VLT
®
6000 HVAC
21
MG.60.B1.02 - VLT is a registered Danfoss trademark
Introduction to
HV
AC
Water Inlet
Water Outlet
CHILLER
BASIN
Conderser
Water pump
Supply
Temperature
sensor
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Condenser pumps
Condenser Water pumps are primarily used to
circulate water through the condenser section of
water cooled chillers and their associated cooling
tower. The condenser water absorbs the heat from
the chillers condenser section and releases it into the
atmosphere in the cooling tower. These systems are
used to provide the most efficient means of creating
chilled water, they are as much as 20% more efficient
than air cooled chillers.
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The new standard
VLT frequency converters can be added to conden-
ser water pumps instead of balancing the pumps
with a throttling valve, to control the water tempera-
ture instead of tower fans, or to control the water
temperature in addition to controlling the tower fans.
Using a VLT frequency converter instead of a
throttling valve simply saves the energy that would
have been absorbed by the valve. This can amount to
savings of 15-20% or more. VLT frequency
converters are used to control the water temperature
instead of controlling the cooling tower fans when it
is more convenient to access the pumps than the
tower fans.
Pump control is used in conjunction with fan control
to control the water temperature in free cooling
applications or when the cooling towers are signi-
ficantly oversized. In some circumstances the
environment itself causes the water to become too
cool even when the fan is off. The VLT frequency
converter controlled pump maintains the appropriate
temperature by increasing or decreasing the
discharge pressure and flow rate. The decreased
pressure at the spray nozzle in the cooling tower
decreases the surface area of the water exposed to
the air. Cooling is decreases and the design tempe-
rature can be maintained in periods of low loads.