A louver is installed to control air flow to one of several facilities. Louver other equipment (variable fan pitch) compared to the low initial cost, simple maintenance is preferred. The louver is especially installed on HOU, RFCC and used to control the constant cooling effect.

Typically, the louver is separated by forced/induced type and air recirculation type

Forced/Induced Type:

The most basic louver is directly installed on the tube bundle

Air Recirculation Type:

They are used mainly in cold areas such as Russia and Canada and installed on the structure of the box type.

Louvers are composed of three parts (bypass, exhaust, and intake louver).They interact each other so they make a constant cooling effect by hot air recirculation.