At a certain point a vessel becomes to large for small fans to be effective, and the required intake
and exhaust openings required for a natural draft intake start to create design issues. When this
happens it's time to step up to 3 phase A/C fans with variable speed drives and a control such as
the ECV1 Series to manage it.
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By using an intake fan capable of supplying the
combustion air and the exhaust air requirement we can
overcome the static pressure created by the Mist
Eliminators and grills and allow smaller openings for a
given engine size than a natural draft configuration. This
presents it's own set of problems however. If the intake
fan is sized to supply the engines at maximum speed,
without flow control it will pressurize the engine room at
low RPM. This positive pressure will force fumes out of
the engine room and into interior spaces of the vessel.
On the same note, if the fan speed is too low the engine
room pressure will become negative, making the
engines work harder, lowering performance and possibly
causing mechanical failures and voided warranties. The
exhaust fan speed is always controlled based on
temperature. The ECV1 series of controls is designed to
monitor engine room conditions and optimize fan speeds
based on real time events maintaining ideal conditions in
the engine room with the lowest electrical load and
sound levels possible.
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ADVANTAGES:
- Precise control of pressure and temperature
- Reduced opening and moisture eliminators size
- Lightweight
- Automatic operation both underway and
dockside
| DISADVANTAGES:
- Fans sizing becomes critical
- Significant cost
- Complexity
- Large fans present packaging issues
- Large electrical loads
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