How Does Air Conditioning Work?
An air conditioning unit is basically a heat pump which transfers heat from one environment to another, using a refrigerant in the process. Whilst being used in cool mode during the summer, the heat pump removes stale air from the enclosed room and draws fresh air from outside. The fresh air is then passed through the refrigerant for cooling before being transferred into the room. Thus the air entering the room is always fresh and cool.
In heating mode, the same process is employed, but this time the air from outside is heated instead of being cooled, ensuring a constant flow of fresh warm air.