Fresh Water Generator - AFGU Double Stage

AFGU Double Stage

For heating and evaporation of the sea water in the freshwater generator, the waste heat in the jacket cooling water of the Diesel engine is used. The heat exchanger in the freshwater generator is connected to the jacket cooling water system of the Diesel engine, and is thus working as an extra cooler.

The jacket cooling water, whick may reach a temperatur between 60 and 90 °C, is passed outside the tubes of the heat exchanger. During this passage the temperatur will drop between 5 and 12 °C depending on the amount of jacket cooling water used.

The controlled amount of sea feed water is led to the interior of the heat exchanger tubes, where it is heated under vacuum and evaporated by rising film exaporation, meaning that optimum conditions are achieved and scale formation minimized.

The vacuum required is obtained by means of a water ejector which automatically ensures correct donditions. The generated vapours pass through the separator, in which the seawater drops are separated to the brine and discharged by means of a brine pump.


The freshwater Generator, type AFGU 2SA, is supplied with a separate ejector pump supplying sea feed water and sea water to the ejectors from a separate sea-water intake. - The condenser is supplied with water from the main cooling water system.

The saturated vapour is led to the 2nd effect heat exchanger of the freshwater generator, and on the outside of the tubes it will concense into fresh water, and on the outside of the tubes it will condense into fresh water, while heating the sea feed water of the second effect plus the brine of the first effect.

The evaporation process is repeated, and the saturated vapour rises to the sea-water cololed condenser, where it condenses into fresh water on the outside of the tubes, and the fresh water is collected in a shell. The fresh water is discharged from the heat exchanger and the condenser of the secound effect of the freshwater generator by the freshwater pumps.

The salinity of the fresh water produced is automatically controlled by the salinometer. The temperature of the cooling water led through the condenser tubes will rise between 5 and 10 °C depending on the flow chosen.


Generator type AFGU 2SE, is supplied with a built-on ejector pump supplying sea feed water and sea water to the ejectors from the seawater flow which has passed the condenser.