Cost of compressed air?

[ggarnier]

Does anyone have either a figure for kWhr/scfm/degF or $/scfm/degF for compressed air?<br>
<br>
(Don't bother converting units - I can take care of that.)<br>
<br>
Pressure this is based on would obviously be useful too.<br>
<br>
Thanks,<br>
<br>
Gary Garnier<br>
Raytek Corp.<br>

 

[butelja]

The cost of compressed air is directly related to the cost of your electricity, the nominal pressure, and the type of air dryer you use. For a typical plant air compressor (75+ HP) delivering air at 100 PSIG, the rule of thumb is that the compressor will deliver 4-5 CFM per HP. <br>
<br>
Two specific examples in my plant are a 760 CFM screw compressor that requires 165 HP, and a 1400 CFM 3-stage centrifugal compressor that requires 350 HP. Both of these are values at full load. The screw compressor will be less efficient at part load, while the centrifugal maintains a high efficiency at part load. However, the screw machine costs about $50K, while the centrifugal costs about $135K.<br>
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Small compressors such as would be used at a service station will be significantly less efficient.<br>
<br>
If you want to examine the problem in depth, I would suggest contacting some of the major manufacturers such as Ingersoll-Rand, Gardner-Denver, Kaiser, Atlas-Copco, Elliott, or Cooper Turbocompressor (JOY).

 

[gawdzilla]

Contact me at gecofact@wt.net for a complete discussion about
the cost of compressed air. There are more costs involved than
producing the compressed air and drying it.