Retrotec USACE - Manual (Page 164)

D34 ENERGY & PROCESS ASSESSMENT PROTOCOL
D.2.3.8 Use of Excessive Dampers to Achieve Air Balance
(Ineffi ciency)
Figure D56. Shaft for damper shown in
branch duct.
Air dampers are used to balance and control air fl ow to conditioned spaces
within a facility (Figure D56). Typically dampers are installed at strategic loca-
tions that require control of air quantities in such places as at outdoor ventila-
tion intakes, mixing boxes, branch ducts, and diffuser locations. These devices
restrict air fl ow and increase the static pressure that the supply fan has to over-
come. Static pressure increases require more horsepower from the fan motor
and increase the energy consumption of the fan motor. Air dampers are nec-
essary, but excessive use of these dampers creates added static pressure and
requires additional fan energy to handle the added static pressure.
D.2.3.9 Dirty Filters or Coils (Ineffi ciency)
Figure D57. Extremely dirty fi lter from
window air conditioner.
Air cleaning and tempering components can become dirty, causing a reduction
in their performance. Filters are used to collect foreign airborne matter, and as
they get dirty, the pressure drop they cause increases. A certain pressure drop
range is reserved in the air handling unit operation, but when this is exceeded
(Figure D57), air fl ow drops and pressure increases. Air tempering coils can
also collect foreign matter between their fi ns, resulting in reduced heat trans-
fer, lower air fl ows, and increased pressure drops. When this occurs, system
performance is reduced, and energy is wasted.