scholarly journals Study on the preparation and thermal properties of binary mixed chloride salts

2021 ◽  
Vol 2076 (1) ◽  
pp. 012040
Author(s):  
Quanying Yan ◽  
Chao Ma ◽  
Wei Wang
Keyword(s):  
Phase Transition ◽  
Power Generation ◽  
Sodium Chloride ◽  
Melting Point ◽  
Binary Mixture ◽  
Phase Change ◽  
Molten Salt ◽  
Latent Heat ◽  
Lithium Chloride ◽  
Phase Change Materials

Abstract Nitrate phase change materials (PCMs) are the most widely used PCMs in solar thermal power generation technology. The maximum service temperature of Nitrate phase change materials is only 600°C. Therefore, to find a phase change material with large heat capacity, wide temperature range, low heat loss and low price is the focus of current research. According to different mass ratios, nine binary molten salt mixtures were prepared by mixing lithium chloride and sodium chloride. The phase change temperature and latent heat of phase transition of them were studied by differential scanning calorimeter (DSC). The experiment results showed that since the melting point of sodium chloride was high, when the content of sodium chloride in the binary mixture of lithium chloride and sodium chloride was large, a small amount of lithium chloride could not reduce the melting point of the mixture below 600°C, the mixture could not be melted. Meanwhile, when sodium chloride and lithium chloride were melted, the phase transition temperature of lithium chloride and sodium chloride remained at about 540°C and floated at ±15°C. The melting temperature and crystallization temperature of the binary mixture of 90% lithium chloride and 10% sodium chloride were quite different, and the latent heat of phase transformation was relatively high. Therefore, the binary mixed molten salt can be used in the heat transfer and storage technology of solar power generation.

Sunlight-Activated Phase Change Materials for Controlled Heat Storage and Triggered Release

2021 ◽  
Author(s):  
Yuran Shi ◽  
Mihael Gerkman ◽  
Qianfeng Qiu ◽  
Shuren Zhang ◽  
Grace G. D. Han
Keyword(s):  
Phase Transition ◽  
Solar Radiation ◽  
Phase Change ◽  
Latent Heat ◽  
Photon Energy ◽  
Organic Phase ◽  
Phase Change Materials ◽  
Heat Storage ◽  
Triggered Release

We report the design of photo-responsive organic phase change materials that can absorb filtered solar radiation to store both latent heat and photon energy via simultaneous phase transition and photo-isomerization....

scholarly journals Recent Investigations of Phase Change Materials Use in Solar Thermal Energy Storage System

2018 ◽  
Vol 2018 ◽  
pp. 1-13 ◽  
Author(s):  
Qianjun Mao ◽  
Ning Liu ◽  
Li Peng
Keyword(s):  
Energy Storage ◽  
Melting Point ◽  
Phase Change ◽  
Latent Heat ◽  
Thermal Energy ◽  
Thermal Energy Storage ◽  
Phase Change Materials ◽  
Heat Storage ◽  
Solar Thermal Energy ◽  
Temperature Heat

Solar thermal energy storage (TES) is an efficient way to solve the conflict between unsteady input energy and steady output energy in concentrating solar power plant. The latent heat thermal energy storage (LHTES) system is a main method of storing thermal energy using phase change materials (PCMs). Thermal properties, that is, melting points and latent heat, are the key parameters of PCMs for the TES system. In this paper, the PCMs are classified into inorganic and organic by the chemical composition, and according to the melting point, the inorganic PCMs can be divided into three contributions: low-temperature heat storage (less than 120°C), medium-temperature heat storage (120–300°C), and high-temperature heat storage (more than 300°C). The present article focuses mainly on the recent investigations on the melting point and latent heat of PCMs via DSC setup in the solar TES systems. The results can provide a good reference for the selection and utilization of PCMs in the solar TES systems.

Preparation of Expanded Perlite-Based Binary Eutectic Composite of Phase Change Heat Storage Materials

2011 ◽  
Vol 383-390 ◽  
pp. 2889-2893
Author(s):  
Bao Yun Zhang ◽  
Chang Mei Jiao ◽  
Peng Wang ◽  
Long Jiang ◽  
Bao Hua Ji ◽  
...  
Keyword(s):  
Phase Transition ◽  
Transition Temperature ◽  
Phase Change ◽  
Latent Heat ◽  
Phase Transition Temperature ◽  
Phase Change Materials ◽  
Vacuum Impregnation ◽  
Expanded Perlite ◽  
Good Thermal Stability ◽  
Binary Eutectic

The binary eutectic of lauric acid-stearic acid / expanded perlite composite phase change materials (PCM) was prepared using the method of vacuum impregnation. The structures and properties of this composite PCM were characterized by FT-IR, SEM, DSC and TG analysis. The results showed that the binary eutectic of fatty acid had been composed with porous skeleton expanded perlite completely in a physical method, the phase transition temperature of composite PCM was about 33.0 °C and latent heat was 131.3 J/g. it had a good thermal stability after 100 times of recycling and gave the phase transition temperature 33.5 °C and the latent heat of 128.1 J/g respectively.

Preparation and Properties of Form-Stable Phase Change Materials Polyacrylonitrile Fiber / Stearic Acid Blends

2011 ◽  
Vol 197-198 ◽  
pp. 584-588 ◽  
Author(s):  
Jing Guo ◽  
Heng Xue Xiang ◽  
Qian Qian Wang
Keyword(s):  
Phase Transition ◽  
Stearic Acid ◽  
Phase Change ◽  
Latent Heat ◽  
Thermal Insulation ◽  
Phase Change Materials ◽  
Cooling Curve ◽  
Stable Phase ◽  
Polyacrylonitrile Fiber ◽  
Soaking Time

With stearic acid (SA) as phase change material, waste polyacrylonitrile fiber (PAN) as framework material, N,N-dimethylformamide (DMF) as solvent, form-stable PAN/SA blends phase change materials (PCM) are prepared by solution blending process. Phase change temperature and latent heat and the thermal stability of the PAN/SA PCM are characterized using Differential Scanning Calorimetry (DSC). The structure, crystalline morphology, and thermal insulation properties of the PAN/SA PCMs are investigated using Fourier transformation infrared spectroscope (FTIR), polarizing optical microscopy (POM), and temperature-recording instrument. The FTIR and POM results show that PAN and SA are combined by intermolecular forces, and SA is homogeneous distribution in the PAN matrix. The DSC results indicate that PAN/SA PCMs have high latent heat storage capacity of more than 115J/g, the phase transition temperature and phase transition enthalpy of the PCMs increase with increasing the mass percent of SA. Cooling curve of PAN/SA PCMs show that the PCMs have good insulation properties, the soaking time is continued for about six minutes, and the thermal insulation properties remain unchanged after five and ten times of thermal cycling. The best process condition is obtained by the soaking time and orthogonal experiment.

Selection of Phase Change Materials for Latent Heat Storage

2017 ◽  
Vol 13 (1) ◽  
Author(s):  
J. Martínez-Gómez ◽  
E. Urresta ◽  
D. Gaona ◽  
G. Guerrón
Keyword(s):  
Phase Change ◽  
Latent Heat ◽  
Phase Change Materials ◽  
Heat Storage ◽  
Latent Heat Storage ◽  
Toma De Decisiones ◽  
Selection Of

Esta investigación tiene como objetivo seleccionar un material de cambio de fase (PCM) que cumplen mejor la solución del almacenamiento de energía térmica entre 200-400 ° C y reducir el costo de producción. El uso de métodos multicriterios de toma de decisiones (MCMD) para la evaluación fueron proporcionales implementados como COPRAS-G, TOPSIS y VIKOR. La ponderación de los criterios se realizó por el método AHP (proceso analítico jerárquico) y los métodos de entropía. La correlación de los resultados entre los tres métodos de clasificación ha sido desarrollada por el coeficiente de correlación de Spearman. Los resultados ilustran el mejor y la segundo mejor opción para los tres MCDM fueron NaOH y KNO3. Además, tenía valores de correlación de Spearman entre los métodos excede de 0.714.

scholarly journals Enhanced Performance and Diffusion Robustness of Phase-Change Metasurfaces via a Hybrid Dielectric/Plasmonic Approach

Nanomaterials ◽  
2021 ◽  
Vol 11 (2) ◽  
pp. 525
Author(s):  
Joe Shields ◽  
Carlota Ruiz de Galarreta ◽  
Jacopo Bertolotti ◽  
C. David Wright
Keyword(s):  
Melting Point ◽  
Phase Change ◽  
Noble Metals ◽  
Phase Change Materials ◽  
High Efficiency ◽  
The Body ◽  
Design Stage ◽  
High Melting ◽  
Optical Performance ◽  
Electrical Conductors

Materials of which the refractive indices can be thermally tuned or switched, such as in chalcogenide phase-change alloys, offer a promising path towards the development of active optical metasurfaces for the control of the amplitude, phase, and polarization of light. However, for phase-change metasurfaces to be able to provide viable technology for active light control, in situ electrical switching via resistive heaters integral to or embedded in the metasurface itself is highly desirable. In this context, good electrical conductors (metals) with high melting points (i.e., significantly above the melting point of commonly used phase-change alloys) are required. In addition, such metals should ideally have low plasmonic losses, so as to not degrade metasurface optical performance. This essentially limits the choice to a few noble metals, namely, gold and silver, but these tend to diffuse quite readily into phase-change materials (particularly the archetypal Ge2Sb2Te5 alloy used here), and into dielectric resonators such as Si or Ge. In this work, we introduce a novel hybrid dielectric/plasmonic metasurface architecture, where we incorporated a thin Ge2Sb2Te5 layer into the body of a cubic silicon nanoresonator lying on metallic planes that simultaneously acted as high-efficiency reflectors and resistive heaters. Through systematic studies based on changing the configuration of the bottom metal plane between high-melting-point diffusive and low-melting-point nondiffusive metals (Au and Al, respectively), we explicitly show how thermally activated diffusion can catastrophically and irreversibly degrade the optical performance of chalcogenide phase-change metasurface devices, and how such degradation can be successfully overcome at the design stage via the incorporation of ultrathin Si3N4 barrier layers between the gold plane and the hybrid Si/Ge2Sb2Te5 resonators. Our work clarifies the importance of diffusion of noble metals in thermally tunable metasurfaces and how to overcome it, thus helping phase-change-based metasurface technology move a step closer towards the realization of real-world applications.

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