Pub Date : 2023-12-15DOI: 10.1177/14750902231214585
Tengbin Zhu, Yingjie Xiao, Hao Zhang
Multi-extensibility and flexibility of unmanned surface vehicles (USVs) allow them perform many different tasks, further path planning technology is crucial to the safety, autonomy, and intelligent navigation of USVs. Firstly, this paper analyzes the impact of ocean currents and risk constraints on USV based on the electronic chart. Then take the optimal sailing time as the objective function and design a path planning algorithm based on an improved probabilistic roadmap (PRM) algorithm, in which a Gaussian space sampling algorithm based on edge detection is introduced. After building the network topology environment through improved PRM, then a Dijkstra algorithm based on great circle distance is used to solve the optimal path. Finally, the simulation experiment is designed through the MATLAB platform. By comparing the average and the three quartile lengths of the planned paths under three environments, the values of the designed Edge-Gaussion (E-G) PRM algorithm are smaller than Lazy PRM and Gaussian PRM algorithm, which shows that the improved PRM algorithm has better performance. When planning the USV path under the influence of current, compared with traditional length optimal path planning, although the navigation length planned by the designed algorithm is shorter by 972 m, sailing time is improved by 110 s, which efficiency shows the better application on the sea.
{"title":"Path planning of USV based on improved PRM under the influence of ocean current","authors":"Tengbin Zhu, Yingjie Xiao, Hao Zhang","doi":"10.1177/14750902231214585","DOIUrl":"https://doi.org/10.1177/14750902231214585","url":null,"abstract":"Multi-extensibility and flexibility of unmanned surface vehicles (USVs) allow them perform many different tasks, further path planning technology is crucial to the safety, autonomy, and intelligent navigation of USVs. Firstly, this paper analyzes the impact of ocean currents and risk constraints on USV based on the electronic chart. Then take the optimal sailing time as the objective function and design a path planning algorithm based on an improved probabilistic roadmap (PRM) algorithm, in which a Gaussian space sampling algorithm based on edge detection is introduced. After building the network topology environment through improved PRM, then a Dijkstra algorithm based on great circle distance is used to solve the optimal path. Finally, the simulation experiment is designed through the MATLAB platform. By comparing the average and the three quartile lengths of the planned paths under three environments, the values of the designed Edge-Gaussion (E-G) PRM algorithm are smaller than Lazy PRM and Gaussian PRM algorithm, which shows that the improved PRM algorithm has better performance. When planning the USV path under the influence of current, compared with traditional length optimal path planning, although the navigation length planned by the designed algorithm is shorter by 972 m, sailing time is improved by 110 s, which efficiency shows the better application on the sea.","PeriodicalId":20667,"journal":{"name":"Proceedings of the Institution of Mechanical Engineers, Part M: Journal of Engineering for the Maritime Environment","volume":null,"pages":null},"PeriodicalIF":1.8,"publicationDate":"2023-12-15","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"138995911","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2023-12-08DOI: 10.1177/14750902231213449
Baptiste Hochfellner, Friedrich Wirz, Konstantin Pryymak, Ann-Christin Preuss, Gerhard Matz
Pilot-ignition Otto marine engines are known for greatly reduced emissions of air pollutants (sulphur oxides, nitrogen oxide, particulates) compared to marine diesel engines. However, lubricating oil emissions still are about one order of magnitude higher than in land-based systems. To identify reduction potentials, a better understanding of oil emission mechanisms has to be gained. For this purpose, mass spectrometric oil emission measurements and fluorescence lubricating film thickness measurements were performed on a medium-speed marine engine. With the fluorescence measuring system, the varying lubricating oil film on the cylinder wall can be visualised and analysed in sub-crank-angle resolution. By applying the developed calibration method to the measurement data, the oil film thickness can be determined in µm. It is shown that the oil film left by the piston rings on the liner as it moves down is almost halved after ignition compared to during intake stroke. The authors have further been able to detect and time operating point dependent ring rotation and investigations show a connection between ring rotation and cylinder liner temperature distribution. Aligning ring gaps allow blow-by to happen. This and other high intensity events such as engine knock, load shedding or the transition from diesel-mode to gas-mode, heavily disturb the oil layer and cause peaking oil emissions.
{"title":"Investigation of oil emission mechanisms in a marine medium-speed dual-fuel engine","authors":"Baptiste Hochfellner, Friedrich Wirz, Konstantin Pryymak, Ann-Christin Preuss, Gerhard Matz","doi":"10.1177/14750902231213449","DOIUrl":"https://doi.org/10.1177/14750902231213449","url":null,"abstract":"Pilot-ignition Otto marine engines are known for greatly reduced emissions of air pollutants (sulphur oxides, nitrogen oxide, particulates) compared to marine diesel engines. However, lubricating oil emissions still are about one order of magnitude higher than in land-based systems. To identify reduction potentials, a better understanding of oil emission mechanisms has to be gained. For this purpose, mass spectrometric oil emission measurements and fluorescence lubricating film thickness measurements were performed on a medium-speed marine engine. With the fluorescence measuring system, the varying lubricating oil film on the cylinder wall can be visualised and analysed in sub-crank-angle resolution. By applying the developed calibration method to the measurement data, the oil film thickness can be determined in µm. It is shown that the oil film left by the piston rings on the liner as it moves down is almost halved after ignition compared to during intake stroke. The authors have further been able to detect and time operating point dependent ring rotation and investigations show a connection between ring rotation and cylinder liner temperature distribution. Aligning ring gaps allow blow-by to happen. This and other high intensity events such as engine knock, load shedding or the transition from diesel-mode to gas-mode, heavily disturb the oil layer and cause peaking oil emissions.","PeriodicalId":20667,"journal":{"name":"Proceedings of the Institution of Mechanical Engineers, Part M: Journal of Engineering for the Maritime Environment","volume":null,"pages":null},"PeriodicalIF":1.8,"publicationDate":"2023-12-08","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"138589214","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2023-12-08DOI: 10.1177/14750902231213901
N. Ventikos, A. Koimtzoglou, Alexandros Michelis, Angeliki Stouraiti, Ioannis Kopsacheilis, Vassilis Podimatas
Piracy and armed robbery continue to pose significant security threats to the shipping industry. This paper presents a real-time threat assessment and crisis classification tool for piracy or armed robbery incidents. The tool is part of a crisis classification module that addresses various categories of security threats. This module is currently being developed as part of the EU-funded research project ISOLA, which aims to introduce an intelligent security superintendence ecosystem. The ecosystem is designed to complement the existing ship security processes and measures applied onboard passenger ships. The tool operates by providing real-time threat classification and subsequent warnings by analysing data collected from the ship’s legacy systems and installed sensors with the utilisation of Bayesian probabilistic techniques, particularly Bayesian Networks. The BN model developed for this purpose is thoroughly examined, and its validation is presented through indicative case studies involving piracy and armed robbery. The main objective is to improve situational awareness, enhance vigilance and early threat detection, and support the decision-making process for the Master and crew, especially under time-sensitive circumstances and stressful conditions.
{"title":"A Bayesian network-based tool for crisis classification in piracy or armed robbery incidents on passenger ships","authors":"N. Ventikos, A. Koimtzoglou, Alexandros Michelis, Angeliki Stouraiti, Ioannis Kopsacheilis, Vassilis Podimatas","doi":"10.1177/14750902231213901","DOIUrl":"https://doi.org/10.1177/14750902231213901","url":null,"abstract":"Piracy and armed robbery continue to pose significant security threats to the shipping industry. This paper presents a real-time threat assessment and crisis classification tool for piracy or armed robbery incidents. The tool is part of a crisis classification module that addresses various categories of security threats. This module is currently being developed as part of the EU-funded research project ISOLA, which aims to introduce an intelligent security superintendence ecosystem. The ecosystem is designed to complement the existing ship security processes and measures applied onboard passenger ships. The tool operates by providing real-time threat classification and subsequent warnings by analysing data collected from the ship’s legacy systems and installed sensors with the utilisation of Bayesian probabilistic techniques, particularly Bayesian Networks. The BN model developed for this purpose is thoroughly examined, and its validation is presented through indicative case studies involving piracy and armed robbery. The main objective is to improve situational awareness, enhance vigilance and early threat detection, and support the decision-making process for the Master and crew, especially under time-sensitive circumstances and stressful conditions.","PeriodicalId":20667,"journal":{"name":"Proceedings of the Institution of Mechanical Engineers, Part M: Journal of Engineering for the Maritime Environment","volume":null,"pages":null},"PeriodicalIF":1.8,"publicationDate":"2023-12-08","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"138587014","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2023-11-29DOI: 10.1177/14750902231210344
Lei Li, Qinghui Chen, Honggen Zhou, Chunjin Li, Qiang He
The assembly of the ship block is an extremely important stage of the shipbuilding process. Nevertheless, currently, the manual assembly efficiency is low, the accuracy is poor, and collision is very easy to occur. Therefore, there is an urgent need to conduct technical research on the automatic docking of ship blocks. The core of the automated docking technology is the attitude estimation and the trajectory planning of the posturing equipment. However, current data measurement and point set matching methods lead to large attitude-estimation errors, and it is difficult to meet the accuracy requirements of the assembly. Moreover, the current ship block trajectory planning methods pay more attention to single metrics, for example, time or energy consumption, while omitting the shock degree. In response to the above, this study first proposes a high-precision matching method for measuring point sets, in order to estimate the exact attitude of the ship block. Subsequently, trajectory translation for the block is performed using the seventh-degree polynomial. On this basis, a nonlinear weighted improved particle swarm optimization (IPSO) method is proposed to optimize the time, energy consumption and shock degree in the ship block trajectory planning process. Finally, the accuracy of the matching optimization is validated by simulation analysis and it is concluded that the seventh-degree polynomial leads to less shock than other polynomials. Furthermore, the shock force does not change abruptly even when the ship block is poised in steps. Through IPSO, the energy consumption and shock degree performance indices are optimized by 37.07% and 50.06%, respectively, in the ship block translation process.
{"title":"Efficient and precise docking trajectory optimization for the ship block assembly","authors":"Lei Li, Qinghui Chen, Honggen Zhou, Chunjin Li, Qiang He","doi":"10.1177/14750902231210344","DOIUrl":"https://doi.org/10.1177/14750902231210344","url":null,"abstract":"The assembly of the ship block is an extremely important stage of the shipbuilding process. Nevertheless, currently, the manual assembly efficiency is low, the accuracy is poor, and collision is very easy to occur. Therefore, there is an urgent need to conduct technical research on the automatic docking of ship blocks. The core of the automated docking technology is the attitude estimation and the trajectory planning of the posturing equipment. However, current data measurement and point set matching methods lead to large attitude-estimation errors, and it is difficult to meet the accuracy requirements of the assembly. Moreover, the current ship block trajectory planning methods pay more attention to single metrics, for example, time or energy consumption, while omitting the shock degree. In response to the above, this study first proposes a high-precision matching method for measuring point sets, in order to estimate the exact attitude of the ship block. Subsequently, trajectory translation for the block is performed using the seventh-degree polynomial. On this basis, a nonlinear weighted improved particle swarm optimization (IPSO) method is proposed to optimize the time, energy consumption and shock degree in the ship block trajectory planning process. Finally, the accuracy of the matching optimization is validated by simulation analysis and it is concluded that the seventh-degree polynomial leads to less shock than other polynomials. Furthermore, the shock force does not change abruptly even when the ship block is poised in steps. Through IPSO, the energy consumption and shock degree performance indices are optimized by 37.07% and 50.06%, respectively, in the ship block translation process.","PeriodicalId":20667,"journal":{"name":"Proceedings of the Institution of Mechanical Engineers, Part M: Journal of Engineering for the Maritime Environment","volume":null,"pages":null},"PeriodicalIF":1.8,"publicationDate":"2023-11-29","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"139209419","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2023-11-25DOI: 10.1177/14750902231218551
{"title":"Corrigendum to “Guest editorial for the special issue on “marine hydrodynamics for innovative design”","authors":"","doi":"10.1177/14750902231218551","DOIUrl":"https://doi.org/10.1177/14750902231218551","url":null,"abstract":"","PeriodicalId":20667,"journal":{"name":"Proceedings of the Institution of Mechanical Engineers, Part M: Journal of Engineering for the Maritime Environment","volume":null,"pages":null},"PeriodicalIF":1.8,"publicationDate":"2023-11-25","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"139237567","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2023-11-22DOI: 10.1177/14750902231210044
M. Acanfora, M. Altosole, Tommaso Coppola, Riccardo Martino
This paper provides a compendium of the numerical model that goes under the name of FloodW. This code is a fast tool for the simulation and the analysis of the effects of flooding water on ship dynamics and loads in time domain, developed for safety purposes. It has been recently involved in the international benchmark study on simulation of flooding and motions of damaged Ropax vessels within the EU Horizon 2020 project FLARE, where the name FloodW was given for the first time. Indeed, the development of the code started almost 10 years ago for still water applications, limited to ship motions, up to flooding simulation in regular waves with the possibility to study also non-linear hull girder loads. The core feature of the flooding water modeling is in the assumption of a free surface normal to the apparent gravity vector, which is evaluated accounting for ship and water dynamics. Although this approach, from validations with experimental data, was found accurate in the whole range of filling levels of the damaged compartment, with finer accuracy for intermediate fillings, an alternative method was also proposed and implemented, pertinent to low filling levels. Therefore, this paper provides a comprehensive description of the FloodW code together with its applications, including also the recent developments in participating to the benchmark FLARE, regarding ship flooding in irregular wave scenario.
{"title":"A comprehensive description and application of the FloodW simulation code for flooded ship problems: From still water to irregular wave scenarios","authors":"M. Acanfora, M. Altosole, Tommaso Coppola, Riccardo Martino","doi":"10.1177/14750902231210044","DOIUrl":"https://doi.org/10.1177/14750902231210044","url":null,"abstract":"This paper provides a compendium of the numerical model that goes under the name of FloodW. This code is a fast tool for the simulation and the analysis of the effects of flooding water on ship dynamics and loads in time domain, developed for safety purposes. It has been recently involved in the international benchmark study on simulation of flooding and motions of damaged Ropax vessels within the EU Horizon 2020 project FLARE, where the name FloodW was given for the first time. Indeed, the development of the code started almost 10 years ago for still water applications, limited to ship motions, up to flooding simulation in regular waves with the possibility to study also non-linear hull girder loads. The core feature of the flooding water modeling is in the assumption of a free surface normal to the apparent gravity vector, which is evaluated accounting for ship and water dynamics. Although this approach, from validations with experimental data, was found accurate in the whole range of filling levels of the damaged compartment, with finer accuracy for intermediate fillings, an alternative method was also proposed and implemented, pertinent to low filling levels. Therefore, this paper provides a comprehensive description of the FloodW code together with its applications, including also the recent developments in participating to the benchmark FLARE, regarding ship flooding in irregular wave scenario.","PeriodicalId":20667,"journal":{"name":"Proceedings of the Institution of Mechanical Engineers, Part M: Journal of Engineering for the Maritime Environment","volume":null,"pages":null},"PeriodicalIF":1.8,"publicationDate":"2023-11-22","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"139246667","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2023-11-22DOI: 10.1177/14750902231210047
Huirong Yang, Zhuo Sun, Peixiu Han, Mengjie Ma
To improve the energy efficiency of ships and reduce greenhouse gas (GHG) emissions, the implementation of energy-efficient operation measures is particularly important. Driven by this, this study was dedicated to improving the accuracy of ship fuel oil consumption (FOC) prediction and laying the foundation for optimizing energy-efficient operations. Firstly, we combined voyage reports and meteorological data and constructed six datasets containing different features. These features comprise navigation-related features encompassing sailing speed, displacement and trim, as well as meteorological features encompassing wind, wave, sea current, sea water salinity and sea water temperature. Secondly, we conducted experiments with 14 popular ML models on the datasets and compared the prediction performance of different models by a new scoring system. Finally, we explored the advantages and disadvantages of each dataset based on the model performance scoring results and analyzed the effects of related meteorological factors on FOC during navigation. The key findings of the proposed work were that extra trees (ET), random forest (RF), XGBoost, and LightGBM had good fitting and generalization performance. Set5, the dataset containing the most complete meteorological data, achieved the best prediction results. In particular, it had an R2 (test) of 0.9317 on the ET model, which was 1.97% higher than the R2 (test) of the dataset using only voyage reports. The conclusions can assist shipping companies in constructing a ship FOC prediction framework and developing ship fuel-saving strategies.
{"title":"Data-driven prediction of ship fuel oil consumption based on machine learning models considering meteorological factors","authors":"Huirong Yang, Zhuo Sun, Peixiu Han, Mengjie Ma","doi":"10.1177/14750902231210047","DOIUrl":"https://doi.org/10.1177/14750902231210047","url":null,"abstract":"To improve the energy efficiency of ships and reduce greenhouse gas (GHG) emissions, the implementation of energy-efficient operation measures is particularly important. Driven by this, this study was dedicated to improving the accuracy of ship fuel oil consumption (FOC) prediction and laying the foundation for optimizing energy-efficient operations. Firstly, we combined voyage reports and meteorological data and constructed six datasets containing different features. These features comprise navigation-related features encompassing sailing speed, displacement and trim, as well as meteorological features encompassing wind, wave, sea current, sea water salinity and sea water temperature. Secondly, we conducted experiments with 14 popular ML models on the datasets and compared the prediction performance of different models by a new scoring system. Finally, we explored the advantages and disadvantages of each dataset based on the model performance scoring results and analyzed the effects of related meteorological factors on FOC during navigation. The key findings of the proposed work were that extra trees (ET), random forest (RF), XGBoost, and LightGBM had good fitting and generalization performance. Set5, the dataset containing the most complete meteorological data, achieved the best prediction results. In particular, it had an R2 (test) of 0.9317 on the ET model, which was 1.97% higher than the R2 (test) of the dataset using only voyage reports. The conclusions can assist shipping companies in constructing a ship FOC prediction framework and developing ship fuel-saving strategies.","PeriodicalId":20667,"journal":{"name":"Proceedings of the Institution of Mechanical Engineers, Part M: Journal of Engineering for the Maritime Environment","volume":null,"pages":null},"PeriodicalIF":1.8,"publicationDate":"2023-11-22","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"139249322","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2023-11-20DOI: 10.1177/14750902231210564
S. Ergin, L. Mocerino, Franco Quaranta
The emissions from ships are the key factor influencing the air quality near large ports. Although ship emissions are difficult to quantify, doing so can help port management find logistical solutions that can reduce the impact of having a large number of giant ships in a limited space. The joint study between the University of Naples and Istanbul Technical University, which focuses on the investigation of ship emissions in ports, is presented in this paper. It is expected that this study will lead to create new techniques for calculating, measuring, and validating emissions from ships at ports.
{"title":"Possible approaches to the study of emissions from ships during their operations in ports","authors":"S. Ergin, L. Mocerino, Franco Quaranta","doi":"10.1177/14750902231210564","DOIUrl":"https://doi.org/10.1177/14750902231210564","url":null,"abstract":"The emissions from ships are the key factor influencing the air quality near large ports. Although ship emissions are difficult to quantify, doing so can help port management find logistical solutions that can reduce the impact of having a large number of giant ships in a limited space. The joint study between the University of Naples and Istanbul Technical University, which focuses on the investigation of ship emissions in ports, is presented in this paper. It is expected that this study will lead to create new techniques for calculating, measuring, and validating emissions from ships at ports.","PeriodicalId":20667,"journal":{"name":"Proceedings of the Institution of Mechanical Engineers, Part M: Journal of Engineering for the Maritime Environment","volume":null,"pages":null},"PeriodicalIF":1.8,"publicationDate":"2023-11-20","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"139254734","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2023-11-18DOI: 10.1177/14750902231207159
D. Dong, A. Schönborn, Anastasia Christodoulou, A. Ölçer, José González-Celis
Marine fuels are the main sources of pollution from shipping industry. Hydrogen and ammonia have been suggested to be alternative fuels for shipping as these two fuels do not emit carbon dioxides in the combustion process. This study employed life cycle assessment method to compare the environmental performance of propulsion systems using hydrogen and ammonia as marine fuels to fossil fuels. 2-stroke and 4-stroke engines of tankers using fossil fuels were chosen as base case scenarios. Alternative scenarios using ‘green’ and ‘blue’ hydrogen and ammonia with the support of pilot fuel were then compared to the base case scenarios. While the performance of the coming combustion concepts for hydrogen and ammonia engines are still unknown, preliminary estimations were used in this study. The results showed that hydrogen and ammonia could substantially reduce the global warming potential, compared with the fossil fuel scenarios. Hydrogen and ammonia are also expected to be highly effective in cutting down the particulate matter and the emission of black carbon.
{"title":"Life cycle assessment of ammonia/hydrogen-driven marine propulsion","authors":"D. Dong, A. Schönborn, Anastasia Christodoulou, A. Ölçer, José González-Celis","doi":"10.1177/14750902231207159","DOIUrl":"https://doi.org/10.1177/14750902231207159","url":null,"abstract":"Marine fuels are the main sources of pollution from shipping industry. Hydrogen and ammonia have been suggested to be alternative fuels for shipping as these two fuels do not emit carbon dioxides in the combustion process. This study employed life cycle assessment method to compare the environmental performance of propulsion systems using hydrogen and ammonia as marine fuels to fossil fuels. 2-stroke and 4-stroke engines of tankers using fossil fuels were chosen as base case scenarios. Alternative scenarios using ‘green’ and ‘blue’ hydrogen and ammonia with the support of pilot fuel were then compared to the base case scenarios. While the performance of the coming combustion concepts for hydrogen and ammonia engines are still unknown, preliminary estimations were used in this study. The results showed that hydrogen and ammonia could substantially reduce the global warming potential, compared with the fossil fuel scenarios. Hydrogen and ammonia are also expected to be highly effective in cutting down the particulate matter and the emission of black carbon.","PeriodicalId":20667,"journal":{"name":"Proceedings of the Institution of Mechanical Engineers, Part M: Journal of Engineering for the Maritime Environment","volume":null,"pages":null},"PeriodicalIF":1.8,"publicationDate":"2023-11-18","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"139262369","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2023-11-14DOI: 10.1177/14750902231207133
G. Kocak, Y. Durmusoglu
Energy efficiency and environmental protection are becoming more important in the world. Almost 90% of the world trade is carried by sea which makes energy efficiency very important for the maritime sector. Exergetic method is a powerful scientific tool for measuring energy efficiency. The ships are not always cruising at maximum load conditions. The situations such as narrow water passages, maneuvering, and, hoteling etc. are partial load conditions and the exergy loss in power systems reaches maximum values at these conditions. Besides the new IMO regulation forces the sector to reduce emissions through Energy Efficiency Existing Ship Index (EEXI) and one of the most popular solutions is Engine Power Limitation (EPL). In the literature there are limited studies investigating exergy efficiencies of partial load conditions of a marine power plant. In this article, the performance analyses of a combined power system in partial load conditions are carried out using exergy method. The considered partial load conditions are maximum-ahead, full-ahead, half-ahead, slow-ahead and dead-slow-ahead loads of the engine. The results show that, the exergy efficiency of the overall system is decreasing at lower load conditions. It is observed that the maximum exergy efficiency is 51.6% which is reached at 96 rpm. The best condition considering both exergy efficiency and EEXI is 80 rpm of main engine. At slow-ahead and dead-slow-ahead conditions the exergy efficiency decreases to about 33%.
{"title":"Exergy efficiency and EEXI analysis of a marine power plant at partial load conditions","authors":"G. Kocak, Y. Durmusoglu","doi":"10.1177/14750902231207133","DOIUrl":"https://doi.org/10.1177/14750902231207133","url":null,"abstract":"Energy efficiency and environmental protection are becoming more important in the world. Almost 90% of the world trade is carried by sea which makes energy efficiency very important for the maritime sector. Exergetic method is a powerful scientific tool for measuring energy efficiency. The ships are not always cruising at maximum load conditions. The situations such as narrow water passages, maneuvering, and, hoteling etc. are partial load conditions and the exergy loss in power systems reaches maximum values at these conditions. Besides the new IMO regulation forces the sector to reduce emissions through Energy Efficiency Existing Ship Index (EEXI) and one of the most popular solutions is Engine Power Limitation (EPL). In the literature there are limited studies investigating exergy efficiencies of partial load conditions of a marine power plant. In this article, the performance analyses of a combined power system in partial load conditions are carried out using exergy method. The considered partial load conditions are maximum-ahead, full-ahead, half-ahead, slow-ahead and dead-slow-ahead loads of the engine. The results show that, the exergy efficiency of the overall system is decreasing at lower load conditions. It is observed that the maximum exergy efficiency is 51.6% which is reached at 96 rpm. The best condition considering both exergy efficiency and EEXI is 80 rpm of main engine. At slow-ahead and dead-slow-ahead conditions the exergy efficiency decreases to about 33%.","PeriodicalId":20667,"journal":{"name":"Proceedings of the Institution of Mechanical Engineers, Part M: Journal of Engineering for the Maritime Environment","volume":null,"pages":null},"PeriodicalIF":1.8,"publicationDate":"2023-11-14","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"139276768","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
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