A novel systematic methodology for ship propulsion engines energy management

Abstract Establishing an energy monitoring and management methodology is a quintessential milestone for informed energy savings decision making as well as for effectively reducing the cost and the environmental impact of shipping operations. In this study, a novel systematic methodology is proposed for the energy management of the ship propulsion engine, which is the largest ship energy producer. The methodology employs a combination of tools including statistical analysis, compressor modelling to predict the engine airflow and energy and exergy analyses, whereas its output includes the engine operating profile, the most frequently occurring propeller curves and the engine most frequent operating points, the key performance indicators for quantitatively assessing the recorded parameters quality as well as the energy/exergy flows and the engine components exergy destruction. The methodology is implemented for three case studies for a very large crude carrier, a container ship and a bulk carrier, for which recorded data were available by using different monitoring techniques from either noon reports or automatic data acquisition systems. The derived results provide the engine operating profile demonstrating that the investigated vessels were operating in slow steaming conditions with a lower engine efficiency associated with a greater exhaust gas wasted energy. The measured data analysis demonstrates the better quality of the data recorded by automated monitoring systems and pinpoint maintenance issues of the engine components. Lastly, the exergy analysis results demonstrate that the exhaust gas and jacket cooling water provide the greater exergy flows rendering them attractive for energy saving initiatives, whereas the engine block, compressor and turbine are the engine components with the greater exergy destruction, thus requiring closer monitoring for timely identifying mitigating measures.