The indoor unit blows the cooled or heated air into the room. This air is sucked in from the space itself. So when the air conditioning is used for cooling, the indoor unit extracts the warm air from the room and then blows in cool air. Cooling takes place by blowing the warm air through a cold heat exchanger by means of a fan.
The outdoor unit releases excess heat or cold to the outside air and transports the so-called refrigerant. The refrigerant is needed to ensure that the heat exchanger in the indoor unit can cool the air.
An air cooler comes in different shapes. The purpose of the air cooler is to provide cooling air. There are devices that are equipped with an ice pack and devices that provide cooling air with water. The devices with an ice pack are actually fans where the air is guided past this ice pack and where the air will be cooler than without this ice pack.