Danfoss VLT Series Design Manual page 25

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VLT HVAC Drive Design Guide
2.7.18. 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.
2.7.19. The VLT solution
Frequency converters can be added to condenser water pumps instead of balancing the pumps
with a throttling valve or trimming the pump impeller.
Using a 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. Trimming the pump
impeller is irreversible, thus if the conditions change and higher flow is required the impeller must
be replaced.
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MG.11.B2.02 - VLT is a registered Danfoss trademark
2. Introduction to VLT HVAC Drive
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