Air conditioning is less about making things colder and more about absorbing the heat from things. When you feel an air conditioner blowing cold air on you it’s not pumping out cold energy. It’s returning the air it just sucked out of your room with the heat removed. Let’s talk about how it does this. There are basically two main sections in the system. There’s an indoor part and an outdoor part. In a window air conditioner these two parts are situated in the same enclosure. In a central air conditioning system there is a unit outside, usually located in the rear or side of the building, which is the condenser and compressor. The inside unit called the evaporator will usually be hidden in a basement or closet.
The indoor unit will have pipes with fins attached situated in an enclosure with a fan. Coolant, commonly referred to as Freon, is pumped from the outside unit through the pipes where it can absorb the heat from the surrounding room. A fan inside the units speeds up the transfer of heat from the room to the coolant in the pipes. The air from the room is returned to the room with the heat removed. This of course makes the air feel cold to us. The heat from the room has been used to boil the coolant in the pipes which is returned to the outside unit as a gas. This process is also referred to evaporation.
The compressor / condenser unit outside the building processes the coolant expelling the heat into the outside air. The compressor takes the coolant and pumps it through the system and increases the pressure in the pipes. This increase in pressure causes the coolant to condense back to a liquid and another fan is used to transfer the heat from the pipes to the outside air. The chilled refrigerant is now returned to the inside unit to start the whole process again.
Why does this work?
Air conditioners take advantage of a physical law: when a liquid converts into a gas it absorbs heat. This is part of a process called phase change. Freon and other coolants are used because they have very low boiling points. This allows them to absorb heat at room temperature without needing to be heated up to 212 degrees Fahrenheit, like water needs to be in order to boil. The process is however the same. Just as the water absorbs the heat from your stove, coolant absorbs heat from your room.