Modeling Thermoelectric Device Enhancement of Heat Sink Performance

2007 ◽  
Author(s):  
Richard I. Roser ◽  
Robert M. Smythe ◽  
Malkiat Singh
Keyword(s):  
Thermal Resistance ◽  
Thermoelectric Material ◽  
Heat Sink ◽  
Graphical Representation ◽  
Heat Removal ◽  
Effect Of Temperature ◽  
Thermoelectric Device ◽  
Air Cooling ◽  
Material Parameters ◽  
Removal Capacity

Increased power density is straining the ability of air-cooled heat sink technologies to provide adequate cooling for heat-generating components. Several technologies are under investigation as replacements for air-cooling. Under specific conditions, a well-selected thermoelectric device [TED] can act as an enhancement to a heat sink’s heat removal capacity or allow it to achieve lower temperatures. Such improvements to heat sink performance using a thermoelectric device are possible without increasing airflow or heat sink dimensions. Proper sizing of this kind of optimized thermoelectric system involves consideration of multiple conditions, including the amount of heat being generated, the temperatures involved (typically, target case temperature and expected ambient temperature), and available voltage and current. Although thermoelectric devices are often thought of as inefficient, with Coefficients of Performance [COP] of less than 1, a well-selected TED can have a COP of much greater than 10. Existing methods for thermoelectric optimization, for the sake of simplicity, often ignore the thermal resistance of the heat sink or ignore the effect of temperature dependence of the thermoelectric material parameters of resistivity, thermal conductivity, and thermopower. To correctly include these factors in the design of the TED, a methodology has been developed to determine an optimum device while simultaneously considering the input parameters of θCA (case to ambient thermal resistance), heat load, target cooling temperatures, and available DC power. The method is iterative, involving the use of given input conditions to yield an estimate for expected final temperature conditions, which are used to produce an initial estimate of the thermoelectric material parameters, which in turn are used to calculate the optimized device. The performance of this device is calculated to determine a new estimate for temperatures and material parameters. The process is repeated until convergence occurs for the device design. The methodology can also demonstrate the performance benefits of integrating a TED into an existing conventional fan/sink system, and also describes conditions that are unsuitable for the use of TED’s. Graphical representation of the information can be readily generated as an aid to design.

THERMAL AND HYDRODYNAMIC PERFORMANCE OF A MICROCHANNEL HEAT SINK COOLED WITH CARBON NANOTUBES NANOFLUID

2016 ◽  
Vol 78 (10-2) ◽  
Author(s):  
Nik Ahmad Faiz Nik Mazlam ◽  
Normah Mohd-Ghazali ◽  
Thierry Mare ◽  
Patrice Estelle ◽  
Salma Halelfadl
Keyword(s):  
Thermal Resistance ◽  
Heat Sink ◽  
Operating Temperature ◽  
Heat Removal ◽  
Hydrodynamic Performance ◽  
Spherical Particles ◽  
Microchannel Heat Sink ◽  
Pumping Power ◽  
Rectangular Microchannel ◽  
Aspect Ratios

The microchannel heat sink (MCHS) has been established as an effective heat removal system in electronic chip packaging. With increasing power demand, research has advanced beyond the conventional coolants of air and water towards nanofluids with their enhanced heat transfer capabilities. This research had been carried out on the optimization of the thermal and hydrodynamic performance of a rectangular microchannel heat sink (MCHS) cooled with carbon nanotube (CNT) nanofluid, a coolant that has recently been discovered with improved thermal conductivity. Unlike the common nanofluids with spherical particles, nanotubes generally come in cylindrical structure characterized with different aspect ratios. A volume concentration of 0.1% of the CNT nanofluid is used here; the nanotubes have an average diameter and length of 9.2 nm and 1.5 mm respectively. The nanofluid has a density of 1800 kg/m3 with carbon purity 90% by weight having lignin as the surfactant. The approach used for the optimization process is based on the thermal resistance model and it is analyzed by using the non-dominated sorting multi-objective genetic algorithm. Optimized outcomes include the channel aspect ratio and the channel wall ratio at the optimal values of thermal resistance and pumping power. The optimized results show that, at high operating temperature of 40°C the use of CNT nanofluid reduces the total thermal resistance by 3% compared to at 20°C and consequently improve the thermal performance of the fluid. In terms of the hydrodynamic performance, the pumping power is also being reduced significantly by 35% at 40°C compared to the lower operating temperature.  

scholarly journals Thermal analysis of proposed heat sink design under natural convection for the thermal management of electronics

2021 ◽  
pp. 307-307
Author(s):  
Numan Habib ◽  
Muftooh ur Rehman Siddiqi ◽  
Muhammad Tahir
Keyword(s):  
Fluid Flow ◽  
Natural Convection ◽  
Thermal Resistance ◽  
Heat Sink ◽  
Rapid Development ◽  
Transfer Model ◽  
Air Cooling ◽  
Computational Domain ◽  
The Novel ◽  
Compact Size

The rapid development in the field of electronics has led to high power densities and miniaturization of electronic packages. Because of the compact size of electronic devices, the rate of heat dissipation has increased drastically. Due to this reason, the air-cooling system with a conventional heat sink is insufficient to remove large quantity of heat. A novel macro-channel ?L-shaped heat sink? is proposed and analyzed to overcome this problem. The thermal resistance and fluid flow behavior under natural convection, of the novel and conventional air-cooled heat sink designs, are analyzed. Governing equations are discretized and solved across the computational domain of the heat sink, with three-dimensional conjugate heat transfer model. Numerical results are validated through experimentation. The effect of parameters i.e., fin height, number of fins and heat sink size, on the thermal resistance and fluid flow are reported. Examination of these parameters provide a better physical understanding from energy conservation and management view point. Substantial increase in the thermal performance is noted for the novel ?L-shaped heat sink? compared to the conventional design.

Experimental Study on the Double-Sided Air Cooling for Integrated Power Electronics Modules

2005 ◽  
Author(s):  
Ying Feng Pang ◽  
Elaine P. Scott ◽  
Zhenxian Liang ◽  
J. D. van Wyk
Keyword(s):  
Thermal Resistance ◽  
Power Electronics ◽  
Thermal Management ◽  
Heat Sink ◽  
Three Dimensional ◽  
Management Approach ◽  
Air Cooling ◽  
Thermal Tests ◽  
Heat Spreaders ◽  
Embedded Power

The objective of this work is to quantify the advantages of using double-sided cooling as the thermal management approach for the integrated power electronics modules. To study the potential advantage of the Embedded Power packaging method for the double-sided cooling, experiments were conducted. Three different cases were studied. To eliminate the effect of the heat sink on either side of the module, no heat sink was used in all three cases. The thermal tests were conducted such that the integrated power electronics modules were placed in the middle of flowing air in an insulated wind tunnel. Modules without additional top DBC, with additional top DBC, and with additional top DBC as well as heat spreaders on both sides were tested under the same condition. A common parameter, junction-to-ambient thermal resistance, was used to compare the thermal performance of these three cases. Despite the shortcoming of this parameter in describing the three-dimensional heat flow within the integrated power electronics modules, the concept of the thermal resistance is still worthwhile for evaluating various cooling methods for the module. The results show that increasing the top surface area can help in transferring the heat from the heat source to the ambient through the top side of the module. Consequently, the ability to handle higher power loss can also be increased. In summary, the Embedded Power technology provides an opportunity for implementing double-sided cooling as thermal management approach compared to modules with wire-bonded interconnects for the multichips.

Optimized Ionic Wind-Based Cooling Microfabricated Devices for Improving a Measured Coefficient of Performance

2011 ◽  
Author(s):  
Andojo Ongkodjojo ◽  
Alexis R. Abramson ◽  
Norman C. Tien
Keyword(s):  
Three Dimensional ◽  
Heat Removal ◽  
Temperature Data ◽  
Coefficient Of Performance ◽  
Comsol Multiphysics ◽  
Air Cooling ◽  
Ionic Wind ◽  
Cooling Systems ◽  
Removal Capacity ◽  
Cooling Technology

This work is a continuation of previous investigations aimed at developing an innovative microfabricated air-cooling technology that employs an electrohydrodynamic corona discharge (i.e. ionic wind pump) [1], [2]. This technology enables the miniaturization of cooling systems for next generation electronics. Our single ionic wind pump element consists of two parallel collecting electrodes between which a single emitting tip is positioned. Two-dimensional (2-D) and three-dimensional (3-D) simulations using COMSOL Multiphysics™ are additionally employed to predict the temperature distribution, the flow field, and the heat removal capacity of the device in operation. One such model utilizes a small gap between collector and emitter electrodes and demonstrates an improvement in the COP (coefficient of performance) of a single device. Comparisons are made with experimental temperature data on an actual device. The purpose of this work is therefore to optimize the performance of a single microfabricated ionic wind pump to enable the development of an array of these elements for use in larger-scale heat transfer applications.

Thermal Performance of High-Flow Single-Phase Liquid-Cooled Heat Sinks

2012 ◽  
Author(s):  
Ildar F. Akhmadullin ◽  
Randall D. Manteufel ◽  
Christopher Greene
Keyword(s):  
Thermal Resistance ◽  
Flow Rate ◽  
Heat Sink ◽  
Heat Removal ◽  
Internal Flow ◽  
Maximum Flow ◽  
High Flow ◽  
Repeated Measurements ◽  
Heat Sinks ◽  
Flow Rates

Experimental measurements are reported for high-flow liquid-cooled heat sinks designed for cooling electronics components such as a CPU. The flow rate is up to 2 GPM with internal flow passage length scales on the order of 0.1 to 1.0 mm in the primary heat transfer region. Of the designs tested, three achieved maximum flow rates with pressure drops of less than 1.5 psi. Two have lower maximum flow rates because of higher internal flow resistance. In the experiments, particular attention is given to sources of experimental uncertainty and the propagation of uncertainty through the calculations to reported thermal resistance, R (°C/W). Analysis includes bias and precision errors for direct measurement of temperature, flow rate, and pressure drop. Additionally, a separate thermocouple calibration test is reported to establish measurement uncertainties for the system. Main emphasis is made to the error propagation in thermal resistance calculations of each heat sink and measurement of heat removal rate from the CPU. Data is used to determine the standard error for R which ranges up to about 0.05 °C/W with the maximum for one heat sink up to 0.07 °C/W. Averaging of repeated measurements at the same flow rate without accounting for the range of the original data will result in lower uncertainties in the reported results.

Optimized Thermoelectric Module-Heat Sink Assemblies for Precision Temperature Control

2011 ◽  
Author(s):  
Rui Zhang ◽  
David A. Brooks ◽  
Marc Hodes ◽  
Matthew van Lieshout ◽  
Vincent P. Manno
Keyword(s):  
Power Consumption ◽  
Thermal Resistance ◽  
Ambient Temperature ◽  
Thermoelectric Material ◽  
Temperature Control ◽  
Heat Sink ◽  
Heat Sinks ◽  
Temperature Range ◽  
Precision Temperature ◽  
Precision Temperature Control

Robust precision temperature control of photonics components is achieved by mounting them on thermoelectric modules (TEMs) which are in turn mounted on heat sinks. However, the power consumption of TEMs is high because high currents are driven through Bi2Te3-based semiconducting materials with high electrical resistivity and finite thermal conductivity. This problem is exacerbated when the ambient temperature surrounding a TEM varies in the usual configuration where the air-cooled heat sink a TEM is mounted to is of specified thermal resistance. Indeed, heat sinks of negligible and relatively high thermal resistances minimize TEM power consumption for sufficiently high and low ambient temperatures, respectively. Optimized TEM-heat sink assemblies reduce the severity of this problem. In the problem considered, total footprint of thermoelectric material in a TEM, thermoelectric material properties, heat load, component operating temperature, relevant component-side thermal resistances and ambient temperature range are prescribed. Provided is an algorithm to compute the unique combination of the height of the pellets in a TEM and the thermal resistance of the heat sink attached to it which minimizes the maximum power consumption of the TEM over the specified ambient temperature range. This optimization maximizes the fraction of the power budget in an optoelectronics circuit pack available for other uses. Implementation of the algorithm is demonstrated through an example for a typical set of conditions.

Numerical Analysis of Single Phase Multi Layered Micro-Channel Heat Sink With Inter-Connects Between Vertical Channels

2010 ◽  
Author(s):  
A. K. M. M. Morshed ◽  
Jamil A. Khan
Keyword(s):  
Thermal Resistance ◽  
Flow Velocity ◽  
Heat Sink ◽  
Cross Flow ◽  
Heat Removal ◽  
Electronics Cooling ◽  
Solid Matrix ◽  
High Heat Flux ◽  
Micro Channel ◽  
Micro Channels

Micro-channels embedded in solid matrix have already proven to be a very efficient way of electronics cooling. Traditional micro-channel heat sinks consist of single layer of parallel channels. Although micro-channel heat sink can achieve very high heat flux, its pumping requirement for circulating liquid through the channel increases very sharply as the flow velocity increases. The pumping requirement can be reduced by stacking multi layers of micro-channels. By introducing multi layers of channels, the flow velocity through each channel is reduced for the same total mass flow rate of the coolant. A novel approach to take advantage of multi layered channel is proposed in this study where the vertical channels are interconnected to allow cross flow of the coolant. The cross-flow between the channels disrupts boundary layer enhancing heat removal capacity of the heat sink. A CFD model has been developed using commercially available software package FLUENT to evaluate overall thermal performance of multi layered micro-channel heat sink. A parametric study of the flow rates and the effect of the number of layers and interconnections have been performed. Significant reduction in thermal resistance has been observed for multiple layers, it is also observed that this reduction in thermal resistance is dependent on the thermal conductivity of the heat sink material.

Thermal Characteristics of a Synthetic Jet Integrated Heat Sink Design for Air-Cooled Electronics

2009 ◽  
Author(s):  
Yogen Utturkar ◽  
Mehmet Arik ◽  
Tunc Icoz
Keyword(s):  
Heat Sink ◽  
Low Cost ◽  
Thermal Characteristics ◽  
Heat Removal ◽  
Synthetic Jet ◽  
Air Cooling ◽  
Air Jets ◽  
Trade Offs ◽  
Thermal Solution ◽  
Near Term

Thermal management is currently one of the key limitations in the design of electronic systems. Parallel to the advancements in the electronics industry and increase in power dissipation the development of effective, low-cost, compact heat removal solutions become extremely critical to ensure a failsafe and reliable operation. While liquid cooling is poised to provide the cooling capability for next generation electronics, its use in present-day products is less prevalent due to risks associated with condensation, leakage, and pumping power. Consequently, air-cooling strategies still continue to vie for near-term cooling needs in the electronic industry. In cohort with these trends, an advanced air-cooling solution in form of a synthetic jet assisted heat sink has been investigated in the present study. The study focuses on key design aspect of the heat sink fin design, synthetic jet design and characterization, and the interaction of unsteady air jets with the heat sink fins. Numerical simulations are employed to investigate 3D unsteady flow dynamics and experimental setup is designed and built for validation. The paper systematically presents the design trade-offs associated with the number of jets in the thermal solution and the jet driving conditions (voltage and frequency), in terms of the thermal performance and the cost. Overall, the synthetic jet integrated heat sink has demonstrably been shown to dissipate up to 4.7 times better than conventional natural convection heat sink with a COP value of greater than 40 within a volume of 25 in3.

Optimized Thermoelectric Module-Heat Sink Assemblies for Precision Temperature Control

2012 ◽  
Vol 134 (2) ◽  
Author(s):  
Rui Zhang ◽  
Marc Hodes ◽  
David A. Brooks ◽  
Vincent P. Manno
Keyword(s):  
Thermal Resistance ◽  
Ambient Temperature ◽  
Thermoelectric Material ◽  
Temperature Control ◽  
Heat Sink ◽  
Heat Sinks ◽  
Ambient Temperatures ◽  
Precision Temperature ◽  
Precision Temperature Control ◽  
Heat Loads

Robust precision temperature control of heat-dissipating photonics components is achieved by mounting them on thermoelectric modules (TEMs), which are in turn mounted on heat sinks. However, the power consumption of such TEMs is high. Indeed, it may exceed that of the component. This problem is exacerbated when the ambient temperature and/or component heat load vary as is normally the case. In the usual packaging configuration, a TEM is mounted on an air-cooled heat sink of specified thermal resistance. However, heat sinks of negligible thermal resistance minimize TEM power for sufficiently high ambient temperatures and/or heat loads. Conversely, a relatively high thermal resistance heat sink minimizes TEM power for sufficiently low ambient temperatures and heat loads. In the problem considered, total footprint of thermoelectric material in a TEM, thermoelectric material properties, component operating temperature, relevant component-side thermal resistances, and ambient temperature range are prescribed. Moreover, the minimum and maximum rates of heat dissipation by the component are zero and a prescribed value, respectively. Provided is an algorithm to compute the combination of the height of the pellets in a TEM and the thermal resistance of the heat sink attached to it, which minimizes the maximum sum of the component and TEM powers for permissible operating conditions. It is further shown that the maximum value of this sum asymptotically decreases as the total footprint of thermoelectric material in a TEM increases. Implementation of the algorithm maximizes the fraction of the power budget in an optoelectronics circuit pack available for other uses. Use of the algorithm is demonstrated through an example for a typical set of conditions.

Experimental Investigation of Liquid Cooling Through Shallow Copperclad Cavities With Etched Pin-Fin Arrays

2018 ◽  
Author(s):  
Yin Lam ◽  
Nicole Okamoto ◽  
Younes Shabany ◽  
Sang-Joon John Lee
Keyword(s):  
Pressure Drop ◽  
Thermal Resistance ◽  
Surface Area ◽  
Flow Rate ◽  
Heat Sink ◽  
Heat Removal ◽  
Heat Sinks ◽  
Liquid Cooling ◽  
Pin Fin ◽  
Pin Fin Arrays

Heat removal is an increasing engineering challenge for higher-density packaging of circuit components. Microchannel heat sinks with liquid cooling have been investigated to take advantage of high surface-to-volume ratio and higher heat capacity of liquids relative to gases. This study experimentally investigated heat removal by liquid cooling through shallow copperclad cavities with staggered pin-fin arrays. Cavities with pin-fins were fabricated by chemical etching of a copperclad layer (nominally 105 μm thick) on a printed-circuit substrate (FR-4). The overall etched cavity was 30 mm wide, 40 mm long, and 0.1 mm deep. The pins were 1.1 mm in diameter and were distributed in a staggered arrangement. The cavity was sealed with a second copperclad substrate using an elastomer gasket. This assembly was then connected to a syringe pump delivery system. Deionized water was used as the working fluid, with volumetric flow rate up to 1.5 mL/min. The heat sink was subjected to a uniform heat flux of 5 W on the underside. Performance of the heat sink was evaluated in terms of pressure drop and the convection thermal resistance. Pressure drop across the heat sinks was less than 10 kPa, dominated by wall surface area rather than the small surface area contributed by cylindrical pins. At low flow rate, caloric thermal resistance dominated the overall thermal resistance of the heat sink. When compared to a microchannel without pins, the pin-fin microchannel reduced convective thermal resistance of the heat sink by approximately a factor of 4.

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