HCLT Whitepaper: Thermal Management in Electronic Equipment

February 2010

Thermal Management in
Electronic Equipment

Thermal Management in Electronic Equipment | February 2010

Contents
Abstract 2

Introduction 3

Market Trend and Consumer Demand 3

Need for Thermal Management 4

Thermal Management: Challenges and Solutions 6

Medical Electronics 9

Consumer Electronics 11

Aero Defense Electronics 13

Automotive Electronics 15

Process Flow 16

Conclusion 17

Appendix 18

Acronyms 18

References 19

Authors 19

ABOUT HCL 20

Abstract
Development in the electronics industry has come a long way
from nascent low performing devices to advanced devices with
high computational speed and power. The advancement in the
industry led to an exponential increase in power densities, which in
turn drove the innovation of smarter and smaller products. These
advanced technologies, coupled with miniaturization requirements,
guided innovation-driven thermal management in electronic devices.
Thermal management is essential in electronics, as it improves
reliability and enhances performance by removing heat generated
by the devices.
This paper highlights the development and challenges faced in the
thermal management of electronic equipment in various domains.
It gives an overview of innovative cooling solutions developed
over the years. It presents HCL case studies in various domains
such as medical, consumer, aerospace and defense, and automotive
electronics. It also gives a process flow chart which demonstrates
the thermal methodology of electronic equipment in general.

© 2010, HCL Technologies. Reproduction Prohibited. This document is protected under Copyright by the Author, all rights reserved.


Introduction
The phrase thermal management encompasses the technology of the
generation, control and dissipation of heat generated in electronic
devices and systems. Heat is an inevitable by-product of every
electronic device, and is usually disadvantageous to performance and
reliability. The electronic packaging trend has been to reduce size
and increase performance of the product, both of which contribute
to exponential increase in power consumption of the system.

Figure 1: World thermal management market trend
(Source: BCC Research, USA)

BCC Research[6] has estimated that global thermal management
technology spending increased to an estimated $6.8 billion by the
end of 2008 and should reach $11 billion by 2013 [Fig.1]. Report[6]
highlights are given below.
• The largest end-markets for thermal management technologies
in 2007 were the computer industry (57% of total revenues) and
telecommunications (16%)
• By 2013, medical and office electronics should move into a tie
for second place with telecommunications, each with a 12%
market share

Market Trend and Consumer Demand
In the past two decades, the conventional electronic industry has
become digital savvy, where consumer needs and demands are driving
the design and manufacture of products. The electronic industry
responded to consumer demand with innovation, offering products
which were more powerful than conventional ones, and matching
the endless needs of the consumer. The electronic industry can be
divided into four broad categories. These categories represent all of
the electronic devices in the industry. This section gives the market
trend and consumer demands for the aforesaid categories.



Medical Electronics

• According to Prismark Partners[13], approximately $53 billion
was spent on non-IT medical electronics equipment in 2006,
accounting for 4% of the global electronics industry
• This amount is expected to reach $66 billion in 2010
Consumer Electronics
• Consumer electronics[14] sales are expected to hit 724 billion
dollars in 2009, That’s up 4.3 percent from the 694 billion dollars
in 2008
• Flat panel displays were accounted for 57.2% of materials by
2003, and then to grow to 82.3% of the total by 2013
• The value of worldwide shipments of display materials were
reached $13.6 billion by 2003 and then to the growth of $30.8
billion by 2013
• The value of CRT glass represented more than 88% of all CRT
materials used
Aero Defense Electronics
• The performance of the market[10] is forecast to decelerate,
with an anticipated CAGR of 3.6 percent for the five-year
period 2006-2011, expected to drive the market to a value of
US$1,096 billion by the end of 2011
• The US and European markets will grow over the same period
with CAGRs of 3.4 percent and 3.9 percent respectively, to reach
the values of US$594.5 billion and US$284.3 billion respectively
in 2011
Automotive Electronics
• The automotive ASIC market[11] was worth $2.99 billion in 2006,
and a compound annual growth rate of 8.2 percent would put it
at $4.10 billion by 2010

Need for Thermal Management
If we observe the statistics of market trends and consumer demand in
electronics, there has been an explosive growth in the industry. The
tremendous growth in electronic equipment demands innovative
solutions to the new challenges of thermal management. The major
challenges on the thermal management front can be understood
by the heat dissipation of electronic devices, which vary from
5 W/cm2 on a PWB to 2000 W/cm2 for a semiconductor laser.
Providing cooling solution for former heat flux is manageable, but
for later heat flux is very difficult, and needs novel cooling solutions.
This will be further explained in Fig. 2.
In general, a vehicle re-entering the Earth’s atmosphere will have
the highest heat flux on its surface. Figure 2 shows the heat flux
variation with comparative technologies trend. VLSI electronics
heat flux can be comparable with that of re-entry heat flux; this
heat flux is very high. Thermal management must be provided for
these electronics.



Figure 2: Heat flux vs. comparative technologies trend
(Source: Charlespoint Group Boston, MA)

Further, the junction temperature of the chip has to be maintained
below the allowable limit specified by the vendor in most cases for
both performance and reliability factor. Reliability[1] is defined as the
probability that a device will perform its required function under
stated conditions for a specific period of time. Product reliability is
seen as the single most important factor to determine the quality
and superiority of product technology. Stringent standards and
guidelines to ensure user safety have revolutionized development
in the packaging industry The need for increased reliability has
energized the industry to seek the latest cutting-edge technology
solutions.
From a reliability and performance point of view, thermal
management needs to be carried out for every electronic device
which dissipates heat. This is essential for modern electronics,
for as they consume more power, they also generate more heat.
This has led to the development of computational fluid dynamics
(CFD) simulation software and advances in thermal management
techniques. The increasing complexity and power density of
modern electronics has challenged the traditional approach of using
prototypes and testing. The modern CFD simulation software
developed for challenging environments and high power dissipation
devices has led to a reduction in the product development cycle.



Thermal Management: Challenges and Solutions
This section describes various challenges faced in thermal management
and the novel solutions for the ever growing challenges.

Thermal Management Challenges
The following are thermal management challenges in electronic
equipment:
• Reduced form factors
• Ever growing power densities
• Harsh environments
• Product miniaturization
• Reducing product cost
• Reliability and performance constraints
• Meeting stringent standards
• Development of advanced technologies and materials
• Increasing consumer demands and needs
The next section explains some of the thermal management solutions
developed over the years.

Thermal Management Solutions
Solutions were developed based on thermal requirements of
electronic equipment. Thermal management of electronic devices
can be classified on two broad-based parameters, i.e. product level
and industry level. The product level can be further classified into
two levels.
• Printed wire board (PWB) level
– DIMMs, power cards, processors, chips and various
components
• System level
– Single rack (e.g. servers, etc.)
– Multiple racks (e.g. data center, etc.)

Figure 3: Analysis level vs. industry trend
(Source: HCL Technologies Ltd)



Figure 3 shows the distribution of thermal management in industry
levels with that of component, board and system level analysis.
The comparative data highlights the focus of industry led
innovation. For instance, the medical electronics industry is more
focused on making products at system level, whereas consumer
electronics focuses more on component level analysis (like the
semiconductor industry).
The latest technologies in the thermal management arena function
in and around the basic heat transfer modes, i.e. conduction,
convection (natural and forced) and radiation. Development has
reached a stage where the technologies overlap the basic functional
industrial domains. Figure 4 gives the usage percentage of each
mode of heat transfer technology in various domains. Depending
upon the requirement in the respective domains, a different mode
of heat transfer will be chosen accordingly. For example, the
medical electronics domain will use primarily conduction cooling
technology, whereas consumer electronics will mostly use natural
convection heat transfer technology.

Figure 4: Industry vs. heat transfer technologies trend

Figure 5: Heat flux vs. year of cooling technology development
(Source: IBM USA[7])



The chip cooling technologies are evolving over the years to
accommodate steep increase in heat flux. Figure 5 shows the plot
between advancement in cooling technology and chip heat flux.
The exponential curve shows the increase in the heat flux and
changes in the cooling technologies. Future cooling solutions are
being developed around multi-phase heat transfer technologies. The
cooling technologies such as thermal vapor chamber, cold plates
and jet impingement mechanisms have revolutionized the future of
the thermal management landscape.
The solution for these challenging thermal tasks has led to novelty
in thermal management. The development of technologies is
moving from single-phase heat transfer to multi-phase heat transfer,
which has led to the design of advanced cooling solutions. The latest
cooling technologies leverage nanotechnology and the advancement
in smart materials. Figure 6 briefly explains the various innovative
cooling solutions available in the thermal management industry.

Figure 6: Innovative cooling solutions



Medical Electronics
The medical electronics area has traditionally included implantable
medical devices, medical diagnostic tools and monitoring devices.
Today, however, the market is being fueled by an explosive growth
in personal medical equipment. Driven by the need to reduce
healthcare costs, patients’ desires to manage their own health, and
an increased emphasis on preventive medicine, the adoption of
consumer based, portable and often wearable medical products is
increasing at a substantial rate. The major medical products can be
classified into two categories.
• Large infrastructure equipment
– Medical imaging systems (e.g. X-ray and MRI)
– IT equipment (e.g. picture archival communication systems)
– Biochemical analysis equipment (e.g. lab instruments and
DNA analyzers)
• Small stationary - portable equipment
– Patient monitoring systems
– Bedside monitoring units

Challenges

• Meeting stringent medical standards
• Overall reliability requirements, including component reliability,
test methods and standards
• Limited space and closed-case environment
• The acoustic design standards limit the use of moving parts
• Advancement in printed circuit board (PCB) substrate
technology provides a new challenge when using conduction
cooling technique
• In-depth understanding of RF technology and potential
communication interference between medical devices and
other products

HCL Case Study: Thermal Analysis of Bed Side Monitor Unit
The bedside monitor unit is designed for high packaging factor,
plus low EMI/EMC and noise levels. It consists of multiple input
output boards dissipating 90W of heat, and was designed to meet
Ingress protection standards. A typical bedside monitor unit is
shown in Fig. 7.
Thermal Challenges
• Low EMI/EMC design
• High packaging factor
• Very low noise levels
• Power dissipation is 80W
• Qualifying for ingress protection standards


10

Cooling Solution
• Special baffles were designed to divert the flow from fans to heat
sink as the EMI/EMC shields were obstructing the flow
• With the help of dedicated ducts, pressure drop was optimized
inside the system
• To reduce the temperature of the unit, low thermal conductive
material was used between heat dissipating chips and the
unit surface
• A low-noise fan was chosen to meet noise and
vibration standards

Figure 7: Bedside monitor unit


11

Consumer Electronics
In this era of communications and entertainment, growth of
consumer electronics is exploding. Consumer demand for increased
mobility, wireless connectivity and advanced features demand has
paved the way for a variety of new products, including servers,
laptops, ruggedized laptops, hybrid routers, data centers and
cameras. The silicon solutions driving these products are more
highly integrated than ever before, as advancements in process
technology are delivering system-on-a-chip (SoC) solutions that are
smaller, faster, and lower cost. These trends, along with the broad
range of emerging equipment, require diversity in new IC package
types to meet specific applications.
The evolution of the microprocessor from a 486 Intel chip to a
multi-core processor shows the exponential increase in power
density needed to achieve superior computing power. Figure 8
shows the comparative changes in processor wattage over the years.
The obvious change in the processors is the amount of power
consumption, which has increased from 70W to 250W in the last
decade. This power consumption has challenged the industry to
create cutting edge technologies to deal with thermal management.
Consumer electronics thermal management is one of the most
challenging and innovative in the entire technological landscape.
The semiconductor which involves chip cooling to server and
datacenter cooling has led to innovation of some of the finest cooling
technologies in the field of thermal management (Fig. 6).

Figure 8: Power vs. chip development

Challenges

• Harsh environment
• High power dissipation
• Miniaturization
• Competitive packaging factor with overall high heat flux


12

• Components with a lower form factor pose a challenge due to
obstructed flow passage
• Acoustic and vibration standards
• Ineffective and insufficient airflow distribution

HCL Case Study: Thermal Management of
Multi-Core Processor
Until now in the electronic industry, a passive cooling solution has
dominated previous generation processors. This solution is very
cumbersome and noisy because it contains a big heat sink, heat pipes
and a dedicated fan. This system consists of a multi-core processer.
The total power consumption of the unit is 220W. Since it is a next
generation processor (number of cores and power dissipation was
more), the thermal management is even more cumbersome and
challenging. There is a need to provide a feasible thermal cooling
solution for this processor at high ambient temperature. Thermal
management in a multi-core processor is shown in Fig. 9.
Thermal Challenges
• High ambient temperature
• High power dissipation = 220W
• Pressure drop should be minimum
Cooling Solution
• A novel cold plate has been designed for the
multi-core processor
• The number of passes for the cold plate was optimized with a
constraint on minimizing the pressure drop
• A simple, reliable, hassle-free and optimal cold plate has been
designed for next generation processors

Figure 9: Cold plate technology for
multi-core processor cooling


13

Aero Defense Electronics
The Aero and Defense industry is entering a transformational change
with more power efficient and higher power density components.
Thermal and power management are widely considered to be the
crucial links in the ability to embrace high performance advanced
technology. The development in directed-energy weapons and
UAVs is growing, and these innovations require ultra-efficient
energy systems. The products include electric power generating,
distribution, management and control systems, auxiliary power
units, LRUs, and environmental control systems
Current and future generation processors are making it difficult for
military systems designers to efficiently manage thermals in mission
critical systems, forcing thermal engineers to devise novel methods
of thermal management.
Aero and Defense electronics thermal management is one of
the most sensitive to the environment and most stringent in
the entire technological landscape. The lightweight carbon
thermal-management systems, fuel cells, CNT thermal interface
and spray cooling are innovations of the decade which are meeting
the tough requirement of Aero standards.

Challenges

• Require more power, but have less space
• High functional density
• Compatibility with two-level maintenance
• Ability to facilitate insertion of new technology and mitigate
component obsolescence
• Harsh environment conditions with high product reliability
• Adherences to RTCA DO Standards

HCL Case Study: Thermal Simulation of Line Replace Unit
In Aero and Defense, the typical field problem in line replacement
units (LRUs) of an aircraft involves the rapid thermal runaway in
electrical components due to the high power density of 6,750W. It
consists of electrical components including IGBTs, transformers,
inductors and bus bars. There is a need to consider the joule heating
effect on bus bars while optimizing them. A detailed modeling of
these components was done, and the LRU is shown in Fig. 10.
Thermal Challenges
• Altitude condition
• Cooling high power density components such as IGBTs,
transformers and inductors
• High power dissipation = 6,750W
• Bus bars design and optimization with joule heating effect
• Pumping power should be minimum
• Detailed modeling of transformers, inductors and bus bars
• Preventing thermal runaway


14

Cooling Solution
• Detailed modeling was done for complex transformers, inductors
and bus bars
• The cooling solution was provided using liquid technology
• The cold plate was designed for optimum velocity and
pressure drop
• Complex bus bars were designed and optimized
• Joule heating effect was evaluated with respect to optimum
bus bar design
• Transformers and inductors were cooled by routing the flow
through the optimized channels
• Cold plate has been optimized with respect to pressure drop

Figure 10: Line replacement unit


15

Automotive Electronics
The quantity, value and complexity of electronics in passenger
vehicles continue to rise. This brings a corresponding increase in
shielding, grounding and thermal management challenges for the
automotive design engineer. Vehicle electronics can be loosely split
into ‘in cab’ and ‘out of cab’ applications.
• In cab applications
– Heating ventilation and air conditioning (HVAC)
– Instrument panels
– Radios
– Infotainment
– Satellite navigation
– Head-up displays
• Out of cab applications
– Engine management ECUs
– Braking ECUs
– Diverse array of sensor units
The emergence and evolution of thick, soft thermal gap fillers in
either die-cut sheet or form-in-place formats range has enabled
engineers to effectively couple surface-mount devices to a chassis
or enclosure. At the same time, this approach can often simplify
and speed module assembly by removing the need for some
mechanical fixes.

Challenges

• High engine temperature environment
• Harsh operating conditions
• Stringent automobile standards
• Use of commercially available, off-the-shelf items to control
product cost
• Electronics modules in passenger vehicles, particularly those
mounted out-of-cab, are often sealed to prevent moisture ingress,
which makes it very challenging to provide a cooling solution
• Cooling techniques are limited to conduction and
“limited” convection
• Under-bonnet modules are often exposed to extreme temperatures
coupled with smaller footprints
• Protecting modules from damage or malfunction due to spurious
electrical signals through EMI/EMC shielding

HCL Case Study: Thermal Analysis of Motor Control Unit
The development of the electric car has propelled the need for
thermal management in the electric motor. The electric motor
couples inductors and a rotating hub to produce wheel motion.


16

Heat is a by-product of this mechanism. The thermal wattage is
around 1.5kw A typical motor control unit is shown in Fig. 11.
Thermal Challenges
• High thermal dissipation = 1.5kw Modeling of inductors
• Design of an optimal flow channel
• Selection of a coolant
• Pumping power should be minimized
• Complexity of the model and flow
Cooling Solution
• Glycol-based water cooling jackets were designed to transfer the
high wattage
• Optimal coolant pumping rate was found where pumping power
is minimized
• Coolant fluid flow channels are optimized for maximum heat
transfer and minimum pressure drop
• Complex inductors were modeled

Figure 11: Motor control unit

Process Flow
A thermal engineer makes use of industry-wide best practices and his
judgment for engineering design decisions. The three most important
proponents in making engineering decisions: 1. Understand the
heat transfer circuit of the system (i.e. convection, conduction and
radiation); 2. A thermal equivalent model for analysis needs to be
identified for mimicking the exact model; 3. A process flow chart
must be designed to reduce errors in the model and analysis, and
to obtain the results quickly. Figure 12 shows the indicative best
practice for the thermal simulation of board level and system level
product designs.


17

Figure 12: Thermal management methodology

Conclusion
This paper highlights the importance of thermal management
(reliability and performance of devices) in electronic equipment
with respect to ever increasing product packaging factors, thermal
wattages, and consumer needs. A glimpse of market trends and
consumer demand for electronics was presented, with a view
of the increasing importance of thermal management. Thermal
management needs, challenges and solutions were also highlighted.
An overview of specialized cooling solutions has been given with
respect to product advancement. Case studies were presented in
various domains (medical, consumer, aero defense and automotive
electronics) to illustrate HCL’s capabilities. A thermal management
methodology flow chart was designed using best practices, and
simulation approaches from the industry were also presented.
As needs and demands grow every day, thermal management
technology will continue to evolve.


18

Appendix
Source HCL Technologies Ltd: The data represented in
this paper is from the vast experience of HCL Technologies
in Thermal Management. The data is collected from
100 different products in each of the following domains (Medical
electronics, Consumer electronics, Aero/ Defense electronics and
Automotive electronics).

Acronyms
CFD Computational Fluid Dynamics
CNT Carbon Nanotubes
CRT Cathode Ray Tube
DIMM Dual In-line Memory Module
ECU Engine Control Unit
EMI/EMC Electromagnetic Interference/ Compatibility
IC Integrated Circuit
IGBT Insulated Gate Bipolar Transistor
LRU Line Replace Unit
PWB/PCB Printed Wiring Board/ Printed Circuit Board
RF Radio Frequency
UAV Unmanned Aerial Vehicle
VLSI Very Large Scale Integration


19

References
1. Scott Speaks Vicor, ‘Reliability and MTBF Overview’, Vicor Reliability
Engineering, Europe
2. Tai Phan and Joseph Steinman, ‘AMC/ATCA Thermal Management:
A Case Study’, Interphase Corporation
3. Dr. Robert Hannemann, ‘Thermal Control of Electronics: Perspectives
and Prospects’, Charlespoint Group, Boston, MA
4. Joseph Fjelstad, ‘Thermal Management Challenges’, Verdant
Electronics
5. Roger Schmidt, ‘Data Center Trends and Power Management’,
IBM USA
6. BCC Research, http://www.bccresearch.com/report/SMC024E.html
7. Richard C. Chu, ‘Thermal Management Roadmap: Cooling Electronic
Products from Hand-Held Devices to Supercomputers’, IBM USA
8. http://www.omai.com.cn/en/shownews.asp?id=165
9. http://en.kioskea.net/news/11734-growth-in-consumer-electronics-
sales-to-slow-in-2009
10. http://www.ebis.com.sg/Portals/0/pdfs/InfoByte/Public/
Aerospace%20%20Defense.pdf
11. http://www.eetasia.com/ART_8800480602_499501_NT_d2dce9db.
HTM
12. http://www.ti.com/research/docs/SemiconductorPackagingWP.pdf
13. http://www.prismark.com/

Authors
Jagadish Thammanna is a Manager and Heads the CFD and
Thermal team at HCL Technologies. He has 15 years of experience
in Thermal management in all the niche domains and various
cross-application industries. His areas of interest include
Computational Fluid Dynamics, heat transfer and scientific
programming. In his vast experience, he has presented and published
many national and international papers at technical symposiums.

Ambuj Srivastav is a Thermal Analyst at HCL Technologies. He
has 5 years of experience in designing and developing innovative
solutions for the thermal management of electronic devices, and his
core domain areas expertise lies in thermal management of aerospace
and automotive lines of products. His experience in industry wide
practices has given him insight to work on the cutting edge and the
latest technologies in thermal management.


20

ABOUT HCL

HCL Technologies
HCL Technologies is a leading global IT services company, working
with clients in the areas that impact and redefine the core of their
businesses. Since its inception into the global landscape after its IPO
in 1999, HCL focuses on ‘transformational outsourcing’, underlined
by innovation and value creation, and offers integrated portfolio of
services including software-led IT solutions, remote infrastructure
management, engineering and RD services and BPO. HCL
leverages its extensive global offshore infrastructure and network of
offices in 26 countries to provide holistic, multi-service delivery in
key industry verticals including Financial Services, Manufacturing,
Consumer Services, Public Services and Healthcare. HCL takes
pride in its philosophy of ‘Employee First’ which empowers our
55,688 transformers to create a real value for the customers. HCL
Technologies, along with its subsidiaries, had consolidated revenues
of US$ 2.5 billion (Rs. 11,833 crores), as on 31st December 2009 (on
LTM basis). For more information, please visit www.hcltech.com

About HCL Enterprise
HCL is a $5 billion leading global Technology and IT Enterprise
that comprises two companies listed in India - HCL Technologies
HCL Infosystems. Founded in 1976, HCL is one of India’s
original IT garage start-ups, a pioneer of modern computing, and
a global transformational enterprise today. Its range of offerings
spans Product Engineering, Custom Package Applications,
BPO, IT Infrastructure Services, IT Hardware, Systems
Integration, and distribution of ICT products across a wide range
of focused industry verticals. The HCL team comprises over
62,000 professionals of diverse nationalities, who operate from
26 countries including over 500 points of presence in India. HCL
has global partnerships with several leading Fortune 1000 firms,
including leading IT and Technology firms. For more information,
please visit www.hcl.in


HCLT Whitepaper: Thermal Management in Electronic Equipment

Recommandé

Recommandé

Contenu connexe

En vedette

En vedette (20)

Similaire à HCLT Whitepaper: Thermal Management in Electronic Equipment

Similaire à HCLT Whitepaper: Thermal Management in Electronic Equipment (20)

Plus de HCL Technologies

Plus de HCL Technologies (20)

Dernier

Dernier (20)

HCLT Whitepaper: Thermal Management in Electronic Equipment