scholarly journals Research on xylitol crystallization by shearing and seeding for its use as a phase change material

2021 ◽  
Vol 2116 (1) ◽  
pp. 012046
Author(s):  
Mónica Delgado ◽  
Miguel Navarro ◽  
Ana Lázaro ◽  
Séverine A E Boyer ◽  
Edith Peuvrel-Disdier
Keyword(s):  
Crystal Structure ◽  
Phase Change ◽  
Phase Change Materials ◽  
Crystallization Rate ◽  
New Materials ◽  
Sugar Alcohols ◽  
Secondary Nucleation ◽  
Scanning Calorimetry ◽  
Shear Cell ◽  
Change Material

Abstract As thermal energy storage is becoming more important, new materials are being studied. Sugar-alcohols (SA) are very promising as phase change materials (PCM) because they are non-toxic, affordable and their latent heat is high. However, undercooling and low crystallization rates are some of the problems present in these materials. The SA studied in this work is xylitol, and using a microscope connected to a transparent counter-rotating shear cell, the effect of secondary nucleation is studied, as well as the crystallization rate of xylitol and how undercooling affects it. From the results, it is deduced that a proper seed preparation and handling is needed. The crystal structure is also studied, using XRPD diffractograms and differential scanning calorimetry.

The Properties of OMMT-PAN-Binary of Fatty Acids Blends as Phase Change Materials

2011 ◽  
Vol 239-242 ◽  
pp. 1101-1104
Author(s):  
Jing Guo ◽  
Heng Xue Xiang ◽  
Cheng Nv Hu
Keyword(s):  
Fatty Acid ◽  
Phase Change ◽  
Phase Change Material ◽  
Phase Change Materials ◽  
Heat Insulation ◽  
Cooling Curve ◽  
Polyacrylonitrile Fiber ◽  
Scanning Calorimetry ◽  
Thermal Circulation ◽  
Change Material

Using stearic acid-lauric acid binary of fatty acid as phase change material, waste polyacrylonitrile fiber (PAN) as supporting material, organic montmorillonite (OMMT) as modifier, and N, N-dimethylformamide as solvent, OMMT-PAN-binary fatty acid composite phase change materials(PCM) is prepared by solution blending. Using Scanning Electron Microscopy (SEM), Differential Scanning Calorimetry (DSC), Thermogravimetric analysis (TG) study the structure and properties of PCM, the optimized preparation techniques of PCM obtained by orthogonal tests. SEM results showed that the PCM was homogeneous structure, binary of fatty acid dispersed in the continuous phase PAN; TGA results indicated that the degradation of the phase change material can be divided into three steps; DSC results showed that the crystallization enthalpy of PCM reached 143.27 J/g, the phase change temperature was around 23°C, and the DSC thermal circulation showed good thermal stability of the PCM; cooling curve showed that the PCM had good heat insulation properties, holding time reached 800s, and after repeated thermal circulation, heat insulation properties remained the same.

scholarly journals Granulation Of Porous Materials with Phase Change Material (PCM)

2021 ◽  
Vol 20 (3) ◽  
pp. 135-144
Author(s):  
Tomasz Bien
Keyword(s):  
Mechanical Strength ◽  
Phase Change ◽  
Construction Industry ◽  
Phase Change Materials ◽  
Nitrogen Adsorption ◽  
X Ray Diffraction ◽  
Scanning Calorimetry ◽  
Method Of Production ◽  
Adsorption Desorption ◽  
Change Material

The paper describes the research on the method of production of granulated phase-change materials (PCM) used in construction industry for the accumulation of thermal energy. As mineral materials for the granules preparation zeolite from fly ash Na-P1 and natural diatomite dust were used which were impregnated with paraffinic filtration waste and granulated using a combined granulation method. Obtained granules were characterized using X-ray diffraction (XRD), scanning electron microscopy (SEM), nitrogen adsorption/desorption isotherm, and differential scanning calorimetry (DSC). Mechanical strength of the materials was determined in a “drop strength” test. Performed analyses revealed that mineral composition and micromorphology of the diatomite and zeolite granules were varied, with zeolite granules having higher mechanical strength.

Properties of a Solid–Solid Phase Change Material PAN/SA-LA/ZMS

2014 ◽  
Vol 703 ◽  
pp. 3-8 ◽  
Author(s):  
Jing Guo ◽  
Xiang Kang You ◽  
Li Zhang ◽  
Heng Xue Xiang ◽  
Sen Zhang ◽  
...  
Keyword(s):  
Phase Change ◽  
Phase Change Materials ◽  
Solid Phase ◽  
The Novel ◽  
Structure And Properties ◽  
Scanning Calorimetry ◽  
Solution Blending ◽  
Blending Process ◽  
Change Material ◽  
Insulating Properties

In this study, novel solid–solid phase change materials (PCM) composed of polyacrylonitrile, binary of fatty acids ((blending of stearic acid (SA) and lauric acid (LA)) and zeolite molecular sieve (ZMS) were prepared by solution blending process. The structure and properties of the PCM were characterized using flourier transform infrared spectroscopy (FTIR), scanning electron microscopy (SEM), polarized optical microscopy (POM), differential scanning calorimetry (DSC) and thermogravimetric analysis (TG), respectively. DSC analysis indicated that the crystallization latent heat of the PCM was 125.22 J/g and its phase transition temperature was about 17 °C. The temperature curve for step cooling of the PCM showed that it’s holding time achieved 1 480 s, which explains that the PCM had excellent heat-insulating properties. Based on all results it can be concluded that the novel PCM can be considered as potential PCM for thermal energy storage.

Characterization Phase Change Materials (PCM) Using T-History Method

2016 ◽  
Author(s):  
Navin Kumar ◽  
Debjyoti Banerjee
Keyword(s):  
Phase Change ◽  
Experimental Validation ◽  
Phase Change Materials ◽  
Reference Sample ◽  
Cost Effective ◽  
Experimental Protocol ◽  
Scanning Calorimetry ◽  
Numerical Predictions ◽  
Change Material

“T-history method” is widely used for characterization of thermal properties of Phase Change Material (PCM). In this study improvements are proposed to the experimental protocol used in the conventional T-History method. Experimental validation of numerical predictions for various samples of PCM were performed using the proposed measurement technique. This enabled the evaluation of the improvements in the proposed approach as well as for analyzing the experimental results. This involved measurement of temperature at the surface and in the center of the PCM samples (as well as that of the reference sample materials). The proposed modifications enable enhanced accuracy for estimation of the material properties (when compared to the conventional approaches). The estimates from the proposed approach were observed to be within 10% of the measured values obtained using Differential Scanning Calorimetry (DSC). The proposed approach is amenable to testing large sample sizes, is simpler to implement, provides more rapid data collection and is more cost-effective than that obtained using standard DSC protocols.

Phase Change Materials: A Prospective Solution for Surface Layers of Building Envelopes

2015 ◽  
Vol 749 ◽  
pp. 415-419
Author(s):  
Zbyšek Pavlík ◽  
Anton Trník ◽  
Milena Pavlíková ◽  
Jan Fořt ◽  
Robert Černý
Keyword(s):  
Phase Change ◽  
Phase Change Materials ◽  
Phase Changes ◽  
Surface Layers ◽  
Scanning Calorimetry ◽  
Powder Density ◽  
The Difference ◽  
And Storage ◽  
Change Material

A Phase Change Material (PCM) based on paraffinic wax encapsulated in polymer shell is used for improvement of the heat storage capacity of commercially produced dry plaster, originally developed for both exterior and interior hand application. The composition of PCM modified plasters is designed with respect to the workability of fresh mixtures. Characterization of applied PCM is done using the measurement of particle size distribution, powder density, and matrix density. For the newly developed composite plasters, basic physical properties, mechanical properties, and thermal properties are accessed, whereas a specific attention is paid to the Difference Scanning Calorimetry (DSC) analysis. Using DSC measurement, temperatures of phase change transitions and phase changes enthalpies are identified. The obtained results show that the temperature induced phase change can be used for the release and storage of thermal energy in buildings, which can be beneficially utilized for saving the energy spent for the achievement of the indoor thermal comfort.

Enhanced Heat Conduction in Cellulose Nanocrystals Grafting Polyethylene Glycol as Solid-Solid Phase Change Materials

2012 ◽  
Vol 557-559 ◽  
pp. 563-566 ◽  
Author(s):  
Yan Nan Liu ◽  
Hou Yong Yu ◽  
Zong Yi Qin ◽  
Long Chen
Keyword(s):  
Polyethylene Glycol ◽  
Phase Change ◽  
Cellulose Nanocrystals ◽  
Thermal Conduction ◽  
Phase Change Materials ◽  
Solid Phase ◽  
Scanning Calorimetry ◽  
Thermal Delay ◽  
Change Material ◽  
Molecular Skeleton

Green copolymers as phase change material were prepared by grafting polyethylene glycol(PEG) onto a rigid molecular skeleton of cellulose nanocrystals (CNs), and their thermal properties were studied by thermal delay method and differential scanning calorimetry. The influences of the CNs on the thermal conductivity behavior and thermal energy storage capacity of the copolymers were evaluated. As expected, a great enhancement on thermal conduction can be achieved by introducing CNs.

Effects of carbon nanotubes additive on thermal conductivity and thermal energy storage properties of a novel composite phase change material

2018 ◽  
Vol 53 (21) ◽  
pp. 2967-2980 ◽  
Author(s):  
Ahmet Sarı ◽  
Alper Biçer ◽  
Gökhan Hekimoğlu
Keyword(s):  
Thermal Conductivity ◽  
Carbon Nanotubes ◽  
Differential Scanning Calorimetry ◽  
Phase Change ◽  
Phase Change Material ◽  
Phase Change Materials ◽  
Scanning Calorimetry ◽  
Composite Phase Change Materials ◽  
Composite Phase Change Material ◽  
Change Material

Fatty acids are commonly preferred as phase change materials for passive solar thermoregulation due to their several advantageous latent heat thermal energy storage (LHTES) properties. However, further storage container requirement of fatty acids against leakage problem during heating period and also low thermal conductivity significantly limit their application fields. To overcome these drawbacks of capric acid–stearic acid eutectic mixture as phase change material, it was first impregnated with expanded vermiculite clay by melting/blending method and then doped with carbon nanotubes. The effects of carbon nanotubes additive on the chemical/morphological structures and LHTES properties of the composite phase change material and thermal enhanced change phase change materials were investigated by scanning electron microscope, Fourier transform infrared spectroscopy, X-ray diffraction, differential scanning calorimetry and thermogravimetric analysis analysis techniques. The differential scanning calorimetry results showed that the form-stable composite phase change materials and thermal enhanced composite phase change materials have melting temperatures in the range of 24.35–24.64℃ and latent heat capacities between 76.32 and 73.13 J/g. Thermal conductivity of the composite phase change materials was increased as 83.3, 125.0 and 258.3% by carbon nanotubes doping 1, 3 and 5 wt%. The heat charging and discharging times of the thermal enhanced -composite phase change materials were reduced appreciably due to the enhanced thermal conductivity without notably influencing their LHTES properties. Furthermore, the thermal cycling test and thermogravimetric analysis findings proved that all fabricated composites had admirable thermal durability, cycling LHTES performance and chemical stability.

Studies on Preparation and Properties of PEG/MMT Solid-Solid Phase Change Material

2012 ◽  
Vol 512-515 ◽  
pp. 1712-1715
Author(s):  
Xiao Hua Gu ◽  
Bao Yun Xu ◽  
Jia Liang Zhou ◽  
Shi Wei Li
Keyword(s):  
Thermal Stability ◽  
Energy Storage ◽  
Phase Change ◽  
Phase Change Material ◽  
Phase Change Materials ◽  
Solid Phase ◽  
Energy Storage Materials ◽  
Scanning Calorimetry ◽  
Storage Behavior ◽  
Change Material

This paper details the preparation of one kind of PEG/MMT solid-solid phase change materials. With polyethylene glycol (PEG) as the phase change materials, montmorillonite (MMT) as skeletons, through the graft copolymerization method, prepare PEG/MMT solid-solid phase change energy storage materials. The structure, the phase transition behavior and thermal stability of PEG/MMT phase change materials were analyzed and studied by infrared spectroscopy (FTIR), thermogravimetry (TG) and differential scanning calorimetry (DSC), and studied the influence of different molecular weight PEG on the capability and structure of the material, polymer phase change energy storage behavior and crystallization behavior. Finally, The PEG/MMT solid-solid phase change material could improve enthalpy value and thermal stability.

scholarly journals Form-Stable Phase Change Materials Based on SEBS and Paraffin: Influence of Molecular Parameters of Styrene-b-(Ethylene-co-Butylene)-b-Styrene on Shape Stability and Retention Behavior

Materials ◽  
2020 ◽  
Vol 13 (15) ◽  
pp. 3285
Author(s):  
Ralf Rickert ◽  
Roland Klein ◽  
Frank Schönberger
Keyword(s):  
Mechanical Properties ◽  
Molecular Weight ◽  
Phase Change ◽  
Phase Change Materials ◽  
Matrix Material ◽  
Stable Phase ◽  
Scanning Calorimetry ◽  
Molecular Parameters ◽  
Styrene Content ◽  
Change Material

In this work, the influence of molecular parameters of styrene-b-(ethylene-co-butylene)-b-styrene (SEBS) triblock copolymer as matrix material in form-stable phase change material (FSPCM) on the thermo-mechanical properties and leakage behavior are studied. Various SEBS grades differing in their molecular weight, styrene content, and ethylene/butylene ratio are used as supporting matrix in composites with 90 wt.% paraffin. Thermo-mechanical properties are determined by rheological measurements. The results show phase transitions temperatures from solid to hard gel, hard gel to soft gel, and soft gel to gel fluid. Paraffin leakage in FSPCM is analyzed by mass loss over time in an oven at 60 °C. Differential scanning calorimetry (DSC) and thermogravimetric analysis (TGA) are applied to determine the thermal energy storage capacity. Finally, the molecular weight and the styrene content are combined to the molecular weight of styrene block which is identified as the authoritative parameter for the thermo-mechanical properties of the SEBS/PCM composite.

scholarly journals A SUSTAINABILITY APPROACH: INTEGRATION OF A MICROENCAPSULATED PHASE CHANGE MATERIAL TO A RECYCLED PES NONWOVEN FABRIC TO DEVELOP A HEAT STORING RECYCLED MATERIAL

2021 ◽  
Vol 2021 ◽  
pp. 58-64
Author(s):  
E.G. Saraç ◽  
E. Öner ◽  
M.V. Kahraman
Keyword(s):  
Phase Change ◽  
Phase Change Material ◽  
Phase Change Materials ◽  
In Situ Polymerization ◽  
Coconut Oil ◽  
Nonwoven Fabric ◽  
Scanning Calorimetry ◽  
The Core ◽  
Needle Punching ◽  
Change Material

Phase change materials (PCMs) are thermal energy storing materials which are adopted in various industries including textiles. They provide temperature regulation by absorbing the heat from the ambiance or releasing the latent heat that they store. PCMs are widely integrated into textiles in microencapsulated form where the core PCM is covered by the microcapsule shell and protected during phase change. This form also provides a higher thermal conductivity. In this work, a blend of organic coconut oil and n-octadecane were used as phase change material in core, and melamine formaldehyde was used as shell material to develop microencapsulated PCM for heat storage. The microcapsules were produced by using in situ polymerization method. The developed microcapsules (MPCMs) were integrated to a recycled PES (polyester) nonwoven fabric, generated from PET (polyethylene terephthalate) fibres, and manufactured by combing and needle punching technique. The MPCMs were implemented to the fabric by coating method. The core PCM, MPCM, and the coated nonwoven fabric were assessed by Differential Scanning Calorimetry (DSC), Scanning Electron Microscopy (SEM) and Fourier Transform Infrared Spectroscopy (FT-IR). SEM results indicated that spherical and uniform microcapsules were obtained with a particle size of 3-9 μm. DSC results revealed that MPCM and the MPCM coated nonwoven fabric possessed a remarkable melting enthalpy of 111 J/g and 30.9 J/g, respectively at peak melting temperatures of 28.1°C and 27.4°C.

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