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

Cooling energy distribution at various load Cooling Systems Cooling energy distribution at various load Radiation Mechanical energy 1 % 47% Exhaust gas 26 % Fuel energy 100% Exhaust gas heat recovery can increase the produced mechanical energy 3% Cooling water loss 26%

Cooling energy distribution at various load Cooling systems Cooling energy distribution at various load 120120100100 80 80 60 60 40 40 20 20 Radiation Heat flow relative to full power % Exhaust gas Cooling Charge air 20 40 60 80 100 110 Power along propeller law

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.

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

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

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

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

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

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

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