An air conditioning (AC) system can be of different types, and whether it uses outside air or not depends on the specific type of AC and its design.
Window AC or Portable AC: These types of air conditioners typically do not use outside air. They are self-contained units that recirculate and cool the air within the room they are installed in. They draw warm air from the room, pass it over the evaporator coil to cool it, and then blow the cooled air back into the room. There is no exchange of air with the outside environment.
Split AC or Central AC: Split air conditioners or central AC systems have two main components: an indoor unit and an outdoor unit. In these systems, the indoor unit cools the air within the room, but it does not use outside air directly. Instead, it circulates and cools the air within the room it serves.
Evaporative Cooler: Evaporative coolers, also known as swamp coolers, do use outside air. These systems work by pulling warm outside air through water-saturated pads. As the air passes through the wet pads, it cools down through the evaporation process, and the cooler air is then blown into the living space.
Ventilation Systems: Some AC systems are integrated with ventilation systems that allow the exchange of indoor air with outside air. These systems provide fresh air from the outside and remove stale air from the indoors. They are commonly used in commercial buildings and homes seeking better indoor air quality.
It's important to note that the use of outside air in an AC system may depend on factors such as climate conditions, energy efficiency requirements, and the type of cooling technology used. In most standard residential air conditioning systems, the emphasis is on recirculating and cooling the indoor air, rather than introducing outside air, as this helps maintain the desired indoor temperature efficiently.