How Does an Air Conditioner Work?

July 18, 2016

The summer season has arrived with record heat across the country, and with the vast majority of homes having some sort of air conditioner, it’s the most effective way to get out of the heat. As you are relaxing in your comfortably cool home or office, appreciating that your air conditioner works, let’s look at how a normal AC system works.

The Basics

Your air conditioner runs the just like your refrigerator, but obviously compared to keeping a little space cool, it has to cool your entire home. Both use a refrigerant that changes simply from liquid to gas, back to liquid again. In your air conditioner, the refrigerant is on a constant circle from the outdoors to indoors. It goes into the home as a sub-cooled liquid that evaporates and collects or takes in heat from your indoor air, expands back into vapor, then back to the outside condensing unit where it dissipates the heat and is switched back to a sub-cooled liquid.

The Components

Your AC system is made of four critical pieces: an evaporator coil, a compressor, a condensing coil, and an expansion valve or metering device.

The component where your refrigerant evaporates from a sub-cooled liquid to a super-heated vapor is called the evaporator coil, which may be inside, in your attic, or situated in the garage. As warm indoor air is blown across the cold evaporator coil, heat is pulled from the air…and the cooled air is blown among your home.

From the evaporator coil, the now super-heated vapor refrigerant flows to the compressor based in your outdoor condensing unit. The compressor increases the pressure of the vapor until it shifts into a hot, high pressure vapor. The now super-hot vapor meets the condenser coil where a lower amount hot air blows by the coil, moving heat to the outdoors, and switches the refrigerant to a sub-cooled liquid. The sub-cooled liquid refrigerant is sent to the indoor evaporator coil where, through an expansion valve or metering device, the process is replicated.

Your air conditioner is an endless loop of physics at work. We know the important thing to you isn’t really how it works, but that it’s functioning correctly. If you’d like to talk science or just about keeping cool, give our professionals a call at 319-229-2318. We will partner with you and the laws of physics to keep you happy this season.