Accelerated long-term assessment of thermal and chemical stability of bio-based phase change materials

2016 ◽  
Vol 40 (4) ◽  
pp. 299-310 ◽  
Author(s):  
Jignesh S Patel ◽  
Elizabeth Gao ◽  
Veera M Boddu ◽  
Larry D Stephenson ◽  
Ashok Kumar
Keyword(s):  
Differential Scanning Calorimetry ◽  
Phase Change ◽  
Phase Change Material ◽  
Latent Heat ◽  
Chemical Stability ◽  
Phase Change Materials ◽  
Scanning Calorimetry ◽  
Change Material ◽  
Scanning Electron

Thermal energy storage systems incorporated with phase change materials have potential applications to control energy use by building envelopes. However, it is essential to evaluate long-term performance of the phase change materials and cost-effectiveness prior to full-scale implementation. For this reason, we have used the accelerated long-term approach for studying the thermal performance and chemical stability of a commercially available bio-based phase change material during thermal cycling over a simulated period of 20 years. The phase change material was subjected to accelerate thermal aging under controlled environmental conditions. Small samples of the phase change material were periodically removed to measure its latent heat, thermal decomposition, and chemical stability using various analytical methods such as differential scanning calorimetry, thermogravimetry analysis, and infrared spectroscopy. The topographic changes in the phase change material due to the aging process were observed using scanning electron microscopy. The differential scanning calorimetry data indicate a significant reduction of 12% in the latent heat during heating and cooling cycles during the initial 6.2 years remain nearly constant thereafter. The thermogravimetry analysis results showed that the phase change material has excellent thermal stability within the working temperature range and also shows long-term decomposition temperature stability. The Fourier transform infrared spectra of the phase change material indicate absorption of moisture but the phase change material was chemically stable over the duration of accelerated aging cycles. After several aging cycles, the baseline surface morphology appeared to be changed from uniform mix of phase change material with microstructures to segregated microstructures as evidenced by the observation of the scanning electron micrographs.

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.

Developing a thermo-regulative system for nonwoven textiles using microencapsulated organic coconut oil

2020 ◽  
pp. 152808372092149
Author(s):  
Saraç E Gözde ◽  
Öner Erhan ◽  
Kahraman M Vezir
Keyword(s):  
Phase Change ◽  
Phase Change Material ◽  
Coconut Oil ◽  
Nonwoven Fabric ◽  
Scanning Calorimetry ◽  
Microencapsulated Phase Change Material ◽  
Nonwoven Textiles ◽  
Composite Fabrics ◽  
Change Material ◽  
Scanning Electron

Organic coconut oil was investigated as a bio-based phase change material in core, and melamine formaldehyde was used as shell material to fabricate microencapsulated phase change material for thermo-regulation in nonwoven textiles. The microcapsules were synthesized using in situ polymerization method. The produced microcapsules (microencapsulated phase change material) were applied by knife coating in different ratios (1:5 and 1.5:5; MPCM: coating paste by wt.) to 100% polypropylene nonwoven, porous, and hydrophilic layer of a laminated, spunbond, and double-layer fabric. The coated layer was confined within two layers of the fabric to develop a thermo-regulative system on the nonwoven fabric to regulate the body temperature in surgeries. The two layers were composed by applying heat (140°C) and pressure (12 kg/cm2). Organic coconut oil, the fabricated microcapsule, and the composite fabrics were characterized by Fourier transform infrared spectroscopy, differential scanning calorimetry, and scanning electron microscopy. Scanning electron microscopy results revealed that spherical and uniform microcapsules were obtained with an approximate particle size of 2–6 µm. Differential scanning calorimetry results indicated that microencapsulated phase change material and the composite fabrics possessed significant melting enthalpies of 72.9 and 8.4–11.4 J/g, respectively, at peak melting temperatures between 21.6 and 22.8°C within human comfort temperature range. The utilization of coconut oil as a phase change material and the composite integration of this phase change material to a nonwoven fabric bring forward a novelty for future applications.

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.

Microencapsulation of n-hexadecane as phase change material by suspension polymerization

e-Polymers ◽  
2007 ◽  
Vol 7 (1) ◽  
Author(s):  
Ai Yafei ◽  
Jin Yong ◽  
Sun Jing ◽  
Wei Deqing
Keyword(s):  
Melting Point ◽  
Phase Change ◽  
Phase Change Material ◽  
Latent Heat ◽  
Suspension Polymerization ◽  
Average Diameter ◽  
Heat Of Fusion ◽  
Synthetic Surfactant ◽  
Scanning Calorimetry ◽  
Change Material

AbstractIn this study, suspension polymerization is described to fabricate microcapsules containing n-hexadecane as phase change material. In the suspension polymerization, casein is employed as emulsifier and stabilizer instead of synthetic surfactant. Microcapsules with polystyrene as shell and n-hexadecane as core have an average diameter of 3~15μm and the size distribution are narrow. Thermal properties are investigated by differential scanning calorimetry (DSC) showing that the microcapsules can store and release an amount of latent heat over a temperature range nearing the melting point of pure n-hexadecane. The latent heat of fusion of microencapsulated n-hexadecane decreases after microencapsulation. The melting point of microencapsulated n-hexadecane is near but higher than that of pure n-hexadecane, and the polymerization time has little effect on the melting point.

Thermal Properties and Morphology of Electrospun PEG/PVP Composite Fibers as Novel Phase Change Materials

2012 ◽  
Vol 204-208 ◽  
pp. 3998-4001
Author(s):  
Qi Song Shi
Keyword(s):  
Electron Microscopy ◽  
Scanning Electron Microscopy ◽  
Differential Scanning Calorimetry ◽  
Thermal Properties ◽  
Phase Change ◽  
Phase Change Materials ◽  
Composite Fibers ◽  
Scanning Calorimetry ◽  
Ultrafine Fibers ◽  
Scanning Electron

The ultrafine fibers based on the composites of polyethylene glycol(PEG) and polyvinylpyrrolidone(PVP) were prepared successfully via electrospinning as phase change materials. The thermal properties and morphology of the composite fibers were studied by differential scanning calorimetry(DSC) and scanning electron microscopy(SEM), respectively.

scholarly journals Analysis on the Improvement of Thermal Performance of Phase Change Material Ba (OH)2·8H2O

Energies ◽  
2021 ◽  
Vol 14 (22) ◽  
pp. 7761
Author(s):  
Xiaohui Lu ◽  
Xiaoxue Luo ◽  
Shibo Cao ◽  
Changzhen Zou
Keyword(s):  
Phase Change ◽  
Phase Change Material ◽  
Latent Heat ◽  
Large Scale ◽  
Phase Change Materials ◽  
Graphite Powder ◽  
Stable Phase ◽  
Heat Conducting ◽  
Supercooling Degree ◽  
Change Material

Benefitting from the characteristics of a high latent heat capacity and stable phase change behavior, phase change materials have widely received concerns in the field of thermodynamic management. Ba(OH)2·8H2O is an ideal phase change material (PCM) in the mid-to-low temperature range, but its large-scale application is still limited by severe supercooling during the nucleation process. In this paper, the experimental analysis and comparison are performed via an Edisonian approach, where Ba(OH)2·8H2O is adopted as an original substrate; BaCO3, CaCl2, NaCl, KH2PO4, and NaOH are selected as nucleating agents; and graphite is used as a heat-conducting agent. The results show that Ba(OH)2·8H2O containing 1.2% BaCO3 and 0.2% graphite powder has the best performance. Compared with pure Ba(OH)2·8H2O, the supercooling degree is reduced to less than 1 °C, the phase change latent heat duration is extended, and the thermal conductivity is significantly improved. Therefore, this study not only provides a reference for the application of Ba(OH)2·8H2O, but can also be used as a guidance for other material modifications.

Setting for the Application of Phase Change Paraffin in Block Masonry

2013 ◽  
Vol 448-453 ◽  
pp. 1308-1311
Author(s):  
Feng Jiang ◽  
Yong Le Hou ◽  
Yong Lin Hu ◽  
Wei Dong Zhu ◽  
Qing Hua Wang
Keyword(s):  
Phase Change ◽  
Phase Change Material ◽  
Latent Heat ◽  
Phase Change Materials ◽  
Liquid Paraffin ◽  
Change Temperature ◽  
Composite Phase Change Material ◽  
Heat Preservation ◽  
Solid Liquid ◽  
Change Material

This paper studies the insulation properties of masonry filling paraffin composite phase change material. With high density polyethylene (HDPE) as wrapping materials and solid-liquid mixing paraffin as phase change materials, solid-liquid mixed paraffin phase change material with different amount of admixture is prepared, and the problem of flowing after paraffin phase change is then solved. The phase change temperature and the phase change latent heat of composite phase change material with different amount of admixture are tested. The results showed that the composite material with 30% of 52 # solid paraffin, 70% of liquid paraffin, 70% of HDPE coating performs best as to the phase transition temperature and latent heat. On this basis, This paper studies the composite phase change wall with phase change materials 0%, 33%, 66% and100%. Results show that the composite phase change material wall’s heat preservation performance has significantly improved. the temperature fluctuation range of internal and external wall surface is 4.2 °C lower than unfilled wall.

scholarly journals Phase Change Material dari Campuran Parafin untuk Tekstil Swa-Termoregulasi

Texere ◽  
2020 ◽  
Vol 18 (2) ◽  
pp. 162-176
Author(s):  
Tisna Kusumah ◽  
Tatang Wahyudi ◽  
Mohamad Widodo
Keyword(s):  
Differential Scanning Calorimetry ◽  
Energy Storage ◽  
Phase Change ◽  
Phase Change Material ◽  
Thermal Energy ◽  
Thermal Energy Storage ◽  
Scanning Calorimetry ◽  
Change Material

Phase change material (PCM) organik seperti lilin parafin memiliki kemampuan untuk menyerap sejumlah energi panas atau entalpi (kJ/kg) pada saat lilin parafin mengalami perubahan fasa dari padat ke cair, dan sebaliknya, melepaskan energi panas saat berubah fasa dari cair ke padat. Kemampuan unik lilin parafin ini telah diteliti oleh banyak peneliti seperti mengenai sifat-sifat termal dan pemanfaatannya sebagai thermal energy storage. Penelitian-penelitian tentang PCM organik yang telah banyak dikerjakan, umumnya menggunakan bahan kelas sintesa yang memiliki keunggulan dalam hal kemurnian tetapi memiliki kesulitan untuk diaplikasikan dalam skala industri karena faktor keekonomisan dan ketersediaan bahan yang sulit didapat dalam skala besar. Oleh karena itu, penelitian ini difokuskan untuk mengetahui perubahan sifat termal dari campuran lilin parafin padat dan cair kelas mutu industri sebagai bahan utama PCM yang dapat dimanfaatkan dalam industri tekstil untuk membuat material tekstil yang responsif dan adaptif terhadap perubahan suhu lingkungan. Hasil analisa DSC (differential scanning calorimetry) menunjukkan bahwa pencampuran lilin parafin padat:cair dengan komposisi 9:1, 8:2, 7:3, dan 6:4 memperlihatkan adanya pembentukan entitas senyawa baru dengan sifat termal yang berbeda. Masing-masing kombinasi campuran yang berbeda memiliki titik leleh dan kandungan entalpi yang semakin menurun dari 60,4 ºC (9:1) ke 51,4 (6:4) seiring dengan menurunnya komposisi lilin parafin padat dan bertambahnya komposisi lilin parafin cair.

Sign in / Sign up

Export Citation Format

Share Document