An Investigation on the Overall Efficiency of a Ship with Shaft Generator Using an Engine Room Simulator

Abstract

The use of a marine shaft generator onboard is considered an alternative means to reduce fuel consumption and improve the energy efficiency of a ship. It is a type of an electric generator driven by the main propulsion diesel engine to supply the electric power requirement of the ship at sea. It is intended to take advantage of the low specific fuel consumption of the main propulsion diesel engine when engaged and in operation. Since it is a power take-off appliance, its operation causes an increase in load on the main propulsion diesel engine as compared to when a separate auxiliary diesel generator is running to generate and supply electricity onboard. To determine the effectiveness of this auxiliary equipment, this paper attempted to investigate and compare the overall plant efficiency of a ship when running on a shaft generator as against an auxiliary diesel generator for electric power generation, using an engine room simulator. Data were gathered from a series of simulations on a main propulsion diesel engine load of 50–100% with a steady power load on the running electric generator. The theoretical overall efficiency of the combined propulsion and electric power plant in both scenarios were calculated, compared and presented in this paper.