Cooling System of The Marine Diesel Engine

COOLING SYSTEM IN MARINE ENGINEERING

1. Pentti Häkkinen ER auxiliaries 9.2.
Wärtsilä New Professionals 3.-7.11.2008
COOLING SYSTEMS
MARINE ENGINEERING

2. Pentti Häkkinen ER auxiliaries 9.2.
Wärtsilä New Professionals 3.-7.11.2008
Machinery Support Systems
Cooling systems
Heat from diesel engine and auxiliary units is directly or
indirectly dissipated to sea water. Exceptions are exhaust
gas and radiation.
Temperature control is important
• Wide variation of the cooling energy demand.
• Wide variation of sea water temperature
• Engine sensitivity to temperature deviations
• Preferably independent systems for ME’s (2x) and AE’s for
simple adjustment
Water flow can be prevented by air pockets, ice slush or
entered material.
Chemical purity is important

3. Pentti Häkkinen ER auxiliaries 9.2.
Wärtsilä New Professionals 3.-7.11.2008
Cooling Systems
Cooling energy distribution at various load
Fuel energy
100%
Radiation Mechanical
energy
1 % 47%
Exhaust gas
26 %
Exhaust gas
heat recovery
can increase
the produced
mechanical
energy 3%
Cooling water
loss 26%

4. Pentti Häkkinen ER auxiliaries 9.2.
Wärtsilä New Professionals 3.-7.11.2008
LT Cooling System
Bypass
line for
low load
HT water
cooler
Lub oil
cooler
Air cooler
II stage
Gear cooler Other coolers
Therm. valve Central coolers
Air evacuation, expansion tk
Throttle

5. Pentti Häkkinen ER auxiliaries 9.2.
Wärtsilä New Professionals 3.-7.11.2008
Direct driven pumps
Direct driven
cooling water
pumps
Direct driven
lubrication oil
pump

6. Pentti Häkkinen ER auxiliaries 9.2.
Wärtsilä New Professionals 3.-7.11.2008
Sea Water Cooling System
Components
Low and high sea chests:
Volume in GA drawings. 1m
3
/750kW.
Not necessarily on opposite sides.
Sea water main line:
Cunifer or rubber coated steel pipe
ND250 … 600 or duct in double bottom,
often in the very crowded area
Central coolers:
2 easily cleaned titanium plate coolers
Main sea water pumps:
SW and ballast pumps directly above
SW main line

7. Pentti Häkkinen ER auxiliaries 9.2.
Wärtsilä New Professionals 3.-7.11.2008
Sea Water Cooling System
Intake Filter Temper. Main SW Isolation Double
grating basket sensor line valve bottom
3-way valve
Side valve
Central coolers Air pipe
Ice
sea chest
(which is
extending
above CWL)
Non-return
valve
S.W. pump

8. Pentti Häkkinen ER auxiliaries 9.2.
Wärtsilä New Professionals 3.-7.11.2008
Sea Water Cooling System
Sea water and
fresh water cooling pumps
Main sea water cooling
line, mixing valve and filter

9. Pentti Häkkinen ER auxiliaries 9.2.
Wärtsilä New Professionals 3.-7.11.2008
Sea Water Cooling Systems
Alternatives
Box cooler, good operation
record in smaller ships
Vent pipe
Inlet grid Outlet grid
Shelter plate
Bolted
flange
Cleaning
air feed
Keel cooler, used in
Mississippi muddy
waters, in river boats
Shallow (H= 100 mm)
tank against bottom
plate. Internal baffle
plates promote the
heat transfer

10. Pentti Häkkinen ER auxiliaries 9.2.
Wärtsilä New Professionals 3.-7.11.2008
Position of Cooling System & Air Units
LT, SW pumps Sea water pumps
High sea chest
Central coolers
Lub oil coolers
Low sea chest
Start. air vessels & compressors

11. Pentti Häkkinen ER auxiliaries 9.2.
Wärtsilä New Professionals 3.-7.11.2008
Starting Air System
General
Common 30 bar system for main and auxiliary engines. Control air and
work tool air 7 bar systems may be integrated in simple ships.
Location
In engine room (redundant engine rooms). Receivers can be stowed on wall.
Main components
Duplicate compressors and air receivers, separate receiver for aux. engines.
For low speed engines compressor motor 2 * 50kW, air receivers 2 *10m
3
.
Design problems
Very seldom
Operation problems
Neglected draining, water or air accumulation. Explosion risk

12. Pentti Häkkinen ER auxiliaries 9.2.
Wärtsilä New Professionals 3.-7.11.2008
Engine Room Ventilation System
Inlet blowers
2 … 4 in main engine room.
Often 1 … 2 are reversible / 2 speed motors.
Total capacity is engine nominal air consumption + 70 … 100%
Free air exhaust through engine casing
Exhaust blowers & ducts from purifier room & other oil mist
areas
Channels: round fabricated ducts or square welded air channels.
Dampers arranged for closing of all air channels.
Design problems
reserved space consumed by other systems. Collision with girders,
holes needed in girder web. Horizontal channels below car deck
are often rectangular and flat.

13. Pentti Häkkinen ER auxiliaries 9.2.
Wärtsilä New Professionals 3.-7.11.2008
Engine Room Ventilation Systems
Casing can be tightly
closed in case of fire
Main ventilation
fans (or located
at lower end)
Accommodation
ventilation room
Separate air
channel to
control room
Air cooling
unit
Branch duct
to spaces
below floor
Suction from purifier room and below floor
Main duct with major
branches to engines
and burners

14. Pentti Häkkinen ER auxiliaries 9.2.
Wärtsilä New Professionals 3.-7.11.2008
Exhaust Gas System
Exhaust gas piping has influence on engine performance,
noise emission and general fire safety. Flow velocity 35 m/s
Support must permit thermal expansion, disconnect
structural noise and prevent loads on turbine casing. Special
demands in resiliently mounted engines.
Space problems in engine room (below car deck) and inside
the too crowded casing
Heat recovered from main engines, sometimes aux. engines
Catalyst reactor fitted before boiler. Separate noise silencer
needed in most ships
Exhaust gas boilers have separate gas side, water side may
be common.

15. Pentti Häkkinen ER auxiliaries 9.2.
Wärtsilä New Professionals 3.-7.11.2008
Pakoputken vienti autokannen alla

16. Pentti Häkkinen ER auxiliaries 9.2.
Wärtsilä New Professionals 3.-7.11.2008
Exhaust Gas System
Bellows and
supports allow
thermal
expansion.
Overhaul space
of exhaust boiler
tube bundles
Strong support
on pipe corners
is vital.
Boiler by-pass line is
seldom used in Europe
for capacity control
Heavy boiler demands
strong support structure
Rain or boiler wash water
must in no conditions
reach engine

17. Pentti Häkkinen ER auxiliaries 9.2.
Wärtsilä New Professionals 3.-7.11.2008
Exhaust Gas Piping
Steam boiler
exhaust pipe
Ventilation air exit Aux. engine exhaust pipe Exhaust gas boilers
Main engine
exhaust pipe

18. Pentti Häkkinen ER auxiliaries 9.2.
Wärtsilä New Professionals 3.-7.11.2008
Ventilation Systems – MS Seahorse
30 35 40 45 50 55 60 65 70 75-5 0 5 10 15 20 25
4 Engine room
supply fans
Air suction fans and
ducts from purifier room
4 main air inlet channels,
some extend to ER floor
Free air exhaust
through casing
Silencing air intake
grid and chamber

19. Pentti Häkkinen ER auxiliaries 9.2.
Wärtsilä New Professionals 3.-7.11.2008
Exhaust Gas System
Typical exhaust boiler
Feed
water in
Steam &
feed water
mixture out
Rotatable
soot removal
steam blower
Hatch to
tube end
chamber
Water circulates in
30mm steel tubes,
rib distance 15mm
Hatch to
exhaust gas
chamber

20. Pentti Häkkinen ER auxiliaries 9.2.
Wärtsilä New Professionals 3.-7.11.2008
Starting Air and Exhaust Gas Systems – MS Seahorse
30 35 40 45 50 55 60 65 70 75-5 0 5 10 15 20 25
Main air
compressors
Main air
receivers
Main engine
exhaust pipe
Aux engine
exhaust pipe
Working air
receiver

21. Pentti Häkkinen ER auxiliaries 9.2.
Wärtsilä New Professionals 3.-7.11.2008
Starting Air and Exhaust Gas Systems – MS Seahorse
Third deck 12200
Main deck 19500
Double bottom 2700
Base line
Main air
compressors
Main air
receivers
Main engine
exhaust pipe
& composite
steam boiler
Working air
receiver and
compressor