scholarly journals Thermal Management of Transient Power Spikes in Electronics: Phase Change Energy Storage or Copper Heat Sinks??

2003 ◽  
Author(s):  
Shankar Krishnan ◽  
Suresh V. Garimella
Keyword(s):  
Phase Change ◽  
Phase Change Material ◽  
Phase Change Materials ◽  
Electronics Cooling ◽  
Thermal Control ◽  
Heat Sinks ◽  
Melting Time ◽  
Power Semiconductors ◽  
Design Calculations ◽  
Change Material

A transient thermal analysis is performed to investigate thermal control of power semiconductors using phase change materials, and to compare the performance of this approach to that of copper heat sinks. Both the melting of the phase change material under a transient power spike input, as well as the resolidification process, are considered. Phase change materials of different kinds (paraffin waxes and metallic alloys) are considered, with and without the use of thermal conductivity enhancers. Simple expressions for the melt depth, melting time and temperature distribution are presented in terms of the dimensions of the heat sink and the thermophysical properties of the phase change material, to aid in the design of passive thermal control systems. The simplified analytical expressions are verified against more complex numerical simulations, and are shown to be excellent tools for design calculations. The suppression of junction temperatures achieved by the use of phase change materials when compared to the performance with copper heat sinks is illustrated. Merits of employing phase change materials for pulsed power electronics cooling applications are discussed.

scholarly journals Thermal Management of Transient Power Spikes in Electronics—Phase Change Energy Storage or Copper Heat Sinks?

2004 ◽  
Vol 126 (3) ◽  
pp. 308-316 ◽  
Author(s):  
Shankar Krishnan ◽  
Suresh V. Garimella
Keyword(s):  
Phase Change ◽  
Phase Change Material ◽  
Phase Change Materials ◽  
Electronics Cooling ◽  
Thermal Control ◽  
Heat Sinks ◽  
Melting Time ◽  
Power Semiconductors ◽  
Design Calculations ◽  
Change Material

A transient thermal analysis is performed to investigate thermal control of power semiconductors using phase change materials, and to compare the performance of this approach to that of copper heat sinks. Both the melting of the phase change material under a transient power spike input, as well as the resolidification process, are considered. Phase change materials of different kinds (paraffin waxes and metallic alloys) are considered, with and without the use of thermal conductivity enhancers. Simple expressions for the melt depth, melting time and temperature distribution are presented in terms of the dimensions of the heat sink and the thermophysical properties of the phase change material, to aid in the design of passive thermal control systems. The simplified analytical expressions are verified against numerical simulations, and are shown to be excellent tools for design calculations. The suppression of junction temperatures achieved by the use of phase change materials when compared to the performance with copper heat sinks is illustrated. Merits of employing phase change materials for pulsed power electronics cooling applications are discussed.

scholarly journals The effect of water’s presence around the Phase Change Material

2020 ◽  
Vol 24 (6 Part B) ◽  
pp. 4049-4059 ◽  
Author(s):  
Haythem Shili ◽  
Kamel Fahem ◽  
Souad Harmand ◽  
Jabrallah Ben
Keyword(s):  
Phase Change ◽  
Phase Change Material ◽  
Thermal Protection ◽  
Flow Direction ◽  
Operating Time ◽  
Thermal Control ◽  
Melting Time ◽  
Standard Case ◽  
Time Flow ◽  
Change Material

As part of the research in the field of thermal control of electronic components, a phase change material is confined in a liquid and is heated vertically on one side by a hot plate. The presence of the liquid around the phase change material prevents the formation of air bubbles produced in case of direct contact between the hotplate and the phase change material (extends the lifetime of the phase change material by reducing overheating zones). It improves heat transfer by increasing the thermal conductivity around the phase change material (raising the thermal exchange surface) and by accelerating the convective transfer. This work examines experimentally and numerically the effect of the water on the phase change material and on the heating plate. The water is used around the phase change material and a comparative study of the comportment of some important parameters like the melt front form, melting time, flow direction, temperature, and operating time is realized. It is found that the presences of the liquid around the phase change material seems to be more interesting for a thermal protection role than the standard case of the phase change material directly heated by the hotplate.

Cooling Management of Highly Powered Chips Packed in an Insulated Cavity Filled with a Phase Change Material

2010 ◽  
Vol 7 (2) ◽  
pp. 79-89 ◽  
Author(s):  
Mustapha Faraji
Keyword(s):  
Phase Change ◽  
Phase Change Material ◽  
Heat Sink ◽  
Phase Change Materials ◽  
Operating Time ◽  
Thermal Control ◽  
Numerical Approach ◽  
High Energy ◽  
The Impact ◽  
Change Material

This work describes and analyses a novel computer's thermal management system based on a phase change material (PCM) heat storage reservoir. The proposed heat sink consists of a PCM filled enclosure heated by substrate-mounted protruding heat sources (micro processors). PCMs, characterized by high energy storage density and small transition temperature interval, are able to store a high amount of generated heat; which provides a passive cooling of microprocessors. The advantage of this cooling strategy is that the phase change materials are able to absorb a high amount of generated heat without energizing the fan. The proposed strategy is suitable and efficient for situations where the cooling by air convection is not practical (thermal control of recent multiprocessors computers, for example). The problem is modelled as, two dimensional, time dependent and convection–dominated phenomena. A finite volume numerical approach is developed and used to simulate the physical details of the problem. This approach is based on the enthalpy method which is traditionally used to track the motion of the liquid/solid front and obtain the temperature and velocity profiles in the liquid phase. The study gives an instruction on the presentation of PCM heat sink used for cooling management of recent computers. Numerical investigations have been conducted in order to examine the impact of several parameters on the thermal behaviour and efficiency of the proposed PCM-based heat sink. Correlation for the secured operating time (time required by the heat sink before reaching the critical temperature, Tcr) is developed.

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).

Thermal Energy Storage Through Melting of a Commercial Phase Change Material in an Annulus with Radially Divergent Longitudinal Fins

2020 ◽  
Vol 7 (1) ◽  
Author(s):  
Tonny Tabassum Mainul Hasan ◽  
Latifa Begum
Keyword(s):  
Energy Storage ◽  
Phase Change ◽  
Phase Change Material ◽  
Thermal Energy ◽  
Thermal Energy Storage ◽  
Storage System ◽  
Operating Conditions ◽  
Melting Time ◽  
Bottom Part ◽  
Change Material

This study reports on the unsteady two-dimensional numerical investigations of melting of a paraffin wax (phase change material, PCM) which melts over a temperature range of 8.7oC. The PCM is placed inside a circular concentric horizontal-finned annulus for the storage of thermal energy. The inner tube is fitted with three radially diverging longitudinal fins strategically placed near the bottom part of the annulus to accelerate the melting process there. The developed CFD code used in Tabassum et al., 2018 is extended to incorporate the presence of fins. The numerical results show that the average Nusselt number over the inner tube surface, the total melt fraction, the total stored energy all increased at every time instant in the finned annulus compared to the annulus without fins. This is due to the fact that in the finned annulus, the fins at the lower part of the annulus promotes buoyancy-driven convection as opposed to the slow conduction melting that prevails at the bottom part of the plain annulus. Fins with two different heights have been considered. It is found that by extending the height of the fin to 50% of the annular gap about 33.05% more energy could be stored compared to the bare annulus at the melting time of 82.37 min for the identical operating conditions. The effects of fins with different heights on the temperature and streamfunction distributions are found to be different. The present study can provide some useful guidelines for achieving a better thermal energy storage system.

scholarly journals Latent Heat Thermal Storage of Nano-Enhanced Phase Change Material Filled by Copper Foam with Linear Porosity Variation in Vertical Direction

Energies ◽  
2021 ◽  
Vol 14 (5) ◽  
pp. 1508
Author(s):  
Mohammad Ghalambaz ◽  
Mohammad Shahabadi ◽  
S. A. M Mehryan ◽  
Mikhail Sheremet ◽  
Obai Younis ◽  
...  
Keyword(s):  
Natural Convection ◽  
Phase Change ◽  
Phase Change Material ◽  
Metal Foam ◽  
Vertical Direction ◽  
Melting Time ◽  
Copper Foam ◽  
Average Porosity ◽  
The Impact ◽  
Change Material

The melting flow and heat transfer of copper-oxide coconut oil in thermal energy storage filled with a nonlinear copper metal foam are addressed. The porosity of the copper foam changes linearly from bottom to top. The phase change material (PCM) is filled into the metal foam pores, which form a composite PCM. The natural convection effect is also taken into account. The effect of average porosity; porosity distribution; pore size density; the inclination angle of enclosure; and nanoparticles’ concentration on the isotherms, melting maps, and the melting rate are investigated. The results show that the average porosity is the most important parameter on the melting behavior. The variation in porosity from 0.825 to 0.9 changes the melting time by about 116%. The natural convection flows are weak in the metal foam, and hence, the impact of each of the other parameters on the melting time is insignificant (less than 5%).

Numerical Thermal Performance Investigation of an Electric Motor Passive Cooling System Employing Phase Change Materials

2021 ◽  
Author(s):  
Ali Deriszadeh ◽  
Filippo de Monte ◽  
Marco Villani
Keyword(s):  
Phase Change ◽  
Phase Change Material ◽  
Electric Motor ◽  
Phase Change Materials ◽  
Cooling System ◽  
Passive Cooling ◽  
Time Step ◽  
Cooling Performance ◽  
Passive Cooling System ◽  
Change Material

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.

Three-dimensional computational study in a corrugated pipe inserted system filled with phase change material

2021 ◽  
Vol ahead-of-print (ahead-of-print) ◽  
Author(s):  
Ömer Akbal ◽  
Hakan F. Öztop ◽  
Nidal H. Abu-Hamdeh
Keyword(s):  
Phase Change ◽  
Phase Change Material ◽  
Computational Analysis ◽  
Computational Study ◽  
Three Dimensional ◽  
Simple Algorithm ◽  
Melting Time ◽  
Geometrical Parameters ◽  
Content Type ◽  
Change Material

Purpose The purpose of this paper is to make a three-dimensional computational analysis of melting in corrugated pipe inserted system filled with phase change material (PCM). The system was heated from the inner pipe, and temperature of the outer pipe was lower than that of inner pipe. Different geometrical ratio cases and two different temperature differences were tested for their effect on melting time. Design/methodology/approach A computational analysis through a pipe with corrugated pipe filled with PCM is analyzed. Finite volume method was applied with the SIMPLE algorithm method to solve the governing equations. Findings The results indicate that the geometrical parameters can be used to control the melting time inside the heat exchanger which, in turn, affect the energy efficiency. The fastest melting time is seen in Case 4 at the same temperature difference which is the major observation of the current work. Originality/value Originality of this work is to perform a three-dimensional analysis of melting of PCM in a corrugated pipe inserted pipe.

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