Analysis of the influence of the engine, propeller and auxiliary generation interaction on the energy efficiency of controllable pitch propeller ships

Paper i proceeding, 2014

In a context of increasing requirements for energy efficiency, this paper aims at improving the understanding on the interaction between engine, propeller, and auxiliary heat and power generation in the particular case of controllable pitch propeller (CPP) ships. The case study of a CPP propelled chemical tanker is used to analyze the application of the proposed approach. The performance of the ship’s standard arrangement using a shaft generator for the fulfillment of auxiliary power demand is compared to the operational alternative of using auxiliary engines, and with the possibilities for retrofitting with frequency converters and waste heat recovery systems. The influence of control systems parameters and of sea state are also analyzed and compared. The results show a large possibility for improvements, both via operational optimization (up to 8.3% increased energy efficiency) and via different types of retrofitting (with increased efficiencies of up to 11.4% for frequency converters, and 16.5% for WHR systems). The influence of a broad operational envelope brings even larger improvements to the efficiency of the energy system at low speeds. The results of the paper provide useful information about the influence of different technologies for auxiliary power generation on the efficiency of CPP propelled vessels.