Types of AС Compressors: How Do They Work?

Chance are that you have an air conditioner but how familiar are you with its inner working parts? Inside every air conditioning unit is a compressor.

This compresses, or makes smaller, the refrigerant that is needed to cool the air. There is also a condenser, where the gas that goes through to complete the cooling cycle.

There are many types of AC compressors and while it can get a bit technical, it is useful information to have. The more you know about your AC unit, the better you are able to troubleshoot problems as well as perform routine maintenance.

What is it for and how does it work?

ac compressor work

Many experts refer to an AC compressor as the heart of the entire unit. An air conditioning unit uses a refrigerant, also known as Freon.

This gas needs to be pumped through the unit, which is where the compressor comes in. As the gas becomes more compact, the pressure is increased. Then, it will naturally flow to an area where it is less compressed.

Scroll compressors

Newer in technology, scroll compressors use a fixed coil. If you have an older air conditioning unit and you need to replace it, a scroll compressor is usually used.

Design-wise, you will find a stationary coil next to another coil that moves or vibrates. The refrigerant is pressurized as the moving coil rotates.

What’s good about them?

Because of their newer technology scroll compressors are very efficient. They work better, give off less heat, and will cost less money on your energy bill.

Another benefit of their new technology is that scroll compressors will last longer. Many come with 20-uear warranties, and some even come with lifetime warranties.

What are the drawbacks?

Really, there aren’t any drawbacks to scroll compressors. They have been designed to be efficient and last a long time. While your current air conditioning unit probably doesn’t have a scroll compressor, when you go to replace your current one, this model is often recommended.

Rotary compressors

As there are many types of air conditioners, you need to match your current unit with a specific type of AC compressor.

For example, if you have a through-the-wall AC unit, like this Friedrich model, then a rotary compressor will pair well with it.

For composition, rotary compressors have a cylinder shape and discharge ports that are then connected to refrigerant lines.

What’s good about them?

One of the best benefits or rotary compressors is that the are efficient. They are able to alter their rate of speed in conjunction with your temperature demands. This makes them not produce more heat than necessary while working.

Furthermore, rotary compressors are quite silent. You can expect noise levels around 40 to 55 decibels, which is great if you have a unit in your bedroom.

Rotary compressors are often compared with reciprocating compressors as the work with similar types of AC units. Usually, this model is the one recommended.

What are the drawbacks?

While rotary compressors are good for through-the-wall AC units or ductless units, they aren’t great for larger, central air conditioners.

Reciprocating compressors

If you have an older air conditioning unit, it probable has a reciprocating compressor. While you can still find them in newer units, they are being phased out as more energy efficient units become available. Structure-wise, reciprocating compressors have a cylinder which houses pistons that move back and forth.

What’s good about them?

There is a reason reciprocating compressors have been used. They are reliable and they get the job done. They are easy to understand as the design is simple.

Furthermore, reciprocating compressors come in many different sizes which means the can be used for both home central air and even commercial use.

What are the drawbacks?

Unfortunately, reciprocating compressors are not as energy efficient as newer types. While you can certainly try to repair your current compressor, you might want to think about upgrading for a newer, better designed model.

Screw compressors

Large, commercial air conditioning units need powerful compressors. Screw compressors uses rotating and interlocking screws. The action of the screws takes the refrigerant and compresses it.

What’s good about them?

Powerful devices, such as screw compressors, are needed for large AC units. They are reliable and simple to understand, making repairs easier. Furthermore, they are good at conserving energy, leading to less expensive energy bills.

Another benefit to screw compressors is that they are safe to use. Their longevity and high-standards of craftsmanship means that you shouldn’t have any major issues.

What are the drawbacks?

Again, there’s nothing wrong with a screw compressor but you certainly wouldn’t install it in your home AC unit.

Centrifugal compressors

Another type of air conditioning compressor is the centrifugal model. It is made for larger AC units. A centrifugal compressor is created by using a cylinder and a piston which causes the refrigerant to move at a very high speed.

What’s good about them?

Centrifugal compressors are a good solution for large AC units. They are more energy-efficient than other types of compressors and they are also on the cheaper end of the spectrum. Furthermore, the airflow is usually at a more constant amount.

What are the drawbacks?

Centrifugal compressors may sound great but they are for commercial use only. Residents won’t be able to benefit from them.

Final thoughts

Hopefully, the world of AC compressors makes a bit more sense. They can be quite technical in nature and while you don’t really need to have the information, it will make understanding your AC unit a lot easier.

The basics when deciding between different types of AC compressors is understanding which are for residential use and which are for commercial use.

Once you have those categories sorted, you can better understand which will work for your specific AC unit. One nice aspect about AC compressors is that there have been great technological advances in the field.

You can now count on units to work well, be energy efficient, and come with amazing warranties.


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