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Solid–Liquid Phase Change Materials for Energy Storage
Published in Moghtada Mobedi, Kamel Hooman, Wen-Quan Tao, Solid–Liquid Thermal Energy Storage, 2022
A. Stamatiou, S. Maranda, L. J. Fischer, J. Worlitschek
Supercooling is a phenomenon that occurs in all types of materials and is defined as the temperature difference between the onset melting point of a material and the temperature of the material at which it starts to crystalize (nucleate) (see Figure 2.2). In most applications where PCM is used, a large degree of supercooling is undesirable. Supercooling of more than a few degrees will interfere with proper heat extraction from the storage unit or can even prevent it entirely. The degree of supercooling strongly depends on the material, the environment and the purity. Salt hydrates and SA in general exhibit a larger degree of supercooling than other classes of PCM.
Cold Adapted Microorganisms
Published in Ajar Nath Yadav, Ali Asghar Rastegari, Neelam Yadav, Microbiomes of Extreme Environments, 2021
Deep Chandra Suyal, Ravindra Soni, Ajar Nath Yadav, Reeta Goel
Supercooling is the process in which the temperature of a gas or liquid lowers down below their freezing point without reaching a solid-state. The microorganisms residing under these cloud droplets are known to be metabolically active at subzero temperatures.
Lyophilization of Protein Pharmaceuticals
Published in Kenneth E. Avis, Vincent L. Wu, Biotechnology and Biopharmaceutical Manufacturing, Processing, and Preservation, 2020
John F. Carpenter, Byeong S. Chang
Supercooling is defined as cooling a sample below its equilibrium melting temperature without the formation of ice. Supercooling can be achieved in a lyophilizer by equilibrating the product just above the melting temperature and then cooling slowly through this point. Samples can also be supercooled by slowly reducing the product temperature from ambient. The rate of the formation of ice nuclei in a supercooled solution is greater than that for ice crystal growth. Thus, there is a relatively homogenous distribution of ice nuclei just prior to ice crystal formation. Once ice crystal formation begins, freezing takes place instantaneously throughout the product, with the formation of numerous small ice crystals and the uniform distribution of the product throughout the container. Usually, the greatest degree and uniformity of supercooling throughout the container are obtained at moderate cooling rates (≈ 1°C/min). The advantage of having some degree of supercooling is the consistency of product throughout the vials, which includes moisture content, crystallinity of excipient, and distribution of product. In addition, the increased surface area of the amorphous phase remaining after ice crystals are removed by sublimation improves the rate of secondary drying (MacKenzie 1976; Pikal 1990b; Nail and Gatlin 1993). However, if ice crystals are excessively small, the pathways for water vapor removal from the cake become restricted, thus slowing sublimation. Therefore, excessive supercooling should be avoided.
Evaluation of the impact of Mn and Al on the microstructure of Fe–Co–Ni–Cr based high entropy alloys
Published in Canadian Metallurgical Quarterly, 2023
M. Ilinich-Shaw, D. Wang, X. Huang, S. Yandt
Figure 2 shows sample DSC scans of the three HEAs (showing one out of two samples per alloy), outlining their endothermic behaviours. The averaged solidus and liquidus temperatures, TS and TL, respectively, from two samples per alloy are summarised in Table 2. Of the three alloys, HEA-3 exhibited the highest averaged endothermic peak at 1392°C. HEA-1 displayed an average endothermic peak at 1326°C, whereas HEA-2 at 1307°C. It can be noted that all alloys exhibited super/under cooling, yielding a difference of 12.3°C, 26.2°C, 18.9°C for HEA-1, HEA-2, and HEA-3, respectively. The degree of supercooling is dependent upon the heating/cooling rate and alloy composition; it is a common phenomenon observed in conventional alloy systems [33].
Experimental correlations for the solidification and fusion times of PCM encapsulated in spherical shells
Published in Experimental Heat Transfer, 2020
Taynara G. S. Lago, Kamal A. R. Ismail, Fátima A. M. Lino, Ahmad Arabkoohsar
In the three cases shown in Figure 3, one can observe some super cooling before the solidification starts. The state of supercooling is the condition where the liquid state persists below the solid–liquid equilibrium temperature. The supercooling makes it necessary to reduce the temperature below the solid–liquid equilibrium temperature to start crystallization and to release the latent heat stored in the material. If crystallization does not occur, the latent heat is not released and the material only stores sensible heat.