Plate heat exchangers are commonly used cooling equipment in ship cooling systems. lt is divided into main engine cooling system and central cooling system. The central cooling system includes high-temperature hot fresh water and low-temperature warm water closed systems. The central cooling system is used to cool hot fresh water and various coolers. The heated warm water is cooled by an open seawater system in a central cooler, Therefore, using only one cooler that uses sea water as the coolant simplifies the layout of the seawater piping system. The seawater and fresh water pipelines in the central cooling system are separated, with less corrosion and cleanliness in the water pipelines, low management costs, and strong system reliability. High temperature and low temperature fresh water are used to cool different ship equipment separately, making the system more adaptable and improving equipment performance.