How to Size an Air Receiver Tank
A practical, step-by-step guide for engineers and plant managers. Includes the air receiver sizing formula, worked examples, and ready-to-use size recommendations by compressor kW.
Get a Free Sizing AssessmentWhy Correct Sizing Matters
An undersized air receiver causes the compressor to cycle on and off excessively, increasing wear, raising energy consumption, and shortening compressor service life. An oversized receiver adds unnecessary cost and space. Correct sizing gives you a stable system pressure, optimal energy efficiency, and adequate surge capacity for peak demand.
The Standard Sizing Formula
The most commonly used formula for air receiver sizing is derived from the ideal gas law and accounts for your compressor's flow rate, the acceptable pressure drop during demand peaks, and the duration of the peak demand event.
Where:
V = Receiver volume required (litres)
Q = Peak demand above compressor output (litres/min)
T = Duration of peak demand event (minutes)
P_atm = Atmospheric pressure (1 bar absolute = 100 kPa)
ΔP = Acceptable pressure drop (bar) — typically 0.5 to 1.0 bar
This formula gives you the theoretical minimum receiver size. In practice, add 25–50% to account for moisture accumulation, real-world inefficiencies, and future capacity growth.
Quick Reference: Rule-of-Thumb by Compressor Size
For rotary screw compressors operating in general manufacturing and industrial environments, use the following as a starting guide. These assume a single wet + dry receiver or a combined receiver installation.
| Compressor Size | FAD (approx.) | Minimum Receiver | Recommended Receiver |
|---|---|---|---|
| 5.5 kW | ~500 L/min | 100L | 200L |
| 7.5 kW | ~700 L/min | 100L | 200L |
| 11 kW | ~1 050 L/min | 200L | 300L |
| 15 kW | ~1 450 L/min | 200L | 500L |
| 18.5 kW | ~1 800 L/min | 300L | 500L |
| 22 kW | ~2 100 L/min | 300L | 500L |
| 30 kW | ~2 900 L/min | 500L | 750L |
| 37 kW | ~3 500 L/min | 500L | 1000L |
| 45 kW | ~4 300 L/min | 750L | 1000L |
| 55 kW | ~5 200 L/min | 1000L | 1500L |
| 75 kW | ~7 000 L/min | 1000L | 2000L |
| 90 kW+ | ~8 500+ L/min | 1500L | 2000L–5000L |
Worked Examples
Example 1: Workshop with 22 kW Screw Compressor
Scenario: Engineering workshop, 22 kW rotary screw compressor, FAD = 2 100 L/min. Peak demand (sandblasting) adds 800 L/min above compressor output for approximately 2 minutes. Acceptable pressure drop: 0.8 bar.
Calculation: V = (800 × 2 × 1) ÷ 0.8 = 2 000L theoretical minimum
Recommendation: Install a 500L wet receiver before the dryer + 1000L dry receiver after the dryer, or a single 2000L combined receiver. The wet/dry split is preferred for moisture management.
Example 2: Automotive Spray Booth, 30 kW Compressor
Scenario: Spray painting application requiring very stable, dry air. 30 kW compressor, FAD ~2 900 L/min. Spray guns consume ~1 200 L/min each, 2 guns operating simultaneously. Compressor can satisfy demand — receiver needed for surge buffering and moisture management.
Recommendation: 300L–500L wet receiver before refrigerant dryer, 750L–1000L dry receiver after dryer. The dry receiver ensures perfectly stable pressure at the spray guns.
Example 3: Factory with Multiple Shifts, 55 kW Compressor
Scenario: 24-hour manufacturing plant, 55 kW screw compressor, multiple pneumatic actuators and tools on a long ring main. Pressure drop across the distribution pipe adds 0.3 bar before reaching end users.
Recommendation: 1000L wet receiver at compressor + 1000L dry receiver at far end of ring main to support end-of-network users. Total storage: 2000L. This reduces pressure variation across shift changes significantly.
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