Heat Pipe Fundamentals

What Are Heat Pipes?

Heat pipes are highly efficient conductors of heat and can transport, in some cases, 1000’s times better than a solid copper conductor.

A heat pipe is sealed under a vacuum with a small, prescribed amount of working fluid. During non-operation, the fluid is contained inside the wick structure that lines the inner diameter of the heat pipe. When a heat source, such as an electronic component, generates heat, the fluid vaporizes at what is known as the evaporator section. The fluid vapor quickly spreads to the other end of the heat pipe, using pressure generated by the temperature difference. At the opposite end, known as the condenser, the fluid gives up its latent heat, which is rejected to an external heat sink. The fluid then returns to liquid form, and the wick structure passively pumps the fluid back to the evaporator using capillary force.

By utilizing liquid and vapor phases, the heat transport is extremely efficient. Because it’s a closed-loop system, heat pipes operate continuously and passively, creating a very reliable component in your thermal management system.

A typical tubular heat pipe is illustrated below.

Heat Pipe Resources


Check with our experienced engineers to see if a heat pipe solution will solve your thermal issues. The more details you can provide about the application, the better we can assist you!

Contact ACT today!

Heat Pipe History


heat pipe article

ELECTRICALLY INSULATING MATERIALS were used exclusively in the construction of this heat pipe, designed to remove large quantities of heat from high-voltage electrical circuits. The containment vessel is made of glass, the wick of fiber glass, and the working fluid is a fluoridated hydrocarbon. The two tubes extending from the pipe are employed to measure thermal conductance. circa. 1960’s

The original heat pipe operating principle was developed by Richard S. Gaugler of the General Motors Corporation in 1942. Modern heat pipe technology was originated from the Los Alamos Scientific Laboratory by George Grover in 1963.

Advanced Cooling Technologies’ Yale Eastman (formerly a Director of ACT) described the theory and history of the heat pipe technology a few years later in an article published in Scientific American, May 1968 (click to view the original article).

Since then, heat pipe technology has progressed from cooling vacuum tubes to being applied on the CPU chip of modern laptop computers, cooling mobile phones, and facilitating thermal management of satellite electronics in zero gravity orbit.

Have a Question or Project to Discuss?