Preparation of microencapsulated KNO3 by solvothermal technology for thermal energy storage

Romero-Sánchez, Marı́a D.; Piticescu, Radu Robert; Motoc, Adrian Mihail; Popescu, Madalina Laura; Tudor, Ioan Albert

doi:10.1007/s10973-019-08825-1

Cited by 12 publications

(8 citation statements)

References 33 publications

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“…Additionally, the combination of NaNO 3 and KNO 3 in percentages of 60 and 40, respectively, is a mixture is known as “Solar Salt”, whose eutectic is around 54% KNO 3 and 46% NaNO 3 and its melting point is approximately 222 °C, its minimum operating temperature is 290 °C, and the maximum operating temperature is about 585 °C [ 7 , 8 , 9 , 10 , 11 , 12 , 16 , 17 , 18 , 27 , 28 , 29 , 30 , 31 , 32 , 33 , 34 , 35 , 36 , 37 , 38 , 39 , 40 , 41 , 42 , 43 , 44 , 45 , 46 , 47 , 48 , 49 , 50 , 51 , 52 , 53 , 54 , 55 , 56 , 57 , 58 , 59 , 60 , 61 , 62 , 63 , 64 , 65 , 66 , 67 , 68 , …”

Section: Introductionmentioning

confidence: 99%

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Thermal Storage of Nitrate Salts as Phase Change Materials (PCMs)

et al. 2021

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This study presents the energy storage potential of nitrate salts for specific applications in energy systems that use renewable resources. For this, the thermal, chemical, and morphological characterization of 11 samples of nitrate salts as phase change materials (PCM) was conducted. Specifically, sodium nitrate (NaNO3), sodium nitrite (NaNO2), and potassium nitrate (KNO3) were considered as base materials; and various binary and ternary mixtures were evaluated. For the evaluation of the materials, differential Fourier transform infrared spectroscopy (FTIR), scanning calorimetry (DSC), thermogravimetric analysis (TGA), and scanning electron microscopy (SEM) to identify the temperature and enthalpy of phase change, thermal stability, microstructure, and the identification of functional groups were applied. Among the relevant results, sodium nitrite presented the highest phase change enthalpy of 220.7 J/g, and the mixture of 50% NaNO3 and 50% NaNO2 presented an enthalpy of 185.6 J/g with a phase change start and end temperature of 228.4 and 238.6 °C, respectively. This result indicates that sodium nitrite mixtures allow the thermal storage capacity of PCMs to increase. In conclusion, these materials are suitable for medium and high-temperature thermal energy storage systems due to their thermal and chemical stability, and high thermal storage capacity.

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Section: Introductionmentioning

confidence: 99%

“…On the other hand, although non-eutectic mixtures present segregation, they provide a higher range of temperature of phase change. Hence, mixtures of NaNO 3 , NaNO 2 , and KNO 3 have been identified as non-eutectic mixtures [ 7 , 51 , 52 , 53 ]. Nonetheless, further study is required due to the discrepancies.…”

Section: Introductionmentioning

confidence: 99%

Thermal Storage of Nitrate Salts as Phase Change Materials (PCMs)

et al. 2021

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“…41,42 This verifies that microencapsulation technology could improve the thermal stability of the material. 43 The crystallization properties of microcapsules were acquired from DSC curves (Supplementary Material Figure S8). It can be seen from the figure that the prepared microcapsules begin to crystallize at around 26°C and the crystallization enthalpy was about 1.71 J/g.…”

Section: Resultsmentioning

confidence: 99%

“…In contrast, the weight loss when the temperature was over 380 C might be attributed to the decomposition of the PU shell and samples became totally weightless at 426 C, leaving only 13.15% of the mass, which indicates that the decomposition temperature of SP microcapsule was much higher than the initial decomposition temperature of SP material at about 139 C. 41,42 This verifies that microencapsulation technology could improve the thermal stability of the material. 43 The crystallization properties of microcapsules were acquired from DSC curves (Supplementary Material Figure S8). It can be seen from the figure that the prepared microcapsules begin to crystallize at around 26 C and the crystallization enthalpy was about 1.71 J/g.…”

Section: Properties Of Sp Microcapsulesmentioning

confidence: 99%

Preparation of multicolor microcapsules and their application in smart color-switching textiles

Zhang

Meng

Liu

et al. 2022

Textile Research Journal

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Spiropyran and spiroxazine photochromics have attracted increasing attention in optical data storage, optical switches, and anti-counterfeiting for decades. To expand the applications of spiropyran and spiroxazine, the durability and multi-color changes of spiropyran and spiroxazine still need to be explored. In this article, based on the subtractive principle of dyes, multi-color spiropyran and spiroxazine microcapsules with uniform particle sizes were prepared by the interfacial polymerization method via using compounds (spiropyran and spiroxazine) of different colors as the core material, and polyurethane as the shell material. Among them, toluene diisocyanate and polyethylene glycol constitute the hard and soft segments of polyurethane, respectively. The color of spiropyran and spiroxazine microcapsules can effectively switch between color and colorless, showing excellent photo fatigue resistance. The average particle size of microcapsules is 2.951 µm, and the particle distribution index value is 0.314, which shows the particle size is small and uniform. The maximum thermal decomposition temperature is 426°C, demonstrating good thermal stability. The hydrophobic photochromic fabric was prepared by coating multi-color spiropyran and spiroxazine microcapsules on cotton knitted fabric and hydrophobic treatment. The hydrophobic photochromic fabric is hydrophobic and stain resistant, and exhibits multi-color dynamic switching and long-lasting use. After 50 cycles of washing, the water contact angle of the fabric remains about 109°, showing its good washing resistance and water repellency. In addition, spiropyran and spiroxazine microcapsules are also applied in template and screen printing to impart rich and dynamic color-changing effects to fabrics, fabricating photochromic fabrics. Photochromic fabrics have potential applications in civilian and military fields.

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“…Furthermore, Romero‐Sachez et al 71 microencapsulated KNO 3 with ZnO shell by the same method as in Reference 53. The samples were prepared at various KNO 3 /ZnO mass ratios and different temperatures in solvothermal process.…”

Section: Microencapsulation Of Medium and High‐melting Temperature Pcmsmentioning

confidence: 99%

The microencapsulation, thermal enhancement, and applications of medium and high‐melting temperature phase change materials: A review

Sinaga

Darkwa

Omer

et al. 2022

Intl J of Energy Research

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Summary Microencapsulated phase change materials (MEPCMs) have made tremendous advancements in recent years, owing to their increased demand for a variety of energy storage applications. In this paper, current microencapsulation techniques, enhancement, and use of medium‐ and high‐melting phase change materials (PCMs) are reviewed, as well as their potential benefits and limitations. The most frequently employed PCMs for medium‐ and high‐temperature applications were recognized as salt‐based, metallic, inorganic compound, and eutectic. Meanwhile, polymethyl methacrylate (PMMA), polystyrene‐butylacrylate (PSBA), polyethyl‐2‐cyanoacrylate (PECA), and polyurethane were widely used as polymer shell materials for encapsulating medium‐ and high‐melting point PCMs via chemical method, whereas inorganic silica shell was synthesized via various techniques. Hydrolysis followed by heat‐oxidation treatment has been extensively studied since 2015 to encapsulate either metal or alloy within Al2O3 shells. Different techniques were developed to generate void between core and shell material to accommodate volume expansion during phase transition. Numerous approaches, including the incorporation of metal particles, carbon, and ceramic, have been found as ways to enhance the thermal performance of PCMs. Multiple storage arrangements were also established to be an effective way of enhancing the overall efficiency of medium‐high melting PCM storage systems. Finally, the paper highlights the potential of medium‐ and high‐melting temperature PCMs for solar power generation, solar cooking, and industrial waste heat recovering applications.

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Preparation of microencapsulated KNO3 by solvothermal technology for thermal energy storage

Cited by 12 publications

References 33 publications

Thermal Storage of Nitrate Salts as Phase Change Materials (PCMs)

Thermal Storage of Nitrate Salts as Phase Change Materials (PCMs)

Preparation of multicolor microcapsules and their application in smart color-switching textiles

The microencapsulation, thermal enhancement, and applications of medium and high‐melting temperature phase change materials: A review

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