1. Machinery Auxiliary 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

2. Cooling energy distribution at various load
Cooling Systems
Cooling energy distribution at various load
Radiation Mechanical energy % %
Exhaust gas 26 %
Fuel energy 100%
Exhaust gas heat recovery can increase the produced mechanical energy 3%
Cooling water loss 26%

3. Cooling energy distribution at various load
Cooling systems
Cooling energy distribution at various load
80 80
60 60
40 40
20 20
Radiation
Heat flow relative to full power %
Exhaust gas
Cooling
Charge air
Power along propeller law

4. Cooling Systems LT and HT systems
HT = high temperature
LT = low temperature
HT water can be cooled either in coolers by LT or SW or by mixing with LT (preferred method).
LO cooler
Central cooler
Air cooler I II
LT circuit is often common but each engine has its own LT pumps.
Each engine has its independent HT circuit and pump. Preheating line is connecting engines.

5. HT Cooling System Throttle flange in gravity tank line Temper. sensor
Fresh water generator
Preheater
Separate HT cooler
Thermostatic mixing valve
Thermostatic bypass valve

6. LT Cooling System Air evacuation, expansion tk Throttle
Gear cooler Other coolers
HT water cooler
Lub oil cooler
Air cooler II stage
Bypass line for low load
Therm. valve Central coolers

7. Sea Water Cooling System
Components
Low and high sea chests:
Volume in GA drawings. 1m3 /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

8. Sea Water Cooling System
Central coolers Air pipe
Ice sea chest (which is extending above CWL)
3-way valve
Side valve
Non-return valve
S.W. pump
Intake Filter Temper. Main SW Isolation Double grating basket sensor line valve bottom

9. Sea Water Cooling System
Sea water and fresh water cooling pumps
Main sea water cooling line, mixing valve and filter

10. Sea Water Cooling Systems
Alternatives
Box cooler, good operation record in smaller ships
Keel cooler, used in Mississippi muddy waters, in river boats
Vent pipe
Shelter plate
Shallow (H= 100 mm) tank against bottom plate. Internal baffle plates promote the heat transfer
Bolted flange
Cleaning air feed
Inlet grid Outlet grid

11. Position of Cooling System & Air Units
LT, SW pumps Sea water pumps
High sea chest
Central coolers
Lub oil coolers
Low sea chest