A data-driven process control topology for energy efficiency optimization of fan operation in E/R ventilation system of marine vessels

The capacity of engine room (E/R) ventilation fans installed in marine vessels is defined during design stage based on maximum air flow required by Main Engine (M/E), Diesel Generators (D/Gs) and Boilers. However, the actual vessel's operating profile at reduced M/E power and speed does not justify the use of full capacities. In this paper, a data-driven process control topology is proposed to adjust the speed of E/R ventilation fan motors according to the variation of combustion air flow requirements in order to optimize energy efficiency during ship's sea-going and cargo operation periods. The controller dynamics are established through parameter monitoring, regardless of the model of the controlled plant. For the tanker vessel under investigation, a case study initially defines the plant operational constraints and its power saving potential. The proposed variable frequency process control topology is then applied as a retrofit installation to the existing 18.5kW E/R fan motor starters. Onboard experimental results show significant improvement in vessel's power balance, D/G fuel consumption and level of emission factors (CO2, SO2, NOx), validating the performance of the proposed control topology, which is implemented using commercial Programmable Logic Controllers (PLCs) and Variable Speed Drive (VFD) units.