Analy sis of container ship energy systems

Abstract

Nowadays energy efficiency is a global concern for the maritime organization and business. Rising operating costs, mainly fuel prices and stricter environmental regulations are forcing the shipping industry to find more effective ways of designing and operating the ships in an energy-efficient manner. An analysis of the energy system of ships and understanding the different energy flows can contribute to better energy management and efficiency in the ships. Keeping this objective in mind, the energy systems of typical medium-sized container ships are analysed in this paper based on the vessel's operating data and equipment parameters collected by the crew over three months. The study focuses on the energy and exergy balances of the main components. It has been shown that more than 80% of total energy consumption is caused by the propulsion plant, while the electric power generation accounts for 14-17%. Up to 60% of the energy supply is lost to the environment through the cooling system, radiation, friction and exhaust from diesel engines. Exergy losses caused by the exhaust gas and heat transfer are other contributors. Roughly 6% of the fuel exergy input is lost due to heat transfer. The exergy lost through the exhaust gas flue mainly from the main engine is estimated at 12% of the total exergy input. There is considerable potential for waste heat recovery on container vessels. However, to improve the overall energy efficiency, a techno-economic study has to be carried out on waste heat recovery solutions for each category of vessels and trading mode.