Retrotec USACE - Manual (Page 214)

D84 ENERGY & PROCESS ASSESSMENT PROTOCOL
situation requires more compressed air to be generated during this time to
keep the compressed air lines pressurized. Air bleeds can also be used in the
compressed air system use to keep air fl owing for removal of moisture and
other unwanted liquids such as lubricating oils. Excessive use of continuous air
bleeds wastes compressed air energy.
D.4.3.10 Compressed Air Used for Cooling, Agitating Liquids,
Moving Product, or Drying (Ineffi ciency)
Figure D136. Welding work station with
compressed air hose on left that is used for
part cleaning. Figure D137. Use of compressed air to agitate
liquid in tank.
Compressed air is used for a number of purposes in an industrial facility. It is
a very expensive source of energy, several times more costly than electricity
for the same work output. It is used to power pneumatic tools, hoists, spray-
ing, clamping, controls, and actuators and to clean surfaces. Since compressed
air in an easily accessible source of energy in a plant, it is often used for some
wasteful purposes. These include cooling one’s work station, agitating liquids
in vats or tanks, moving dust and other materials from one location to another,
and drying of parts (Figures D136 and D137). In many cases, an individual
worker may add an outlet to the compressed air system for his or her conve-
nience. If an area needs to be cooled, additional ventilation could be added,
avoiding the extra compressed air use. If liquid agitation is desired, an electric
powered mixer could be added. There are numerous ways to move materials.
Drying can also be accomplished using radiant heat or ventilation air. Some
of these wasteful practices are unregulated users or openings in the system
whose fl ow increases with an increase in pressure. Since they are often turned
on by manually opening a valve, it is common for their use to continue after the
worker who wanted them goes home. The result is energy waste.
D.4.3.11 Providing Compressed Air to Unused Areas (Waste)
As areas of a facility change function and compressed air is no longer required,
such service should be stopped. This can be done by closing area isolation
valves that stop the fl ow to areas not requiring compressed air. This will elimi-
nate the waste due to leaks that are present in the unused area. Care should