Heat Pipes is a device for transferring heat efficiently between two locations by using the evaporation and condensation of fluid contained therein. It is a sealed tube that has been partially filled with a working fluid which is a mixture of liquid and vapour in saturated state.
Originally invented by NASA scientists for space applications, Heat Pipe seems like a simple device that has heat transfer capacities some 1000 times higher than copper and can transfer heat from one point to another without having to use an external power supply.
The simple Heat Pipe is called thermosyphon which relies on gravity for return of liquid and is therefore unidirectional. More advanced Heat Pipes are provided with capillary action of “wick” to provide bi-directional operation and can work without aid of gravity.
Operating Principle:
The Evaporator, which is the hot end of the heat pipe, is exposed to the source of heat. It absorbs heat and uses it to convert working fluid to vapour, which expands to fill the entire internal space of the heat pipe.
The condenser, which is at the other side of the tube, is in contact with heat sink that has temperature lower than the heat source i.e. the evaporator. The condenser rejects heat which leads to the vapour losing the heat and condensing back to liquid. This condensed liquid again returns to evaporator and the cycle repeats itself.
Over the years, Heat Pipe technology has evolved and today there are countless shapes of Heat Pipes which transfer heat through distances as small as 100-150 mm from computers chips in a PC to significant distances ranges in several meters between the evaporator and condenser.
Today Heat Pipes are considered the most economical and efficient method for Humidity Control which also results in better IAQ and Energy Savings.
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