A medium-temperature, metal-based, microencapsulated phase change material with a void for thermal expansion

Bao, Jiaming; Zou, Deqiu; Zhu, Sixian; Ma, Qun; Wang, Yinshuang; Yun-ping, HU

doi:10.1016/j.cej.2021.128965

Cited by 53 publications

(21 citation statements)

References 49 publications

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“…For SiO 2 encapsulated Sn microspheres of about 40 µm in diameter, undercooling of about 76 • C can be found in Bao's work [13]. A similar result can be observed for Al 2 O 3 microencapsulated Sn particles in Zhu's work [15]. The very high undercooling of micro-sized Sn greatly restricts their practical application as PCMs.…”

Section: Introductionsupporting

confidence: 63%

“…However, the direct use of liquid metals as PCMs suffers from significant drawbacks, including the leakage or coalescence of metal droplets during operation and the difficulty in handling them compared to their solid counterparts. To overcome these problems, effectively encapsulating them in chemically stable oxides, e.g., SiO 2 , Al 2 O 3 , or TiO 2 , to form microcapsules [10] has drawn increasing attention in recent years [11][12][13][14][15].…”

Section: Introductionmentioning

confidence: 99%

“…As a non-toxic, low-melting-point (about 231 • C), high-density (about 7.3 g/cm 3 ) metal, with a much higher thermal conductivity (about 67 W•m −1 •K −1 at 20 • C [19]) compared to the inorganic salts (e.g., the thermal conductivity of commercial molten salts for applications over 200-1000 • C is in the range of 0.515-0.586 W•m −1 •K −1 [4]), Sn microparticles encapsulated in chemically stable oxides should be potential phase change material (PCM) for latent heat storage [13,15]. For example, they might serve as substitutes for nitrate-based PCMs in thermal energy storage due to having a melting point close to some of nitrate eutectic salts-based PCMs [4] or a potential candidate for temperature stabilizer of the catalyst bed in low-temperature (220-240 • C) Fischer-Tropsch synthesis because of their melting point matches well with the reaction temperature.…”

Section: Introductionmentioning

confidence: 99%

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Undercooling, Thermal Stability, and Application in Exothermic Catalytic Reaction of SiO2 Encapsulated SnZnCu Microspheres

Tang

Zheng

et al. 2022

Catalysts

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SiO2 encapsulated SnZnCu microspheres (several micrometers to about 30 μm in diameter) with very low undercooling, narrow freezing/melting range, and high thermal cycling stability have been produced and used as the temperature stabilizer of the packed bed in highly exothermic Fischer–Tropsch reaction. The core–shell structured SnZnCu@SiO2 microspheres are prepared in a two-step way, namely SnZnCu microspheres are firstly produced via a molten LiCl–KCl–CsCl eutectic-based metal emulsion method, and then a sol–gel approach is employed to coat them with a uniform, anti-leakage SiO2 layer. It is found that raising the amount of Zn to 4.0 at.% is critical for achieving a very low undercooling (<5 °C for SnZn0.04Cux@SiO2 vs. about 84 °C for Sn@SiO2) and a narrow freezing/melting peak width, and both undercooling and peak width are almost unchanged as the Cu content (x) increases from 1.5 to 3.0 at.%. However, their thermal cycling stability depends positively on the amount of Cu and can be remarkably improved when 3.0 at.% Cu is added. The results also show that low undercooling and narrow freezing/melting peak width are associated with the formation of Sn–Zn–Cu ternary eutectic and metastable phase Cu5Zn8, and poor thermal cycling stability of SnZn0.04Cux@SiO2 microspheres with low Cu content is related to the decomposition of Cu5Zn8 during thermal cycling. By embedding thermally stable SnZn0.04Cu0.03@SiO2 microspheres into the Co/SiO2 catalyst for Fischer–Tropsch synthesis, the temperature gradient in the catalyst bed can be significantly reduced by suppressing the formation of hot spots or thermal runaway and thus rapid deactivation of Co catalyst that occurs in the SnZn0.04Cux@SiO2-absent Co/SiO2 catalyst can be avoided.

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Section: Introductionsupporting

confidence: 63%

Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

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Undercooling, Thermal Stability, and Application in Exothermic Catalytic Reaction of SiO2 Encapsulated SnZnCu Microspheres

Tang

Zheng

et al. 2022

Catalysts

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“…Acoustic insulators, on the other hand, are materials of high density (heavy) and greater rigidity, for each type of noise there are certain physical characteristics that the materials must meet so that their use contributes to noise reduction (Sato, Kurisu, Morimoto & Maeda, 2021). In the same manner, as the chosen insulation will be applied in the Sierra del Ecuador area in height ranges from 2,000 to 6,700 m above sea level, relevant characteristics must be considered in terms of functionality; more specifically to the data on the coefficient of thermal expansion (Bao et al, 2021). Table 3 shows the value of this characteristic of the materials and shows characteristics to be considered for the functionality of the material.…”

Section: Resultsmentioning

confidence: 99%

Sustainable acoustic insulation for prefabricated concrete homes in Andean zones

Paredes

Andrade

Arroba

et al. 2021

srees

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The construction sector is undoubtedly one of the main promoters for economic and social development. The modern concept of the prefabrication of elements originated from the industrial revolution to reduce costs and increase production through the mechanization of work, increasing the quality and ease of control in the plant. Prefabricated concrete homes are aimed at the popular sectors, however, when talking about acoustic habitability comfort we refer to constructive solutions used in a building to minimize the transmission of sounds (noise pollution) from outside or from an adjoining enclosure. This is achieved with the use of acoustic insulation materials. In the present research, through a bibliographic review, the updated state-of-the-art search methodology is developed, supported by the Delphi and AHP (hierarchical analytical process) methods and with the opinion of experts to compare the properties of acoustic insulating materials; in order to publicize the best acoustic insulators to be installed inside prefabricated concrete homes. Within the bibliographic review, new technologies with sustainable materials found as feasible prototypes were investigated in Ecuador, where thanks to its diversity of ecosystems and the necessary existing technology, the natural fibers used in the prototypes for insulation/absorption are easily found acoustics in homes.

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“…Even for the metal Bi with a very poor thermal conductivity, for example, its thermal conductivity (about 8 W•m −1 •K −1 ) is much higher than that of the available commercial molten salts (less than 0.6 W•m −1 •K −1 ) [3]. As a result, metal-based PCMs have recently drawn increasing attention [5][6][7][8][9][10].…”

Section: Introductionmentioning

confidence: 99%

Metal Emulsion-Based Synthesis, Characterization, and Properties of Sn-Based Microsphere Phase Change Materials

Zheng

Luo

et al. 2021

Molecules

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A comparative study of the metal emulsion-based synthesis of Sn-based materials in two different types of molten salts (namely LiCl–KCl–CsCl and LiNO3-NaNO3-KNO3 eutectics) is presented, and the properties of Sn, Sn-Cu and Sn-Cu-Zn microsphere phase change materials prepared in chloride salts are evaluated by differential scanning calorimetry (DSC) to understand the effect of element doping. Despite a high ultrasonic power (e.g., 600 W or above) being required for dispersing liquid Sn in the chloride system, well-shaped Sn microspheres with a relatively narrow size range, e.g., about 1 to 15 µm or several micrometers to around 30 µm, can be prepared by adjusting the ultrasonic power (840–1080 W), sonication time (5–10 min) and the volume ratio of salts to metal (25:1–200:1). Such a method can be extended to the synthesis of Sn-based alloy microspheres, e.g., Sn-Cu and Sn-Cu-Zn microspheres. In the nitrate system, however, a very low ultrasonic power (e.g., 12 W) can be used to disperse liquid Sn, and the particles obtained are much smaller. At low ultrasonic power (e.g., 12 W), the particle size is generally less than 10 or 4 µm when the sonication time reaches 2 or 5 min, and at high ultrasonic power, it is typically in the range of hundreds of nanometers to 2 µm, regardless of the change in ultrasonic power (480–1080 W), irradiation time (5–10 min), or volume ratio of salts to metal (25:1–1000:1). In addition, the appearance of a SnO phase in the products prepared under different conditions hints at the occurrence of a reaction between Sn droplets and O2 in situ generated by the ultrasound-induced decomposition of nitrates, and such an interfacial reaction is believed to be responsible for these differences observed in two different molten salt systems. A DSC study of Sn, Sn-Cu, and Sn-Cu-Zn microspheres encapsulated in SiO2 reveals that Cu (0.3–0.9 wt.%) or Cu-Zn (0.9 wt.% Cu and 0.6% Zn) doping can raise the onset freezing temperature and thus suppress the undercooling of Sn, but a broad freezing peak observed in these doped microspheres, along with a still much higher undercooling compared to those of reported Sn-Cu or Sn-Cu-Zn solders, suggests the existence of a size effect, and that a low temperature is still needed for totally releasing latent heat. Since the chloride salts can be recycled by means of the evaporation of water and are stable at high temperature, our results indicate that the LiCl–KCl–CsCl salt-based metal emulsion method might also serve as an environmentally friendly method for the synthesis of other metals and their alloy microspheres.

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A medium-temperature, metal-based, microencapsulated phase change material with a void for thermal expansion

Cited by 53 publications

References 49 publications

Undercooling, Thermal Stability, and Application in Exothermic Catalytic Reaction of SiO2 Encapsulated SnZnCu Microspheres

Undercooling, Thermal Stability, and Application in Exothermic Catalytic Reaction of SiO2 Encapsulated SnZnCu Microspheres

Sustainable acoustic insulation for prefabricated concrete homes in Andean zones

Metal Emulsion-Based Synthesis, Characterization, and Properties of Sn-Based Microsphere Phase Change Materials

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