Fuel efficiency of the main marine diesel scavenge air cooling by the waste heat recovery chiller on the route line
It is considered a waste heat recovery scavenge air cooling system that consists of three stage air cooler: the first stage extracting a high potential heat from the scavenge air after the turbo-charger (so called utilizing or cogenerative stage), the second convention stage using sea water as cooling medium and the third stage using a cold from the waste heat recovery refrigerant ejector chiller utilizing the heat of scavenge air extracting in the first stage. The heat load on the first high-temperature stage of the scavenge air cooler has been supposed as the heat source to produce a refrigeration capacity wasted for scavenge air deep cooling in the low temperature section by refrigerant ejector chiller of waste heat recovery cooling system. It is shown that a scavenge air heat is quite enough to cover the heat wasted for addition scavenge air cooling from the temperature of air after a convention sea water cooler to the potential minimal temperature that provides reducing the engine fuel consumption. The rational temperature of the scavenge air after heat extraction from it in the high-temperature stage of the scavenge air cooler that limits a magnitude of the heat to be used by waste heat recovery refrigeration ejector chiller for scavenge air deep cooling in the low temperature stage of the scavenge air cooler of the marine low speed diesel engine for climate conditions of the ship performance on the route line has been defined. A reduction of specific fuel consumption and fuel saving due to scavenge air cooling for the main marine low speed diesel engine for climate conditions of the ship performance on the Odessa-Yokogama route line were estimated.