Choosing a Refrigerant Compressor: Scroll vs Reciprocating

What's the Difference, and Which Is Right for Your System?

When you’re designing a refrigeration system, the compressor might not seem like the most exciting part. But truth is, choosing the right one can save you a lot of headaches, and costs, down the line. Whether you're trying to hit energy targets, stay ahead of F-Gas regs, or just make sure your cases perform reliably once they're out in the field, the compressor has a big role to play. 

In this article, we’ll cover the basics of the role of the refrigerant compressor and specifically look at the types of compressors you’re probably considering; reciprocating and scroll compressor technologies, so you can get a clearer idea of what’ll work best in your setup. 

What is a Refrigerant Compressor, and What Does It Actually Do? 

You probably already know this but just to set the scene... 
 
In any refrigeration or air conditioning system, you need to move heat from one place to another? (Because refrigeration is about heat removal, not cooling of course). The refrigerant compressor is basically the heart of that process. Think of it as a pump for the refrigerant gas, it takes in low-pressure refrigerant from the evaporator, squeezes it to a higher pressure, and sends it off to the condenser. This compression process is what lets the system shift heat out, whether it’s from a merchandiser cabinet, walk-in, or air-cooled chiller. 
 
In simple terms, without the compressor, the whole refrigeration cycle would stall. No compressor means no cooling. It’s what keeps the refrigerant circulating, allowing the system to absorb heat from inside a fridge, freezer, or display case and release it somewhere else. Whether you’re dealing with a small beverage cooler or a massive industrial chiller, the compressor is what makes the magic happen. It’s a critical component, and the type you choose can really impact efficiency, noise levels, and maintenance down the line. 

The Big Question: Scroll vs. Reciprocating Compressors Technology? 

You get it, no compressor; no cooling, so we need them. Then there’s the type. The type of refrigerant compressor you choose affects how well your system performs, how quiet it runs, how long it lasts and even how simple it is to service later.  
Both types do the same basic job, but they go about it very differently, and those differences show up in performance, maintenance, cost and efficiency outcomes as well as mechanical methods. Depending on your setup and what you're trying to achieve, one might make a lot more sense than the other. 
 
Let’s break it down in generalist terms while also taking into account that modern units and contonuous technology developments focus on making all products fit for purpose, but that fit depends on what you’re looking to achieve:

*For clarification on that last point, scroll compressors do have fewer moving parts, which can mean less wear and lower maintenance, but they are also more sensitive to system cleanliness and oil quality. If contaminants or poor lubrication are present, scrolls can fail quickly while reciprocating compressors would be tougher and more durable.

If you’re focus is on energy efficiency, low noise, and the system isn’t running at full blast all the time, like variable load setups, then a scroll refrigerant compressor could be a great fit. They can become less efficient at extreme-pressure ratios, but in most standard refrigeration and air conditioning uses, their efficiency is competitive or superior to reciprocating compressors.

In short, if you’re staying away from a higher upfront cost on small capacities, have extreme pressure ratios, or a contaminated, dusty environment you’re probably better with a reciprocating refrigerant compressor.

Scroll compressors are generally less tolerant of significant refrigerant charge variations compared to reciprocating compressors. They can be damaged by running with too little refrigerant, whereas many reciprocating designs are more forgiving in this respect.  
 
While scrolls are usually quieter and have less vibration, some modern reciprocating compressors, especially hermetic types, can also be very quiet. The difference is notable but not absolute. 

So, if you’re dealing with a system that needs has extreme pressures, sees tougher conditions such as contamination and oil, or you’re trying to keep upfront costs down on smaller capacities, a reciprocating unit might be the way to go.