scholarly journals Influence of the Fin Shape on Heat Transport in Phase Change Material Heat Sink with Constant Heat Loads

Energies ◽  
2021 ◽  
Vol 14 (5) ◽  
pp. 1389
Author(s):  
Nadezhda S. Bondareva ◽  
Mohammad Ghalambaz ◽  
Mikhail A. Sheremet
Keyword(s):  
Heat Transfer ◽  
Phase Change ◽  
Phase Change Material ◽  
Heat Sink ◽  
Phase Change Materials ◽  
Heat Removal ◽  
Melting Process ◽  
Material Behavior ◽  
Cooling Effects ◽  
Change Material

Nowadays, the heat transfer enhancement in electronic cabinets with heat-generating elements can be achieved using the phase change materials and finned heat sink. The latter allows to improve the energy transference surface and to augment the cooling effects for the heat sources. The present research deals with numerical analysis of phase change material behavior in an electronic cabinet with an energy-generating element. For an intensification of heat removal, the complex finned heat sink with overall width of 10 cm was introduced, having the complicated shape of the fins with width of 0.33 cm and height H = 5 cm. The fatty acid with melting temperature of 46 °C was considered as a phase change material. The considered two-dimensional challenge was formulated employing the non-primitive variables and solved using the finite difference method. Impacts of the volumetric heat flux of heat-generating element and sizes of the fins on phase change material circulation and energy transference within the chamber were studied. It was shown that the presence of transverse ribs makes it possible to accelerate the melting process and reduce the source temperature by more than 12 °C at a heat load of 1600 W/m. It should also be noted that the nature of melting depends on the hydrodynamics of the melt, so the horizontal partitions reduce the intensity of convective heat transfer between the upper part of the region and the lower part.

Alternate PCM with air cavities in LED heat sink for transient thermal management

2019 ◽  
Vol 29 (11) ◽  
pp. 4377-4393 ◽  
Author(s):  
Sana Ben Salah ◽  
Mohamed Bechir Ben Hamida
Keyword(s):  
Phase Change ◽  
Phase Change Material ◽  
Heat Sink ◽  
Phase Change Materials ◽  
Melting Process ◽  
Junction Temperature ◽  
Melting Time ◽  
Content Type ◽  
Good Ability ◽  
Change Material

Purpose The purpose of this paper is to optimize the configuration of a heat sink with phase change material for improving the cooling performance of light emitting diodes (LED). Design/methodology/approach A numerical three-dimensional time-dependent model is developed with COMSOL Multiphysics to simulate the phase change material melting process during both the charging and discharging period. Findings The model is validated with previously published works. It found a good agreement. The difference between filled cavities with phase change materials (PCM) and alternate cavities air-PCM is discussed. The last-mentioned showed a good ability for reducing the junction temperature during the melting time. Three cases of this configuration having the same total volume of PCM but a different number of cavities are compared. The case of ten fins with five PCM cavities is preferred because it permit a reduction of 21 per cent of the junction temperature with an enhancement ratio of 2:4. The performance of this case under different power input is verified. Originality/value The use of alternate air-PCM cavities of the heat sink. The use of PCM in LED to delay the peak temperature in the case of thermal shock (for example, damage of fan) An amount of energy is stored in the LED and it is evacuated to the ambient of the accommodation by the cycle of charging and discharging established (1,765 Joule stored and released each 13 min with 1 LED chip of 5 W).

Heat Transfer Enhancement of Finned Copper Foam/Paraffin Composite Phase Change Material

2021 ◽  
Vol 14 ◽  
Author(s):  
Tingting Wu ◽  
Yanxin Hu ◽  
Xianqing Liu ◽  
Changhong Wang ◽  
Zijin Zeng ◽  
...  
Keyword(s):  
Heat Transfer ◽  
Phase Change ◽  
Transfer Rate ◽  
Flow Resistance ◽  
Phase Change Materials ◽  
Heat Transfer Performance ◽  
Melting Process ◽  
Copper Foam ◽  
Composite Phase Change Material ◽  
Change Material

Background: The employment of Phase Change Materials (PCMs) provides a potential selection for heat dissipation and energy storage. The main reason that hinders the wide application is the low thermal conductivity of PCMs. Combining the proper metal fin and copper foam, the fin/composite phase change material (Fin-CPCM) structure with good performance could be obtained. However, the flow resistance of liquid paraffin among the porous structure has seldom been reported, which will significantly affect the thermal performance inside the metal foam. Furthermore, the presence of porous metal foam is primarily helpful for enhancing the heat transfer process from the bottom heat source. The heat transfer rate is slow due to the one-dimensional heat transfer from the bottom. It should be beneficial for improving the heat transfer performance by adding external fins. Therefore, in the present study, a modified structure by combining the metal fin and copper foam is proposed to further accelerate the melting process and improve the temperature uniformity of the composite. Objective: The purpose of this study is to research the differences in the heat transfer performance among pure paraffin, Composite Phase Change Materials (CPCM) and fin/Composite Phase Change Material (Fin-CPCM) under different heating conditions, and the flow resistance of melting paraffin in copper foam. Methods: To experimentally research the differences in the heat transfer performance among pure paraffin, CPCM and Fin-CPCM under different heating conditions, a visual experimental platform was set up, and the flow resistance of melting paraffin in copper foam was also analyzed. In order to probe into the limits of the heat transfer capability of composite phase change materials, the temperature distribution of PCMs under constant heat fluxes and constant temperature conditions was studied. In addition, the evolution of the temperature distributions was visualized by using the infrared thermal imager at specific points during the melting process. Results: The experimental results showed that the maximum temperature of Fin-CPCM decreased by 21°C under the heat flux of 1500W/m2 compared with pure paraffin. At constant temperature heating conditions, the melting time of Fin-CPCM at a temperature of 75°C is about 2600s, which is 65% less than that of pure paraffin. Due to the presence of the external fins, which brings the advantage of improving the heat transfer rate, the experimental result exhibited the most uniform temperature distribution. Conclusion: The addition of copper foam can accelerate the melting process. The addition of external fins brings the advantage of improving the heat transfer rate, and can make the temperature distribution more uniform.

scholarly journals Phase Change Material Used for Masonry Joints: Numerical Simulation and Scale Test

Proceedings ◽  
2019 ◽  
Vol 34 (1) ◽  
pp. 16
Author(s):  
Jiang ◽  
Liu ◽  
Yuan
Keyword(s):  
Heat Transfer ◽  
Numerical Simulation ◽  
Phase Change ◽  
Phase Change Material ◽  
Phase Change Materials ◽  
Masonry Wall ◽  
Wall Structure ◽  
Thermal Coefficient ◽  
New Form ◽  
Change Material

In order to effectively improve the thermal performance of the thermal insulation masonry wall, the thermal bridge effect of the grey joint on the heat transfer of the wall structure was studied. A brand-new form of phase change material walls, which used phase change materials in the wall parts to build ash joints, was carried out. The application of phase change material mortar, which was different from conventional "Hamburger" phase change material walls, was demonstrated to be a useful tool to reduce the thermal coefficient of the masonry wall. Furthermore, the scale-down test and numerical simulation of the heat transfer coefficient of the phase change material wall with different distribution of ash joints were experimented and discussed, and the feasibility of the new-form phase change material wall within the error range was verified.

Preparation and Numerical Simulation of Heat Transfer Performance for Methyl Palmitate-Methyl Stearate Binary Eutectic Mixture/Expanded Graphite Composite Phase Change Material

2020 ◽  
Vol 993 ◽  
pp. 920-926
Author(s):  
Bi Chuan Chi ◽  
Yan Yao ◽  
Su Ping Cui
Keyword(s):  
Heat Transfer ◽  
Phase Change ◽  
Phase Change Material ◽  
Phase Change Materials ◽  
Heat Transfer Performance ◽  
Eutectic Mixture ◽  
Fatty Acid Esters ◽  
Transfer Performance ◽  
Binary Eutectic ◽  
Change Material

The binary eutectic mixtures of fatty acid esters are promising phase change materials for energy storage application. However, the low thermal conductivity which is a common problem for organic phase change materials restricts their further and better applications. In order to solve the problem, a novel composite phase change material (CPCM) was prepared in this research by using methyl palmitate-methyl stearate (MP-MS), a typical binary eutectic mixture of fatty acid esters, as phase change material and expanded graphite (EG) as heat transfer enhancer. The heat transfer performance of MP-MS/EG CPCM was numerical simulated by finite element analysis software ABAQUS. Numerical simulation results revealed that EG could notably enhance the heat transfer performance of MP-MS eutectic mixture. The heat transfer rate and phase change reaction rate of MP-MS/EG CPCM were 14 times and 3 times that of MP-MS eutectic mixture, respectively.

scholarly journals Experimental evaluation of phase change material in radiant cooling panels integrated with thermoelectric modules

2019 ◽  
Vol 111 ◽  
pp. 01002
Author(s):  
Yong-Kwon Kang ◽  
Beom-Jun Kim ◽  
Soo-Yeol Yoon ◽  
Jae-Weon Jeong
Keyword(s):  
Phase Change ◽  
Phase Change Material ◽  
Thermal Energy ◽  
Phase Change Materials ◽  
Target Surface ◽  
Melting Process ◽  
Night Time ◽  
Thermoelectric Modules ◽  
Radiant Cooling ◽  
Change Material

This study proposes a phase change material for use in radiant cooling panels integrated with thermoelectric modules (PCM–TERCP) and evaluates its performance characteristics during the solidification and melting process of phase change materials in design conditions. The PCM–TERCP consists of phase change materials (PCMs), thermoelectric modules (TEMs), and aluminumpanels. TEMs operate to freeze the PCM, and PCM stores the cooling thermal energy to maintain the constant surface temperature of the panel for radiant cooling. The main purpose of thermal energy storage systems is the shift of the electricity consumption from day-time to night-time during the summer season. Therefore, PCM–TERCP can implement off-peak operation according to which energy is expected to be saved. The melting temperature of PCM and the target surface temperatures of the bottom panels of PCM–TERCP were designed to be 16°C. Additionally, the room temperature and mean radiant temperature (MRT) was set to 24°C, while the thickness of the PCM pouch was 10 mm. As a result, the solidification process required 4 h and the total input power was 0.528 kWh. Correspondingly, the melting process can operate passively over a period of 4 h. In most cases, the operating temperature was lower than 19°C, which validates the temperature response of PCM–TERCP.

Experimental Validation of Phase Change Material Cooling Performance Integrated into Finned Heat Sink

2021 ◽  
Vol 1039 ◽  
pp. 274-280
Author(s):  
Hussein Salah Mahdi ◽  
Jalal Muhammad Jalil ◽  
Asim Sahib Allawy
Keyword(s):  
Phase Change ◽  
Phase Change Material ◽  
Heat Sink ◽  
Time Lag ◽  
Temperature Drop ◽  
Heat Removal ◽  
Power Input ◽  
Cooling Performance ◽  
Fan Speed ◽  
Change Material

The aim of this study is to analyze the phase change material cooling performance integrated into heat sink experimentally. a paraffin wax as phase change material is used in this experiment and it placed under the heat sink with thickness 30mm , various power input at 11W,13W and 15W used in this experiment to generate heat at different levels also several fan speed at 15m/s,2.5m/s and 3.4m/s. the surface temperature of the heat sink is monitored over the time to evaluate the phase change material thermal performance . From the results ,temperature drop and the time lag in case of without PCM compared to with PCM shows the effect of cooling of adding PCM under low and high speeds of heat removal. It found that inclusion of PCM into heat sink with forced convection shows high temperatures drop up to 18 °C.

The Investigation of Phase Change Emulsion (PCE): Fabrication, Thermal Conductivity and Utilization of Nanoparticles

2013 ◽  
Vol 860-863 ◽  
pp. 862-866 ◽  
Author(s):  
Yi Fei Zheng ◽  
Zhong Zhu Qiu ◽  
Jie Chen
Keyword(s):  
Heat Transfer ◽  
Thermal Conductivity ◽  
Energy Storage ◽  
Phase Change ◽  
Phase Change Material ◽  
Phase Change Materials ◽  
Heat Storage ◽  
Change Material

Phase change materials in the form of emulsion (PCE) is a category of novel phase change fluid used as heat storage and transfer media. It plays an important role in commercially viable applications (energy storage, particularly).The emulsion is made of microparticles of a phase change wax (a kind of paraffin or mixture ) as a phase change material (PCM), mixed paraffin directly with water. This paper presents information on the different PCM emulsions by different researchers. It gives the method of preparation of the PCE, and makes a special effort to investigate the heat transfer phenomena and the method of enhancing the thermal conductivity of the emulsion.

scholarly journals Impact of ultrasound on the melting process and heat transfer of phase change material

2019 ◽  
Vol 158 ◽  
pp. 5014-5019
Author(s):  
Zhongjun Yan ◽  
Zhun (Jerry) Yu ◽  
Tingting Yang ◽  
Shuishen Li ◽  
Guoqiang Zhang
Keyword(s):  
Heat Transfer ◽  
Phase Change ◽  
Phase Change Material ◽  
Melting Process ◽  
Change Material

scholarly journals Application of Phase Change Material-Based Thermal Capacitor in Double Tube Heat Exchanger—A Numerical Investigation

Energies ◽  
2020 ◽  
Vol 13 (17) ◽  
pp. 4327
Author(s):  
Matthew Fong ◽  
Jundika Kurnia ◽  
Agus P. Sasmito
Keyword(s):  
Heat Transfer ◽  
Heat Exchanger ◽  
Phase Change ◽  
Phase Change Material ◽  
Phase Change Materials ◽  
Oscillation Period ◽  
Temperature Oscillation ◽  
Tube Heat Exchanger ◽  
Inlet Conditions ◽  
Change Material

In many heat transfer related applications, there is a need for a stable, constant supply temperature. As a result, the integration of intermittent renewable sources of heat into these processes can prove to be challenging, requiring special temperature smoothing devices or strategies. This study focuses on the application of phase change materials integrated into a double tube heat exchanger as a possible thermal smoothing device. The objective of this study is to evaluate the ability of the exchanger to smoothen out temperature variations within the cold stream outlet while the hot stream is subject to oscillating inlet conditions. A computational fluid dynamics approach is used where a numerical model is developed, validated and then used to model the conjugate heat transfer within the heat exchanger. Four organic phase change materials (PCM) with different phase change temperatures were selected for investigation (myristic, octadecane, eicosane, and wax) to study the relationship between melting temperature and stabilization performance. A parametric study was then conducted by varying the Reynolds number of the flow as well as temperature oscillation period and amplitude to study the sensitivity of the system. The results confirm the potential of a phase change material-based thermal capacitor at dampening oscillations across the heat exchanger.

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