ASHRAE posted the top ten things you should know about your Air Conditioning System. Today we will address number one on that list. How an Air Conditioner Works.
The basics are: warm air is pulled by a fan over a coil of cold pipes (an Evaporator Coil) filled with a refrigerant, as the refrigerant absorbs heat it turns from a liquid to a gas, it is then pumped into another coil (Condensing Coil) where it is condensed back to a liquid and the process cycles again. This process requires a lot of movement, air, liquid and gases are all cycling through the system. If the flow is interrupted, issues arise. The interruption might be as simple as a clogged filter, which will cause the entire system to work harder and possibly overheat. Maintenance, is the single most important thing you can do to keep cool and lower operating costs.
Below is a more detailed explanation written by ASHRAE:
The job of your home air conditioner is move heat from inside your home to the outside, thereby cooling you and your home. Air conditioners blow cool air into your home by pulling the heat out of that air. The air is cooled by blowing it over a set of cold pipes called an evaporator coil. This works just like the cooling that happens when water evaporates from your skin. The evaporator coil is filled with a special liquid called a refrigerant, which changes from a liquid to a gas as it absorbs heat from the air. The refrigerant is pumped outside the house to another coil where it gives up its heat and changes back into a liquid. This outside coil is called the condenser because the refrigerant is condensing from a gas back to a fluid just like moisture on a cold window. A pump, called a compressor, is used to move the refrigerant between the two coils and to change the pressure of the refrigerant so that all the refrigerant evaporates or condenses in the appropriate coils.
The energy to do all of this is used by the motor that runs the compressor. The entire system will normally give about three times the cooling energy that the compressor uses. This odd fact happens because the changing of refrigerant from a liquid to a gas and back again lets the system move much more energy than the compressor uses. The harder the compressor has to work the less efficient it is.