Air Receiver Sizing Calculator
Size a compressed air receiver for a demand event: the receiver must supply the shortfall between demand and compressor output while pressure falls from its upper to its lower limit.
- V = t × (C − S) × Pa ÷ (P₁ − P₂) = 5 × 3 × 1.0132 ÷ 2 = 7.599 m³
Receiver Drawdown Formula
V is the receiver volume in m³, t the event duration in minutes, C the demand and S the compressor supply during the event in m³/min of free air, Pa the atmospheric pressure and P₁, P₂ the start and minimum pressures in bar (the gauge difference equals the absolute difference). This is the storage method used in compressed air system guides.
Worked example
To carry 3 m³/min of instrument air for 5 minutes with no compressor while pressure falls from 7 to 5 barg: V = 5 × 3 × 1.013 ÷ 2 = 7.6 m³.
Frequently Asked Questions
Why is free air delivery used?
Compressor capacity and demand are normally stated as free air at inlet conditions, which matches the atmospheric pressure in the formula.
Does temperature matter?
The formula assumes air in the receiver stays near ambient. Fast drawdown cools the air and gives slightly less usable air.
How big should an instrument air receiver be?
Large enough to keep instruments working long enough for a safe shutdown after a compressor trip. Company standards often set the hold up time.
Learn more on the blog
Instrumentation and control standards
A practical, field focused guide on instrumentationblog.in that explains the theory behind this calculator and how engineers apply it on real plants.
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