scholarly journals The impact of employing a magnetic field as well as Fe3O4 nanoparticles on the performance of phase change materials

2022 ◽  
Vol 16 (1) ◽  
pp. 196-214
Author(s):  
Mohammad Zandie ◽  
Amirhossein Moghaddas ◽  
Alireza Kazemi ◽  
Mohammad Ahmadi ◽  
Hadi Nikbin Feshkache ◽  
...  
Keyword(s):  
Magnetic Field ◽  
Phase Change ◽  
Fe3o4 Nanoparticles ◽  
Phase Change Materials ◽  
The Impact

scholarly journals Thermo-physical characteristics of building integrated phase change materials (PCM) and their applicability to energy efficient homes

2021 ◽  
Author(s):  
Omar Siddiqui
Keyword(s):  
Compressive Strength ◽  
Phase Change ◽  
Phase Change Materials ◽  
Energy Savings ◽  
Physical Characteristics ◽  
Comfort Level ◽  
Thermal Mass ◽  
Lower Phase ◽  
Physical Test ◽  
The Impact

The applicability of utilizing a variety of thermal mass including phase change materials with commonly used building materials is investigated through the use of simulations and physical testing. The thermal performance and occupant comfort potential of a novel solid-solid phase change material, known as Dal HSM, is compared and contrasted to commonly available forms of thermal mass. Detailed experimentation is conducted to successfully integrate Dal HSM with gypsum and concrete. The measurement of physical characteristics such as compressive strength and modulus of rupture is conducted to ensure that the PCM-composite compound retains the structural integrity to be utilized in a typical building. The use of thermal mass in the Toronto Net Zero house was found to contribute to energy savings of 10-15% when different types of thermal mass were used. The comfort level of the indoor occupants was also found to increase. The performance of Dal HSM was found to be comparable to a commercially available PCM known as Micronal in the heating mode. The cooling mode revealed that Dal HSM provided slightly lower energy savings when compared to Micronal due to a lower phase transition temperature and latent heat. The performance of physical test revealed a decrease in the compressive strength as the concentration of Dal HSM was increased in the PCM-gypsum specimens. Tests were also performed to analyze the impact of increasing the PCM concentration on the flexural strength of PCM-gypsum composite.

scholarly journals Computational Study of Heat Transfer inside Different PCMs Enhanced by Al2O3 Nanoparticles in a Copper Heat Sink at High Heat Loads

Nanomaterials ◽  
2020 ◽  
Vol 10 (2) ◽  
pp. 284 ◽  
Author(s):  
Nadezhda S. Bondareva ◽  
Nikita S. Gibanov ◽  
Mikhail A. Sheremet
Keyword(s):  
Phase Change ◽  
Phase Change Materials ◽  
Computational Study ◽  
Conjugate Problem ◽  
High Heat ◽  
Solid Particles ◽  
Heat Sinks ◽  
Al2o3 Nanoparticles ◽  
Electronic Elements ◽  
The Impact

The cooling of electronic elements is one of the most important problems in the development of architecture in electronic technology. One promising developing cooling method is heat sinks based on the phase change materials (PCMs) enhanced by nano-sized solid particles. In this paper, the influence of the PCM’s physical properties and the concentration of nanoparticles on heat and mass transfer inside a closed radiator with fins, in the presence of a source of constant volumetric heat generation, is analyzed. The conjugate problem of nano-enhanced phase change materials (NePCMs) melting is considered, taking into account natural convection in the melt under the impact of the external convective cooling. A two-dimensional problem is formulated in the non-primitive variables, such as stream function and vorticity. A single-phase nano-liquid model is employed to describe the transport within NePCMs.

Extending Die-Attachment Fatigue Life of Power Electronics Using Phase Change Materials

2016 ◽  
Author(s):  
Levi J. Elston
Keyword(s):  
Phase Change ◽  
Power Electronics ◽  
Phase Change Materials ◽  
Operating Conditions ◽  
Device Structure ◽  
Die Attachment ◽  
Advanced Packaging ◽  
Life Improvement ◽  
Solid Liquid ◽  
The Impact

The ever-increasing power throughput and ever-decreasing size of modern electronics, specifically power electronics, requires more advanced packaging techniques and materials to maintain thermal limits and sustain mechanical life. Specific applications with known operating conditions for these components can realize added benefits through a tailored thermal-mechanical-electrical optimized assembly, potentially utilizing niche material classes. Without losing any expected functionality, solid-liquid phase change materials could be incorporated into the device structure to reduce peak temperature and/or suppress high-cycle fatigue problems commonly found at die-attachment interfaces. The purpose of this study was to investigate, through model-based design and analysis, the impact of using organic phase-change materials (PCMs) at two strategic locations in the standard device stack. The results suggest noteworthy life improvement (40%) is possible when optimizing for a given melt point material. Additionally, further improvements were predicted through future material enhancements, namely thermal conductivity and latent heat.

Magnetically Assembling Nanoscale Metal Network Into Phase Change Material—Percolation Threshold Reduction in Paraffin Using Magnetically Assembly of Nanowires

2014 ◽  
Vol 5 (3) ◽  
Author(s):  
Junwei Su ◽  
Iman Mirzaee ◽  
Fan Gao ◽  
Xiao Liu ◽  
Majid Charmchi ◽  
...  
Keyword(s):  
Magnetic Field ◽  
Electrical Conductivity ◽  
Energy Storage ◽  
Phase Change ◽  
Percolation Threshold ◽  
Phase Change Materials ◽  
Optical Microscope ◽  
Nickel Particles ◽  
Solid Foundation ◽  
Energy Storage Applications

A high throughput manufacturing process to magnetically assembling nanowire (NW) network into paraffin was developed for enhancing conductivity in phase change materials (PCMs) used in energy storage applications. The prefabricated nickel NWs were dispersed in melted paraffin followed by magnetic alignment under a strong magnetic field. Measuring electrical conductivity of the nanocomposite, as well as observing cross section of the sample slice under an optical microscope characterized the alignment of NWs. As a comparison, nickel particles (NPs) based paraffin nanocomposites were also fabricated, and its electrical conductivity with and without applied magnetic field were measured. The effects of aspect ratio of fillers (particles and NWs) and volume concentration on percolation threshold were studied both experimentally and theoretically. It was found that the NW based paraffin nanocomposite has much lower percolation threshold compared to that of particle based paraffin composite. Furthermore, the alignment of particles and NWs under magnetic field significantly reduces the threshold of percolation. This work provides solid foundation for the development of a manufacturing technology for high thermal conductivity PCMs for thermal energy storage applications.

scholarly journals Effect of Inclined Magnetic Field on the Entropy Generation in an Annulus Filled with NEPCM Suspension

2021 ◽  
Vol 2021 ◽  
pp. 1-14
Author(s):  
Seyyed Masoud Seyyedi ◽  
M. Hashemi-Tilehnoee ◽  
M. Sharifpur
Keyword(s):  
Magnetic Field ◽  
Heat Transfer ◽  
Phase Change ◽  
Entropy Generation ◽  
Phase Change Materials ◽  
Transfer Problem ◽  
Mass Conservation ◽  
Melting Process ◽  
Industrial Applications ◽  
Inclined Magnetic Field

The encapsulation technique of phase change materials in the nanodimension is an innovative approach to improve the heat transfer capability and solve the issues of corrosion during the melting process. This new type of nanoparticle is suspended in base fluids call NEPCMs, nanoencapsulated phase change materials. The goal of this work is to analyze the impacts of pertinent parameters on the free convection and entropy generation in an elliptical-shaped enclosure filled with NEPCMs by considering the effect of an inclined magnetic field. To reach the goal, the governing equations (energy, momentum, and mass conservation) are solved numerically by CVFEM. Currently, to overcome the low heat transfer problem of phase change material, the NEPCM suspension is used for industrial applications. Validation of results shows that they are acceptable. The results reveal that the values of N u ave descend with ascending Ha while N gen has a maximum at Ha = 16 . Also, the value of N T , MF increases with ascending Ha . The values of N u ave and N gen depend on nondimensional fusion temperature where good performance is seen in the range of 0.35 < θ f < 0.6 . Also, Nu ave increases 19.9% and ECOP increases 28.8% whereas N gen descends 6.9% when ϕ ascends from 0 to 0.06 at θ f = 0.5 . Nu ave decreases 4.95% while N gen increases by 8.65% when Ste increases from 0.2 to 0.7 at θ f = 0.35 .

scholarly journals Effects of Neglecting PCM Hysteresis While Making Simulation Calculations of a Building Located in Polish Climatic Conditions

2021 ◽  
Vol 11 (19) ◽  
pp. 9166
Author(s):  
Anna Zastawna-Rumin ◽  
Katarzyna Nowak
Keyword(s):  
Surface Temperature ◽  
Phase Change ◽  
Phase Change Materials ◽  
Model Building ◽  
Experimental Tests ◽  
Climatic Conditions ◽  
Heat Accumulation ◽  
Noticeable Effect ◽  
Change Temperature ◽  
The Impact

The use of phase change materials (PCM) in different building applications is a hot topic in today’s research and development activities. Numerous experimental tests confirmed that the hysteresis of the phase change process has a noticeable effect on heat accumulation in PCM. The authors are trying to answer the question of whether the neglecting of hysteresis or the impact of the speed of phase transformation processes reduce the accuracy of the simulation. The analysis was performed for a model building, created to validate the energy calculations. It was also important to conduct simulations for the polish climatic conditions. The calculations were conducted for three variants of materials. In addition, in the case of models containing layers with PCM, calculations were made both taking into account, as well as excluding material hysteresis in the calculations. In the analyzed examples, after taking into account hysteresis in the calculations, the period of time when surface temperature is below the phase change temperature of the materials decreased by 10.6% and 29.4% between 01 June to 30 September, for the options with PCM boards and Dupont boards, respectively. Significant differences in surface temperature were also observed. The effects of neglecting, even relatively small hysteresis, in the calculations are noticeable and can lead to significant errors in the calculation.

scholarly journals Thermal diode based on a multilayer structure of phase change materials

2021 ◽  
Vol 2116 (1) ◽  
pp. 012115
Author(s):  
T Swoboda ◽  
K Klinar ◽  
A Kitanovski ◽  
M Muñoz Rojo
Keyword(s):  
Phase Change ◽  
Thermal Management ◽  
Multilayer Structure ◽  
Phase Change Materials ◽  
Rectification Ratio ◽  
Optimum Conditions ◽  
Space Applications ◽  
Thermal Rectification ◽  
Management Capability ◽  
The Impact

Abstract Thermal diodes are devices that allow heat to flow preferentially in one direction. This unique thermal management capability has attracted attention in various applications, like electronics, sensors, energy conversion or space applications, among others. Despite their interest, the development of efficient thermal diodes remains still a challenge. In this paper, we report a scalable and adjustable thermal diode based on a multilayer structure that consists of a combination of phase change and phase invariant materials. We applied a parametric sweep in order to find the optimum conditions to maximize the thermal rectification ratio. Our simulations predicted a maximum thermal rectification ratio of ~20%. To evaluate the impact of these devices in real applications, we theoretically analysed the performance of a magnetocaloric refrigerating device that integrates this thermal diode. The results showed a 0.18 K temperature span between the heat source and the heat sink at an operating frequency of 25 Hz.

The Influence of Nanoparticle Type on the Viscosity of Nanoenhanced Energy Storage Materials

2015 ◽  
Author(s):  
Kieran Hess ◽  
Amy S. Fleischer
Keyword(s):  
Phase Change ◽  
Base Fluid ◽  
Phase Change Materials ◽  
Base Material ◽  
Energy Storage Materials ◽  
Graphite Nanoplatelets ◽  
Loading Level ◽  
Graphite Nanofibers ◽  
Multi Walled Carbon Nanotubes ◽  
The Impact

The use of nanoparticles to improve the thermal properties of low thermal conductivity phase change materials is of significant interest. However, the addition of nanoparticles to a base fluid is known to result in an increase in viscosity. An increase in viscosity can suppress convective currents, reducing overall heat transfer thus it necessary to quantify the impact of nanoparticle addition on the viscosity of a PCM. In this work nanoparticle enhanced phase change mateirals are synthesized using paraffin and three different types of nanoparticles: exfoliated graphite nanoplatelets (xGNP), multi-walled carbon nanotubes (MWCNT) and herringbone graphite nanofibers (HGNF). The particles are loaded at rates between 0.0024wt% to 0.1wt%. The viscosity is analyzed at temperatures between 60 and 100°C. The influence of temperature, nanoparticle type and nanoparticle loading level on viscosity are presented and discussed. The results show that for xGNP and HGNF within the operating condition studied here that there is no impact of the nanoparticle addition on the viscosity of the base material. However, the addition of MWCNT is found to increase the viscosity of the base fluid with the impact increasing with loading level.

Thermal Stability of Attic Spaces with Integrated PCMs during the Climatic Year

2013 ◽  
Vol 649 ◽  
pp. 175-178
Author(s):  
David Bečkovský ◽  
Milan Ostrý ◽  
Tereza Kalábová ◽  
Vladimír Tichomirov
Keyword(s):  
Phase Change ◽  
Phase Change Materials ◽  
Transition Period ◽  
Temperature Stability ◽  
Building Structures ◽  
Heating Period ◽  
Indoor Climate ◽  
Summer Time ◽  
The Impact ◽  
Thermal Stability Of

This paper deals with the impact of using phase change materials (PCM) in light building constructions. It describes how these materials react during the whole year, how they impact the summer temperature stability of a room and how they react in the transition period and in the heating period. Measuring was carried out in the experimental and reference room in the attic of the Institute of Building Structures. The layout of these identical rooms enables to compare the measured values. The measuring of the indoor climate, which had been carried out during the whole year in the reference and experimental room, was analyzed. The analysis was used to create the basic methodological procedure for using PCM in light building constructions. These materials proved to be efficient in the summer time. During the heating period the power consumption was monitored in relation to the application of the phase change materials.

scholarly journals Thermo-physical characteristics of building integrated phase change materials (PCM) and their applicability to energy efficient homes

2021 ◽  
Author(s):  
Omar Siddiqui
Keyword(s):  
Compressive Strength ◽  
Phase Change ◽  
Phase Change Materials ◽  
Energy Savings ◽  
Physical Characteristics ◽  
Comfort Level ◽  
Thermal Mass ◽  
Lower Phase ◽  
Physical Test ◽  
The Impact

The applicability of utilizing a variety of thermal mass including phase change materials with commonly used building materials is investigated through the use of simulations and physical testing. The thermal performance and occupant comfort potential of a novel solid-solid phase change material, known as Dal HSM, is compared and contrasted to commonly available forms of thermal mass. Detailed experimentation is conducted to successfully integrate Dal HSM with gypsum and concrete. The measurement of physical characteristics such as compressive strength and modulus of rupture is conducted to ensure that the PCM-composite compound retains the structural integrity to be utilized in a typical building. The use of thermal mass in the Toronto Net Zero house was found to contribute to energy savings of 10-15% when different types of thermal mass were used. The comfort level of the indoor occupants was also found to increase. The performance of Dal HSM was found to be comparable to a commercially available PCM known as Micronal in the heating mode. The cooling mode revealed that Dal HSM provided slightly lower energy savings when compared to Micronal due to a lower phase transition temperature and latent heat. The performance of physical test revealed a decrease in the compressive strength as the concentration of Dal HSM was increased in the PCM-gypsum specimens. Tests were also performed to analyze the impact of increasing the PCM concentration on the flexural strength of PCM-gypsum composite.

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