Energy Saving Optimization Of Ship Cooling Water System Based On Variable Flow Regulation

Ship cooling system is one of the important systems to ensure the reliable operation of the ship,its development has been the people's attention.At present,the ship cooling water system mainly through the PID regulation control the opening of three-way valve in the cooling water pipe to achieve the cooling system temperature control,although this control method can reach the purpose of cooling,but the centrifugal pump water supply is always greater than the equipment required cooling water,which will result energy wasting,which does not meet the current energy-saving theme..This article theme is the energy-saving and optimization.By comparing the different energy saving optimization methods of cooling water system,selecting the energy saving optimization method which is most suitable for ship cooling water system,that is the variable regulation of centrifugal pump.The method can change the centrifugal pump flow in real time according to the change of the running condition of the main engine,and finally achieve the purpose of energy saving optimization of the cooling water system.In this paper,the cooling water system is briefly introduced,then select the cooling water system of the target ship and optimize the energy saving of the cooling water system.In this article,the cooling system equipment and pipelines are modeled respectively,including the heat transfer model of the cooling water system,the central cooler heat transfer model,the centrifugal pump speed model,the pipeline energy consumption model and the heat exchanger fluid velocity and the centrifugal pump traffic relationship model.Through the above model,the cooling system heat transfer,power consumption and flow can be linked.Then,based on these models,the energy saving optimization model of cooling water system is established.The model can be based on the host operating power and the ship's environment,get the current conditions,the best flow of centrifugal pump and low temperature fresh water outlet set temperature.Subsequently,this paper sets the ship operating conditions,and take the host rated power and 60%rated power for example,optimization the cooling water system.The energy consumption of the cooling system is only 23%and 18.3%of the design case,respectively,when the host is running at 100%,60%of the rated power.This shows that the frequency conversion regulation of energy-saving effect is remarkable.At the same time,through comparison,we can see that the energy-saving effect of variable regulation will rise as the operation power of the main engine drops.