How Does a Room Air Conditioner Work?

Parts

A room air conditioner is a compact-sized refrigerating unit that fits into the window frame of a room. Unlike central air conditioning, which cools a whole house, room air conditioning is meant to cool down one room. Inside the unit is a compressor, filter, thermostat sensor, expansion valve, control unit, cold and hot coils and fans to move the air. A room air conditioner also contains a refrigerant, such as Freon, that can change between liquid and gas forms.

Room air conditioners must have a refrigerant in order to function properly. While this refrigerant is often called Freon, that has become a generic term that refers to any one of a number of nonflammable fluorocarbons. The refrigerant allows the room air conditioner to generate cold air. Normally, a small quantity of oil is mixed into it, which helps keep the compressor lubricated.

The refrigerant in a room air conditioner is compressed by the compressor unit, which transforms it into a hot, high-pressure gas. This gas goes through a series of coils, which dissipate its heat and condense it into a liquid. Next it runs through the expansion valve, which makes it evaporate into a cold, low-pressure gas. It runs through another series of coils in the room air conditioner, cooling the air by absorbing heat. The fans circulate air over both sets of coils, returning heat to the outside air and blowing cold air into the room.

A room air conditioner is easy to install and can be used to cool a room immediately after installation. The room must have a window so the air conditioner can be set in the window frame, and there must be a nearby electrical outlet to power it. Simply close the window to hold the unit in place. If there is space on the sides of the room air conditioner, it needs to be blocked to keep heat, moisture, insects and other things from getting in. When the room air conditioner is secure, you can plug it into an outlet and turn it on.

Room air conditioners don't require much maintenance, other than keeping the filter and coils clean so they can function properly. In harsh climates with severe winter weather, you can take the air conditioner out of the window and store it until spring.