| Since entering 21 th century,the ship was developed very fast.Nowadays,with the serious energy consumption and the ever-worsening environment,the work of energy saving and emission Reduction became a severe and knotty problem in current period.At present,the research of related technology in our country's ship building industry was lagged behind and there were some problems such as the energy consumption distribution of the ship system especially the enexgy distribution was not chear.Therefore,it is of great importance in the research of ship's energy consumption distribution in different conditions,finding the weak link of energy using by effective energy,developing the ship energy efficiency evaluation software platform,for energy research with the exergy distribution and saving potential effects of program systems.In this study,two calculation models-the thermal performance of diesel engine cylinder process and the thermal system and the Ship's exergy analysis were build based on the distribution of phase and Seiliger circulation and average method using the average method and Volumetric method,enexgy analysis software of ship integrated energy system and the evaluate of energy saving potential was developed.In this paper a MAN B&W 7L16/24 dynamoelectric diesel system of a typical 75000 ton oil tanker was chosen as the research objece and the crirical thermal performance parameters of the diesel at six different working conditions in the range of 50%~70% were calculated through the software platform.The ship integrated energy system and subsystem of three oil tranks-48,000 DWT,72,000 DWT and 75,000 DWT were analyzed at the SMCR steady-state conditions,different working conditions of main engine and different operational status of ship by using exergy analysis method.The energy losses and energy loss distribution were analyzed according to the results,and put forward some energy saving measures for improvement and energy saving projects.At the six working conditions of 50%,60%,70%,80%,90% and 100%,the error of diesel key performance parameters through software and the design data were in 3%.This result verified the correctness of calculation model and the software development.The energy efficiency in ship integrated energy system of the 75000 tons oil ship was 48.26%,and among this the output power of main engine was account for 42.99%,the electric power of power plant system was account for 4.61%,the effective utilization of waste heat from boiler heat recovery steam was account for 0.37%,and the production of freshwater from the host heat recovery system was account for 0.28%.The Main exergy lost of integrated energy system are from the diesel engine fire-cylinder of the host and the power system,accounting for 33.03% and 5.62%,respectively,are accounted for 71.14% of the integrated energy system.In different conditions of host,the result shows that at 70% below operating point,the exergy efficiency of whole ship are around 44%,as decreasing as the loading decrease;more than 70% of the operating point,the whole ship exergy efficiency are about 48% for floating little change.For different tonnage tanker series,in sailing condition,the exergy efficiency of integrated energy system are 44% to 48% with the highest,in the handling and washing conditions,are 15% to 18% with the lowest.Ship energy losses concentrated in the main oil-fired boiler unit.The study of Exergy analysis of integrated energy system helps ship designer and management personnel to grasp the ship's weaknesses,energy-saving technologies and measures for the ship direction more effectively. |
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