WÄRTSILÄ WARTSILA32, Product Manual, Page: 142 / 254

9.3.1 Cooling water system for arctic conditions
At low engine loads the combustion air is below zero degrees Celsius after the compressor
stage, it cools down the cooling water and the engine instead of releasing heat to the cooling
water in the charge air cooler. If the combustion air temperature reaching the cylinders is too
cold, it can cause uneven burning of the fuel in the cylinder and possible misfires. Additionally
overcooling the engine jacket can cause cold corrosion of the cylinder liners or even a stuck
piston.
Thus maintaining nominal charge air receiver and HT-water inlet temperature are important
factors, when designing the cooling water system for arctic conditions. Depending on the
engine type an additional heater might be needed in the HT-water system as for some engine
types the HT-charge air cooler is replaced with a double-stage cooler on the engine LT-water
cooling water system. For other engine types the HT-water charge air cooler is kept as it is
on a non-arctic package engine. If the setup is with additional HT-heater then the engine
build-on self-sensing thermostatic control valve is removed and replaced with an external
electrically controlled thermostatic control valve.
9.3.1.1 Dimensioning the HT water heaters
Dimensioning the arctic package HT water heaters is based on the number of cylinders and
the minimum specified suction air temperature. The heater can be either electric, steam or
thermal oil operated depending on the installation and customer preference. An example
diagram for dimensioning the HT heater is shown in 9-10.
Fig 9-10 HT-circuit heating operational field
9.3.1.2 The arctic sea water cooling system
In arctic conditions, the hot sea water from the central cooler outlet is typically returned back
to the sea chest in order to prevent ice slush from blocking the sea water filters. An example
flow diagram of the arctic sea water system is shown in .
9-12 Wärtsilä 32 Product Guide - a21 - 7 September 2016
Wärtsilä 32 Product Guide 9. Cooling Water System