfer and thermal energy storage in concentrated solar power (CSP) system. To improve the overall efficiency of the CSP plants, it is important to increase the specific heat capacity of molten salt to the extent possible. Nanomaterials have been doped in molten salt to enhance the specific heat capacity of molten salt; however, the mechanism of enhancement in specific heat capacity caused by doping of nanoparticles in molten salt is still unclear. In this work, the Buckingham force field parameters for alkali metal chloride molten salts (KCl, NaCl, LiCl) were first derived and carefully validated. The specific heat capacities, viscosities, and self-diffusion coefficients of pure molten salts and the specific heat capacities of molten-salt-based nanofluids with SiO2 nanoparticles were investigated by molecular dynamics (MD) simulations. The calculated thermophysical properties of the chloride molten salts using the derived Buckingham potential parameters are in good agreement with the experimental data, and the overall prediction performance is better than that of the BMH potential. Results show that the specific heat capacity of molten salt first increases and then decreases with increasing SiO2 doping ratio, reaching a maximum value at 1 wt%. The specific heat capacities of KCl, NaCl and LiCl nanofluids with 1 wt% SiO2 nanoparticle are increased by 6.2 %, 8.6 % and 19.8 % compared to the base salts, respectively. Number density, radial distribution function, coordination number curves, and energy of the nanofluid system were systematically analyzed. It is found that the increase of the specific heat capacities of the molten salt-based nanofluids can be explained by the energy and coordination number change caused by the number density mismatch of cations and anions. Interestingly, the local delamination of cations around SiO2 nanoparticle surfaces in LiCl-SiO2 nanofluids is clearly observed and visualized for the first time; it is a phenomenon well explained by the analysis of number density and contributes to the further enhancement of the heat capacity. The findings of this work could provide important fundamentals in understanding and designing more efficient molten salt nanocomposites for thermal energy storage in future studies.

Investigation of heat transfer characteristics of graphene nanoplatelets dispersed aluminium composite

The thermal stability and specific heat capacity of Graphene Nanoplatelets (GNPs) dispersed aluminium composites are determined using Differential Scanning Calorimetry (DSC) and Thermogravimetric Analysis (TGA). Results of DSC analysis of the Al/2.0 wt-% GNPs composite show a 174% enhancement in specific heat capacity. Compared to pure aluminium, the Al/2.0 wt-% GNPs composite’s TGA results show a 2% mass reduction. Heat transfer characteristics like heat transfer coefficient, fin efficiency, and heat transfer through a fin were determined using a pin-fin heat transfer apparatus under free and forced convection. Compared to pure aluminium, graphene nanoplatelets reinforcement in an aluminium matrix improves the heat transfer characteristics of prepared composites under both free and forced convection.

Effect of Morphology and Concentration of Two Carbon Allotropes on the Enhancement of Specific Heat Capacity of Eutectic Molten Salt

Abstract This study aims at investigating the effect of nanoparticle morphology and concentration on the specific heat capacity of a molten salt used as thermal energy storage material in concentrated solar power plants. Binary carbonate salt eutectic (lithium carbonate and potassium carbonate at a molar ratio of 62:38, respectively) is used as the base material. Two different carbon allotropes, graphite nanoparticles (Gp) and carbon nanotube (CNT) are used as dopants to look into the morphological effect on specific heat (Cp). A series of experiments are carried out to systematically investigate the effect of nanoparticle concentration by varying the mass percentages of carbon allotropes (2 wt.%, 4 wt.%, and 6 wt.%) in the base material. The specific heat capacity of the samples is measured both in solid (250 °C and 400 °C) and liquid phases (520°–560 °C) using a differential scanning calorimeter (DSC). The results show a maximum enhancement of 35% in Cp for 6 wt.% Gp -based salt in the liquid phase. CNT-based nanomaterials exhibit a maximum enhancement of 20% for 4 wt.% CNT inclusion in the liquid phase. The superior performance of Gp compared to CNT and mass concentration-controlled specific heat is explained using field emission scanning electron microscope (FESEM) and energy-dispersive X-ray spectroscopy (EDS) analysis. FESEM and EDS analysis confirm the presence and the composition of the compressed layer, respectively. These layers are considered to be responsible for the anomalous increase in specific heat capacity at different mass concentrations for the carbon allotropes.

Effect of silica nanoparticle size on the stability and thermophysical properties of molten salts based nanofluids for thermal energy storage applications at concentrated solar power plants

Molten salts-based nanofluids are attractive candidates for thermal energy storage applications due to their enhanced thermophysical properties. However, their stability remains an open issue. In the present work, the size effect of SiO2 nanoparticles on the stability and thermophysical properties of molten binary nitrate salt was studied. For that purpose, the effect of SiO2 based nanofluids was systematically studied by using in-situ high-temperature observations and zeta potential experiments. From the analysis, the nanofluids having nanoparticles larger than 450 nm demonstrate superior stability compared to the ones with nanoparticles of 27 nm. Moreover, in contrast to the case of 27 nm particles increase of viscosity was shown to be negligible for particles larger than 450 nm. The absence of specific heat capacity (Cp) or thermal conductivity enhancement for the cases of larger nanoparticles suggests that the development of molten salts-based nanofluids is bounded by the compromise between the stability and improvement of thermophysical properties, depending on the particle size. These results open a pathway for the development of stable molten salt-based nanofluids with enhanced thermophysical properties where the size of the nanoparticles must be optimized.

Thermophysical properties enhancement and characterization of CuO nanoparticles enhanced HITEC molten salt for concentrated solar power applications

Molten salts are utilized in concentrated solar power (CSP) as a working fluid to store and transfer solar thermal energy. In this study, we attempted to enhance the thermal energy storage (TES) characteristics of the ternary nitrate molten salt of KNO3, NaNO2, and NaNO3, also known as HITEC molten salt, using cupric oxide (CuO) as additives for CSP applications. HITEC was doped with 0.1, 1, 3, and 5 wt% of CuO nanoparticles using the two-step wet method. Differential scanning calorimeter (DSC) was utilized to evaluate the specific heat capacity, melting point, and latent heat of the prepared material. Thermal stability was measured by thermogravimetric analysis (TGA) while the characterization analysis was performed using Fourier-Transform Infrared (FT-IR) spectroscopy, Field Emission Scanning Electron Microscope (FESEM), and Energy Dispersive X-ray Spectroscopy (EDS). The results showed that 0.1 wt% CuO nanoparticles is the optimum CuO nanoparticles concentration which resulted in a specific heat capacity enhancement of 5.6%, a 30% improvement of latent heat, and 9% enhancement of thermal stability. The morphological analysis revealed the formation of bright chain-like nanostructure due to nanoparticle dispersion, which may the possible reason for the thermophysical property enhancement.

A novel model for predicting the effective specific heat capacity of molten salt doped with nanomaterial for solar energy application

In order to establish instructions for high-performance molten salt preparation, this paper focuses on accurate prediction method on the effective heat capacity of nanomaterial-enhanced molten salt (NMS). With carbon nanotube (CNT) enhanced carbonate eutectic (Li2CO3-K2CO3) taken as the study subject, the microscopic mechanism of nanomaterial on the effective specific heat capacity enhancement of molten salt is revealed. The nanolayer content is calculated, and the specific heat capacity of CNT and nanolayer is quantified. Accordingly, the effective heat capacity prediction model is completed. In addition, the CNT-enhanced carbonate eutectic is experimentally prepared with a high-energy ball milling method. Its effective specific heat capacity is measured and used to validate the prediction model. The results show that, firstly, the thickness of nanolayer is 0.65 nm and 0.98 nm in the single-walled CNT case and multi-walled CNT case, respectively. Secondly, the specific heat capacity of CNT is 1.613 J·g−1·K−1 at 800 K, and the specific heat capacity of nanolayer increases with increasing the surface atom ratio. Finally, the effective specific heat capacity of CNT-enhanced carbonate salt is predicted and validated with experimental results. It is revealed that, in the cases of well-dispersed nanomaterial-enhanced molten salt, the prediction method presented in this research has considerable accuracy (error < 2.90%). Furthermore, the effective specific heat capacity of NMS doped with CNT of various diameter is given.

A Literature Review on Novel Nitrate Molten Salt for Heat Storage

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

Effects of SiO2 Nanoparticle Dispersion on The Heat Storage Property of the Solar Salt for Solar Power Applications

The effects of SiO2 nanoparticles on the heat storage properties of Solar Salt (NaNO3-KNO3) are studied using experimental and molecular dynamics (MD) simulations. The experiment results show the specific heat capacity of the molten salt-based nanofluids is higher than that of the pure base salt. We focus on the inference regarding the possible mechanisms behind the enhancement of the specific heat capacity which are considered more acceptable by the majority of researchers, the energy and force in the system are analyzed by MD simulations. The results demonstrate that the higher specific heat capacity of the nanoparticle is not the reason leading to the heat storage enhancement. Additionally, the analysis of potential energy and system configuration shows that the other possible mechanisms (i.e., interfacial thermal resistance theory and compressed layer theory) are only superficial. The forces between the nanoparticle atoms and base salt ions construct the constraint of the base salt ions, further forms the interfacial thermal resistance, and the compressed layer around the nanoparticle. This constraint has a more stable state and requires more energy to deform it, leading to the improvement of the heat storage property of nanofluids. Our findings uncover the mechanisms of specific heat capacity enhancement and guide the preparation of molten salt-based nanofluids.

Thermophysical characteristics and enhancement analysis of carbon-additives phase change mono and hybrid materials for thermal management of electronic devices

A novel zero-noise and clean thermal management technology (TMT), based on phase-change thermal energy storage (TES) technology, has turned out the new vision for researchers and industrialist involved in electronics industry. Therefore, this paper highlights a new direction by developing the nano-enhanced phase change materials (NePCMs) by combining the carbon-additives with phase change material. Four different types of carbon-additives of multi-wall carbon nanotube (MWCNT), graphene oxide (GO), reduced graphene oxide (rGO) and graphene nanoplatelet (GNP) were dispersed in RT-35HC, used as a PCM, with the combinations of mono (MWCNT, GO, rGO and GNP) and hybrid (GO+MWCNT, rGO+MWCNT and GNP+MWCNT) nanoparticles. A constant mass percentage of 1.0 wt.% was selected for both mono and hybrid combinations of nanoparticles to explore the best type and dispersion scheme for productive and effective thermal management applications. All the synthesized NePCMs were characterized using various characterization methods to study microstructural features, surface chemistry, lattice dimensions, stability, thermal and phase-change TES characteristics. The key findings reveal the best chemical and thermal stability, uniform dispersion of carbon-based nanoparticles in RT-35HC without modifying the molecular structure. The highest thermal conductivity enhancements of 182.7%, 183.8% and 185.3%, and optimum value of enthalpy of fusions of 237.42, 235.35 and 230.82 J/g were achieved for hybrid NePCMGO+MWCNT, NePCMrGO+MWCNT, and NePCMGNP+MWCNT, respectively in comparison of mono NePCMs. The phenomenon of thermal conductivity and specific heat capacity were explained systematically. Conclusively, the minimum subcooling, specific heat capacity enhancement and smaller phase-transition temperature reveal that GNP+MWCNT dispersed hybrid NePCM can be potentially used for thermal management applications.

Synthesis and Characterization of Molten Salt Nanofluids for Thermal Energy Storage Application in Concentrated Solar Power Plants-Mechanistic Understanding of Specific Heat Capacity Enhancement.

Molten salts mixed with nanoparticles have been shown as a promising candidate as the thermal energy storage (TES) material in concentrated solar power (CSP) plants. However, the conventional method used to prepare molten salt nanofluid suffers from a high material cost, intensive energy use, and laborious process. In this study, solar salt-Al2O3 nanofluids at three different concentrations are prepared by a one-step method in which the oxide nanoparticles are generated in the salt melt directly from precursors. The morphologies of the obtained nanomaterials are examined under scanning electron microscopy and the specific heat capacities are measured using the temperature history (T-history) method. A non-linear enhancement in the specific heat capacity of molten salt nanofluid is observed from the thermal characterization at a nanoparticle mass concentration of 0.5%, 1.0%, and 1.5%. In particular, a maximum enhancement of 38.7% in specific heat is found for the nanofluid sample prepared with a target nanoparticle mass fraction of 1.0%. Such an enhancement trend is attributed to the formation of secondary nanostructure between the alumina nanoparticles in the molten salt matrix following a locally-dispersed-parcel pattern. These findings provide new insights to understanding the enhanced energy storage capacity of molten salt nanofluids.

Specific heat capacity enhancement studied in silica doped potassium nitrate via molecular dynamics simulation

Molten salts serve an important purpose for short term heat energy storage and as heat transfer fluids in solar power plants. Different experimental groups have shown that certain mixtures containing salts doped with small amounts of nanoparticles exhibit much greater specific heat capacities compared to the same base salts without nanoparticles. This effect is technically interesting and economically important. Thus far, however, it is not understood. Our aim is the theoretical investigation of the specific heat capacity in the aforementioned nanofluids on the molecular level using simulations. Here we present results for liquid potassium nitrate doped with silica nanoparticles. We discuss the observed increase of the specific heat in terms of the particle induced hydrodynamic reinforcement and liquid structure. The theoretical background of this discussion is a ω-space resolved phonon theory of liquids in conjunction with differential spectral densities, computed for the different systems with and without nanoparticles.

Specific heat capacity improvement of molten salt for solar energy applications using charged single-walled carbon nanotubes

This work focuses on the effects of charged single-walled carbon nanotubes (SWCNT) on the heat capacity of composite carbonate salt (Li2CO3-K2CO3) using the Electric Double-Layer modeling (EDL) and the Molecular Dynamics (MD) simulation. The nanoparticle-enhanced molten salt ensemble is modeled considering the compressed ion layer surrounding the SWCNT, and the specific heat capacity (cp) enhancement of the nanoparticle-enhanced molten salt is analyzed. The results present the following issues. First, compressed ion layer is formed around the SWCNT surface. The density distributions of Li+, K+ and CO32– are strongly related to the SWCNT charge. The density distributions of the ions present characteristics of oscillatory, and the densities of the ions can be increased by rise of SWCNT charge. Second, the charge density distribution is analyzed. The local enrichment of positive and negative charges is found to occur inside the compressed ion layer. It is found that increasing the SWCNT charge can promote the local enrichment of positive and negative charges, which contributes to the increase of the internal energy of the nanoparticle-enhanced molten salt ensemble and results in cp enhancement. Finally, cp is found to be increased with increasing SWCNT charge. The cp enhancement of 19.2% is achieved when the SWCNT carries surface charge of −280e. The obtained results can provide guidance on the application of charged nanoparticles to enhance the specific capacity of molten salt.

Experimental investigations on the thermal properties of binary molten salt based AlN nanofluids for high temperature applications

Typical binary nitrate (NaNO3-KNO3 as 60:40 rat io by weight) based AlN nanofluid was prepared by a two-step solutionmethod. The specific heat capacities of nanofluids with AlN amount ranging from 0.5 to 4 wt. % were investigated. The results suggest a good compatibility between AlN and molten binary nit rates. Meanwhile, AlN nanoparticles are proved to be an effective additive in improving the thermal properties of binary nitrates. For binary nitrate-based materials, samples with AlN amount as 1 wt. % shows the best thermal enhancement of specific heat capacity.

Experimental investigation of specific heat capacity improvement of a binary nitrate salt by addition of nanoparticles/microparticles

Abstract Several recent studies reported anomalous enhancement of specific heat capacity by doping minute concentration (e.g. 1 wt.%) of nanoparticles into the eutectic salt. In this work, silica particles with three different sizes and nano-sized silicon nitride and silicon carbide particles were dispersed in solar salt with particle concentrations of 0.5–7 wt.%. To prepare the composite material, a conventional two-step aqueous solution method was used and the drying approach was modified to suit large-scale production. The specific heat capacities of the composites, pure solar salt and particles were measured using differential scanning calorimetry in a temperature range of 300–400 ᵒC and the results were compared. Silicon nitride and silicon carbide nanoparticles have marginal effect on the specific heat capacity of solar salt over the examined concentration of 0.5–3 wt.%. The specific heat capacity of silica composites with 3 wt.% of silica were enhanced by 4.3–9.7% over that of the pure solar salt. However, when 5 wt.% and 7 wt.% of silica (30 μm) were dispersed, the specific heat capacity was reduced by 10.6% and 9%, respectively. Material characterization of the composite material proved the formation of sodium silicate due to reaction of silica and sodium nitrate, which is probably correlated to the reduction of specific heat capacity.