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11
11
Operation
The Nexus
®
Modular Hybrid Cooler balances energy and water savings by operating each
module wet or dry. One of the following operating modes can be selected (see
page 40)
to
best fit your system needs:
Energy Saver Mode
Maximum Energy Savings
In Energy Saver Mode, energy savings are
maximized by leveraging the full power of
evaporative cooling. During periods when
ambient temperatures or loads from the building
or process are relatively high, the Nexus
®
Modular
Hybrid Cooler operates with all spray systems
active across all modules. During off-design
conditions, the EC Fan System will automatically
and intelligently reduce speed whenever possible.
As the load is satisfied, the fans and spray pumps
will cycle off.
When demand increases and calls for heat rejection, each module turns on in sequence.
Once all modules are turned on, all fans operate at a synchronized speed.
Nexus Mode
Balanced Energy and Water Savings
In the revolutionary Nexus Mode, you can
prioritize water and energy savings to achieve the
right balance of both. Your climate, cooling load
profile and the rates you pay for water and energy
will determine your specific settings, which can
easily be re-adjusted as needed. You can specify
the importance of water versus energy savings to
automatically achieve the right balance for your
specific situation.
When demand increases and calls for heat rejection, all fans ramp up simultaneously.
Once all fans reach 100% fan speed, each pump turns on one module at a time to meet
building demand. In Nexus mode, the user can choose how to balance energy savings and
water savings by adjusting the iPilot
®
Control System by selecting a program setting from
1-7 with 1 being maximum energy savings while dry and 7 being maximum water saving.
EVAPORATIVE
MAXIMUM ENERGY SAVINGS
Figure 6.
Energy Saver Mode
HYBRID
EVAPORATIVE
Figure 7.
Nexus Mode
Start-Up & Operation
Start-Up
Start-up
Operation
Energy Saver Mode
Nexus Mode
–
Conductivity-based Bleed
: Conductivity threshold value for bleed (recommended)
–
Time-based Drain
: Time and frequency of complete basin drain (optional)
•
PI-Parameters
–
Prop. Band
– Proportional band of PI controller
–
Integr. Time
– Integration time of PI controller
– For addition parameters, see the “iPilot
®
Control System Appendix” on
page 45
.