Heat pipes are at the core of the ETEKINA project, as they are an incredibly efficient tool to recover heat from one industrial process, allowing the recovered heat to be used in a different process.
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.
In the ETEKINA project, the engineers will combine many heat pipes to create a heat exchanger design according to the specific needs of each production plant.
The diagram below 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 of those 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.
The challenge: within the production lines there are different exhaust streams at different compositions, flow rates and temperatures that could possibly damage the system. The engineers need to find the right set-up and select the right materials for the heat pipes so that the thermal recovery will work efficiently inside the plant’s environment and within the temperature range applied. Moreover, ETEKINA aims to re-use the recovered heat in the recipient processes without compromising on the quality of the produced parts.