A comparison of advanced heat recovery power cycles in a combined cycle for large ships
There is a strong motivation within the marine sector to reduce fuel expenses and to comply with ever stricter regulations on exhaust gas emissions.Heat recovery provides a tool to address both of these issues.The organic Rankine cycle,the Kalina cycle and the steam Rankine cycle have received the majority of the focus in the relevant literature.It is the objective of the present work to compare these three cycles in the context of combined cycle application with a large marine two-stroke diesel engine.Different aspects of the three cycles are compared.The combined cycle performance parameters are evaluated.Additionally,a qualitative comparison of the environmental impact,safety concerns and practical aspects of each of the cycles is presented.In order to obtain the optimum configuration and figures for design parameters for each of the cycles,an optimisation methodology is employed.The study is done based on numerical models derived using Matlab and the optimisations are done using a genetic algorithm.A model of a two-stroke,low speed diesel engine,validated in previous work,is combined with a turbocharger model and models of advanced Rankine cycle processes,using steam,organic fluids,or a mixture of ammonia and water as working fluids.The results suggest that the Kalina cycle possess no significant advantages compared to the organic Rankine cycle or the steam cycle.While contributing to very high efficiencies,the organic working fluids possess high global warming potentials and hazard levels.It is concluded that the organic Rankine cycle has the greatest potential for increasing the fuel efficiency,and in combination with the two-stroke,low speed diesel engine,it seems to offer very high thermal efficiency.While being less efficient,the steam cycle has the advantages of being well proven,harmless to the environment as well as being less hazardous in comparison.
Ship propulsion Heat recovery Organic Rankine cycle Kalina cycle Steam Rankine cycle
Ulrik Larsen Fredrik Haglind Oskar Sigthorsson
Technical University of Denmark,Kgs.Lyngby,Denmark
国际会议
桂林
英文
1-13
2013-07-16（万方平台首次上网日期，不代表论文的发表时间）