This document discusses different cooling techniques for electronic devices, including air cooling, liquid cooling, and their components. It provides details on heat sinks, thermal interface materials, fans, blowers, and their differences. Liquid cooling uses water to transmit heat more efficiently than air cooling due to water's higher heat capacity and conductivity. While more effective, liquid cooling systems are more expensive, larger, require technical skills, and carry safety risks if leaked.
4. HEAT SINKS
* Heat sinks are needed when the heat transfer to the
ambient air directly from the top of the device is not sufficient
to keep the semiconductor device within the allowable
temperature range.
* heat sink was supplanted in
higher power applications .
* increasing the thermal conductance
of components and increasing
the fin area exposed to the airflow
is very important.
5. THERMAL INTERFACE MATERIALS
• TIM is essential when two or more solid surfaces are in
the heat path.
• The air gaps created by multiple voids of "contacting"
hard surfaces are simply too large a thermal barrier for
even modest power applications.
• The first tactic in overcoming this barrier is to fill the
voids and eliminate air by introducing a third material to
the heat path that is fluidic and wets the surfaces.
6. Cont.
• An important property of any TIM is its thermal
conductivity.
• grease and Elastomeric pads are used as TIM.
7. COOLING FANS AND BLOWERS
• Cooling fans and blowers are essential to systems
that produce a significant amount of heat like
computers and other electronic components.
• Different systems are
engineered to work with
specific types of fans.
• Cooling fans come in all
shapes and sizes.
as well as voltage,
airflow, and case size.
8. Difference Between Fans and Blowers
Axial fans:
• Create an air flow that is parallel to the axis of the
fan blade.
• designed to work with systems that have low back
air pressure and high rate air flow.
• less noise.
• Quite common and the most
economical cooling solution.
• they are normally used
in computers.
9. CONT.
Blowers :
• Send air on a perpendicular direction in relation
to its axis.
• Designed to work with systems that have high
impedance (i.e. high back pressure) and low rate air flow.
• It produce a more concentrated airflow
in a system, So they tend to generate
a significant amount of noise.
• they are used in Servers.
10. AC AND DC COOLING FANS
property DC FANs AC Fans
voltages 5V, 12V, or 24V 110v , 220v
frequency 0 50 Hz , 60 Hz
Air Flow speed Variable Constant
Power consuming Low ( 60 percent less) high
Electro Magnetic
and Lower level Higher level
Radio Frequency
Interference
Life longer shorter
11. CONT.
• The difference in the cost between AC fan and DC fan is
negligible.
• When choosing fan for your applications, it is important
to look at the cooling requirements of the system and
applications, the fan type, the air flow, and AC or DC
power operation.
• AC fans are used when DC voltage is not available.
• All types of computer equipment rely on DC cooling fans.
16. IBM BLADE CENTER H:
COOLING SUBSYSTEM
Hot-swap customer serviceable Hot-swap customer serviceable
fan packs AC blower units
BladeCenter H rear chassis
18. COOLING OF RACKS WITH CONDITIONED AIR
AIRFLOW
Front or
Footprint Inlet
Raised Floor Supply Air Raised Floor Supply Air
Front In – Rear Out Front In – Top Out
20. What is liquid cooling ?
• Liquid (Water)cooling is a method of heat removal
from electrical components . As opposed to air
cooling, water is used as the heat conductor.
21. History
• Cooling hot computer components with various
fluids has been in use since at least as far back as
the development of Cray-2 in 1982.
• Through the 1990s, water cooling for home PCs
slowly gained.
• it started to become noticeably more prevalent after
the introduction of AMD's hot-running Athlon
processor in mid 2000
22. Cont.
• As of 2011, there are several manufacturers of
water cooling components and kits, and some
custom computer retailers include various setups of
water cooling for their high performance systems.
• Apple's Power Mac G5 was the first mainstream
desktop computer to have water cooling as
standard.
• Dell followed suit by shipping their XPS computers
with liquid cooling.
27. cont.
Radiators have different FPI (fins per inch) and therefor optimized for different type
of fans, the ones with high FPI are optimal with powerful fans where ones with low
FPI are better for lower RPM fans.
32. Advantages
of liquid cooling over air cooling
• water's higher specific heat capacity, density, and
thermal conductivity. This allows water to transmit
heat over greater distances with much less
volumetric flow and reduced temperature difference.
• Drawing heat away from the processor and outside
of the system. This allows for higher clock speeds in
the processor as the ambient temperatures of the
CPU core are still within the manufacturer's
specifications.
33. Advantages
cont.
• The water jacket around an engine is also very
effective at deadening mechanical noises, which
makes the engine quieter, Many high performance
CPUs require fan speeds in excess of 7000 rpm that
generate noise of 60+ decibels of noise.
• No DUST and no need to open computer to clean it.
34. Disadvantages.
• Costs significantly more than an air-cooled engine
system, approx. 600$.
• Size and weight ,need large area inside and out
side the computer require larger desktop system
cases to fit all of these parts within the computer
case itself ,approx.6.5Kg.
• and technical skills required to install a kit , suitable
tubes length , leaks could cause severe damage to
the components inside of the system.
35. cont.
• Leaking .
• Condensation, due to the ambient air right around
the pelt being cold.
• Water freezes at 0℃.
36. Usage
• Water cooling can be used to cool many computer
components.
• especially the CPU.
• GPU.
• Northbridge's.
• Southbridge's.
• Hard disk drives.
• Memory.
• Voltage regulator modules (VRMs).
• Power supplies can be water-cooled.
37. Coolant.
• This coolant contains a high quality anti-corrosion agent
for various materials including copper, aluminum, and
plastic, that prevents corrosion for long term operation.
• Material : Propylene Glycol & Anti-Corrosion Agent.
• Freezing Point : -9℃.
• Exchange Cycle : 1 year.
38. Liquid vs. Air cooling
Liquid Air
Cost high low
size big small
compatibility Specific CPU All CPU
safety less more
Skill required yes no
efficiency high moderate
spread low high