| 1. |
- Baldi, Francesco, 1986, et al.
(författare)
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Optimal load allocation of complex ship power plants
- 2016
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Ingår i: Energy Conversion and Management. - : Elsevier BV. - 0196-8904 .- 1879-2227. ; 124, s. 344-356
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Tidskriftsartikel (refereegranskat)abstract
- In a world with increased pressure on reducing fuel consumption and carbon dioxide emissions, thecruise industry is growing in size and impact. In this context, further effort is required for improvingthe energy efficiency of cruise ship energy systems.In this paper, we propose a generic method for modelling the power plant of an isolated system withmechanical, electric and thermal power demands and for the optimal load allocation of the different componentsthat are able to fulfil the demand.The optimisation problem is presented in the form of a mixed integer linear programming (MINLP)problem, where the number of engines and/or boilers running is represented by the integer variables,while their respective load is represented by the non-integer variables. The individual components aremodelled using a combination of first-principle models and polynomial regressions, thus making thesystem nonlinear.The proposed method is applied to the load-allocation problem of a cruise ship sailing in the Baltic Sea,and used to compare the existing power plant with a hybrid propulsion plant. The results show thebenefits brought by using the proposing method, which allow estimating the performance of the hybridsystem (for which the load allocation is a non-trivial problem) while also including the contribution ofthe heat demand. This allows showing that, based on a reference round voyage, up to 3% savings couldbe achieved by installing the proposed system, compared to the existing one, and that a NPV of11 kUSD could be achieved already 5 years after the installation of the system.
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| 2. |
- Andersson, Karin, 1952, et al.
(författare)
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Shipping and the environment
- 2016
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Ingår i: Shipping and the Environment: Improving Environmental Performance in Marine Transportation. - Berlin, Heidelberg : Springer Berlin Heidelberg. - 9783662490457 ; , s. 3-27
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Bokkapitel (övrigt vetenskapligt/konstnärligt)abstract
- Humans have always had a close relationship with the aquatic environment, including the early use of the sea for food harvesting and communication. Today, the sea is an important component of the transportation system, with large amounts of cargo and passengers. This chapter provides a short introduction to ships and shipping, focussing primarily on commercial ships; nonetheless, many of the emissions, impacts and measures discussed throughout this book are common to other sectors, such as leisure, research and fishing. This chapter also introduces the environmental impacts related to ship operations. Ship transportation has increased tremendously since the industrial revolution, which has resulted in increased emissions due to shipping and increased stresses on the environment. However, this trend is not only related to shipping. Currently, there are several warning signs that we are not taking care of the Earth and its ecosystem in a sustainable manner, that the Earth's ecosystems are degrading and that natural capital is being exploited, e.g., by the burning of fossil fuels. The marine industry is a component of our society; similar to all industry sectors, it contributes to unsustainable patterns in our society. Although the marine industry is a contributor to these problems, it can also be part of the solution, yet several challenges must be addressed. Sustainability and related concepts, such as ecosystem services, planetary boundaries and resilience thinking, could be used as guidance in addressing these challenges. Humans have always had a close relationship with the aquatic environment. Indeed, a scientific discussion debates whether the first humans evolved in a dry land environment, on the savannah, or in shallow water environments (as the "water man" or "aquatic ape") [1]. With respect to environmental awareness, the sea has come into focus relatively late compared with other natural areas. Independent of this observation, the sea has served as an important transportation route and a source of food and recreation throughout history. In a world where more than 70 % of the surface is covered by oceans, our interaction with and dependence on the sea in numerous aspects is obvious.
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| 3. |
- Baldi, Francesco, 1986
(författare)
-
Modelling, analysis and optimisation of ship energy systems
- 2016
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Doktorsavhandling (övrigt vetenskapligt/konstnärligt)abstract
- Shipping is the backbone of today's economy, as 90% of global trade volumes is transported by sea. Much of our lifestyle today is only made possible by the existence of shipping as a cheap and reliable mean of transportation across the globe.However, the shipping industry has been challenged in the latest years by, among others, fluctuating fuel prices and stricter environmental regulations. Its contribution to global warming, although today relatively small, has been set under scrutiny: for shipping to be part of a sustainable economy, it will need to reduce its emissions of greenhouse gases.Increasing ship energy efficiency allows reducing fuel consumption and, hence, carbon dioxide emissions. The latest years have witnessed a multiplication of the efforts in research and development for increasing ship energy efficiency, ranging from improvements of existing components to the development of new solutions. This has also contributed to ship energy systems to become more complex. The optimisation of the design and operation of complex systems is a challenging process and the risks for sub-optimisation are high.This thesis aims at contributing to the broader field of energy efficiency in shipping by adopting a systems perspective, which puts a special focus on system requirements and on interactions within the system. In this thesis, the energy systems of two case study ships were analysed using energy and exergy analysis to identify energy flows and inefficiencies. Then, solutions for improving the energy efficiency of the existing systems were proposed and evaluated accounting for the ship's observed operating range and for how added elements influenced the existing systems and their performance. The results of this thesis show the importance of modelling the interactions between different parts of the energy systems. This allows not only a more accurate estimation of the benefits from the installation of new technologies, but also the identification of potential for additional energy savings. This is particularly important when the broad range of ship operations is included in the analysis, rather than focusing on the performance of the system in design conditions. In addition, the results of this thesis also show that there is potential for further improving ship energy efficiency by putting additional focus on heat losses from the engines and on how to efficiently recover them.
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| 4. |
- Baldi, Francesco, 1986, et al.
(författare)
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The application of process integration to the optimisation of cruise ship energy systems: A case study
- 2016
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Ingår i: ECOS 2016 - Proceedings of the 29th International Conference on Efficiency, Cost, Optimisation, Simulation and Environmental Impact of Energy Systems. - 9789616980159
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Konferensbidrag (refereegranskat)abstract
- In recent years, the shipping industry has faced an increasing number of challenges in terms of fluctuating fuel prices, stricter environmental regulations, and concerns about global warming. In this situation, passenger volumes on cruise ships have increased from around 4 million to 13 million from 1990 to 2008 and keep growing today. A small cruise ship can emit about 85 tons of CO2 per day, and require around 27 tons of fuel per day. To keep up with market demand, while reducing their impact on the environment, cruise ships will need to improve their energy efficiency. Most previous research in marine technology relates to energy efficiency focused on propulsion, which for most ship types constitutes the largest energy demand. On cruise ships, however, auxiliary heat and electric power also have a significant importance. For this reason, we focus in this paper on the heat demand and its integration with available sources of waste heat on board. In this study, the principles of process integration are applied to the energy system of a cruise ship operating in the Baltic Sea. The heat sources (waste heat from the main and auxiliary engines in form of exhaust gas, cylinder cooling, charge air cooling, and lubricating oil cooling) and sinks (HVAC, hot water, fuel heating) are evaluated based on one year of operational data and used to generate four operating conditions that best represent ship operations. Applying the pinch analysis to the system revealed that the theoretical potential for heat integration on board could potentially allow the reduction of the external heat demand by between 35% and 85% depending on the investigated case. A technoeconomic optimisation allowed the identification of the most economically viable heat exchanger network designs: two in the “retrofit” scenario and one in the “design” scenario, with a reduction of 13-33%, 15-27% and 46-56% of the external heat demand, respectively. Given the high amount of heat being available after the process integration, we also analysed the potential for the installation of a steam turbine for the recovery of the energy available in the exhaust gas, which resulted in up to 900 kW of power being available for on board electric power demand.
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| 5. |
- Brynolf, Selma, 1984, et al.
(författare)
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Energy efficiency and fuel changes to reduce environmental impacts
- 2016
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Ingår i: Shipping and the Environment: Improving Environmental Performance in Marine Transportation. - Berlin, Heidelberg : Springer Berlin Heidelberg. - 9783662490457 ; , s. 295-339
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Bokkapitel (övrigt vetenskapligt/konstnärligt)abstract
- Many different emissions from ships are directly related to a ship's fuel consumption. This is particularly true for emissions to air, which are generated during the combustion process in the engines. Hence, improving the conversion process from fuel energy to transport work can be an effective means of reducing ship emissions. Solutions for reducing ship fuel consumption are generally divided into design and operational measures. Design measures primarily include technical solutions implemented when the ship is designed, constructed, and retrofitted, such as weightreduction, hull coatings, air lubrication, improvement of hull design, optimal propulsion systems and harvesting waste energy. Operational measures are related to how the ship or the fleet is operated and include measures such as weather routing, optimal ship scheduling, improved ship logistics, and on-board energy management. Although reducing fuel consumption always generates an environmental benefit, it should be noted that the use of different fuels results in different impacts on the environment for a given energy conversion efficiency. Another way to reduce emissions is therefore related to the type of fuel used on a ship, e.g., diesel fuels, gases, alcohols and solid fuels. However, choosing a fuel is not an easy process because it is influenced by a broad range of criteria, including technical, environmenta l and economic criteria.
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| 6. |
- Brynolf, Selma, 1984, et al.
(författare)
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Improving environmental performance in shipping
- 2016
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Ingår i: Shipping and the Environment: Improving Environmental Performance in Marine Transportation. - Berlin, Heidelberg : Springer. - 9783662490457 ; , s. 399-418
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Bokkapitel (övrigt vetenskapligt/konstnärligt)abstract
- This book addresses the environmental issues related to shipping and the natural environment, including descriptions of and proposed solutions to the issues. Currently, challenges exist that must be addressed if shipping is to become sustainable and fulfil the zero vision of no harmful emissions to the environment. In this chapter, we evaluate the steps that have been taken (if any) to limit the various environmental issues and discuss possible steps to be taken to improve environmental performance. Furthermore, future challenges must also be addressed, e.g., the current trend of increasing ship operations in the Arctic. In general, three factors could be addressed in order to reach environmentally sustainable shipping: regulations, technical solutions, and increased environmental awareness. © Springer-Verlag Berlin Heidelberg 2016. All rights are reserved.
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