Thermal properties improvement of Lithium nitrate/Graphite composite phase change materials

Lachheb, Mohamed; Adili, A.; Albouchi, Fethi; Mzali, Foued; Nasrallah, Sassi Ben

doi:10.1016/j.applthermaleng.2016.03.167

Cited by 39 publications

(10 citation statements)

References 25 publications

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“…Extensive amounts of researches have focused on organic PCMs, such as paraffin waxes (Huang et al, 2009), but few inorganic PCMs have been investigated for operation in high-temperature applications. Nitrate-based molten salts have received more attention due to their availability in a wide range of temperatures (Lachheb et al, 2016). Solar salt is a eutectic, nitrate-based, alkali molten salt with combination of 60 wt.% sodium nitrate and 40 wt.% potassium nitrate.…”

Section: Introductionmentioning

confidence: 99%

Experimental Investigation of Thermal Stability and Enthalpy of Eutectic Alkali Metal Solar Salt Dispersed with MgO Nanoparticles

Aslfattahi¹,

Saidur²,

Sabri³

et al. 2019

IJTech

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In this study, nanocomposites containing a pre-defined mass ratio of solar salt (NaNO3-KNO3: 6040 wt.%) dispersed with magnesium oxide (MgO) nanoparticles with nominal sizes of 100 nm were prepared in solid and liquid states. The proposed amounts of sodium nitrate and potassium nitrate were added to certain amounts of ultrapure deionized (DI) water comprising a 5 wt.% concentration of MgO nanoparticles. Afterward, the prepared mixture was placed in a dry oven to mix in a liquid state to obtain well-dispersed nanocomposites. Scanning electronic microscopy (SEM) was conducted to evaluate the uniformity of synthesized, molten salt-based magnesium oxide-nanoparticles, revealing a uniform dispersion. Enthalpy and melting point measurements were performed using differential scanning calorimetry. The experimental results of solar salt-based MgO indicated decreases in melting point and enthalpy by 7% and 12.4%, respectively. The reduction of enthalpy indicated that, with the addition of magnesium oxide to solar salt, the final nanocomposite tends to have more exothermic reactions and enhanced thermal conductivity performance at the melting point. Lower melting points constitute one of the major concerns regarding molten salt-based nanofluids. MgO nanoparticles with a concentration of 5 wt.% have a melting point decreased by 7%. Mass loss and thermal stability measurements were conducted using thermogravimetric analysis (TGA). The experimentally acquired results revealed an increment of decomposition temperature from 734.29°C to 750.73°C, demonstrating the enhancement of thermal stability at high temperatures.

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Section: Introductionmentioning

confidence: 99%

Experimental Investigation of Thermal Stability and Enthalpy of Eutectic Alkali Metal Solar Salt Dispersed with MgO Nanoparticles

Aslfattahi¹,

Saidur²,

Sabri³

et al. 2019

IJTech

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“…In the spectra of LiNO 3 , the peak at 831 cm −1 was assigned to the N–O symmetric stretching vibration. The peaks at 1384 and 1632 cm −1 , respectively, corresponded to the symmetric and antisymmetric stretching vibrations of N–O . In the spectra of NaNO 3 and KNO 3 , the peaks at 829, 1378, and 2418 cm −1 were attributed to the N–O stretching vibration .…”

Section: Resultsmentioning

confidence: 96%

“…The molten PCMs can be effectively confined into the pore structures of encapsulation materials under the action of capillary force and surface tension, thereby maintaining the form stability. Recently, expanded graphite (EG)‐based fs‐CPCMs have been extensively reported . EG can effectively improve the thermo‐physical properties of nitrates and their eutectics PCMs, especially the thermal conductivity.…”

Section: Introductionmentioning

confidence: 99%

Expanded Vermiculite: A Promising Natural Encapsulation Material of LiNO₃, NaNO₃, and KNO₃ Phase Change Materials for Medium‐Temperature Thermal Energy Storage

Deng

Nian

2018

Adv Eng Mater

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In the study, with LiNO 3 , NaNO 3 , and KNO 3 as medium-temperature phase change materials (PCMs) and expanded vermiculite (EVM) as the encapsulation material, form-stable composite PCMs (fs-CPCMs) are prepared. The experimental value of maximum encapsulation mass fractions of LiNO 3 -EVM, NaNO 3 -EVM, and KNO 3 -EVM is, respectively, 84.6, 85.7, and 87.0 wt%, which is lower than the theoretical value since the pore structures of EVM are not fully filled by PCMs. SEM results indicate that the PCMs are uniformly distributed and embedded into the pores or on the surfaces of EVM. The excellent chemical compatibility of PCMs with EVM is confirmed by XRD and FT-IR results. DSC tests indicate the phase change temperatures of three fs-CPCMs are between 243.1 and 325.1 C and that latent heats are between 83.1 and 295.4 J g À1 . After 100 melting/solidification cycles, the decrease in latent heats of fs-CPCMs are below 1.91%, exhibiting desirable thermal reliability. The thermal conductivity of LiNO 3 -EVM, NaNO 3 -EVM, and KNO 3 -EVM is, respectively, 0.51, 0.44, and 0.33 W/(m K), indicating acceptable thermal energy charging/discharging rate. TGA analysis reveal that fs-CPCMs show good thermal stability within the designed working temperature range. Therefore, EVM is a promising natural encapsulation material for medium-temperature heat storage.

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“…Supporting material used in ss-composites studied so far can be classified into three main groups: Carbon-based supporting materials, such as expanded graphite and graphite foams [ 14 , 15 , 16 , 17 , 18 , 19 , 20 , 21 , 22 , 23 , 24 , 25 , 26 , 27 , 28 ]. They have proven to be compatible with nitrites and chlorides and have high salt absorption capacity (>85 wt.%).…”

Section: Introductionmentioning

confidence: 99%

Li4(OH)3Br-Based Shape Stabilized Composites for High-Temperature TES Applications: Selection of the Most Convenient Supporting Material

et al. 2021

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Peritectic compound Li4(OH)3Br has been recently proposed as phase change material (PCM) for thermal energy storage (TES) applications at approx. 300 °C Compared to competitor PCM materials (e.g., sodium nitrate), the main assets of this compound are high volumetric latent heat storage capacity (>140 kWh/m3) and very low volume changes (<3%) during peritectic reaction and melting. The objective of the present work was to find proper supporting materials able to shape stabilize Li4(OH)3Br during the formation of the melt and after its complete melting, avoiding any leakage and thus obtaining a composite apparently always in the solid state during the charge and discharge of the TES material. Micro-nanoparticles of MgO, Fe2O3, CuO, SiO2 and Al2O3 have been considered as candidate supporting materials combined with the cold-compression route for shape-stabilized composites preparation. The work carried out allowed for the identification of the most promising composite based on MgO nanoparticles through a deep experimental analysis and characterization, including chemical compatibility tests, anti-leakage performance evaluation, structural and thermodynamic properties analysis and preliminary cycling stability study.

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Thermal properties improvement of Lithium nitrate/Graphite composite phase change materials

Cited by 39 publications

References 25 publications

Experimental Investigation of Thermal Stability and Enthalpy of Eutectic Alkali Metal Solar Salt Dispersed with MgO Nanoparticles

Experimental Investigation of Thermal Stability and Enthalpy of Eutectic Alkali Metal Solar Salt Dispersed with MgO Nanoparticles

Expanded Vermiculite: A Promising Natural Encapsulation Material of LiNO₃, NaNO₃, and KNO₃ Phase Change Materials for Medium‐Temperature Thermal Energy Storage

Li4(OH)3Br-Based Shape Stabilized Composites for High-Temperature TES Applications: Selection of the Most Convenient Supporting Material

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Thermal properties improvement of Lithium nitrate/Graphite composite phase change materials

Cited by 39 publications

References 25 publications

Experimental Investigation of Thermal Stability and Enthalpy of Eutectic Alkali Metal Solar Salt Dispersed with MgO Nanoparticles

Experimental Investigation of Thermal Stability and Enthalpy of Eutectic Alkali Metal Solar Salt Dispersed with MgO Nanoparticles

Expanded Vermiculite: A Promising Natural Encapsulation Material of LiNO3, NaNO3, and KNO3 Phase Change Materials for Medium‐Temperature Thermal Energy Storage

Li4(OH)3Br-Based Shape Stabilized Composites for High-Temperature TES Applications: Selection of the Most Convenient Supporting Material

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Expanded Vermiculite: A Promising Natural Encapsulation Material of LiNO₃, NaNO₃, and KNO₃ Phase Change Materials for Medium‐Temperature Thermal Energy Storage