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Freshwater Generators from Wärtsilä
Also known as 'Serck Como'

Horizontal inner Tube Evaporators

The Wärtsilä Horizontal inner Tube Evaporator (HiTE) is a multi-effect evaporator specifically designed for producing small to medium capacities of 30 to 175 tons of distillate per day. This marine freshwater generator guarantees potable water for human consumption and clean process water for technical applications. It serves in a wide range of operational areas where alternative technologies like reverse osmosis or plate technology reach their limits. Shallow waters with poor seawater quality is an example of this. 

The HiTE operates smoothly even at partial load. For example during dynamic positioning (DP) operations. The unit’s control system can be fully or semi-automated. Its smart processes adapt automatically to the amount of energy available. The HiTE is able to use waste heat. This is very convenient for vessels with varying engine profiles. The 4-stage HiTE offers up to 75% energy savings with a specific heat consumption of 180 kWh/t compared to single stage designs (700 kWh/t). For a 3-stage HiTE this is 240 kWh/t.  

Low operational cost | High reliability | 30 - 175 tons distillate per day | Uses waste heat from ships with varying engine profiles

The HiTE is able to utilise waste heat. This is very convenient for vessels with varying engine profiles.


    • Efficient & reliable multi-effect distilling process
    • Low operational cost
    • Lowest energy consumption in its range
    • Most efficient solutions when utilizing engine waste heat
    • Water conductivity of distillate < 4μS/cm
    • Designed for easy maintenance and long service intervals
    • Flexible adaptation to demand and/or supply (down to 50%) thanks to exceptional part-load capability
    • Flexible use of heat sources: engine jacket water, steam or combination
    • Fully automatic system
    • Also suited for land-based applications  


    • Seawater inlet temperature: 0 – 35°C
    • Capacity 30 – 175 tons/day
    • Footprint: 5,4 – 24 m2
    • Weight empty: 2100 – 8100 kg
    • Heating water inlet temperature from 70 – 90°C
    • Specific thermal power consumption: 195 - 240 kWh/t
    • Electrical power consumption: 2.9 - 5.9 kWh 


    The HiTE freshwater generator consists of 3 film evaporators (connected in series) and one condenser (1). The seawater is passing through the condenser. The major portion – after being used as cooling medium – is flowing back to the sea. A certain (minor) quantity is distributed in three parallel streams (2) directly into the evaporators. The 1st effect is heated by hot engine cooling water. Before evaporation can start, the feed water entering evaporator effect one is heated inside the tubes up to the boiling temperature.
    HiTE process illustration
    The released vapours (3) are separated from the water/vapour mixture and are entering the 2nd and possible 3rd effects as heating medium. The procedure of condensation/evaporation is repeated in the 2nd and 3rd effect before the residual vapours produced in the 3rd effect are entering the condenser. 
    The surplus brines are cascaded via syphon pipes from stage to stage, as well as the collected distillates. The distillate from the 3rd effect is flashing into the condenser hot well which also serves as distillate collecting tank. The distillate is pumped into the collecting tank.


    System Capacity
    Specific thermal power
    Electrical power*
    Dry weight
    Wet weight
    L x W x H
    HiTE 30-3 30 240 5,9 2100 2415 1800x1500x2000 5,4
    HiTE 50-3 50 240 5,3 3500 4025 2300x2000x2000 9,2
    HiTE 80-3 80 240 4,2 5100 5865 2750x2000x2000 11,0
    HiTE 120-3 120 240 4,1 6500 7475 3250x2000x2000 14,0
    HiTE 120-4 120 195 3.2 7200 8280 3750x2000x2000 19,0
    HiTE 175-3 175 240 3,8 7500 8550 4250x2300x2200 21,5
    HiTE 175-4 175 195 2,9 8100 9315 4750x2300x2200 24,0
    * Electrical power consumption can vary depending on conditions

    Water conductivity of distillate for all models: < 4 μS/cm
    Seawater inlet temperature: 0 – 35°C
    Heating water inlet temperature from 70 – 90°C


    Tandem ejector: without brine pump, but with higher electrical power
    Heating water source: for all qualities of water between 70 °C and 95 °C, steam or a combination of both
    Electrical control: PLC or manual control


    Delivered as standard  

    • Tube evaporator with condenser 
    • Distillate pump 
    • Ejector pump 
    • Seawater pump
    • Chemical dosing tank with dosing instruments
    • Solenoid valve for draining lower quality distillate
    • Siemens S7 control panel 


    • Steam booster
    • Distillate cooler
    • Frequency converters for pumps
    • Cleaning stations


    The Horizontal inner Tube Evaporator is predominantly known as a marine freshwater generator. It suites a wide range of vessel types such as chemical tankers, small cruise ships, ferries and special purpose vessels. Did you know that also offshore and land-based applications are equipped with HiTE’s? 

    Also land-based industry
    orders HiTE units

    Wärtsilä has strong roots in the maritime industry and has been supplying freshwater generation systems...

    Read more »


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