Ship's Central Cooling System Live Performance Optimisation And Modeling

Central cooling systems play an essential role in ship operations, since guarantee the correct operating mode of vital users such as the main engine and generators. These systems are normally sized according to the design point so that they can deliver the cooling demand even in extreme conditions, while these conditions are very rare events in the ship’s life. In order to improve the overall cooling efficiency, a variable frequency drive can be adopted [1-3]. In this work, a physical model of a real Ro/Con (i.e. Roll on roll off Cargo ship) central cooling system is presented with an integrated process control scheme. An experimental campaign has been carried out for six months to collect the overall cooling demand (e.g. seawater and fresh water temperatures, flows and valve position) before and after the introduction of variable speed drive on the seawater pump. An algorithm for the control of the cooling water system is proposed and implemented in the model in order to improve the performances and guarantee the basic features of each component. The estimated annual saving coming from the recoded data and the model are around 40 to 60 percent obtained with a reduction between 10 to 27 percent for the pump speed. The methodology and model are proposed and developed in order to better exploit the data gathered during the on-board measuring period.