The Energy Audit 187assembly tasks can still be performed adequately under high pressure
sodium lighting. These typically include metal fabrication, wood prod-
uct fabrication, plastic extrusion, and many others.
Electric Motors
A common characteristic of many industries is their extensive use
of electric motors. A complete inventory of all motors over 1 hp should
be taken, as well as recording data on how long each motor operates
during a day. For motors with substantial usage times, replacement with
high-efficiency models is almost always cost effective. In addition, con-
sideration should be given to replacement of standard drive belts with
synchronous belts that transmit the motor energy more efficiently. For
motors which are used infrequently, it may be possible to shift the use
to off-peak times and achieve a kW demand reduction which would
reduce energy cost.
HVAC Systems
An inventory of all space heaters and air conditioners should
be taken. Btu per hour ratings and efficiencies of all units should be
recorded, as well as usage patterns. Although many industries do not
heat or air condition the production floor area, they almost always have
office areas, cafeterias, and other areas that are normally heated and air
conditioned. For these conditioned areas, the construction of the facility
should be noted—how much insulation, what the walls and ceilings
made of, how high the ceilings are. Adding additional insulation might
be a cost effective ECO.
Production floors that are not air conditioned often have large
numbers of ventilating fans that operate anywhere from one shift per
day to 24 hours a day. Plants with high heat loads and plants in mild
climate areas often leave these ventilating fans running all year long.
These are good candidates for high efficiency motor replacements. Tim-
ers or an energy management system might be used to turn off these
ventilating fans when the plant is shut down.
Boilers
All boilers should be checked for efficient operation using a stack
gas combustion analyzer. Boiler specifications on Btu per hour ratings,
pressures, and temperatures should be recorded. The boiler should be
varied between low-fire, normal-fire, and high-fire, with combustion gas
and temperature readings taken at each level. Boiler tune-up is one of