Lämpöjohtoja

Lämpöjohtoja, often translated as heat pipes, are passive two-phase heat transfer devices that rely on the phase transition of a working fluid to transfer heat. They consist of a sealed tube, typically made of copper, containing a small amount of working fluid and a wick structure. The working fluid is carefully selected based on the operating temperature range.

The heat transfer process in a heat pipe occurs in several stages. Heat applied to one end of the pipe, known as the evaporator section, causes the working fluid within the wick to vaporize. This vapor then travels rapidly along the hollow core of the pipe to the cooler end, the condenser section. At the condenser, the vapor releases its latent heat and condenses back into a liquid. The liquid then returns to the evaporator section through capillary action within the wick structure, completing the cycle.

This continuous evaporation and condensation process allows for very high thermal conductivity, effectively transferring heat from a hot spot to a cooler area with minimal temperature drop. The absence of moving parts makes heat pipes highly reliable and maintenance-free. They are widely used in various applications, including electronics cooling, aerospace, HVAC systems, and solar thermal energy. The efficiency of a heat pipe is influenced by factors such as the working fluid, wick material, pipe geometry, and operating temperature.