9.3.6 Temperature control valve for heat recovery (4V02)
The temperature control valve after the heat recovery controls the maximum temperature of the water that
is mixed with HT water from the engine outlet before the HT pump. The control valve can be either self-
actuated or electrically actuated.
The set-point is usually somewhere close to 75 ºC.
9.3.7 Coolers for other equipment and MDF coolers
The engine driven LT circulating pump can supply cooling water to one or two small coolers installed in
parallel to the engine, for example a MDF cooler or a reduction gear cooler. This is only possible for engines
operating on MDF, because the LT temperature control valve cannot be built on the engine to control the
temperature after the engine. Separate circulating pumps are required for larger flows.
Design guidelines for the MDF cooler are given in chapter Fuel system.
9.3.8 Fresh water central cooler (4E08)
Design data:
see chapter Technical Data
Fresh water flow
see chapter Technical Data
Heat to be dissipated
max. 60 kPa (0.6 bar)
Pressure drop on fresh water side
acc. to cooler manufacturer, normally 1.2 - 1.5 x the fresh water flow
Sea-water flow
acc. to pump head, normally 80 - 140 kPa (0.8 - 1.4 bar)
Pressure drop on sea-water side, norm.
max. 38°C
Fresh water temperature after cooler
15%
Margin (heat rate, fouling)
Figure 9.7
Central cooler main dimensions. Example for guidance only
Weight [kg]
D [mm]
C [mm]
B [mm]
A [mm]
Number of cylinders
1200
2150
700
425
720
6
1230
2150
700
425
720
9
1250
2150
700
425
720
12
1310
2150
950
425
720
16
As an alternative for the central coolers of the plate or of the tube type a box cooler can be installed. The
principle of box cooling is very simple. Cooling water is forced through a U-tube-bundle, which is placed
in a sea-chest having inlet- and outlet-grids. Cooling effect is reached by natural circulation of the surrounding
Product Guide Wärtsilä 34DF - 3/2012
93
Product Guide
9. Cooling Water System
