scholarly journals Determining the Heat of Fusion and Specific Heat of Microencapsulated Phase Change Material Slurry by Thermal Delay Method

Energies ◽  
2020 ◽  
Vol 14 (1) ◽  
pp. 179
Author(s):  
Krzysztof Dutkowski ◽  
Marcin Kruzel ◽  
Bartosz Zajączkowski
Keyword(s):  
Phase Change ◽  
Specific Heat ◽  
Phase Change Material ◽  
Water Solution ◽  
Heat Of Fusion ◽  
Main Peak ◽  
Liquid Form ◽  
Microencapsulated Phase Change Material ◽  
Thermal Delay ◽  
Change Material

This paper details an experimental study that was performed to investigate the specific heat of microencapsulated phase change material (mPCM) slurry and its heat of fusion at the PCM phase change transition temperature. Six samples (mPCM slurry concentrate with the water solution of propylene glycol used as a main base liquid) were prepared. As the concentrate contains 43.0% mPCM, the actual mass fraction amounts to 8.6, 12.9, 17.2, 21.5, 25.8, and 30.1 wt%, respectively. The thermal delay method was used. Samples were cooled from 50 °C to 10 °C. A higher concentration of microcapsules caused a proportional increase in the specific heat of slurry at the main peak melting temperature. The maximum value of the specific heat changed from 9.2 to 33.7 kJ/kg for 8.6 wt%, and 30.1 wt%, respectively. The specific heat of the mPCM slurry is a constant quantity and depends on the concentration of the microcapsules. The specific heat of the slurry (PCM inside microcapsules in a liquid form) decreased from 4.0 to 3.8 kJ/(kgK) for 8.6 wt%, and 30.1 wt% of mPCM, respectively. The specific heat of the slurry (PCM inside microcapsules in a liquid form) was higher than when the PCM in the microcapsules is in the form of a solid and increased from 4.5 to 5.2 kJ/(kgK) for 8.6 wt% and 30.1 wt% of mPCM, respectively.

Experimental Study of a Closed-Loop Thermosyphon Operating With Slurries of a Microencapsulated Phase-Change Material

2013 ◽  
Author(s):  
Alexandre Lamoureux ◽  
B. Rabi Baliga
Keyword(s):  
Phase Change ◽  
Phase Change Material ◽  
Closed Loop ◽  
Effective Density ◽  
Heat Of Fusion ◽  
Bulk Temperature ◽  
Effective Diameter ◽  
Distilled Water ◽  
Microencapsulated Phase Change Material ◽  
Change Material

An experimental investigation of steady, laminar, fluid flow and heat transfer in a vertical closed-loop thermosyphon operating with slurries of a microencapsulated phase-change material (MCPCM) suspended in distilled water is presented. The MCPCM particles consisted of a solid-liquid phase-change material (PCM) encapsulated in a thin polymer resin shell. Their effective diameter was in the range 0.5 to 12.5 micrometers, and had a mean value of 2.5 micrometers. The melting and freezing characteristics and the latent heat of fusion of the PCM were determined using a differential scanning calorimeter. The effective density of the MCPCM was measured, and the effective thermal conductivity of the slurries was determined using a published correlation. In the range of parameters considered, it was determined that the slurries exhibit non-Newtonian behavior. The closed-loop thermosyphon consisted of two vertical straight pipes, joined together by two vertical semi-circular 180-degree bends made of the same pipe. An essentially constant heat flux was imposed on a portion of one of the vertical pipes. The wall temperature of a portion of the other vertical pipe was maintained at a constant value. The outer surfaces of the entire thermosyphon were very well insulated. Calibrated thermocouples were used to measure the outer-wall-surface temperature at numerous points over the heated portion and the bulk temperature of the slurry at four different locations. A special procedure was formulated, benchmarked, and used to deduce the mass flow rate of the slurries in the thermosyphon. The investigation was conducted with slurries of MCPCM mass concentration 0% (pure distilled water), 7.471%, 9.997%, 12.49%, 14.95%, and 17.5%. The results are presented and discussed.

Synthesis and properties of multifunctional microencapsulated phase change material for intelligent textiles

2020 ◽  
Vol 56 (3) ◽  
pp. 2176-2191
Author(s):  
Jun Li ◽  
Xiaoyun Zhu ◽  
Huichang Wang ◽  
Pengcheng Lin ◽  
Lisi Jia ◽  
...  
Keyword(s):  
Phase Change ◽  
Phase Change Material ◽  
Microencapsulated Phase Change Material ◽  
Change Material

scholarly journals Diffusion of Shape Stabilized PEG-SiO2 as a Driver for Producing Thermoregulating Facing Bricks

Materials ◽  
2021 ◽  
Vol 14 (6) ◽  
pp. 1395
Author(s):  
Angel Serrano ◽  
Ana M. Borreguero ◽  
Isabel Iglesias ◽  
Anselmo Acosta ◽  
Juan F. Rodríguez ◽  
...  
Keyword(s):  
Phase Change ◽  
Phase Change Material ◽  
Sol Gel ◽  
Effective Diffusion ◽  
Gelation Time ◽  
Stable Phase ◽  
Liquid Form ◽  
Indoor Temperature ◽  
Adsorption Capacities ◽  
Change Material

A novel form-stable phase-change material (PCM) based on facing bricks was developed by incorporating thermoregulating PEG-SiO2, synthetized by sol-gel method and based on polyethylene glycol as phase-change material and silica as stabilizer compound. The PEG-SiO2 in its liquid form (sol) is firstly adsorbed inside the porous brick and lastly stabilized (gel) by controlling its gelation time, obtaining form-stable PCMs with PEG-SiO2 contents within 15–110 wt.%. Kinetic adsorption curves of the sol into bricks having different porosities as well as maximum adsorption capacities were obtained. The effective diffusion coefficients (Deff) were estimated by means of Fick’s second law, it being possible to predict the adsorption of sol PEG-SiO2 by the brick as function of its porosity and the free diffusion coefficient. Finally, form-stable PCMs demonstrated an improvement in their thermal energy storage capacity (up to 338%), these materials being capable of buffering the indoor temperature during an entire operational day

scholarly journals Thermal and breathability management of microencapsulated phase change material (MPCM) incorporated jute fabric

2021 ◽  
Vol 16 ◽  
pp. 155892502110295
Author(s):  
Abdus Shahid ◽  
Solaiman Miah ◽  
Abdur Rahim
Keyword(s):  
Phase Change ◽  
Phase Change Material ◽  
Thermal Fluctuation ◽  
Water Repellency ◽  
Air Permeability ◽  
Jute Fabric ◽  
Moisture Management ◽  
Microencapsulated Phase Change Material ◽  
Fabric Surface ◽  
Change Material

Jute bags are widely used to carry food grains and other materials that may be prone to quality deterioration due to thermal fluctuation. Thermal and moisture properties play a significant role in the packaging materials in the form of a container. This study deals with the effect of microencapsulated phase change material (MPCM) with hydrophobic binder on thermal and moisture management properties of jute fabric. Jute fabric was treated with MPCM by pad-dry-cure method. The treated sample was characterized by thermogravimetric analysis (TGA), differential scanning colorimeter (DSC), scanning electron microscope (SEM), moisture management tester (MMT), and air permeability tester. The results revealed that MPCM treated jute fabric shows greater thermal stability and heat absorption ability of 10.58 J/g while changing from solid to liquid phase. The SEM image ensures even distribution of MPCMs on fabric surface and surface roughness was also observed using image processing software. The air permeability was found to decrease whereas the water repellency enhanced in the developed sample.

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