Seminar slides about the topic "HEAT PIPES".

1. HEAT PIPES…

2. Introduction
• A heat pipe is a device that efficiently
transports thermal energy from its one point to
the other.
• It utilizes the latent heat of the vaporized
working fluid instead of the sensible heat.
• As a result, the effective thermal conductivity
may be several orders of magnitudes higher
than that of the good solid conductors.

3. Heat
Transfer of Heat
Heat Pipe
Heat Sink
Processor
Heat Added Heat Released
*Drawing is not to scale.

4. Basic Components of a Heat pipe

5. Evaporation Condensation
Heat Absorbed
Heat Absorbed Heat Released
Heat Released
Heat Transfer within
a Heat Pipe
Wick Structure
Wick Structure
Container
Container

6. Component of heat pipe
1.Container
• Metal Tubing, usually
copper or aluminum.
• Provides a medium
with high thermal
conductivity.
• Shape of tubing can be
bent or flattened.

7. 2.Working Fluid
• Pure liquids such as helium, water and liquid
silver
• Impure solutions cause deposits on the interior
of the heat pipe reducing its overall
performance.
• The type of liquid depends on the temperature
range of the application.

8. MEDIUM
MELTING
PT. (° C )
BOILING PT. AT
ATM. PRESSURE
(° C)
USEFUL
RANGE
(° C)
Helium
Ammonia
Water
Silver
- 271
- 78
0
960
- 261
- 33
100
2212
-271 to -269
-60 to 100
30 to 200
1800 to 2300
Examples of Working Fluid

9. 3.The wicking structure
Axial Groove Wick
Created by carving out grooves on the interior core
of the Heat Pipe.

10. Screen Mesh Wick
Utilizes multiple wire layers to create a porous wick.
Sintering can be used.

11. Sintered Powder Wick
Utilizes densely packed metal spheres.
Sintering must be used to solidify the spheres.

12. Purpose of the Wick
• Transports working fluid from the Condenser to the
Evaporator.
• Provides liquid flow even against gravity.

13. How the Wick Works
• Liquid flows in a wick due to capillary action.
• Intermolecular forces between the wick and the fluid
are stronger than the forces within the fluid.
• A resultant increase in surface tension occurs.

14. Ideal Thermodynamic Cycle
• 1-2 Heat applied to evaporator through external sources
vaporizes working fluid to a saturated(2’) or superheated
(2) vapor.
• 2-3 Vapor pressure drives vapor through adiabatic
section to condenser.
• 3-4 Vapor condenses, releasing heat to a heat sink.• 4-1 Capillary pressure created by menisci in wick pumps
condensed fluid into evaporator section.
• Process starts over.

15. Heat Pipe Applications
• Electronics cooling- small high performance
components cause high heat fluxes and high heat
dissipation demands. Used to cool transistors and
high density semiconductors.
• Aerospace- cool satellite solar array, as well as
shuttle leading edge during reentry.
• Heat exchangers- power industries use heat pipe
heat exchangers as air heaters on boilers.
• Other applications- production tools, medicine and
human body temperature control, engines and
automotive industry.

16. LAPTOP HEAT PIPE SOLUTION

17. Heat pipes used in processor

18. HEAT PIPE IN CPU

19. Camera

20. Types of Heat Pipes
• Thermosyphon- gravity assisted wickless heat pipe.
Gravity is used to force the condensate back into the
evaporator. Therefore, condenser must be above the
evaporator in a gravity field.
• Leading edge- placed in the leading edge of
hypersonic vehicles to cool high heat fluxes near the
wing leading edge.
• Rotating and revolving- condensate returned to the
evaporator through centrifugal force. No capillary
wicks required. Used to cool turbine components and
armatures for electric motors.
• Cryogenic- low temperature heat pipe. Used to cool
optical instruments in space.

21. Advantages Of Heat Pipes
• Last a very long time.
• Completely noiseless.
• Requires no mechanical or electrical
input.
• Provide lower operating costs.
• Are virtually maintenance free.
• Are environmentally safe.

22. Disadvantages
• High cost.
• Requires that the air streams must be
relatively clean and may require filtration.
• Requires that the two air streams be adjacent
to each other,

23. CONCLUSION
• Heat pipe is a thermal super conductor under
certain heat transfer condition they can transfer
the heat energy 100 times more than available
best conductive materials, because of negligible
temp. Gradient exist in heat pipe.
• The heat pipe has compactness, light weight,
reversible in operation and high thermal flux
handling capability makes heat pipe to use new
modern era and in many wide variet application
to overcome critical heat dissipation problem.

24. References
• www.heatpipe.com.
• www.cheresources.com.
• www.indek.com
• www.wikipedia.org

25. THANK YOU…