Types of Air Compressors - The Ultimate Cheat Sheet

Selecting the right industrial air compressor for your industrial application is a critical decision that impacts energy efficiency, reliability, and long-term operational costs. With a wide range of compressor types available, understanding their differences is key to optimizing performance and ensuring your system meets the specific demands of your facility.

This guide provides an overview of the two primary categories of air compressors—dynamic compressors and positive displacement compressors—along with their advantages and typical applications.
 

Dynamic compressors use rotating impellers to accelerate air and then convert that kinetic energy into pressure by slowing or restricting the airflow. Many of these compressors are completely oil-free, making them ideal for highly sensitive environments. They are particularly well-suited for high-volume, high-flow applications and include centrifugal and axial types. 
 

Best for: Large-scale industrial operations requiring continuous high-volume air supply (250-6,000 HP).
 

Centrifugal compressors produce compressed air through a multi-stage impeller system that increases pressure while continuously cooling the air. This design offers high efficiency and delivers oil-free air, with the added advantage of operating continuously for years with minimal maintenance requirements. 
 

One of the most valuable advantages of centrifugal compressors is their ability to supply oil-free air, classified as Class 0 per ISO 8573-1:2010. The immediate benefits include lower consumable costs—since oil is never introduced into the airstream, post-compression filtration is unnecessary. Additionally, oil changes are required only every two to three years, compared to the six- to twelve-month intervals needed for oil-flooded compressors. 

Beyond reducing maintenance and energy costs, oil-free air is essential for industries like pharmaceuticals, food and beverage processing, electronics manufacturing, and textiles, where even the slightest oil contamination in the final product is unacceptable.
 

High flow capacity – Designed for operations requiring above 250 HP

Continuous operation – Can run for years with minimal maintenance

Oil-free air output (ISO 8573-1:2010 Class 0) – Eliminates risk of oil contamination

Lower lifecycle costs – More efficient at high volumes than reciprocating and rotary screw compressors
 

Best for: Aerospace jet engines, high-speed ship engines, and small-scale power stations.

Axial compressors use a series of rotating and stationary blades to compress air in stages. While they are extremely efficient in high-speed applications, they are rarely used in industrial settings due to their complexity and high cost.
 

Positive displacement compressors work by forcing air into a chamber. The volume of this chamber is then decreased, which compresses the air. Once maximum pressure is reached within the chamber, a valve opens, and the air is then discharged into the outlet system. This category includes rotary screw compressors and reciprocating (piston) compressors.
 

Best for: Industrial applications requiring moderate air flow 25-600 HP.

Rotary screw compressors use two interlocking helical rotors to compress air as it moves through the chamber, into a smaller and smaller space, steadily increasing the pressure. Oil is used throughout for lubrication, sealing, and heat absorption. Before usable air exits the chamber, the oil must be removed. This process uses oil filters that must be replaced regularly. Although oil-free options exist, trace amounts are commonly found in regular screw compressors.
 

Key Features:

Lower initial cost – However, the higher number of moving parts can lead to increased lifecycle costs.

Efficient energy use – Lower heat generation and reduced power consumption compared to reciprocating compressors

Lubricated and oil-free options – Oil-injected models require filtration, while oil-free variants are available but trace amounts are commonly found in regular screw compressors.

 

Best for: Intermittent use in smaller applications (1-1,000 HP).

Reciprocating compressors rely on a piston-and-cylinder mechanism to compress air. These units come in single-acting and double-acting designs:

Key Features:

Lower upfront cost – More affordable than rotary screw 

High-pressure capabilities – Suitable for applications requiring pressure above 100 psi

Widely available – Used in automotive, small industrial, and repair shop settings
 

Selecting the right air compressor involves more than just determining the required cubic feet per minute (CFM). Download our How to Choose the Right Air Compressor White Paper to learn what facilities should also consider like:
 

Application demands – Continuous vs. intermittent operation

Pressure and flow requirements – Ensuring the compressor can handle peak loads

Energy efficiency – Lowering operating costs over time

Maintenance and lifecycle costs – Evaluating long-term expenses beyond the initial purchase

Oil-free vs. oil-lubricated needs – Identifying contamination risks for sensitive environments
 

Each type of air compressor serves a specific purpose, and selecting the right one depends on your facility's operational needs. Rotary screw compressors are well-suited for applications with fluctuating demand, while reciprocating compressors excel in intermittent use. For industries requiring high-capacity, oil-free air, centrifugal compressors are the preferred choice, delivering reliable performance and long-term efficiency. 
 

By evaluating key factors such as efficiency, maintenance, and lifecycle costs, facilities can make informed decisions that lead to lower operating costs and improved system performance.

We invite you to use the AirCompare lifecycle costs calculator to further narrow down your options and discover potential savings you may be missing out on in your compressed air system.
 

Choosing the right air compressor is critical for your operation’s success. FS-Elliott’s centrifugal and engineered air compressors deliver high-efficiency, oil-free air designed for demanding industrial applications. Explore Our Products