Photo: Copeland
Compressors come in various types and styles meant for different applications, but two of the most popular ones are scroll and rotary compressors. Both types have their merits and demerits, but the most important thing is to choose the right one for your intended use.
This article looks at the differences between the scroll and rotary air compressors in more detail to help ensure you know what will work best for your specific needs.
Overall Findings
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Scroll Compressor vs. Rotary Compressor
1. How they Work: Rotors vs. Spiral Elements
The main difference between the scroll and rotary compressor is how they work. While both aim to compress and cool air, they use different mechanisms to achieve this, which means they offer different efficiency levels.
Scroll compressors are elegant devices that compress air using a couple of spiral elements. One of the elements is stationary, while the second one moves in eccentric circles inside the first one.
Because of how the two spirals move, the air pulled in gets trapped before getting transported to the spiral center in small pockets. In most instances, it takes at least two and a half turns for the compressed air to get to the output pipe at the center of the device.
On the other hand, rotary compressors come in both oil-injected and oil-free models, but the working mechanism is the same for both. These compressors use two rotors, which are just helical screws.
The two rotors come in unique shapes. Also, they turn in different directions and have very little clearance between them. Air is drawn in at one end and then trapped between the two rotors, where it is compressed before being released out through the smaller output opening.
2. Applications: Rotary Compressor Offer More Versatility
Since the rotary compressors provide a higher compressed air output, they will be ideal for more applications than the scroll compressors. They can compress and cool more air, meaning you can use them for various industrial and commercial applications.
The high capacity of the rotary compressors also makes them more ideal for the large central unit air conditioners. However, it also means they are not suitable for window air conditioners or smaller central unit conditioners as a lot of compressed air will be wasted.
Scroll compressors might not have a capacity that is as high as the rotary types, but they make up for this with increased efficiency. They offer one of the greatest cooling capabilities you can get from any air compressor, which makes them very ideal for refrigerators and air conditioners.
Additionally, scroll compressors are highly energy-efficient, making them more ideal for those that want to keep their electric bills down. However, the impressive cooling capability often causes them to overheat.
3. Noise: Scroll Compressor Are Extremely Quiet
There is hardly any compressor type out there that can beat the scroll compressors when it comes to the noise output. These machines are extremely quiet, and most people will hardly even notice them running.
Rotary compressors are also quieter than many other types out there, but they are still not as silent as the scroll types. While you can put them in the workshop without wearing any ear protection, they are not the kind you want to leave running as you sleep.
4. Maintenance: Rotary Compressors Require More Frequent Maintenance
While it is vital to maintain both the scroll and rotary compressors to keep them in good working condition, the latter requires relatively more maintenance.
Rotary compressors have a more complex design that includes more parts than the scroll types. Hence, more components are likely to fail on these machines, meaning regular maintenance is crucial to keep them in good working conditions.
Scroll compressors have a more straightforward design with fewer parts, and you will hardly ever need to do any significant maintenance. However, they are tougher to repair, and if one part fails or breaks, you will typically need to buy a new one.
5. Cost: Scroll Compressors Are Pricier
Compared to rotary and other compressor types, the scroll types tend to be relatively more expensive to buy. While there are still some inexpensive or budget models out there, prices for the best ones in the market typically start at around $500. The prices can go up to $1,500, but some high-end models cost way much more than this.
Rotary compressors are often more affordable as you can get one for as little as $50 and the average price for most models in the market hardly goes beyond the $100 mark.
Conclusion
Scroll and rotary compressors are two of the most popular types in the market. The right one for you between the two depends on your compressed air needs or how you intend to use the machine.
For those that want a high-capacity compressor for commercial or industrial use, the rotary compressor is perfect. But, if you are looking for an energy-efficient option with greater cooling capability, the scroll compressor is a great choice.