Effect of nanoparticles on heat capacity of nanofluids based on molten salts as PCM for thermal energy storage.
Effect of nanoparticles on heat capacity of nanofluids based on molten salts as PCM for thermal energy storage.
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DOI：
10.1186/1556-276x-8-448
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发表时间：
2013-10-29
影响因子：
--
通讯作者：
Kenny JM
中科院分区：
文献类型：
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作者：
Chieruzzi M;Cerritelli GF;Miliozzi A;Kenny JM
在这项研究中，不同的纳米流体与相变行为的开发通过混合熔盐基流体（选择作为相变材料）与纳米粒子使用直接合成方法。研究了所得纳米流体的热性质。这些纳米流体可以用于聚光太阳能发电厂，如果实现比热的改善，则可以减少存储材料。碱盐混合物是NaNO 3-KNO 3（60：40比例）二元盐。使用的纳米颗粒是二氧化硅（SiO2）、氧化铝（Al 2 O3）、二氧化钛（TiO 2）和二氧化硅-氧化铝（SiO2-Al 2 O3）的混合物。评价了三种重量分数：0.5、1.0和1.5重量%。在水溶液中制备每种纳米流体，超声处理并蒸发。通过差示扫描量热法对纳米粒子的热物理性质进行了测量，并通过扫描电子显微镜（SEM）对纳米粒子的分散性进行了分析。所获得的结果表明，添加1.0 wt.%纳米颗粒与碱盐的混合使固相的比热增加15%至57%，液相的比热增加1%至22%。特别是，这项研究表明，二氧化硅-氧化铝纳米粒子的加入具有显着的潜力，提高了NaNO 3-KNO 3二元盐的储热特性。这些结果偏离了所用理论模型的预测。SEM表明这些纳米颗粒和盐之间的相互作用更大。
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.