THE HEATSINK GUIDE: Heat pipe information


The days where heat pipes were mostly used for temperature equalization in spacecrafts and satellites are over. Nowadays, we commonly find heat pipes in notebook computers, game consoles, and even integrated into normal PC CPU coolers. One reason for the rise in popularity is the fact that prices have dropped dramatically, since high-volume cooling product manufacturers like Asia Vital Components now have their own heat pipe manufacturing facilities, and heat pipe manufacturing is no longer reserved to a few specialized companies.

When it comes to PC cooling, "heat pipe" has become a buzzword; but still, few people understand how heat pipes work, and what factors must be considered when using a heat pipe-based cooling system. This article should provide some clarifications.

What are heat pipes?

A heat pipe is a device has an extremely high thermal conductivity, and is used to transport heat. In order to achieve this, heat pipes take advantage of simple physical effects:
As a liquid evaporates, energy - in the form of heat - must be taken from the environment. Therefore, an evaporating liquid will cool the surrounding area. This is how a heat pipe effectively cools the heat source. However, this doesn't get rid of the heat; heat is just transported with the vapor. At the target side for heat transport, the heat pipe must be cooled, for example using a heatsink. Here, the inverse effect takes place: The liquid condenses, and therefore emits heat.

Using these effects, it is possible to build heat pipes that have a thermal conductivity that is many thousand times higher than a copper piece of the same size. Note that unlike Peltier elements, a heat pipe does not consume energy or produce heat itself. It is also not possible to cool a device below ambient temperature using a heat pipe.

Thermacore Heatpipe

Heat pipe made by Thermacore

Design of heat pipes, and heat pipe related problems

Sounds great? Sure, but there are a few things to consider. In order to understand heat pipe-related problems, we will look at a simple model heat pipe, which is actually more of a thermosyphon.

Following the explanations in the above paragraph, you can imagine a simple device: A closed metal tube in vertical orientation, filled with a small amount of water, and a heatsink mounted on its upper side. If you apply a heat source to the lower side, the water will evaporate, while cooling the heat source. The vapor will move up, and condense near the heatsink on top. From there, water will drip back to to the bottom, evaporate again, etc.
This simple model already shows the common problems related to heat pipe technology:

Usage of heat pipes

Given the excellent thermal conductivity of heat pipes, there are two situations in which heat pipes are particularly suitable:

Taisol heatpipe-based CPU cooler

Unusual heatpipe-based cooler from Taisol (detail view):
In this design, the fan is located between CPU and heatsink, and blows air away
from the CPU, through the heatsink. Thermal transfer from CPU to heatsink
is done by heat pipes.


When used properly, heat pipes can do wonders. However, they are certainly not the ultimate solution to all cooling related problems. Due to the number of factors to consider when applying heat pipes, my advice is: Use ready-made heatpipe-based coolers only if you are absolutely sure that they are suitable for your particular cooling problem. Do not try to build your own heatpipe-based cooling system, unless you really know what you are doing.

If you found this article not technical enough, and missed details and in-depth information, please visit In this excellent article, you will find a more scientific approach to heat pipe technology.

All pages copyright © 1997-2010 Tillmann Steinbrecher
Legal information / Disclaimer / Impressum