In general, a two-stage plate heat exchanger consists of two paragraphs and an intermediate plate. (See figure below)
The first stage is cooled with city water and the second stage is cooled with a coolant, such as glycol or alcohol. City water for the first stage is preferably below 20°C, and then the wort can be cooled to 40-50°C before entering the second stage. The coolant for the second stage is around -3-4°C, and then the wort will be cooled to fermentation temperature. The water from the first stage can be recycled as brewing water after heat exchange.
The resistance of the plate heat exchanger is about 0.25-0.35Mpa, so the wort and coolant need to be pressed in with a pump. It cools the wort at 90-95°C from the whirlpool to the fermentation temperature. The cooling time should preferably be less than 50 minutes.
After wort cooling, the heat exchanger must be cleaned and disinfected with hot water and caustic soda water in full circulation to prevent scaling.