【作者】

Mia Elg

【摘要】

该论文已在赫尔辛基举行的第28届CIMAC世界大会上发表，论文的版权归CIMAC所有。 During the recent years, considerable efforts have been made to improve the fuel efficiency of ocean-going ships. The main focus of the design improvements has been an efficient hull form and main engine choice and tuning. Furthermore, the new global and local rules for energy efficiency or emission limits in shipping are creating opportunities for introducing new alternatives to the machinery and fuel choice in even the simplest cargo ships. In current ships, with diesel engines as main source of power, approximately half of the fuel energy is utilized as propulsion power or electricity to ship processes. The other half is lost and delivered to sea as waste heat. The four main sources of waste heat in a marine internal combustion engine are the flue gases, scavenge air, jacket water and lubrication oil cooling. These waste heat streams can be divided into different temperature categories. Furthermore, depending on the temperature level a portion of this waste heat could be utilized as electricity or heating energy purposes in ships. In this article, several interesting technologies for enhancing ship energy efficiency were reviewed. The selected energy saving technologies included natural circulated boilers, thermal storage, Organic Rankine cycle, compression heat pump, absorption chilling process, efficient ship auxiliary cooling circuit and onboard direct current distribution. The waste heat recovery technologies require individual power inputs and they also absorb and reject heat at individual temperatures. The target of the study was to apply these technologies to simple cargo ships that represent the most common type of ship machinery set up. The technologies should be integrated in such a way that total fuel consumption of the vessel is minimized. The ship-specific fuel saving potential depends always on the actual operation profile that can be to some extend always evaluated at the early phases of ship design project. A multi-domain ship energy flow model in Simscape simulation environment was utilized for the study. The ship model included all main components in the ship machinery, including the most relevant auxiliaries. The model and its components included the necessary functionalities and the system requirements and limits that are relevant for concept level design. Once the system components were defined, the expected yearly operation profile was included in the model, including estimation of the electricity consumption, propulsion power consumption and heating- and cooling requirements. After this, the true saving potential in the system was evaluated by modelling the ship fuel consumption. Also, exergy analysis was performed for the ship main components. Based on the analysis, the characteristics of improved, energy efficient machinery for a cargo ship could be recognized. As a result of the study, various types of waste heat recovery technologies available onboard ships were studied from the perspective of technical principle and application feasibility. Furthermore, an optimal solution for improved, energy efficient cargo ship machinery was defined, considering the pre-defined system limits. With the studied technologies the excess engine heat could be utilized to meet the cooling, heating and power demand onboard that otherwise would require additional fuel. The developed solution included a new system analysis method for supporting the ship concept development. The whole method aims for holistic optimization of ship energy efficiency.

【会议名称】

第28届CIMAC会议

【会议地点】

芬兰 赫尔辛基

【下载次数】

2

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