Major Considerations in System-Level Thermal Design of Next-Generation Telecommunications Equipment

2009 ◽  
Author(s):  
Lang Yuan ◽  
Jignesh Patel
Keyword(s):  
Thermal Management ◽  
Heat Dissipation ◽  
Acoustic Noise ◽  
Field Tests ◽  
Thermal Design ◽  
System Level ◽  
Next Generation ◽  
Air Filter ◽  
Planning Stage ◽  
The Impact

The thermal management of next-generation telecommunications equipment is becoming more challenging than ever before, thanks to the elevated ambient temperature requirements (up to 65°C) from network carriers, and the thermal limitation of critical components such as optical transceivers (with a max. rating of 85°C). With thousands of watts of heat dissipation from a single shelf, a systematic methodology has to be developed at the planning stage so that every possible means to streamline the thermal management can be integrated into the system-level design. This paper uses a next-generation fiber-optic telecom product as an example to demonstrate the impact of some major mechanical/electrical parameters (such as fan curve, acoustic noise, air filter, copper content of PCB and baffles, etc.) on the thermal performance of the system. Each factor is quantitatively analyzed based on field tests, and good design practices are suggested.

Challenges in Energy Efficient Thermal Management

2003 ◽  
Author(s):  
Kazuaki Yazawa
Keyword(s):  
Thermal Management ◽  
Energy Efficient ◽  
Minimum Energy ◽  
Thermal Design ◽  
System Level ◽  
Total System ◽  
Efficient Design ◽  
Transient Phenomena ◽  
The Impact ◽  
Extended Review

For a surveillance of energy efficient thermal management, an extended review of literatures has been done. Covered cooling technologies are intended for or supposed to relate to energy efficient design. Individual technologies are categorized with the discussion of advantage/disadvantages. In addition, the impact such as volume and mass of total system design is discussed. A universal criterion of metric to measure the effectiveness of optimization for minimum energy input is proposed. Extensive review of the supposed relevant technologies gives the idea that each model could be used for energy efficient thermal design. On the other hand, it has been found that the lack of system level modeling as well as the considerations of transient phenomena is not enough. Since these are essential, it should be the challenge toward the future of environmental friendly thermal designs.

Design of Optimum Plate-Fin Natural Convective Heat Sinks

2003 ◽  
Vol 125 (2) ◽  
pp. 208-216 ◽  
Author(s):  
Avram Bar-Cohen ◽  
Madhusudan Iyengar ◽  
Allan D. Kraus
Keyword(s):  
Nusselt Number ◽  
Specific Heat ◽  
Rectangular Plate ◽  
Heat Sink ◽  
Heat Dissipation ◽  
Thermal Design ◽  
Heat Sinks ◽  
And Performance ◽  
Nusselt Number Correlation ◽  
The Impact

The effort described herein extends the use of least-material single rectangular plate-fin analysis to multiple fin arrays, using a composite Nusselt number correlation. The optimally spaced least-material array was also found to be the globally best thermal design. Comparisons of the thermal capability of these optimum arrays, on the basis of total heat dissipation, heat dissipation per unit mass, and space claim specific heat dissipation, are provided for several potential heat sink materials. The impact of manufacturability constraints on the design and performance of these heat sinks is briefly discussed.

Robust Thermal Management for Embedded CPU and GPUs in Displays

2011 ◽  
Author(s):  
Sung Ki Kim ◽  
Woo Young Kan ◽  
Sang Hak Kim ◽  
Vincent Tan ◽  
Gamal Refai-Ahmed ◽  
...  
Keyword(s):  
Thermal Management ◽  
Heat Dissipation ◽  
Form Factors ◽  
Thermal Design ◽  
Flat Panel Display ◽  
Large Format ◽  
Digital Signage ◽  
Operation Conditions ◽  
Signage System ◽  
Embedded Computing System

Digital signage systems are large format displays that are typically installed in public areas for advertisement and informative publications. This emerging technology is considered as a major category in the large format display market. In general, a digital signage system consists of a flat panel display consisting of high brightness screen and operation circuits. Also, special features of high performance embedded computing system exist in very small form factors. Such products, however, are accompanied with high heat dissipation of the internal components and are usually exposed to very harsh environments for more frequent exposure to customers. Also the installation schemes of the products vary for different objectives, and a robust thermal design is required to guarantee the system reliability considering corner scenarios within the design space. The objective of the present study is to investigate the effect of installation environment on the thermal performance of a display assembly resembling a digital signage system. Design criteria for a proper thermal management scheme are proposed. The thermal characteristics of a digital signage system are presented in various operation conditions and each thermal design parameter is discussed thoroughly to ensure the reliability requirements of the digital signage system are met.

System Level Thermal Optimization of an Automotive Lightning Module Incorporating Several Power Devices

2007 ◽  
Author(s):  
Victor Chiriac ◽  
Tien-Yu Tom Lee
Keyword(s):  
Thermal Performance ◽  
Power Dissipation ◽  
Heat Dissipation ◽  
System Level ◽  
Total Power ◽  
Main Concern ◽  
Optimized Design ◽  
Passive Components ◽  
Thermal Budget ◽  
The Impact

The conjugate thermal performance of microelectronics module incorporating several power packages and additional passive components in a custom environment is evaluated and further optimized using numerical simulation and experimental validation. The automotive industry deals on a daily basis with multiple packaging and module-level thermal issues when reducing the size of components for a lightning system in a car, while managing the routing of very high current. The study provides a better understanding of the strengths and weaknesses of the IC incorporation into a system module level, for both present and future product development. The reference design is evaluated at a system level, and several improvements are identified to enhance the overall thermal performance of the lightning system. The main concern is related to the possibility of exceeding the thermal budget for a large system incorporating several PQFN (Power Quad Flat No-Lead Package) packages with additional heat dissipation devices in an enclosure, at an external ambient temperature of 85°C. Due to the compactness of the device, there are only limited solutions to extract the heat from the high power dissipation system. The impact on the thermal balance of the trace dissipation, the location and size of the pins connecting the two boards (motherboard and daughter board) forming the system, the header heating and other passive components under various powered conditions are evaluated. A revised model includes additional pins (reduced diameter), modified motherboard and harness structures and their locations; the impact of additional heater traces on both top and bottom surfaces of the motherboard, and a modified daughter board design, is also evaluated. The resulting peak temperatures range from 118.3°C to 137.3°C and the corresponding junction-to-ambient thermal resistances (Rja) vary from 8.4°C/W to 8.8°C/W. Rja is defined as the temperature difference between the peak device and ambient divided by the total power dissipation of the PQFN packages. An optimized design is further evaluated, with lowered thermal resistance from the motherboard, the board-to-board pins, the junction box board, and the wiring harness. The thermal budget is satisfied, as the peak temperatures reached by the two designs are below the 150°C limit. Additional experimental results are used to benchmark the simulation results, within 1–6% accuracy.

Thermal Management for High Power Light-Emitting Diode Street Lamp

2010 ◽  
Author(s):  
M. Ying ◽  
S. M. L. Nai ◽  
P. Shi ◽  
J. Wei ◽  
C. K. Cheng ◽  
...  
Keyword(s):  
Thermal Management ◽  
Thermal Performance ◽  
High Power ◽  
Heat Dissipation ◽  
Light Emitting Diode ◽  
System Level ◽  
Light Emitting ◽  
High Power Led ◽  
Street Lamp ◽  
Lamp System

Light-emitting diode (LED) street lamp has gained its acceptance rapidly in the lighting system as one of choices for low power consumption, high reliability, dimmability, high operation hours, and good color rendering applications. However, as the LED chip temperature strongly affects the optical extraction and the reliability of the LED lamps, LED street lamp performance is heavily relied on a successful thermal management, especially when applications require LED street lamp to operate at high power and hash environment to obtain the desired brightness. As such, a well-designed thermal management, which can lower the LED chip operation temperature, becomes one of the necessities when developing LED street lamp system. The current study developed an effective heat dissipation method for the high power LED street lamp with the consideration of design for manufacturability. Different manufacturable structure designs were proposed for the high power street lamp. The thermal contact conductance between aluminum interfaces was measured in order to provide the system assembly guidelines. The module level thermal performance was also investigated with thermocouples. In addition, finite element (FE) models were established for the temperature simulation of both the module and lamp system. The coefficient of natural convection of the heat sink surface was determined by the correlation of the measurement and simulation results. The system level FE model was employed to optimize and verify the heat dissipation concepts numerically. An optimized structure design and prototype has shown that the high power LED street lamp system can meet the thermal performance requirements.

A System to Package Perspective on Transient Thermal Management of Electronics

2020 ◽  
Vol 142 (4) ◽  
Author(s):  
H. Peter de Bock ◽  
David Huitink ◽  
Patrick Shamberger ◽  
James Spencer Lundh ◽  
Sukwon Choi ◽  
...  
Keyword(s):  
Steady State ◽  
Thermal Management ◽  
Thermal Design ◽  
System Level ◽  
Control Mechanisms ◽  
Thermal Loads ◽  
Chip Surface ◽  
Wide Range ◽  
Transient Thermal ◽  
The Way

Abstract There are many applications throughout the military and commercial industries whose thermal profiles are dominated by intermittent and/or periodic pulsed thermal loads. Typical thermal solutions for transient applications focus on providing sufficient continuous cooling to address the peak thermal loads as if operating under steady-state conditions. Such a conservative approach guarantees satisfying the thermal challenge but can result in significant cooling overdesign, thus increasing the size, weight, and cost of the system. Confluent trends of increasing system complexity, component miniaturization, and increasing power density demands are further exacerbating the divergence of the optimal transient and steady-state solutions. Therefore, there needs to be a fundamental shift in the way thermal and packaging engineers approach design to focus on time domain heat transfer design and solutions. Due to the application-dependent nature of transient thermal solutions, it is essential to use a codesign approach such that the thermal and packaging engineers collaborate during the design phase with application and/or electronics engineers to ensure the solution meets the requirements. This paper will provide an overview of the types of transients to consider—from the transients that occur during switching at the chip surface all the way to the system-level transients which transfer heat to air. The paper will cover numerous ways of managing transient heat including phase change materials (PCMs), heat exchangers, advanced controls, and capacitance-based packaging. Moreover, synergies exist between approaches to include application of PCMs to increase thermal capacitance or active control mechanisms that are adapted and optimized for the time constants and needs of the specific application. It is the intent of this transient thermal management review to describe a wide range of areas in which transient thermal management for electronics is a factor of significance and to illustrate which specific implementations of transient thermal solutions are being explored for each area. The paper focuses on the needs and benefits of fundamentally shifting away from a steady-state thermal design mentality to one focused on transient thermal design through application-specific, codesigned approaches.

Numerical Analysis of Mist-Cooled High Power Components in Cabinets

2009 ◽  
Author(s):  
Niru Kumari ◽  
Vaibhav Bahadur ◽  
Marc Hodes ◽  
Todd Salamon ◽  
Alan Lyons ◽  
...  
Keyword(s):  
Numerical Analysis ◽  
Thermal Management ◽  
High Power ◽  
Heat Sink ◽  
Heat Dissipation ◽  
Energy Transport ◽  
Acoustic Noise ◽  
Transport Processes ◽  
Two Phase ◽  
Flow And Heat Transfer

The heat dissipation capacity of air-cooled computing and telecommunications cabinets is limited by acoustic noise and fan reliability considerations. The present work quantifies the potential for thermal management of a sealed cabinet using an evaporating mist introduced upstream of the high-power electronic components. The proposed concept consists of droplets of mist being dispersed in the air flowing through a heat sink. The evaporated mist is condensed at the outlet of the circuit packs and recycled back to the inlet. The flow and heat-transfer characteristics of mist flows in a representative heat sink inside the cabinet are explored through numerical analysis of the coupled mass, momentum and energy transport equations for an evaporating two-phase mixture. The effect of droplet size and the mist loading fraction on the heat sink temperature reduction is computed and parametrically analyzed. The results reveal significant insights into the complex transport processes associated with mist flows. Mist cooling is shown to offer significant promise as a feasible thermal management solution for telecommunications cabinets and data centers.

Two-Phase Liquid Cooling for Thermal Management of IGBT Power Electronic Module

2013 ◽  
Vol 135 (2) ◽  
Author(s):  
Peng Wang ◽  
Patrick McCluskey ◽  
Avram Bar-Cohen
Keyword(s):  
Power Electronics ◽  
Thermal Management ◽  
Single Phase ◽  
Heat Dissipation ◽  
Heat Fluxes ◽  
System Level ◽  
Cooling Power ◽  
Cold Plate ◽  
Two Phase ◽  
Cold Plates

Recent trends including rapid increases in the power ratings and continued miniaturization of semiconductor devices have pushed the heat dissipation of power electronics well beyond the range of conventional thermal management solutions, making control of device temperature a critical issue in the thermal packaging of power electronics. Although evaporative cooling is capable of removing very high heat fluxes, two-phase cold plates have received little attention for cooling power electronics modules. In this work, device-level analytical modeling and system-level thermal simulation are used to examine and compare single-phase and two-phase cold plates for a specified inverter module, consisting of 12 pairs of silicon insulated gate bipolar transistor (IGBT) devices and diodes. For the conditions studied, an R134a-cooled, two-phase cold plate is found to substantially reduce the maximum IGBT temperature and spatial temperature variation, as well as reduce the pumping power and flow rate, in comparison to a conventional single-phase water-cooled cold plate. These results suggest that two-phase cold plates can be used to substantially improve the performance, reliability, and conversion efficiency of power electronics systems.

Microwave Module Thermal Considerations for Future Higher Powered MMICs in Phased Array Radars

2003 ◽  
Author(s):  
James S. Wilson
Keyword(s):  
Thermal Management ◽  
Temperature Difference ◽  
Integrated Circuit ◽  
Heat Dissipation ◽  
Phased Array ◽  
Waste Heat ◽  
Heat Removal ◽  
Thermal Design ◽  
Rf Power ◽  
Phased Array Radar

Advances in RF power generation capability at the device level will soon force a change in phased array radar thermal management. The efficiency in converting electrical power into transmitted power is not increasing as rapidly which means that higher RF power generating devices also dissipate more heat. Removing this waste heat creates several thermal challenges including the topic of this paper, namely thermal issues at the die and package level. A comparison of the temperature differences between the junction and ambient shows that even at present heat dissipation levels, the temperature difference at the integrated circuit level is already a significant fraction of the total rise. Further increases in the device level heat dissipation will increase the temperature difference at the integrated circuit level to nearly unmanageable levels unless device-level design changes are made. Maintaining acceptable junction temperature levels will require lower device mounting surface temperatures or some thermally better method of die attachment and heat removal. Dividing the thermal management of a phased array radar into two portions (integrated circuit level and everything else) reveals that while thermal improvements at the system and packaging level are useful for near-future radar designs, thermal design and management at the device and package levels are crucial.

Implementing Thermal Management Modeling Into SOFC System Level Design

2010 ◽  
Vol 8 (2) ◽  
Author(s):  
K. J. Kattke ◽  
R. J. Braun
Keyword(s):  
Power Systems ◽  
Thermal Management ◽  
System Modeling ◽  
Management Strategies ◽  
System Level ◽  
System Level Design ◽  
Gas Temperature ◽  
Process Gas ◽  
Level Design ◽  
The Impact

Effective thermal management is critical to the successful design of small (<10 kW) solid oxide fuel cell (SOFC) power systems. While separate unit processes occur within each component of the system, external heat transport from/to components must be optimally managed and taken into account in system-level design. In this paper, we present a modeling approach that captures thermal interactions among hot zone components and couples this information with system process design. The resulting thermal model is then applied to a mobile SOFC power system concept in the 1–2 kW range to enable a better understanding of how component heat loss affects process gas temperature and flow requirements throughout the flowsheet. The thermal performance of the system is examined for various thermal management strategies that involve altering the convective and radiative heat transfer in the enclosure. The impact of these measures on internal temperature distributions within the cell-stack is also presented. A comparison with the results from traditional adiabatic, zero-dimensional thermodynamic system modeling reveals that oxidant flow requirements can be overpredicted by as much as 204%, resulting in oversizing of recuperator heat duty by 221%, and that important design constraints, such as the magnitude of the maximum cell temperature gradient within the stack, are underpredicted by over 24%.

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