How does an AC compressor work?

If you know anything about air conditioners, you’ve heard about compressors. You might even know that compressors are one of the most crucial parts of a unit—if your compressor gives out, you’re looking at a costly repair at best and a full AC system replacement in a worst case scenario. 

But unless you were brought up in or around the trades, you probably have no idea how a compressor works or why exactly it’s so important. In this article, we’ll try to demystify the magic of air conditioning!

Refrigerant

In order to understand a compressor, you first need to understand what is being compressed: refrigerant. If the compressor is the heart of your HVAC system, the refrigerant is the blood. In it’s low-pressure (liquid) state, refrigerant is a cool substance that cools the coils through which it flows and, in turn, cools the air around the coils. On the other hand, when refrigerant is compressed, it turns into a hot gas, which can then be cooled using a fan.

How the compressor facilitates air cooling

The section above might have given up the game for the more mechanically-minded readers out there. But now that we know how refrigerant works and what its properties are, we can discuss the function of a compressor in fairly simple terms.

The compressor pressurizes refrigerant, turning it into a hot gas that can be easily cooled with a fan. That cooling occurs outdoors and the heat get blow off into the air. When the refrigerant cools, it enters its liquid state and gets pumped back into your house (usually to an evaporator unit, which we can discuss in a future article). Inside, the cool refrigerant meets warm air in evaporator coils and absorbs the heat through the coils. As the refrigerant warms, it enters a low-pressure gaseous state. That vapor flows back out to the compressor, which compresses the refrigerant (into a hot, high-pressure gas) so that it can be cooled with a fan and flow back inside as a liquid to complete the process. 

What to do if you suspect a problem with your compressor?

If your HVAC system is malfunctioning or failing to cool your home and you think it might be the compressor, it’s important to call a pro to diagnose the situation and offer you some options. It’s important to never try to work on a compressor yourself, as refrigerant is extremely toxic and can damage your health without you even noticing. Always work with licensed and experienced HVAC technicians. If you’re in the Wendell, North Carolina area, we hope you’ll consider us!