Optimization of Bulk Thermoelectric Modules for Chip Cooling Applications

2005 ◽  
Author(s):  
Kazuhiko Fukutani ◽  
Ali Shakouri
Keyword(s):  
Power Density ◽  
Integrated Circuit ◽  
Heat Dissipation ◽  
Thermoelectric Module ◽  
Cooling Power ◽  
Cross Sectional ◽  
Maximum Heat ◽  
Chip Cooling ◽  
Operating Current ◽  
Key Parameter

The use of bulk thermoelectric (TE) coolers for thermal management of integrated circuit (IC) chips is analyzed by a detailed electrothermal model. Various ideal and non-ideal parameters that affect the maximum cooling performance are discussed. Thermal resistance between the hot side of the thermoelectric module and ambient is a key parameter determining maximum heat dissipation in the IC chip if its temperature should be kept below a critical value. We show that the thermoelectric geometry factor (the ratio of the leg’s cross sectional area to its length) and the TE module operating current can be optimized to significantly increase the maximum power dissipation. There is an optimum leg thickness that gives the highest cooling power density to the IC chip and further thinning of the TE module will degrade the performance. The optimum thickness and the corresponding maximum cooling power density are calculated. The effect of various material properties are also discussed.

Investigation of Polymer Based Micro Heat Pipes for a Flexible Spacecraft Radiator

2001 ◽  
Author(s):  
D. McDaniels ◽  
G. P. “Bud” Peterson
Keyword(s):  
Heat Pipe ◽  
Heat Transport ◽  
Power Density ◽  
Polymeric Material ◽  
Heat Dissipation ◽  
Effective Conductivity ◽  
Chemical Reactivity ◽  
Working Fluid ◽  
Maximum Heat ◽  
Micro Heat Pipe

Abstract In response to the space industry’s pursuit of interplanetary travel and a continuous human presence in space, there is increasing focus on spacecraft that change configuration while in space. Flexible thermal radiators are being developed to accommodate various collapse and deployment mechanisms. An analytical model suggests that a lightweight polymeric material with imbedded micro heat pipe arrays can meet heat dissipation requirements while contributing less mass than competing flexible materials. The capillary pumping limit is evaluated as a function of operating temperature using two candidate working fluids. Using water, the maximum heat transport is 18 mW per channel at 140/160 °C. The maximum heat transport using methanol is 2.2 mW at 120 °C, an order-of magnitude difference. A thermal circuit model translates heat transport per channel into total radiator capacity as a function of source temperature and environmental sink temperature. Using water as the working fluid, the radiator capacity was shown to vary from 6.0 kW to 12.2 kW for source temperatures of 20 °C to 50 °C. For source temperatures of 40 °C and higher, the capacity meets or exceeds the dissipation requirements of a reference spacecraft design. While evaluated, methanol is not recommended as a working fluid because its radiator capacity is two to three times lower than water. Although thermal system constraints place limits on the micro heat pipe operating range, design changes directed at alleviating capillary limitations should increase radiator capacity. Technical issues for further study include effects of film billowing, performance limitations related to vapor viscosity, working fluid diffusion, and chemical reactivity between case and working fluid. Compared to a competing graphite fiber weave, the polymeric material has an effective conductivity over ten times higher. Its area power density (in kW/m2) is 18% to 60% lower than the graphite weave, but its mass power density (in kW/kg) is several times higher. Greater flexibility and lower weight also make it more amenable to structural integration. Recently developed space-stable polymers offer resistance to harsh temperature and radiation environments, helping to clear the path toward a more extensive use of polymers within the space industry.

Analysis of an Annular-Geometry Thermoelectric Module (TEM)

2007 ◽  
Author(s):  
Shankar Krishnan ◽  
Marc Hodes ◽  
Christopher Jones ◽  
Oana Malis
Keyword(s):  
Heat Dissipation ◽  
Heat Conduction Problem ◽  
Electrical Contact ◽  
Thermoelectric Module ◽  
Outer Radius ◽  
Coefficient Of Performance ◽  
Cross Sectional ◽  
Annular Geometry ◽  
In Series ◽  
Current Flows

An annular-geometry thermoelectric module (TEM) operating in refrigeration mode is analyzed. As in conventional (Cartesian geometry) TEMs, the pellets are interconnected such that current flows through them in series whilst they act in parallel with respect to conduction heat transfer. Current direction is such that Peltier cooling is provided at the inner radius of an annular TEM and heat dissipation is at its outer radius, where a boundary condition of the first kind is imposed. The cross-sectional area of each pellet increases linearly with radius. Accounting for electrical contact resistances at the interconnects, the necessary (one-dimensional) heat-conduction problem is solved to determine general expressions for the cooling rate provided by and coefficient performance of an annular TEM. Maximum cooling flux into an annular TEM and coefficient of performance for cooling fluxes below the maximum value are calculated and compared to those for conventional TEMs. Finally, the benefits of using an annular-geometry TEM are discussed.

Ion thinning of integrated circuit transverse specimens for transmission electron microscopy

1992 ◽  
Vol 50 (2) ◽  
pp. 1426-1427
Author(s):  
F. Shaapur
Keyword(s):  
Electron Microscopy ◽  
Transmission Electron Microscopy ◽  
Integrated Circuit ◽  
Substrate Surface ◽  
Homogeneous Material ◽  
Material System ◽  
Ion Milling ◽  
Cross Sectional ◽  
Transmission Electron ◽  
Motion Profile

Non-uniform ion-thinning of heterogenous material structures has constituted a fundamental difficulty in preparation of specimens for transmission electron microscopy (TEM). A variety of corrective procedures have been developed and reported for reducing or eliminating the effect. Some of these techniques are applicable to any non-homogeneous material system and others only to unidirectionalfy heterogeneous samples. Recently, a procedure of the latter type has been developed which is mainly based on a new motion profile for the specimen rotation during ion-milling. This motion profile consists of reversing partial revolutions (RPR) within a fixed sector which is centered around a direction perpendicular to the specimen heterogeneity axis. The ion-milling results obtained through this technique, as studied on a number of thin film cross-sectional TEM (XTEM) specimens, have proved to be superior to those produced via other procedures.XTEM specimens from integrated circuit (IC) devices essentially form a complex unidirectional nonhomogeneous structure. The presence of a variety of mostly lateral features at different levels along the substrate surface (consisting of conductors, semiconductors, and insulators) generally cause non-uniform results if ion-thinned conventionally.

TEM Sample Preparation Tricks for Advanced DRAMs

2015 ◽  
Author(s):  
Ching Shan Sung ◽  
Hsiu Ting Lee ◽  
Jian Shing Luo
Keyword(s):  
Electron Microscopy ◽  
Transmission Electron Microscopy ◽  
Sample Preparation ◽  
Integrated Circuit ◽  
Focused Ion Beam ◽  
Ion Beam ◽  
Tem Analysis ◽  
Cross Sectional ◽  
Transmission Electron ◽  
Characterization Of Materials

Abstract Transmission electron microscopy (TEM) plays an important role in the structural analysis and characterization of materials for process evaluation and failure analysis in the integrated circuit (IC) industry as device shrinkage continues. It is well known that a high quality TEM sample is one of the keys which enables to facilitate successful TEM analysis. This paper demonstrates a few examples to show the tricks on positioning, protection deposition, sample dicing, and focused ion beam milling of the TEM sample preparation for advanced DRAMs. The micro-structures of the devices and samples architectures were observed by using cross sectional transmission electron microscopy, scanning electron microscopy, and optical microscopy. Following these tricks can help readers to prepare TEM samples with higher quality and efficiency.

scholarly journals Estimations on Properties of Redox Reactions to Electrical Energy and Storage Device of Thermoelectric Pipe (TEP) Using Polymeric Nanofluids

Polymers ◽  
2021 ◽  
Vol 13 (11) ◽  
pp. 1812
Author(s):  
Qin Gang ◽  
Rong-Tsu Wang ◽  
Jung-Chang Wang
Keyword(s):  
Thermal Conductivity ◽  
Power Density ◽  
Heat Dissipation ◽  
Electrical Energy ◽  
Steel Tube ◽  
Storage Device ◽  
Stainless Steel Tube ◽  
The Novel ◽  
Empirical Formulas ◽  
Dissipative Heat

A thermoelectric pipe (TEP) is constructed by tubular graphite electrodes, Teflon material, and stainless-steel tube containing polymeric nanofluids as electrolytes in this study. Heat dissipation and power generation (generating capacity) are both fulfilled with temperature difference via the thermal-electrochemistry and redox reaction effects of polymeric nanofluids. The notion of TEP is to recover the dissipative heat from the heat capacity generated by the relevant machine systems. The thermal conductivity and power density empirical formulas of the novel TEP were derived through the intelligent dimensional analysis with thermoelectric experiments and evaluated at temperatures between 25 and 100 °C and vacuum pressures between 400 and 760 torr. The results revealed that the polymeric nanofluids composed of titanium dioxide (TiO2) nanoparticles with 0.2 wt.% sodium hydroxide (NaOH) of the novel TEP have the best thermoelectric performance among these electrolytes, including TiO2 nanofluid, TiO2 nanofluid with 0.2 wt.% NaOH, deionized water, and seawater. Furthermore, the thermal conductivity and power density of the novel TEP are 203.1 W/(m·K) and 21.16 W/m3, respectively.

High cooling power density SiGe/Si micro-coolers

2001 ◽  
Vol 37 (2) ◽  
pp. 126 ◽  
Author(s):  
X. Fan ◽  
G. Zeng ◽  
E. Croke ◽  
C. LaBounty ◽  
C.C. Ahn ◽  
...  
Keyword(s):  
Power Density ◽  
Cooling Power

Thermoelectric module design to improve lifetime and output power density

2021 ◽  
Vol 18 ◽  
pp. 100391
Author(s):  
W. Sun ◽  
R. Sui ◽  
G. Yuan ◽  
H. Zheng ◽  
Z. Zeng ◽  
...  
Keyword(s):  
Power Density ◽  
Output Power ◽  
Thermoelectric Module ◽  
Module Design

scholarly journals OPTIMALLY STAGGERED FINNED CIRCULAR AND ELLIPTIC TUBES IN FORCED CONVECTION

2003 ◽  
Vol 2 (2) ◽  
pp. 65 ◽  
Author(s):  
R. S. Matos ◽  
T. A. Laursen ◽  
J. V. C. Vargas ◽  
A. Bejan
Keyword(s):  
Heat Transfer ◽  
Three Dimensional ◽  
Optimization Procedure ◽  
Total Heat ◽  
Cross Sectional ◽  
Maximum Heat ◽  
Pressure Drops ◽  
Tube Cross Section ◽  
Fixed Volume ◽  
Maximum Heat Transfer

This work presents a three-dimensional (3-D) numerical and experimental geometric optimization study to maximize the total heat transfer rate between a bundle of finned tubes in a given volume and a given external flow both for circular and elliptic arrangements, for general staggered configurations. The optimization procedure started by recognizing the design limited space availability as a fixed volume constraint. The experimental results were obtained for circular and elliptic configurations with a fixed number of tubes (12), starting with an equilateral triangle configuration, which fitted uniformly into the fixed volume with a resulting maximum dimensionless tube-to-tube spacing S/2b = 1.5, where S is the actual spacing and b is the smaller ellipse semi-axis. Several experimental configurations were built by reducing the tube-to-tube spacings, identifying the optimal spacing for maximum heat transfer. Similarly, it was possible to investigate the existence of optima with respect to other two geometric degrees of freedom, i.e., tube eccentricity and fin-to-fin spacing. The results are reported for air as the external fluid in the laminar regime, for 125 and 100 Re 2b , where 2b is the ellipses smaller axis length. Circular and elliptic arrangements with the same flow obstruction cross-sectional area were compared on the basis of maximum total heat transfer. This criterion allows one to quantify the heat transfer gain in the most isolated way possible, by studying arrangements with equivalent total pressure drops independently of the tube cross section shape. This paper reports three-dimensional (3- D) numerical optimization results for finned circular and elliptic tubes arrangements, which are validated by direct comparison with experimental measurements with good agreement. Global optima with respect to tube-to-tube spacing, eccentricity and fin-tofin spacing ( 0.5 e 0.5, S/2b and 06 . 0 f for 125 and 100 Re 2b , respectively) were found and reported in general dimensionless variables. A relative heat transfer gain of up to 19% is observed in the optimal elliptic arrangement, as compared to the optimal circular one. The heat transfer gain, combined with the relative material mass reduction of up to 32% observed in the optimal elliptic arrangement in comparison to the circular one, show the elliptical arrangement has the potential for a considerably better overall performance and lower cost than the traditional circular geometry.

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