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

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.

2020 ◽  
pp. 152808372092149
Author(s):  
Saraç E Gözde ◽  
Öner Erhan ◽  
Kahraman M Vezir

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.


2011 ◽  
Vol 239-242 ◽  
pp. 1101-1104
Author(s):  
Jing Guo ◽  
Heng Xue Xiang ◽  
Cheng Nv Hu

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.


2021 ◽  
Vol 13 (19) ◽  
pp. 10731
Author(s):  
Cibele Eller ◽  
Mohamad Rida ◽  
Katharina Boudier ◽  
Caio Otoni ◽  
Gabriela Celani ◽  
...  

One of the most efficient measures to reduce energy consumption in buildings is using passive thermal comfort strategies. This paper shows the potential of coconut oil as a bio-based phase change material (PCM) incorporated into construction components to improve the thermal performance of buildings for several climates, due to its environmental advantages, wide availability, and economic feasibility. The thermophysical properties of coconut oil were determined through differential scanning calorimetry. Numerical simulations were conducted in ESP-r, comparing an office space with a gypsum ceiling to one with coconut oil as PCM for 12 climate types in the Köppen–Geiger classification. The results show that coconut oil is a suitable PCM for construction applications under tropical and subtropical climates. This PCM can provide year-round benefits for these climates, even though a higher melting point is needed for optimum performance during hotter months. The highest demand reduction of 32% and a maximum temperature reduction of 3.7 °C were found in Mansa, Zambia (Cwa climate). The best results occur when average outdoor temperatures are within the temperature range of phase change. The higher the diurnal temperature range, the better the results. Our findings contribute to a better understanding of coconut oil in terms of its properties and potential for application in the building sector as PCM.


2018 ◽  
Vol 53 (21) ◽  
pp. 2967-2980 ◽  
Author(s):  
Ahmet Sarı ◽  
Alper Biçer ◽  
Gökhan Hekimoğlu

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.


2012 ◽  
Vol 512-515 ◽  
pp. 1712-1715
Author(s):  
Xiao Hua Gu ◽  
Bao Yun Xu ◽  
Jia Liang Zhou ◽  
Shi Wei Li

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.


2016 ◽  
Vol 40 (4) ◽  
pp. 299-310 ◽  
Author(s):  
Jignesh S Patel ◽  
Elizabeth Gao ◽  
Veera M Boddu ◽  
Larry D Stephenson ◽  
Ashok Kumar

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.


Author(s):  
Ali Deriszadeh ◽  
Filippo de Monte ◽  
Marco Villani

Abstract This study investigates the cooling performance of a passive cooling system for electric motor cooling applications. The metal-based phase change materials are used for cooling the motor and preventing its temperature rise. As compared to oil-based phase change materials, these materials have a higher melting point and thermal conductivity. The flow field and transient heat conduction are simulated using the finite volume method. The accuracy of numerical values obtained from the simulation of the phase change materials is validated. The sensitivity of the numerical results to the number of computational elements and time step value is assessed. The main goal of adopting the phase change material based passive cooling system is to maintain the operational motor temperature in the allowed range for applications with high and repetitive peak power demands such as electric vehicles by using phase change materials in cooling channels twisted around the motor. Moreover, this study investigates the effect of the phase change material container arrangement on the cooling performance of the under study cooling system.


2017 ◽  
Vol 140 (1) ◽  
Author(s):  
Chenzhen Liu ◽  
Ling Ma ◽  
Zhonghao Rao ◽  
Yimin Li

In this study, micro-encapsulated phase change material (microPCM) was successfully synthesized by emulsion polymerization method, using magnesium sulfate heptahydrate (MSH) as core material and urea resin (UR) as shell material. The surface morphologies and particle size distributions of the microPCM were tested by scanning electron microscopy (SEM) and laser particle size analyzer. The chemical structure of microPCM was analyzed by Fourier-transform infrared spectroscopy (FTIR). The thermal properties were investigated by differential scanning calorimetry (DSC) and thermal conductivity coefficient instrument, respectively.


2021 ◽  
Vol 16 (1) ◽  
pp. 032-041
Author(s):  
Pradeep N ◽  
Somesh Subramanian S

Thermal energy storage through phase change material has been used for wide applications in the field of air conditioning and refrigeration. The specific use of this thermal storage has been for energy storage during low demand and release of this energy during peak loads with potential to provide energy savings due to this. The principle of latent heat storage using phase change materials (PCMs) can be incorporated into a thermal storage system suitable for using deep freezers. The evaporator is covered with another box which has storage capacity or passage through phase change material. The results revealed that the performance is increased from 3.2 to 3.5 by using PCM.


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