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97536784 Air Receiver Sizing

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Page 1: 97536784 Air Receiver Sizing

Air Receiver Volume:

V = t*(qout -qin)*Pa / (P1-P2)

where

V = Volume of the receiver tank, ft3

t = time for the receiver to charge or discharge, min

qout = air flow out of the recieiver (surge flow to consumer), cfm

qin = air flow into the receiver from compressor, cfm

Pa = Atmospheric Pressure (14.7 psia)

P1 = Upper or Maximum operating pressure, psia or psig (P 1 and P 2 should both be either in absolute or gauge units)

P2 = Lower or Minimum operating pressure, psia or psig (P1 and P2 should both be either in absolute or gauge units)

Example:

Inputs:

t = 5 min

qout = 350 cfm

qin = 250 cfm

Pa = 14.7 psia

P1 = 100 psig

P2 = 60 psig

Calculation:

V = 183.75 ft3

1374.546 U.S. gallons

5.20 m3

Prepared by: Ankur Srivastava

Chemical Engineer

e-mail: [email protected]

The output from a compressor is 250 cfm. There is a surge flow requirement of 350 cfm for a period of 5 minutes. The upper

or maximum operating pressure is 100 psig and the lower or minimum operating pressure is 60 psig. What size of receiver

is required to cater to the surge volume rate demand and surge time?

Disclaimer : The information and methods included within this spreadsheet are presented for air receiver sizing. It

is intended to be used by technically skilled persons at their own discretion. I do not warrant the suitability or

accuracy of these methods.

Page 2: 97536784 Air Receiver Sizing

Compressed Air Receiver Volume:

Rule of Thumb for compressed air receiver sizing is 1 U.S. gallon capacity for every ACFM compressor flow

Example Problem:

Calculations:

Volume at actual pressure and temperature is calculated by ideal gas law

Now by ideal gas law

P1*V1 / T1 = P2*V2 / T2

Where the subscript 1 describes the standard conditions of pressure and temperature and subscript 2 describes the actual conditions of temperature and pressure

Standard Pressure = 14.7 psia

Standard Temperature = 68 °F

Flow Rate @std pr.& temp. = 300 scfm

Discharge Pressure = 100 psig

Discharge Temperature = 40 °C

Calculate value of V 2

P1 = 14.7 psia

V1 = 300 scfm

T1 = 528 °R (68+460)

P2 = 114.7 psia (100+14.7)

T2 = 564 °R (1.8*(40+273.15))

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

41.05 acfm

Calculate Compressed Air Receiver Volume

Receiver Vol. per ACFM = 1 gallon

Receiver Vol. for example = 41.05 gallon

5.49 ft3

0.16 m3

Prepared by: Ankur Srivastava

Chemical Engineer

e-mail: [email protected]

If the compressor volume flow is described at standard conditions (14.7 psia, 68°F), it will be needed to convert it to actual volume flow (e.g. compressor

discharge) at actual conditions of pressure and temperature. As an example this means converting volume flow in SCFM (Sm3/h) to ACFM (m

3/h)

The volume flow of a compressor is described in standard conditions as 300 scfm. The compressor discharge conditions are

given as follows: a) Discharge pressure: 100 psig, b) discharge temperature: 40°C. Calculate the compressed air receiver

volume for the given discharge conditions.

Disclaimer : The information and methods included within this spreadsheet are presented for air receiver sizing. It is

intended to be used by technically skilled persons at their own discretion. I do not warrant the suitability or

accuracy of these methods.

Page 3: 97536784 Air Receiver Sizing

Rule of Thumb for compressed air receiver sizing is 1 U.S. gallon capacity for every ACFM compressor flow

Where the subscript 1 describes the standard conditions of pressure and temperature and subscript 2 describes the actual conditions of temperature and pressure

If the compressor volume flow is described at standard conditions (14.7 psia, 68°F), it will be needed to convert it to actual volume flow (e.g. compressor

discharge) at actual conditions of pressure and temperature. As an example this means converting volume flow in SCFM (Sm3/h) to ACFM (m

3/h)

The volume flow of a compressor is described in standard conditions as 300 scfm. The compressor discharge conditions are

given as follows: a) Discharge pressure: 100 psig, b) discharge temperature: 40°C. Calculate the compressed air receiver

volume for the given discharge conditions.

Disclaimer : The information and methods included within this spreadsheet are presented for air receiver sizing. It is

intended to be used by technically skilled persons at their own discretion. I do not warrant the suitability or

accuracy of these methods.