# Preliminary Sizing of Compressed Air Receiver

As a continuation of the post, I want to share you how to size capacity of compressed air receiver.

Compressed air receiver is used as buffer and storage medium between the compressor and air consumers.

A common formula used to size compressed air receiver is as followed:

V = (t/60) x C x pa/(p1-p2)

Where:

V = volume of receiver tank (m3)

t = time for the receiver to go from upper to lower pressure limit (minute)

C = air consumption (m3/h)

pa = atmospheric pressure (1.01 bara)

p1 = maximum tank pressure (bara)

p2 = minimum tank pressure (bara)

Example Sizing of Compressed Air Receiver

For an air compressor system with air consumption 100 Nm3/h, with actual supply pressure 8 barg (8.84 atma) and actual supply temperature 30oC (303.15 K), maximum tank pressure 9 barg (10.01 bara), minimum tank pressure 7 barg (8.01 bara) and 15 minutes time for the receiver to go from upper to lower pressure – the volume of the receiver tank can be calculated by following step.

Step 1: Calculate air consumption (C) at actual condition

Air consumption at actual condition can be simply calculated by using the following formula:

P1 x V1/ T1 = P2 x V2/T2

­Where:

P1 = Pressure at standard condition (1 atma)

T1 = Temperature at standard condition (273 K)

V1 = Air consumption at standard condition (Nm3/h)

P2 = Pressure at actual condition (atma)

T2 = Temperature at actual condition (K)

V2 = Air consumption at actual condition (m3/h)

Equation above is modified into:

V2 = P1 x (V1/ T1) x (T2/P2)

V2 = 1 x (100/273) x (303.15/8.84)

V2 = 12.56 m3/h

So, air consumption at actual condition is 12.56 m3/h.

Step 2: Calculate air receiver capacity

Use this formula to estimate air receiver capacity:

V = (t/60) x C x pa/(p1-p2)

V = (15/60) x 12.56 x 1.01/(10.01-8.01)

V = 1.58 m3

So, estimated air receiver capacity is 1.58 m3.

I hope you find this post useful.

## 7 thoughts to “Preliminary Sizing of Compressed Air Receiver”

1. Clarence says:

In Step 2 of your calculation, you have used the flow rate at actual conditions for C instead of standard conditions as shown in most other references. Is this correct?

1. Rifka Aisyah says:

Hello,

I rechecked the references. My mistake, the correct one is using flow at standard condition.

Thank you for correcting me.

1. Amit says:

We are sizing of a receiver, but what if initially we don’t have an air receiver, so how to find time for this formula?? Please clear my doubt..
And there is also a thumb rule of sizing air receiver by multiplying compressor cfm by 1.5 and receiver size get in gpm

1. Rifka Aisyah says:

In Design Basis, we usually define how long the buffer time of air receiver. Most company use 15-30 minutes buffer time. You can use 15 minutes for initial sizing.

I am not sure about rule of thumb that you mentioned. I usually using buffer time, initial pressure, and final pressure, to get size of receiver.

2. Amit says:

We are sizing of an air receiver, so what if initially, we don’t have an air receiver then how to measure time?
3. Chen says:
1. Rifka Aisyah says: