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

Direct driven pumps Direct driven cooling water pumps Direct driven lubrication oil pump

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 Start. air vessels & compressors

Starting Air System General Location Main components Design problems 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 *10m3. Design problems Very seldom Operation problems Neglected draining, water or air accumulation. Explosion risk

Starting Air System (simple version) Tools on deck Pressure reduction Typhoon To aux. engines To exhaust gas boiler soot blowing High pressure line to main engine starting Air inlet valve controlled by low pressure air Safety valve Water drain Pressure reduction Filter Main compressors

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.

Engine Room Ventilation Systems Main ventilation fans (or located at lower end) Accommodation ventilation room Casing can be tightly closed in case of fire Main duct with major branches to engines and burners Separate air channel to control room Air cooling unit Branch duct to spaces below floor Suction from purifier room and below floor

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.

Pakoputken vienti autokannen alla

Exhaust Gas System 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 Bellows and supports allow thermal expansion. Overhaul space of exhaust boiler tube bundles Strong support on pipe corners is vital.

Exhaust Gas Piping Ventilation air exit Aux. engine exhaust pipe Exhaust gas boilers Steam boiler exhaust pipe Main engine exhaust pipe

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

Typical exhaust boiler Exhaust Gas System Typical exhaust boiler Water circulates in 30mm steel tubes, rib distance 15mm Feed water in Hatch to tube end chamber Rotatable soot removal steam blower Hatch to exhaust gas chamber Steam & feed water mixture out

Starting Air and Exhaust Gas Systems – MS Seahorse Main engine exhaust pipe Main air receivers Aux engine exhaust pipe Main air compressors Working air receiver 30 35 40 45 50 55 60 65 70 75 -5 0 5 10 15 20 25

Starting Air and Exhaust Gas Systems – MS Seahorse Main engine exhaust pipe & composite steam boiler Main air compressors Main air receivers Working air receiver and compressor Main deck 19500 Third deck 12200 Double bottom 2700 Base line