cost comparison of compressed air at 6 bar and 8 bar

[dtwo]

How much air (cfm) can be saved by reducing air pressure from 8 bar to 6 bar in a given pneumatic system assuming no leaks.

 

[dcasto]

depends on the end users. Instruments bleed air not based on inlet pressure. Air motors need volume time pressure so lower pressure will mean more air. Humans use air blowers for several minutes, but they may use it for less time with more pressure.

You need to rephrase your question and give details. I suspect you are looking for HOW MUCH MONEY CAN I SAVE IF.... or HOW MUCH ENERGY CAN I SAVE....

 

[crjones]

In looking for savings look at you compressor as well. Some have built in compression ratio's of 7. This is unaffected by the valving downstream of the compressor. So dropping down the pressure is a net loss.

 

[Feric]

To All:

Here are a few plots indicating the power input requirements for compressor operation -- the plots are valid for ideal isentropic compression:

The above plots could be useful in determining the power requirements and power costs when compressing air to different outlet pressure values.

Thanks,

Gordan Feric, PE
Engineering Software

http://members.aol.com/engware

 

[dcasto]

crjones is refering to screw compressors. I use the simple rule of thumb for compression HP. HP/MMSCFD = 22 * Ratios. If ratios are over 5 use suare root to get two stages and then multiply by 2. If the ratios are ove 25, then cube root and multiply by 3.