This document summarizes research into applying zebra stripe patterns to dissipate heat from electronic equipment. It first discusses how the stripes of zebras help them regulate their temperature via conveying heat. Current methods for cooling electronics like heat sinks and fans are introduced. An experiment is described where metal plates painted different colors (black, white, zebra pattern) are heated and their temperatures measured. The literature gap identified is that no previous work has tested if zebra patterns or colors could improve heat dissipation from electronics. The experiment aims to provide evidence for this application of zebra patterning.
An introduction to application of zebra pattern for dissipation of heat in electronic equipments by sumit s dharmarao
1. International Journal on Mechanical Engineering and Robotics (IJMER)
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ISSN (Print) : 2321-5747, Volume-4, Issue-1,2016
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An Introduction to application of zebra pattern for dissipation of heat
in electronic equipments
1
Sumit S. Dharmarao, 2
Priyanka P. Jadhav, 3
Anjana M Kamble
1
Mechanical Engineering Department, Konkan Gyanpeeth College of Engineering, Karjat, India
2
Electronics & Telecom Dept. Konkan Gyanpeeth College of Engg, Karjat, India
3
Production Engg Dept. Konkan Gyanpeeth College of Engg, Karjat, India
Abstract— This paper helps to correlate unique
characteristics of special animals with the science involved
in it and applying the same principles to solve our technical
problems for better performance of machines & that too at
low cost. This paper focuses at stripes of zebra, scientific
cause of it & checking the possibility for application of
zebra pattern for better dissipation of heat generated
within electronic equipments which results in satisfactory
output of machines & equipments.
Keywords— zebra; stripes; ecology; convective heat
transfer; Electronic Equipment; Thermal Design
I. INTRODUCTION
We human beings always fascinate towards the different
things in nature. By studying those things we understand
the logic & science behind it & we modify this science
and apply to fulfill our requirements .The act of
applying the science for sake of humanity & nature is
called as Engineering. We always fascinates about the
special animals which are different than others like
zebra. They found in particular region of world. They
have attracting combination of black & white stripes on
their body. As an Design Engineer & curious person I
started thinking why zebras having stripes & further I
correlate various answers of this question to technical
cases where generation of heat is undesirable. Various
reasons suggested by scientists are social bonding or
cohesion, predation evasion avoidance of biting of files,
thermoregulation. Study shows that the zebra striping
patterns varies regionally from heavy black stripe
coverage to lighter, thinner stripes in other. In contrast
recent findings the evidence found to which shows
stripes are for escaping from predators or avoid biting of
flies. Temperature successfully predicts a reasonable
pattern variation in various paths of Africa. Another
study shows that leopard may not be able to change
spots but some zebras change these stripes. Zebras in
warmer places have more stripes. It is found that
temperature is the significant predictor for zebra stripe
pattern across the entire region of Africa. The stripe
characteristics are more readily explained by
environmental variation in stripe thickness on forelegs &
hind legs, number of stripes on torso. Two
environmental variables which are involved with stripes
variation are related to thermoregulations and further
study reveals that stripes gives rise to differential air
currents that produce cooling effect.[1] In today’s
technical era we hugely rely on computers & other
automatic devices to perform critical tasks for us. It may
be complex calculations of aerospace or any mechanical
design problem, storing of giant data, it also helpful in
manipulation of critical signals and giving commands to
machines for critical and accurate machining. Now-a-
days it also plays an important role in security of nation
& in medical sector. All this advancement is due to
multidisciplinary efforts i.e. merging of two streams like
Mechanical and Electronics.[2] Take a good look at your
day and we will find quite a number of gadgets,
machines and appliances that in one way have electronic
parts in them. We are awakened by our electronic time
clock in order that we won't be late for our work. We
hurriedly heat our left over from last night on our
microwave oven for our breakfast. Since we still have
some time, we eat breakfast while we turn on our
television to watch the morning news. After which we
gather the things we need to bring with it and we open
our PDA to check on our daily schedule. We get our car
keys and we drive in our car to work. On the way to the
office we listen to some music by turning on the radio or
putting on our favorite CD on We CD player. If we are
the more technological driven type we bring along with
We an MP3 player or an IPod. We get to our building
and take a ride on the elevator while receiving a very
important client call on our mobile phone. We get to our
office and we turn on our computer to check our email
as well as to make our report for that afternoon's
meeting. From these set of activities alone, one can see
how electronics play a special and helpful role in our
lives. All these electronic devices have limited operating
capabilities. Reliable & satisfactory use of devices
depends on circuit conditions imposed on them. To
achieve this device must be surrounded by components
chosen to protect against the extreme conditions. If
extreme conditions of parameters like voltage, current,
temperature are violated then it results in degraded
2. International Journal on Mechanical Engineering and Robotics (IJMER)
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performance or destroyed permanently. [3] It is a type of
converter which converts AC to DC, when compared
with normal converters SCR controls output DC voltage
by applying gate pulse. Thereby power consumption
will be less. When forward voltage reaches the threshold
voltage (break over voltage) thyristor starts conducting
and gate loses its control i.e. remains in ON state. When
latching current reduces below holding current, SCR
turns OFF.
Fig. 01 SCR switching device
Electronics operate when current flows through their
circuitry. How much current is dependent on the
resistance of the wires and voltage source we are using
(the relationship is V=IR, I is current, V is voltage, and
R is resistance). Resistance is temperature dependent,
the colder the object is the less resistance it has. Power
follows the equation P=IV, so, if the temperature drops
then so does the required voltage which means we could
use less power to run our electronics. We are going to
see thermal effects on SCR (Silicon controlled Rectifier)
and how can we minimize it? Basically SCR is a power
controlled device. The SCR has two states, ON or OFF,
and it allows current to flow in only one direction. SCR's
can remain in the off state even though the applied
potential may be several thousand volts. In the on state,
they can pass several thousand amperes. When a small
signal is applied between the gate and cathode terminals,
the SCR will begin conducting within 3 microseconds.
Once turned on, it will remain on until the current
through it is reduced to a very low value, called the
holding current. Silicon shows a peculiar profile, in that
its electrical resistance increases with temperature up to
about 160 °C, then starts decreasing, and drops further
when the melting point is reached. This can lead to
thermal runaway phenomena within internal regions of
the semiconductor junction; the resistance decreases in
the regions which become heated above this threshold,
allowing more current to flow through the overheated
regions, in turn causing yet more heating in comparison
with the surrounding regions, which leads to further
temperature increase and resistance decrease. SCR's
emit about 1.5 watt's of energy in the form of heat, per
ampere conducted. Failure to dissipate this energy is
perhaps one of the main sources of SCR failure. The
reliability of SCR's decreases about 50% for every 10°C
increase of semiconductor temperature. Other critical
parameters such as the dv/dt rating and the blocking
voltage rating also decrease rapidly with temperature.
The heat generated by the SCR must be dissipated, thus,
all controllers have some means to cool the SCR's.
Typically an aluminum heat sink, with fins to increase
the surface area, is used to dissipate this energy to air.
Controllers with relatively small current capacities rely
on natural convection. Higher current capacity
controllers use a fan to force air past the fins in order to
increase heat dissipation .Occasionally, water cooled
heat sinks are used on SCR controllers with very high
current ratings. A case study carried out by one of the
reputed service providing industry at well known bank
shows that failure of electronic equipments at data centre
due to raise in temperature which results in three days
without ATM service in whole Indian Subcontinent. [4]
The delicate electronic device should protect against the
extreme conditions for satisfactory operation so that it
faithfully adheres to the specified characteristics
provided by manufacturing. Power dissipation in
electrical components raises the internal temperature and
affects performance and reliability. High internal
temperature may be detrimental to the physical structure
of the component in designing of small size light weight
electronic systems, removal of heat and control of
internal temperature profile are very important
considerations. [3]
II. PRESENT THEORIES AND PRACTICES
Power losses in devices appear in form of heat.
Accumulation of hear energy increases temperature of
internal structure of devices. Heat must be removed by
transferring it to surroundings. Three modes of heat
transfer are A. conduction – A mode of heat transfer in
which heat is transferred from one molecule to another
without appreciable movement of molecules. B.
Convection – A mode of heat transfer in which actual
movement of molecule takes place. C. Radiation – A
mode of heat transfer in which electromagnetic emission
works as energy carrier. [5] The heat transfer in
electronic system is dominated by conduction &
convection processes.[3] presently there are following
methods to dissipate heat in electronic devices
A. Heat sink
Heat sinks are widely used in electronics, and almost
essential to modern central processing units. Generally it
is a metal object brought into contact with an electronic
component’s hot surface — though in most cases, a thin
thermal interface material mediates between the two
surfaces. Microprocessors and power handling
semiconductors are examples of electronics that need a
heat sink to reduce their temperature through increased
thermal mass and heat dissipation primarily by
conduction and convection and to a lesser extent by
radiation. Heat sinks have become essential to modern
integrated circuits like microprocessors. A heat sink
usually consists of a metal structure with one or more
flat surfaces to ensure good thermal contact with the
components to be cooled, and an array of comb or fins
3. International Journal on Mechanical Engineering and Robotics (IJMER)
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ISSN (Print) : 2321-5747, Volume-4, Issue-1,2016
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to increase the surface contact with the air, and thus the
rate of heat dissipation. A heat sink is commonly used
along with fan to increase airflow rate over the heat sink.
This maintains a large temperature gradient by replacing
warmed air faster than convection. This is known as a
forced air system.
B. Fins (extended surfaces)
Fins (extended surfaces) are used to improve heat
transfer. In electronic devices has space constraint, the
numbers and arrangement of fins must be done in way
that it must dissipate more heat when compared with no
same surface without fins.
C. Cavities (inverted fins)
Cavities (inverted fins) embedded in a heat source, are
the regions formed between adjacent fins that stand for
the essential promoters of nucleate boiling or
condensation. These cavities are usually utilized to
extract heat from a variety of heat generating bodies to a
heat sink.
D. High conductivity materials
Utilization of high-conductivity materials (inserts) are
proposed for electronic cooling and for enhancing the
heat removal from small chips to a heat sink. As the
space occupied by high conductivity materials together
with the cost are the two elements of major concern
therefore designers seeking for more efficient designs of
high conductivity pathways.
E. Cold Plate
Placing a conductive thick metal plate which is referred
as a cold plate acts as heat transfer interface between a
heat source and a cold flowing fluid may improve the
cooling performance. In such arrangement, the heat
source is cooled under the thick plate instead of being
cooled in direct contact with the cooling fluid. It is
observed that heat transfer rate between the heat source
and the cooling fluid by way of conducting the heat in
an optimal manner. The two most attractive advantages
of this method are that no additional pumping power and
no extra heat transfer surface area that is quite different
from fins. Heat sinks are made from a good thermal
conductor such as silver, gold, copper, or aluminum
alloy. Copper and aluminum are among the most-
frequently used materials for this purpose within
electronic devices.
F. Convective air cooling
This term describes device cooling by the convection
flow of the warm air being allowed to escape the body
of the component to be replaced by cooler air. This
method usually requires venting at the top or sides of the
housing to be effective.
G. Forced air cooling
To increase heat transfer rate cooler air is forced to flow
on heated surface with help of a fan or blower.
H. Heat pipes
A heat pipe is a heat transfer device that uses
evaporation and condensation of a two-phase ―working
fluid‖ or coolant to transport large quantities of heat
with a very small difference in temperature between the
hot and cold interfaces. A typical heat pipe consists of
sealed hollow tube made of a thermo conductive metal
such as copper and a wick to return the working fluid
from the evaporator to the condenser. The pipe contains
saturated liquid and vapour of a working fluid (water,
ammonia), all other gases being excluded. The most
common heat pipe for electronics thermal management
has a copper envelope and wick, with water as the
working fluid. The advantage of heat pipes is their great
efficiency in transferring heat.
I. Peltier cooling plates
Peltier cooling plates take advantage of the Peltier effect
to create a heat flux between the junctions of two
different conductors of electricity by applying an electric
current. This effect is commonly used for cooling
electronic components and small instruments.
J. Synthetic jet air cooling
A synthetic jet is produced by a continual flow of
vortices that are formed by alternating brief ejection and
suction of air across an opening such that the net mass
flux is zero. A unique feature of these jets is that they
are formed entirely from the working fluid of the flow
system in which they are deployed can produce a net
momentum to the flow of a system without net mass
injection to the system.
K. Electrostatic fluid acceleration
An electrostatic fluid accelerator (EFA) is a device
which pumps a fluid such as air without any moving
parts. Instead of using rotating blades, as in a
conventional fan, an EFA uses an electric field to propel
electrically charged air molecules. Because air
molecules are normally neutrally charged, the EFA has
to create some charged molecules, or ions, first. Thus
there are three basic steps in the fluid acceleration
process: ionize air molecules, those ions to push many
more neutral molecules in a desired direction, and then
recapture and neutralize the ions to eliminate any net
charge. [6]
Experiment is carried out at university of Texas for
showing effect of colors on temperature. Temperature
measurements taken at centre (internal) of timber for
different ambient over a period of time exposed to full
4. International Journal on Mechanical Engineering and Robotics (IJMER)
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ISSN (Print) : 2321-5747, Volume-4, Issue-1,2016
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sun (except shade measurements). This test is to
compare the heat transfer to the timber for different
colored surfaces. Gives following results- (On Y axis
temperature & on X axis shades of colors) [7]
Fig. 2 relation between temperature & colors
III. LITERATURE GAP
Every technical venture is said to be successful if it is
economically proved beneficial. Market will be
commanded by those products only which are of best
quality at least price. It is newly identified that zebra
pattern has thermal connection and also proved that
color has affect on heat transfer [1],[7] nobody has
checked the possibility of colors & zebra pattern to
dissipate heat from electronic equipments so its output
should not affect.
IV. EXPERIMENTATION
Experimental set up for checking the possibility of
application of zebra pattern to improve the heat transfer
consists of A. Heating coil (V = 230/50, 1000W, Mfg by
-Vikas Appliances) , B. Physical contact type digital
thermometer (HTC DT_1), C. Stand (42cm from base),
D. M.S. Plate (4 Nos, 15cm x 15 cm, thickness = 0.6
cm).
Fig. 3 Physical contact type digital thermometer
Four plates are taken for conducting experiment. Out of
these four plates one is kept as it is (without any paint),
remaining three are painted with black, white & zebra
pattern. Four drills are made at corners for holding it on
heating coil.
Fig. 4 Plates for conducting experiment
A plate is hold by stand, set up is as shown in fig. with
help of string. It is held at approximate distance of 4cm.
heater is switched on to heat plate.
Fig. 5 Actual set up
V. RESULTS
Plates are heated up to 100o
C with help of heating coil
& then cooled to 50 o
C by natural convection and time
required for reducing temperature is measured.
Table. 1 Observations
Sr. No. Color of Plate Time
01 Without any Color 19 min 32 sec
02 Black Coloured 20 min 37 sec
03 White Coloured 18 min 12 sec
04 Zebra Pattern
Coloured
16 min 30 sec
VI. CONCLUSIONS
As from experiment we can observe that time required
to dissipate heat is reduced when it is colored with zebra
pattern it happens due to change in air flow velocity
over black & white stripes. Another reason is due to
formation of eddies at change in phase which accelerates
air flow velocity. Application of this zebra pattern in
electronic equipment helps us to dissipate heat in
quicker time which helps equipments to perform in
better way. Also further study will helps us to move
towards more compact design and reduced size of fans
& lead to overall power requirement of equipment.
REFERENCES
[1] Brenda Larison et. All , ―How the zebra got its
stripes: a problem with too many solutions,‖
Royal Society Open Science, vol. 2, pp. 1-9,
April 2015.
[2] U Bolton, ―An Introduction to Mechatronics,‖
Printess Hall of India, Delhi,Third edition, pp. 1-
24.
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[3] Singh, Khanchandani, ― Power Electronics‖
McGraw Publication, Third edition, pp. 62-69,
823-851.
[4] Technical Expert Assesment Report, by XXX
facility Industry for XXX Bank, India, May
2014. Brenda Larison et. All , ―How the zebra
got its stripes: a problem with too many
solutions,‖ Royal Society Open Science, vol. 2,
pp. 1-9, April 2015.
[5] U Bolton, ―An Introduction to Mechatronics,‖
Printess Hall of India, Delhi,Third edition, pp. 1-
24.
[6] Singh, Khanchandani, ― Power Electronics‖
McGraw Publication, Second edition, pp. 62-69,
823-851.
[7] Technical Expert Assesment Report, by XXX
facility Industry for XXX Bank, India, May
2014.
[8] Pawaskar, Choudhary, ―Heat Transfer,‖ Nishant
Publication, Pune, First edition, pp. 161-207.
[9] A Anand kumar, ―Fundamentals of Digital
Circuits,‖ Printess Hall of India, Delhi,Third
edition, pp. 61-234.
[10] Jhon David, ―Relation between color and heat
transfer,‖ University of Texas press, 2009