How Does an Air Conditioner Work?

Summer is here with record highs across the country, and with the vast majority of homes having some type of air conditioner, it’s the most effective way to escape the sun. As you are sitting in your comfortably cool home or office, grateful that your air conditioner runs well, let’s gain some insight at how an average central heating and cooling system works.

The Basics

Your air conditioner operates the same way as your refrigerator, but clearly rather than keeping a small space cool, it has to work to cool down your whole house. Both use a refrigerant that changes easily from liquid to gas, back to liquid again. In your air conditioner, the refrigerant is on a regular loop from the outdoors to the inside of your home. It goes into the house as a sub-cooled liquid that evaporates and assembles or soaks up heat from the air in your home, expands back into vapor, then heads to the outside condensing unit where it dissipates the heat and is transferred back to a sub-cooled liquid.

The Components

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

The piece where your refrigerant evaporates from a sub-cooled liquid to a super-heated vapor is called the evaporator coil, which may be indoors, in your attic, or located in the garage. As warm indoor air is moved throughout the cold evaporator coil, heat is detached from the air…and the cooler air is driven among your house.

From the evaporator coil, the now super-heated vapor refrigerant flows to the compressor located in your exterior condensing unit. The compressor increases the pressure of the vapor until it turns into a hot, high pressure vapor. The now super-hot vapor meets the condenser coil where a smaller amount hot air blows across the coil, moving heat to the outdoors, and changes 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 repeated.

Your HVAC system 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 working correctly. If you’d like to know the inner workings or just about remaining cool, give our technicians a call at 205-758-2703. We will work with you and the laws of physics to confirm you comfortable this summer.

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