Thermoelectric Heat Recovery From a Tankless Water Heating System

2008 ◽  
Author(s):  
S. A. LeBlanc ◽  
Y. Gao ◽  
K. E. Goodson
Keyword(s):  
Thermoelectric Material ◽  
System Integration ◽  
Waste Heat ◽  
Thermal Interface Materials ◽  
Water Heater ◽  
Thermal Interface ◽  
System Parameters ◽  
Material Parameters ◽  
The Impact ◽  
Interface Materials

Thermoelectric cogeneration promises to recover waste heat energy from a variety of combustion systems. There is a need for computationally efficient simulations of practical systems that allow optimization and illustrate the impact of key material and system parameters. Previous research investigated thermoelectric material enhancement and thermoelectric system integration separately. This work connects material parameters and system integration. We develop a thermal simulation for a 15kW tankless, methane-fueled water heater with thermoelectric modules embedded within a cross-flow heat exchanger. The simulation employs a finite volume method for the two fluids. It links external convection with a surface efficiency of 85%, internal convection for laminar flow, and conduction through the system in order to determine power generation within the thermoelectric. For a single pipe in the water heater system, 126 W of electrical power can be generated, and a typical system could yield 370 W. Realization of effective cogeneration systems hinges on investigating the impact of thermoelectric material parameters coupled with system parameters, so the impact of varying flow rate, convection coefficient, TEM thermal conductivity, Seebeck coefficient, and thermal interface materials are investigated. While varying parameters can improve thermoelectric output by over 50%, thermal interface materials can severely limit cogeneration system power output.

Bond Line Thickness of Thermal Interface Materials With Carbon Nanotubes

2005 ◽  
Author(s):  
Senthil A. G. Singaravelu ◽  
Xuejiao Hu ◽  
Kenneth E. Goodson
Keyword(s):  
Thermal Conductivity ◽  
Carbon Nanotubes ◽  
Volume Fraction ◽  
Bond Line ◽  
Thermal Interface Materials ◽  
Thermal Interface ◽  
Line Thickness ◽  
Bond Line Thickness ◽  
The Impact ◽  
Interface Materials

Increasing power dissipation in today’s microprocessors demands thermal interface materials (TIMs) with lower thermal resistances. The TIM thermal resistance depends on the TIM thermal conductivity and the bond line thickness (BLT). Carbon Nanotubes (CNTs) have been proposed to improve the TIM thermal conductivity. However, the rheological properties of TIMs with CNT inclusions are not well understood. In this paper, the transient behavior of the BLT of the TIMs with CNT inclusions has been measured under controlled attachment pressures. The experimental results show that the impact of CNT inclusions on the BLT at low volume fractions (up to 2 vol%) is small; however, higher volume fraction of CNT inclusions (5 vol%) can cause huge increase in TIM thickness. Although thermal conductivities are higher for higher CNT fractions, a minimum TIM resistance exists at some optimum CNT fraction for a given attachment pressure.

Parametric and Sensitivity Analysis of Power Module Design

2019 ◽  
Author(s):  
L. M. Boteler ◽  
M. C. Fish ◽  
M. S. Berman
Keyword(s):  
Sensitivity Analysis ◽  
Heat Sink ◽  
Thermal Interface Materials ◽  
Power Module ◽  
Thermal Interface ◽  
Module Design ◽  
Die Attach ◽  
Power Modules ◽  
The Impact ◽  
Interface Materials

Abstract As technology becomes more electrified, thermal and power engineers need to know how to improve power modules to realize their full potential. Current power module technology involves planar ceramic-based substrates with wirebond interconnects and a detached heat sink. There are a number of well-known challenges with the current configuration including heat removal, reliability due to coefficient of thermal expansion (CTE) mismatch, and parasitic inductance. Various solutions have been proposed in literature to help solve many of these issues: alternate substrates, advanced thermal interface materials, compliant die attach, thermal ground planes, high performing heat sinks, superconducting copper, wirebondless configurations, etc. While each of these technologies have their merits, this paper will perform a holistic analysis on a power module and identify the impact of improving various technologies on the device temperature. Parametric simulations were performed to assess the impact of many aspects of power module design including material selection, device layout, and heat sink choice. Materials that have been investigated include die attach, substrate, heat spreader, and thermal interface materials. In all cases, the industry standard was compared to the state of the art to quantify the advantages and/or disadvantages of adopting the new technologies. A sensitivity analysis is also performed which shows how and where the biggest benefits could be realized when redesigning power modules and determining whether to integrate novel technologies.

Two-Medium Model for the Bond Line Thickness of Particle Filled Thermal Interface Materials

2004 ◽  
Author(s):  
Xuejiao Hu ◽  
Senthil Govindasamy ◽  
Kenneth E. Goodson
Keyword(s):  
Filler Particle ◽  
Bond Line ◽  
Thermal Interface Materials ◽  
Heterogeneous Structure ◽  
Thermal Interface ◽  
Line Thickness ◽  
Medium Model ◽  
Bond Line Thickness ◽  
The Impact ◽  
Interface Materials

Thermal interface materials (TIMs) are widely used in electronics packaging. Increasing heat generation rates require lower values of the TIM thermal resistance, which depends on the material thermal conductivity and the TIM thickness, or the bond line thickness (BLT). The variation of the TIM thickness is not well understood. The major difficulty comes from the complexity of TIMs as condensed particle systems, especially when the TIM thickness is squeezed to several multiples of the filler particle diameter. This confined heterogeneous structure makes the behavior of TIMs different from that of homogeneous fluids. In this study, we propose a two-medium model for the BLT. The variation of BLT with attachment pressure is modeled using two parameters: the viscidity of the fluids and the interactions of particles. The predictions are compared with the measurements for TIMs made of aluminum oxide particles (sizes: 0.6–6 microns, volume fractions: 30%–50%) and silicon oil (kinematic viscosity: 100 cst and 1000 cst). Reasonable agreement is obtained for different applied pressures. Results indicate that the impact of the particle interactions is an important factor governing the variation of the TIM BLT, especially when the BLT is small.

Effect of Temperature Cycling and High Temperature Aging on the Elastic Properties and Failure Modes of Thermal Interface Materials

2015 ◽  
Author(s):  
Taryn J. Davis ◽  
Tuhin Sinha ◽  
Ken Marston ◽  
Sushumna Iruvanti
Keyword(s):  
Thermal Performance ◽  
Failure Modes ◽  
Coefficient Of Thermal Expansion ◽  
Temperature Cycling ◽  
Thermal Interface Materials ◽  
Thermal Interface ◽  
Main Challenge ◽  
Cte Mismatch ◽  
The Impact ◽  
Interface Materials

Highly filled thermally conductive silicone gels are routinely used as first level thermal interface materials (TIMs) between the die and lid, in flip-chip organic packages. The main challenge for these TIMs is overcoming the Coefficient of Thermal Expansion (CTE) mismatch between the die and lid materials. The TIMs must maintain excellent adhesion to both the die and lid surfaces in order to achieve and maintain optimal thermal performance. The CTE mismatch leads to increased mechanical stress and degradation of the TIM, which in turn degrades the thermal performance. In this work, the effective modulus of several TIMs was calculated by finite element modeling (FEM) in concert with mechanical testing of thin bond-line aluminum-TIM sandwiches subjected to varied stress conditions. These results are correlated to the corresponding stress die shear testing and the impact on package performance is analyzed.

Advanced Thermal Interface Materials for Thermal Management

2018 ◽  
Author(s):  
Wei Yu ◽  
◽  
Changqing Liu ◽  
Lin Qiu ◽  
Ping Zhang ◽  
...  
Keyword(s):  
Thermal Management ◽  
Thermal Interface Materials ◽  
Thermal Interface ◽  
Interface Materials

scholarly journals Carbon Nanotube Films for Energy Applications

Energies ◽  
2021 ◽  
Vol 14 (7) ◽  
pp. 1890
Author(s):  
Monika Rdest ◽  
Dawid Janas
Keyword(s):  
Carbon Nanotube ◽  
Mechanical Energy ◽  
Research Community ◽  
Thermal Interface Materials ◽  
Thermal Interface ◽  
Conductive Coatings ◽  
Storage Devices ◽  
Energy Applications ◽  
Wide Range ◽  
Interface Materials

This perspective article describes the application opportunities of carbon nanotube (CNT) films for the energy sector. Up to date progress in this regard is illustrated with representative examples of a wide range of energy management and transformation studies employing CNT ensembles. Firstly, this paper features an overview of how such macroscopic networks from nanocarbon can be produced. Then, the capabilities for their application in specific energy-related scenarios are described. Among the highlighted cases are conductive coatings, charge storage devices, thermal interface materials, and actuators. The selected examples demonstrate how electrical, thermal, radiant, and mechanical energy can be converted from one form to another using such formulations based on CNTs. The article is concluded with a future outlook, which anticipates the next steps which the research community will take to bring these concepts closer to implementation.

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