| In view of the amount of greenhouse gas emission from the shipping industry which has been increased year by year, and the global policy of energysaving and emission reduction, this paper analyzed both the significance and the way of shipping industry acting accordingly. In complying with the policy, measures of three kinds can help increase the energy efficiency of ships and reduce emissions of GHGs from international shipping, that is, approches based on the use of energy efficiency technology, those based on the operation of the ships in service and those based on the market. Among them, measures of the first two kinds develop much faster recently, which are generally accessed by the new ship Energy Efficiency Design Index (EEDI) and operating ship Energy Efficiency Operating Indicator (EEOI), while EEOI is also used to evaluate the implementation results of Ship Energy Efficiency Management Plan (SEEMP). As a result of debations among the delegations of member states on Marine Environmental Protection Committee (MEPC) conferences, regulations on the EEDI index of new ship and on the SEEMP of operating ship are to enter into enforce on1st January2013. With reference to the current situations of shipbuilding and shipping industries of our country, it’s of great importance to intensify the study on the influence factors on EEDI and EEOI.To study further the global emission reduction regulations metioned above, this article firstly retrospected the evolution of the EEDI and EEOI indexes, and then made much analysis on the latest formulas and then the influence of various items in the formulas on the values of calculation, in order to determine the direction of study to lessen the values of the two indexes to a reasonable level by the use of ship Integrated Energy System thermal analysis theory. After analysis on the formulas, from a view of EEDI index, it is recommended to increase the power by using the waste heat of main engine emission gas by choosing an adequate waste heat recover system and the system parameters after the main propulsion system has been identified. As to the EEOI index, the concept of exergy is used to make a common evaluation, using mathematical model, on the energy efficiency of ship propulsion, power generation, refrigeration and airconditoning, and steam generation systems to find where the most exergy loss occurs and thus should be deemed as the main area to carry out the work of promoting the energy efficiency of the ship Integrated Energy System.In consideration of the complicated calculation in the exergy analysis of the entire Integrated Energy System of a ship, the program Editor/Debugger built in MATLAB was used to write programs to achieve the automatic computation of the values of enthalpy and entropy of working medium within ship Integrated Energy System, which are used to execute the computation of the exergy of the medium, the exergy efficiency and loss of each subsystem in combination with the subsystem mathematical model. The programs written can also putout the calculation results in the form of diagrams, which gives much convenience of comparasion among ship subsytems. A LNG/Chemical tanker was then chosen to carry out the energy efficiency analysis. It shows that among the subsystems which have more exergy loss, the value of exergy loss of the waste heat recovery system is higher than that of the generator set while the former has lower exergy efficiency and thus more potential for exergy saving and energy efficiency improvement. As a result, when efforts are made to improve the energy efficiency of this ship, more study should be carried out on the wasted heat recovery system, which can decrease the value of both EEDI and EEOI. Still, exergy analysis should be done on more ships to find the rules of location of exergy loss in order to offer guidance on the improvement on energy efficiency of ships of different kinds. |
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