Evaluation Of Machinery Installations In Ships For Propulsion To Reduce The Use Of Fossil Fuel

This study deals with the issue of reducing fossil fuel consumption in ship machinery installations.It is a subject of great interest at the moment,due to the high operating cost and the emission of pollutants resulting from the combustion process of these oil products.Initially,the current scenario and future trends of conventional propulsion installations using heavy oil or diesel are presented.Then,alternatives proposal to reduce consumption of fossil fuels on ships are examined,which fall into three categories.The first involves possible design improvements to reduce energy demand.The second categories refer to the use of alternative energy sources which introduce extra propelling force,reducing the propeller's required thrust,or additional power on the propeller shaft.Both cases involve a reduction in the demand for power required from the diesel engine.In addition to comparing alternatives and technological innovations,a new approach is also being presented.It is thermodynamic fundamentals which involves the joint use of energy analysis and exergetic analysis to evaluate the performance of the machinery installations of the different alternatives.The energy analysis and exergetics of the main combustion engine provide basic information useful for evaluating the thermodynamic performance of the ship's machinery installation,which serve to examine possible alternatives for its improvement.The assessment is made for each element representative of the installation.Thus,the relevant points of energy consumption and possible destruction of exergy is considered,identifying whether the existing installation is within the best available technology or if there is a possibility of improvements to be recommended.The calculations and balances of the energy and exergetic analysis for the main combustion engines are performed with the aid of the EES(Engineering Equation Solver)program.Data and real characteristics of an example vessel of the national fleet are used in this work to evaluate the alternatives.Different fuel reduction or replacement options are simulated and compered using the same program.The research revealed the solution to the problem of reducing and replacing fossil fuels in ship which involves the study of improved performance and applications of new alternative energy source as well as the adaption of effective measure for the rational use of energy in the installations of existing ships.It is recommended that the assessment of the energy machines and systems of each ship be based on a thermodynamic analysis to allow complete knowledge of the different energy consumers and the opportunities for replacing their sources.