IDC INDUCED DRAFT EVAPORATIVE CONDENSERS
INSTALLATION - OPERATION - MAINTENANCE
S140-500 IOM (FEB 08)
Page 5
Water Chemistry
– All evaporative-cooled condensers
operate on principles that encourage biological growth in
the recirculating water unless effective treatment is applied.
Recirculating water must be periodically analyzed for biologi-
cal culture plate counts. IDC units should not be operated
without an effective biological treatment program.
NOTE: Emergency “shock” treatment with chemical bio-
cides may upset the unit’s appropriate pH range (creating
an excessively corrosive environment for the materials
of construction) and may expose operators to strong
chemicals that are corrosive or otherwise dangerous if
mishandled (see water treatment page in Section 4.0).
1.6 Placement of IDC Units
All IDC units must be located to minimize the effect of
exhaust air recirculation. This can signifi cantly derate an
evaporative-cooled IDC’s capacity due to the exhaust air’s
relatively higher heat and moisture (gained from evaporation
of tower water).
In some worst case scenarios, up to 30% heat removal
capacity can be lost if a cooling tower is improperly located
or oriented. It is the owner’s responsibility to properly locate
each unit and/or consult with a qualifi ed engineer before
laying out structural/foundation supports and installing the
IDC condenser.
Adequate space must be continuously available to allow
adequate airfl ow to the IDC inlet louvers to prevent discharge
air recirculation.
Figure 1-2.
IDC (Unit to Unit Spacing Re-
quirements)
shows IDC condensers on an open roof with
the minimum required distance between the units.
In general, IDC unit/s should always be located/elevated on
concrete pads, piers or structural steel so that exhaust air
discharge of the fan orifi ce is at or above the elevation of
nearby walls or structures/equipment.
For other minimum spacing requirements see
Figure 1-3.
(IDC Unit/s to Wall Spacing Requirements)
for examples
showing (2) IDC condensers installed next to a single wall
and next to a double wall; and, (1) multiple-cell IDC condenser
installed next to a double wall.
1.7 Field Piping Considerations for IDC Unit
Installation
All IDC units require strongly supported and anchored fi eld
piping. No fi eld piping is to be supported by the IDC itself.
Wind loading, temperature variation, etc., must be considered
to allow for movement between the tower, building, optional
vibration isolator/rails, and fi eld piping. A qualifi ed cooling
system design engineer should provide fi nal fi eld-piping
plans and specifi cations.
Before fi nalizing piping installation plans, it is recommended
that related plans for cooling system/plant expansion be
discussed with your fi eld piping/system designer and Imeco
sales representative. Incorporating pipe openings/sizes now
allows for easier installation in the future.