Retrotec USACE - Manual (Page 210)

D80 ENERGY & PROCESS ASSESSMENT PROTOCOL
have water-cooling jackets at the cylinders and in the cylinder heads. Centrifu-
gal compressors are water-cooled. Some rotary compressors inject lubricant
to remove the heat of compression. The hot lubricant is drained away and air-
cooled in a coil. Multi-stage compressors have intercoolers that remove heat
as the air moves from one stage to the next. Also, aftercoolers are normally
installed to remove heat after the fi nal stage of compression to reduce the air
temperature. This temperature reduction allows moisture to condense in the
heat exchanger and be drained away. If these heat exchangers are dirty, the
desired reduction in compressed air temperature is affected, and a greater load
is placed on the air dryer, resulting in additional energy use.
D.4.3.4 Dirty Air Filters (Waste)
Figure D131. Filter and regulator in compressed
air system.
Filters are required in a compressed air system to remove airborne particles
from the incoming air to the compressor and downstream to protect the equip-
ment using the compressed air (Figure D131). When the fi lters in the com-
pressed air system get dirty, the result is an increased pressure drop. This
causes an increase in the energy required to generate the compressed air if
the affected equipment is maintaining the pressure downstream from the air
fi lters. If the fouled air fi lter is on a piece of equipment in use, the resulting
pressure drop may result in a drop in air pressure to a level too low for the
equipment to perform correctly. Either way, unwanted results occur.