Research On Energy Saving Of Marine Central Cooling System

Accompany with accelerated development of economic globalization, marine shipment has become the major transportation way in the world commodity trading. Ocean shipping has being one of the largest parts of human energy consumption in worldwide. The increased greenhouse gases emission, global warming, human environment deterioration, and trend of fossil energy exhausting, challenges human sustainable development in future. Research on energy saving and emission reduction of ocean ships is critical and realistic.Recent central cooling system energy saving research is dedicated in sea water cooling pump frequency conversion control to maintain fresh water outlet temperature of central cooler to keep up cooler heating exchange with facility heating dissipation to gain sea water cooling pump energy saving. But the research has not included fresh water flow and heat dissipation relation study. It is not achieved on energy saving optimization.This article has analyzed the main engine and auxiliary machinery heat dissipation together with fresh water flow demand based on fluid mechanics and heat transfer theory. Analyzed cooling pipe system hydrostatic distribution and inter-influence among heat dissipation, cooling water flow and cooler heat exchange capacity.The specific research work are as follows, 1. Utilize hydromechanics tools to simplify center cooling piping system and carry out model analysis. Feasibility study of fresh water flow dynamic control to match variable facility heating dissipation. Study the pipe system parameters that will influent fresh water dynamic control. Proposed the various frequency driven to fresh water cooling pump to achieve fresh water flow control. 2. Research heat exchange process on plate cooler. Demonstrates that fresh water flow change has positive effective to central cooler heating exchange. And analyzed the relationship between fresh water flow and sea water flow. 3. Base on above research result and real ship design parameter, simulate and calculate fresh water flow and facility heat dissipation in various scenario. Combined with sea water cooling pump frequency control, analyze pump power consumption in various sea water temperature and heat dissipation. Provide data analysis to evaluate energy saving effectiveness of fresh water cooling pump frequency control. 4. Research of sea water cooling pump and fresh water cooling pump automatic control retrofit plan, including pump speed logical control diagram, pump speed calculation and cooling pipe system scheme, etc. Introduced various control parameters set point and its functionality. Presented main control signal collection sensors, automatic control equipment and human machine interface. 5. Central cooling system operation data collection and analysis after pump automatic control retrofit on real ships, that including sea water cooling pump and fresh water cooling pump power consumption, sea water temperature, main engine speed, generator on duty status and main switch board power indication. Summarize energy saving effectiveness.The research reveals that fresh water cooling pump automatic dynamic control to match cooling water flow demand will get energy saving. Meanwhile sea water cooling pump operation will be optimized base on sea water temperature and machinery heat dissipation to gain energy saving. Fresh water cooling pump optimized operation will lead to more saving on sea water cooling pump. It is proven by sailing test that synchronized optimization of both fresh water cooling pump and sea water cooling pump operation will increase energy saving from 34% to 64%.(Take energy consumption in traditional cooling system as the base with handy size ship.)...