Components for Central Cooling Water System
Central cooling water pumps
The pumps are to be of the centrifugal type.
Central cooling water flow ... see ‘List of Capacities’
Pump head ...................................................2.5 bar
Delivery pressure ...............depends on location of
expansion tank
Test pressure .....................according to class rules
Working temperature ..................................... 80 °C
Design temperature ...................................... 100 °C
The flow capacity must be within a range from
100 to 110% of the capacity stated.
The ‘List of Capacities’ covers the main engine
only. The differential pressure provided by the
pumps is to be determined on the basis of the to-
tal actual pressure drop across the cooling water
system.
Central cooling water thermostatic valve
The low temperature cooling system is to be
equipped with a threeway valve, mounted as a
mixing valve, which bypasses all or part of the
fresh water around the central cooler.
The sensor is to be located at the outlet pipe from
the thermostatic valve and is set so as to keep a
temperature level of minimum 10 °C.
Seawater cooling pumps
The pumps are to be of the centrifugal type.
Seawater flow ..................... see ‘List of Capacities’
Pump head ...................................................2.5 bar
Test pressure .....................according to class rules
Working temperature, normal .....................032 °C
Working temperature .................... maximum 50 °C
The flow capacity must be within a range from
100 to 110% of the capacity stated.
The differential pressure of the pumps is to be de-
termined on the basis of the total actual pressure
drop across the cooling water system.
Central cooler
The cooler is to be of the shell and tube or plate
heat exchanger type, made of seawater resistant
material.
Heat dissipation ..................... see ‘List of Capacities’
Central cooling water flow ..... see ‘List of Capacities’
Central cooling water temperature, outlet ......... 36 °C
Pressure drop on central cooling side ....max. 0.2 bar
Seawater flow ........................ see ‘List of Capacities’
Seawater temperature, inlet ............................. 32 °C
Pressure drop on
seawater side ................................ maximum 0.2 bar
The pressure drop may be larger, depending on
the actual cooler design.
The heat dissipation and the seawater flow figures
are based on MCR output at tropical conditions,
i.e. a seawater temperature of 32 °C and an ambi-
ent air temperature of 45 °C.
Overload running at tropical conditions will slightly
increase the temperature level in the cooling sys-
tem, and will also slightly influence the engine
performance.
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