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Effect of nanoparticles on heat capacity of nanofluids based on molten salts as PCM for thermal energy storage.

Chieruzzi M, Cerritelli GF, Miliozzi A, Kenny JM - Nanoscale Res Lett (2013)

Bottom Line: In particular, this research shows that the addition of silica-alumina nanoparticles has a significant potential for enhancing the thermal storage characteristics of the NaNO3-KNO3 binary salt.These results deviated from the predictions of the theoretical model used.SEM suggests a greater interaction between these nanoparticles and the salt.

View Article: PubMed Central - HTML - PubMed

Affiliation: Civil and Environmental Engineering Department, UdR INSTM, University of Perugia, Strada di Pentima, 4, 05100 Terni, Italy. manila.chieruzzi@unipg.it.

ABSTRACT
In this study, different nanofluids with phase change behavior were developed by mixing a molten salt base fluid (selected as phase change material) with nanoparticles using the direct-synthesis method. The thermal properties of the nanofluids obtained were investigated. These nanofluids can be used in concentrating solar plants with a reduction of storage material if an improvement in the specific heat is achieved. The base salt mixture was a NaNO3-KNO3 (60:40 ratio) binary salt. The nanoparticles used were silica (SiO2), alumina (Al2O3), titania (TiO2), and a mix of silica-alumina (SiO2-Al2O3). Three weight fractions were evaluated: 0.5, 1.0, and 1.5 wt.%. Each nanofluid was prepared in water solution, sonicated, and evaporated. Measurements on thermophysical properties were performed by differential scanning calorimetry analysis and the dispersion of the nanoparticles was analyzed by scanning electron microscopy (SEM). The results obtained show that the addition of 1.0 wt.% of nanoparticles to the base salt increases the specific heat of 15% to 57% in the solid phase and of 1% to 22% in the liquid phase. In particular, this research shows that the addition of silica-alumina nanoparticles has a significant potential for enhancing the thermal storage characteristics of the NaNO3-KNO3 binary salt. These results deviated from the predictions of the theoretical model used. SEM suggests a greater interaction between these nanoparticles and the salt.

No MeSH data available.


Related in: MedlinePlus

Stored heat versus temperature for NaNO3-KNO3 binary salt mixture and nanofluids. Obtained with base salt and 0.5, 1.0, and 1.5 wt.% of oxide nanoparticles.
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Figure 5: Stored heat versus temperature for NaNO3-KNO3 binary salt mixture and nanofluids. Obtained with base salt and 0.5, 1.0, and 1.5 wt.% of oxide nanoparticles.

Mentions: The data obtained from DSC tests were also elaborated in order to evaluate the stored heat as a function of the temperature and these results are reported in FigureĀ 5 for all the nanofluids studied and for the three concentrations considered. It is easy to understand the real effect of the nanoparticles on the storage capacity of the material. In fact, once a minimum (solid phase) and a maximum (liquid phase) working temperature was fixed, the storage capacity of the material was supplied from the integration of the curve under consideration.


Effect of nanoparticles on heat capacity of nanofluids based on molten salts as PCM for thermal energy storage.

Chieruzzi M, Cerritelli GF, Miliozzi A, Kenny JM - Nanoscale Res Lett (2013)

Stored heat versus temperature for NaNO3-KNO3 binary salt mixture and nanofluids. Obtained with base salt and 0.5, 1.0, and 1.5 wt.% of oxide nanoparticles.
© Copyright Policy - open-access
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC4231368&req=5

Figure 5: Stored heat versus temperature for NaNO3-KNO3 binary salt mixture and nanofluids. Obtained with base salt and 0.5, 1.0, and 1.5 wt.% of oxide nanoparticles.
Mentions: The data obtained from DSC tests were also elaborated in order to evaluate the stored heat as a function of the temperature and these results are reported in FigureĀ 5 for all the nanofluids studied and for the three concentrations considered. It is easy to understand the real effect of the nanoparticles on the storage capacity of the material. In fact, once a minimum (solid phase) and a maximum (liquid phase) working temperature was fixed, the storage capacity of the material was supplied from the integration of the curve under consideration.

Bottom Line: In particular, this research shows that the addition of silica-alumina nanoparticles has a significant potential for enhancing the thermal storage characteristics of the NaNO3-KNO3 binary salt.These results deviated from the predictions of the theoretical model used.SEM suggests a greater interaction between these nanoparticles and the salt.

View Article: PubMed Central - HTML - PubMed

Affiliation: Civil and Environmental Engineering Department, UdR INSTM, University of Perugia, Strada di Pentima, 4, 05100 Terni, Italy. manila.chieruzzi@unipg.it.

ABSTRACT
In this study, different nanofluids with phase change behavior were developed by mixing a molten salt base fluid (selected as phase change material) with nanoparticles using the direct-synthesis method. The thermal properties of the nanofluids obtained were investigated. These nanofluids can be used in concentrating solar plants with a reduction of storage material if an improvement in the specific heat is achieved. The base salt mixture was a NaNO3-KNO3 (60:40 ratio) binary salt. The nanoparticles used were silica (SiO2), alumina (Al2O3), titania (TiO2), and a mix of silica-alumina (SiO2-Al2O3). Three weight fractions were evaluated: 0.5, 1.0, and 1.5 wt.%. Each nanofluid was prepared in water solution, sonicated, and evaporated. Measurements on thermophysical properties were performed by differential scanning calorimetry analysis and the dispersion of the nanoparticles was analyzed by scanning electron microscopy (SEM). The results obtained show that the addition of 1.0 wt.% of nanoparticles to the base salt increases the specific heat of 15% to 57% in the solid phase and of 1% to 22% in the liquid phase. In particular, this research shows that the addition of silica-alumina nanoparticles has a significant potential for enhancing the thermal storage characteristics of the NaNO3-KNO3 binary salt. These results deviated from the predictions of the theoretical model used. SEM suggests a greater interaction between these nanoparticles and the salt.

No MeSH data available.


Related in: MedlinePlus