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1. HEAT PIPES…
PREPARED BY …
GOWTHAAM K.

2. INTRODUCTION
A heat pipe is a simple device
used to transfer heat from one
place to another, using
evaporation-condensation cycle.
Heat pipes are referred as
“superconductors” of heat due to
their fast transfer capacity with
low heat loss.

3. Types of heat pipes
• Standard Heat Pipes & Vapor Chambers.
• Variable Conductance Heat Pipes (VCHP)
• Thermosyphon & Loop Thermosyphon.
• Loop Heat Pipes.
• Rotating Heat Pipes.
• Oscillating / Pulsating Heat Pipes.

4. Working principle
The heat input region of the heat pipe is called
evaporator, the cooling region is called condenser.
In between the evaporator and the condenser regions,
there may be an adiabatic region.

5. Components of heat pipes
oContainer
oWorking fluid
oWick (or) capillary
structure

6. container
•The function of the container is to isolate the working
fluid from the outside environment.
•Many materials are available for the container , there are
most common in use – copper , aluminium, stainless
steel.

7. Working fluid
• Compatibility with wick and wall material
• Good thermal stability
• Vapour pressure not too high or low over the operating
temperature range
• High latent heat
• High thermal conductivity
• High surface tension

8. Wick structure
It is a porous structure made of materials like steel , aluminium ,
nickel or copper in various ranges of pore sizes.
The prime purpose of wick is to generate capillary pressure to
transport the working fluid from the condenser to the evaporator.
It must also be able to distribute the liquid around the evaporator
section to any area where heat is likely to be received by the heat
pipes.

9. Advantages of heat pipes
• Energy Recovery Heat Pipes Features.
• Passive Operation. No energy input is required to operate the Heat
Pipes. ...
• Long Life. There is nothing in the Heat Pipes to wear out! ...
• Isolated Air Streams. ...
• Minimum Maintenance. ...
• Flexible Size.

10. Limitations of heat pipes
1.Sonic limit - the rate that vapour travels from evaporator
to condenser
2.Entrainment limit - Friction between working fluid and
vapor which travel in opposite directions
3.Capillary limit - the rate at which the working fluid travels
from condenser to evaporator through the wick
4.Boiling limit - the rate at which the working fluid vaporizes
from the added heat

11. Applications

12. Thank you…