A heat pipe transfers thermal energy passively from a hot to a cold stream by a boiling condensation cycle inside a hermetically sealed metal tube. In this way, heat from the hot area can be transferred very efficiently to a cold part of the pipe. The diagram shows the principle of the heat pipe:
The sealed pipe contains a working fluid. Absorbing heat at the lower end, the liquid vaporises and carries the thermal energy upwards to the condenser section, where it encounters a lower temperature. As a consequence, the vapour condensates (back to a liquid) and thereby releases heat. The liquid runs down the inner walls back to the evaporator section where the process starts over again.
Within a heat exchanger unit many heat pipes work together in parallel in a container where the hot production steam passes by at the bottom to heat the liquid inside the tubes. At the other end of the heat exchanger, cool air flows along, absorbing the heat of the condenser sections. This heated air can now be transported to parts of the production line where it can be re-used.
… for more information please read the latest publications on heat pipe based projects by Prof. Jouhara and the HEAT PIPE AND THERMAL MANAGEMENT RESEARCH GROUP.