The working principle of plate heat exchangers mainly includes three processes: heat transfer, mass transfer, and resistance. Cold and hot fluids flow through both sides of the plate heat exchanger, with the hot fluid releasing heat on the hot side plate and the cold fluid absorbing heat on the cold side plate, thereby achieving heat transfer. Heat is mainly transferred through convection and conduction. In addition, plate heat exchangers can also achieve mass transfer processes by adding appropriate fillers or membranes to transfer substances between the fluids on both sides.