Size Matters for Air Receivers

Many people agree that bigger is better. Whether it’s a larger TV, car or house, we always want more. However, the “bigger is better” mantra doesn’t hold true for compressed air rating – properly sizing your system based on end use is a crucial step before choosing a compressor. But what about air receivers?

Air receivers are vessels or tanks that store compressed air prior to end use. They serve as a buffer between the compressor and the system and modulate pressure variations that may have occurred during compression. Air receivers play a crucial role in the compressed air process and need to be sized properly. An old rule of thumb posits that air receivers should have 1 to 2 gallons for each cfm of compressor capacity, but this only holds true for certain types of air compressors. For more accurate air receiver sizing, consider these four things:

1. Time: Time matters for air receivers. The amount of time (in minutes) they can supply the necessary amount of air without experiencing a crucial drop in air pressure is an important factor. If the air pressure is reduced too much, it may not be viable or effective once it reaches the end use.
2. Air requirement: The air requirement of the system dictates how much air the end uses need at each moment to operate at optimum capacity. Measured in cfm, this number may fluctuate depending on the shift or an unexpected demand increase.
3. Capacity: The capacity of an air receiver is the volume of air it can store, usually measured in gallons. This number needs to be greater than the air requirement. Having more air than the system requires serves as a backup when demand increases. It’s also important to make sure air requirement isn’t equal to a receiver’s full capacity; running some compressors at 100 percent all the time can damage equipment and substantially increase energy costs.
4. Pressure: There are two pressures to consider here: compressor discharge pressure and required pressure at end use. When calculating air receiver size, the greater the difference between the discharge pressure and the required pressure, the less volume is required in the receiver.

Figuring out the right size for your air receiver is important. However, if you’re unsure or you have frequently fluctuating demands, it is always safer to select a larger air receiver. Larger receivers can stabilize pressure, guaranteeing your system won’t suffer unexpected pressure drops or accidentally start another trim compressor to meet increased demand. In this case the adage holds true – bigger really is better. Still not sure which air receiver is right for your system? Contact an Atlas Copco expert today to discuss the needs of your system.