A Study on the Control Solution of Ship’s Central Fresh Water Cooling System for Efficient Energy Control Based on Merchant Training Ship

Abstract

Large ships adopt a central fresh water‐cooling system that indirectly cools waste heat with seawater to discharge the ship′s waste heat out of the ship. Such a central fresh water‐cooling system is essential for future electric powered ships. Since 2010, shipping companies have attempted to save energy by applying variable‐speed cooling pumps to the central FW cooling system, but due to the minimum‐required discharge pressure of the pump, they have applied the existing 3‐way valve system alongside. However, since the control systems of the variable‐speed cooling pump and the 3‐way valve are controlled by the same output variable, the two control systems collide during operation. Therefore, for efficient energy‐saving control, it is important to accurately model the central fresh water‐cooling system and find the optimal control method on this basis. In this study, a ship’s central cooling system was mathematically modeled and verified by comparing it with the actual ship′s operation data. A control solution method to effectively save energy for the central cooling system was proposed.