Compressed air is free - as a power source it is nine times more expensive to use than electricity. More pressure is better - raising pressure system-wide will require more power on-line. Pressure problems are best solved at the point of use where they exist, not with more power in the compressor room. "Our system operates at 100 psiG" - not likely since most compressed air systems have pressure variations of 10% before the air leaves the compressor room. Production needs 100 psiG - maybe one or two applications are thought to require 100 psiG, but for the most part the true minimum requirement for the majority of the plant is much less. Reducing
compressor operating pressure will save energy - how far
pressure is reduced will determine the savings, the further it is
reduced the less stable and reliable the system will become. The first
time production is interrupted operating pressure will be returned to
previous levels and savings will disappear. Increasing
compressor operating pressure increases operating costs -
while it is true that compressing a cubic foot of air to a higher
pressure requires more energy, overall operating costs will increase
only if the entire system is allowed to operate at the elevated
pressure.
Receiver sizing
rule of thumb: 1 gallon per cubic foot of compressor rating
- receivers are sized to manage events in the system, this type of
rule of thumb pays no attention to the needs of the system.
Fixing air
leaks is an easy energy saving measure - reductions in
on-line power are seldom seen until a majority of the system air leaks
are repaired. Repairing some leaks in a compressed air system without
a Demand Expander™ System or similar pressure control device, can
actually cost more money by increasing the volume through the other
leaks.
Dryer is better
- some facilities install -40° F pressure dewpoint dryers in hopes
of fixing their moisture carry over problems. Often the problems have
little to do with dryer type. Installing this type of dryer can pose a
whole new set of system problems to be dealt with - like adding 15%
more compressor power to accommodate the dryer's purge requirements!
A filter
removes 99.9999% of 0.01 micron particles - filter
performance is tested per the DOP (dioctylphthalate) test that
measures the amount of carry over downstream of a filter being tested.
DOP is used because it consistently generates particles that range in
size between 0.3 - 0.6 micron with little variance. A claim that a
filter can remove smaller particles is based on the results of this
test and variances in filtering media, not actual results with 0.01
micron particles. Many of the assumptions
listed above are real barriers to operating compressed air systems
efficiently. Education is the best first-step measure that can be taken in
improving compressed air system operating efficiency. The Compressed Air
Challenge is a voluntary collaboration of industrial users, manufacturers,
distributors, state and federal energy agencies, industry associations,
consultants and utility companies. The goal is to provide education and
technical training to improve compressed air systems. For more
information, please contact PSI or the Compressed Air Challenge at
1.800.862.2086, www.knowpressure.org. |
Contact Details
- 201 Sun Valley Circle, Fenton MO 63026
- 636-343-5252
- 636-343-1580
- powersupply@psiind.com