Direct air cooling system, also known as air cooling system, is a kind of thermal power plant cooling water for the purpose of saving water. It is a cooling method that uses air instead of water as the cooling medium. It refers to the exhaust steam of the steam turbine directly entering The air condenser is used to condense, and the air and steam exchange heat. The required cooling air is usually supplied by mechanical ventilation, and the condensate is discharged into the heat recovery system of the steam turbine unit by the condensate pump. The air-cooled turbine generator set is referred to as the air-cooled unit.
The air-cooled polar steam device has two functions：
(1) Establish and maintain a certain vacuum at the turbine exhaust port.
(2) Collect clean condensed water as a part of the pot protection water supply.

Air cooling system classification:
The air cooling system adopts different technological processes, and the air cooling system is divided into three types:
1. Direct air cooling system, referred to as ACC system (Air cooled Condenser)；
2. Air-cooled pro-system using jet (hybrid) condenser, also known as Heller (HL) indirect cooling pro-system；
3. Indirect air-cooling system with surface condenser. Harmonic indirect air-cooled pro-integration.