The plate heat exchanger is a form of heat exchanger, also known as a heat transfer medium. This term is appropriate, as during the process heat transfer occurs from one medium to another without heat exchange.

The device consists of corrugated plates assembled in a unique way, and between the plates there are gaps where two media circulate alternately: the heat absorption medium and the heat dissipation medium. The sealing of the device can be achieved in various ways.

Plate heat exchangers include bolted plates that are expandable and transfer flow differently. Preferred are the alternative plate heat exchangers, which are characterized by the fact that the various plates are welded together.