Some marine cooling systems use chilled seawater as a direct cooling agent as an alternative to thermal transfer fluid systems. In a water jacket cooling system, seawater is pumped directly into a chamber, known as the “jacket”, that surrounds engine cylinders. Heat transfers from cylinder walls to the water as it cycles through the jacket chamber. In some large scale marine cooling systems, warm water returning from the engine can either be cooled and recirculated or returned to the source by pumping overboard.
