Phasenwechselkühlung

Phasenwechselkühlung, also known as phase‑change cooling, is a method that exploits the latent heat of a substance changing between solid, liquid, and vapor states to remove or supply heat. In a typical system liquid refrigerants absorb heat while evaporating at a constant temperature, then are compressed to a higher pressure and pressure‑raised temperature, where they condense and release the absorbed heat. The phase change occurs at nearly constant temperature, making this method highly efficient for temperature regulation and refrigeration applications such as household refrigerators, air‑conditioning units, automotive air‑conditioning, and industrial cryogenic processes.

The key components of a phase‑change cooling system are the evaporator, compressor, condenser, and expansion device. Heat enters the evaporator, causing the refrigerant to evaporate and absorb the heat. The compressor increases the refrigerant’s pressure and temperature, which flows to the condenser where it releases the absorbed heat to the environment and condenses back to liquid. The expansion device lowers the pressure before the cycle repeats. Modern systems often use h‑134a or CO₂ as refrigerants, selected for energy efficiency and environmental impact. Some designs also combine thermodynamic refrigeration with passive phase‑change materials, such as paraffin wax or phase‑change gels, to smooth temperature fluctuations.

Historically, phase‑change cooling traces back to the 19th‑century discovery of the refrigeration cycle by William Gibbs and later development of vapor compression systems. The introduction of new refrigerants and high‑pressure compressors in the 20th century expanded its use in buildings, transportation, and industrial processes. Today, phase‑change cooling continues to evolve, with research focusing on solid‑state alternatives, improved compressor designs, and integration with renewable energy sources.