What is Heat Pipe?
A heat pipe is a simple device that can quickly transfer
heat from one point to another, which is usually used for cooling an
electronic component in air-conditioners, refrigerators, heat
exchangers, transistors, capacitors, etc. Heat pipes are also used
in laptops to reduce the working temperature for better efficiency.
A efficient heat pipe system can be affected by length of a heat
pipe, type of fluid in a heat pipe, return wick type, and the number
of bends in a heat pipe. Its small, compact profile, light weight,
and cost effective heat pipe solution allow it to meet the demanding
requirements of laptops.
Heat Pipe Structure:
A heat pipe is consisting of following three basic
components:
1. container
2. the wick or capillary.
3. the working fluid
First, the container is a
sealed, hollow tube, which can isolate the working fluid from the
outside environment and can maintain the pressure differential
across its walls, and enable transfer of heat to take place from and
into the working fluid.
Inside walls of the container are lined with a porous structure,
which is called capillary structure or wick. The prime purpose of
the wick is to generate capillary pressure to transport the working
fluid from the condenser to the evaporator.
Finally, the working fluid is contained in wick structured
container. The first consideration of choosing a suitable working
fluid is the operating vapor temperature range. Most pipes use water
and methanol/alcohol as working fluid.
How do Heat Pipes Operate:
One
end of the heat pipe attached to the heat source. As the heat rising
to the desired operating temperature, the tube boils the working
fluid and turns it into a vapor. As the evaporating fluid fills the
hollow center of the wick, it spreads throughout the heat pipe
toward to the other cold end. Condensation of the vapor occurs
wherever the temperature is even slightly below that of the
evaporation area. As it condenses, the vapor gives up the heat it
acquired during evaporation and the condensed working fluid is then
sucked back to the evaporating section along the wick structure.
This thermodynamic cycle continues and helps maintain constant
temperatures.
Attaching a heat sink
to a portion of the heat pipe makes condensation take place at this
point of heat loss and establishes a vapor flow pattern. Capillary
action within the wick returns the condensate to the evaporator
(heat source) and completes the operating cycle.
Features :
Provide high thermal conductivity with small temperature difference
Fast thermal response
Small size and light weight
Large variety of shapes
No electrical power supply required, and maintenance free
Reduce overall system size and costs |