The Heat Capacities of Lithium, Sodium, Potassium, Rubidium, and Caesium Nitrates in the Solid and Liquid States

Ichikawa, Kazuhiko; Matsumoto, Toshiyuki

doi:10.1246/bcsj.56.2093

Cited by 39 publications

(31 citation statements)

References 11 publications

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“…The specific heat of the pure KNO 3 was also close to literature data [ 39 ] that reports specific heats in the range of temperature of solid state (260–390 °C) of 1.29–1.43 J/g °C and of 1.38–1.39 in the liquid state (in accordance with other works [ 40 , 42 ]) and slightly lower with respect to the previous references [ 43 , 44 ].…”

Section: Resultssupporting

confidence: 91%

A New Phase Change Material Based on Potassium Nitrate with Silica and Alumina Nanoparticles for Thermal Energy Storage

et al. 2015

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In this study different nanofluids with phase change behavior were developed by mixing a molten salt base fluid (KNO3 selected as phase change material) with nanoparticles using the direct synthesis method. The thermal properties of the nanofluids obtained were investigated. Following the improvement in the specific heat achieved, these nanofluids can be used in concentrating solar plants with a reduction of storage material. The nanoparticles used (1.0 wt.%) were silica (SiO2), alumina (Al2O3), and a mix of silica-alumina (SiO2-Al2O3) with an average diameter of 7, 13, and 2–200 nm respectively. Each nanofluid was prepared in water solution, sonicated, and evaporated. Measurements of the thermophysical properties were performed by DSC analysis, and the dispersion of the nanoparticles was analyzed by SEM microscopy. The results obtained show that the addition of 1.0 wt.% of nanoparticles to the base salt increases the specific heat of about 5–10 % in solid phase and of 6 % in liquid phase. In particular, this research shows that the addition of silica nanoparticles has significant potential for enhancing the thermal storage characteristics of KNO3. The phase-change temperature of potassium nitrate was lowered up to 3 °C, and the latent heat was increased to 12 % with the addition of silica nanoparticles. These results deviated from the predictions of theoretical simple mixing model used. The stored heat as a function of temperature was evaluated for the base salt, and the nanofluids and the maximum values obtained were 229, 234, 242, and 266 J/g respectively. The maximum total gain (16 %) due to the introduction of the nanoparticles (calculated as the ratio between the total stored heat of the nanofluids and the base salt in the range of temperatures 260–390 °C) was also recorded with the introduction of silica. SEM and EDX analysis showed the presence of aggregates in all nanofluids: with silica nanoparticles they were homogenously present while with alumina and silica-alumina also zones with pure salt could be detected.

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Section: Resultssupporting

confidence: 91%

A New Phase Change Material Based on Potassium Nitrate with Silica and Alumina Nanoparticles for Thermal Energy Storage

et al. 2015

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“…The specific heat of the pure KNO 3 was also close to literature data [39] that reports specific heats in the range of temperature of solid state (260-390°C) of 1.29-1.43 J/g°C and of 1.38-1.39 in the liquid state (in accordance with other works [40,42]) and slightly lower with respect to the previous references [43,44].…”

Section: Heat Capacity Of Nanofluidssupporting

confidence: 91%

A New Phase Change Material Based on Potassium Nitrate with Silica and Alumina Nanoparticles for Thermal Energy Storage

Chieruzzi¹,

Miliozzi²,

Crescenzi³

et al. 2016

Nano Online

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In this study different nanofluids with phase change behavior were developed by mixing a molten salt base fluid (KNO 3 selected as phase change material) with nanoparticles using the direct synthesis method. The thermal properties of the nanofluids obtained were investigated. Following the improvement in the specific heat achieved, these nanofluids can be used in concentrating solar plants with a reduction of storage material. The nanoparticles used (1.0 wt.%) were silica (SiO 2 ), alumina (Al 2 O 3 ), and a mix of silica-alumina (SiO 2 -Al 2 O 3 ) with an average diameter of 7, 13, and 2-200 nm respectively. Each nanofluid was prepared in water solution, sonicated, and evaporated. Measurements of the thermophysical properties were performed by DSC analysis, and the dispersion of the nanoparticles was analyzed by SEM microscopy. The results obtained show that the addition of 1.0 wt.% of nanoparticles to the base salt increases the specific heat of about 5-10 % in solid phase and of 6 % in liquid phase. In particular, this research shows that the addition of silica nanoparticles has significant potential for enhancing the thermal storage characteristics of KNO 3 . The phase-change temperature of potassium nitrate was lowered up to 3°C, and the latent heat was increased to 12 % with the addition of silica nanoparticles. These results deviated from the predictions of theoretical simple mixing model used. The stored heat as a function of temperature was evaluated for the base salt, and the nanofluids and the maximum values obtained were 229, 234, 242, and 266 J/g respectively. The maximum total gain (16 %) due to the introduction of the nanoparticles (calculated as the ratio between the total stored heat of the nanofluids and the base salt in the range of temperatures 260-390°C) was also recorded with the introduction of silica. SEM and EDX analysis showed the presence of aggregates in all nanofluids: with silica nanoparticles they were homogenously present while with alumina and silica-alumina also zones with pure salt could be detected.

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“…Heat capacity data of NaNO 3 are available from various authors [21,[30][31][32][33][34][35] and have been reviewed by Jriri et al [6] (Fig. 5).…”

Section: Heat Capacitymentioning

confidence: 99%

Characterization of Sodium Nitrate as Phase Change Material

2011

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In this article the results of material investigations of sodium nitrate (NaNO 3 ) with a melting temperature of 306 • C as a phase change material (PCM) are presented. The thermal stability was examined by kinetic experiments and longduration oven tests. In these experiments the nitrite formation was monitored. Although some nitrite formation in the melt was detected, results show that the thermal stability of NaNO 3 is sufficient for PCM applications. Various measurements of thermophysical properties of NaNO 3 are reported. These properties include the thermal diffusivity by the laser-flash, the thermal conductivity by the transient hot wire, and the heat capacity by the differential scanning calorimeter method. The current measurements and literature values are compared. In this article comprehensive temperature-dependent thermophysical values of the density, heat capacity, thermal diffusivity, and thermal conductivity in the liquid and solid phases are reported.

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The Heat Capacities of Lithium, Sodium, Potassium, Rubidium, and Caesium Nitrates in the Solid and Liquid States

Cited by 39 publications

References 11 publications

A New Phase Change Material Based on Potassium Nitrate with Silica and Alumina Nanoparticles for Thermal Energy Storage

A New Phase Change Material Based on Potassium Nitrate with Silica and Alumina Nanoparticles for Thermal Energy Storage

A New Phase Change Material Based on Potassium Nitrate with Silica and Alumina Nanoparticles for Thermal Energy Storage

Characterization of Sodium Nitrate as Phase Change Material

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