Background/Tutorial/FAQ

Background

A heat pipe is a pipe used to transfer heat from one location to another. It is often employed to remove heat that is being produced by some object and transfer that heat to the other end of the pipe where it is dissipated into the atmosphere. A heat pipe is partially filled with fluid. When one end of the heat pipe (the heat input/source) is heated by an external source, the fluid inside will absorb the heat and evaporate. The vapor will then travel to the cold end of the pipe where it will release the heat (heat output/sink) and condense back into the liquid phase. Often the pipe is positioned so that gravity aids in bringing the condensed fluid back to the heat source end of the pipe. If gravity cannot be employed, a network which will draw the fluid back is inserted. This is called a wick. A copper pipe is often used to construct a heat pipe. Water is often used as the fluid, although some fluids such as acetone may be desired because they have a lower boiling point.

Sources

The following website was used in helping the group understand the concepts behind a heat pipe. The website explains what heat pipes are used for, how they work, and how they can be built.

http://www.ocmodshop.com/heat-pipes-explained/

The following video was viewed as a demonstration in building a heat pipe. The man builds a straight heat pipe and tests it.

https://www.youtube.com/watch?v=LU4eynU6R-8

In the following site, THERMACORE answers common questions about heat pipes and explains how they operate.

http://www.thermacore.com/documents/common-questions-heat-pipes.pdf

Tutorial

The materials needed to construct this heat pipe include a 10 foot long 3/8 in flexible copper tube, two T-fittings, two end caps, and two screw-on end-caps. First, the tubing is cut into two roughly equal segments. One of these is gently bent into a coil that a pan could rest on. This is the heat source part of the pipe. The other segment is cut into three roughly equal length pieces which will be used for the heat sink part. A 3 in segment is cut from one of these to fit between the two T-fittings. After all the ends have been cleaned with steel wool and flux has been applied, the pipe is assembled in the following order. A regular cap fits on the inside end of the coil. On the other end, one T-fitting is followed by the 3 in connecting piece and the second T-fitting. The three heat sink segments are then fitted into the three remaining openings. One of these has regular end-cap while the other two have screw-on caps. The pipe is then soldered and allowed to cool. It is then filled with hot tap water and the two screw-on caps are screwed on.

FAQ

What is a heat pipe?
A heat pipe is a device which transfers heat through the phase change of an internal liquid.

Where are heat pipes used?
Heat pipes are used in a multitude of systems. Some examples are: computers, cooking devices, spacecrafts, permafrost cooling, solar thermal heating, ventilation heat recovery, and nuclear power conversion.

How is our heat pipe user friendly?
It is hoped that our heat pipe will be able to perform some useful function such as removing heat from a potentially dangerous hot object. The object would cool much faster than it otherwise would and the heat would be dissipated into the air much quicker. This could be of some use to companies that make items that get very hot but can not use a straight conventional heat pipe to cool them. Although our prototype is rather large,  when scaled down the coil shape is actually more compact than a straight pipe.

What are Drexel's Freshman Design Labs?
Freshman undergraduate engineering students are required to enroll in the three design labs offered. Each lab has its own overarching goal, and the first two are partially guided.