| 1. |
- Baldi, Francesco, 1986, et al.
(författare)
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Analysis of the influence of the engine, propeller and auxiliary generation interaction on the energy efficiency of controllable pitch propeller ships
- 2014
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Ingår i: International Conference of Maritime Technology.
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Konferensbidrag (refereegranskat)abstract
- In a context of increasing requirements for energy efficiency, this paper aims at improving theunderstanding on the interaction between engine, propeller, and auxiliary heat and power generation in theparticular case of controllable pitch propeller (CPP) ships. The case study of a CPP propelled chemical tankeris used to analyze the application of the proposed approach. The performance of the ship’s standardarrangement using a shaft generator for the fulfillment of auxiliary power demand is compared to theoperational alternative of using auxiliary engines, and with the possibilities for retrofitting with frequencyconverters and waste heat recovery systems. The influence of control systems parameters and of sea state arealso analyzed and compared. The results show a large possibility for improvements, both via operationaloptimization (up to 8.3% increased energy efficiency) and via different types of retrofitting (with increasedefficiencies of up to 11.4% for frequency converters, and 16.5% for WHR systems). The influence of a broadoperational envelope brings even larger improvements to the efficiency of the energy system at low speeds. Theresults of the paper provide useful information about the influence of different technologies for auxiliary powergeneration on the efficiency of CPP propelled vessels.
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| 2. |
- Baldi, Francesco, 1986, et al.
(författare)
-
Energy analysis of a ship - the case study of a chemical tanker
- 2014
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Ingår i: Energy Procedia. - : Elsevier BV. - 1876-6102. ; 61, s. 1732-1735
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Konferensbidrag (refereegranskat)abstract
- Improved understanding of ship energy use can be a crucial part of the process of increasing ship energy efficiency. In this paper, the methodology of energy analysis is applied to ship energy systems in order to showcase the benefits of such methodology. Data from one year of operations of a case study ship were used, together with mechanistic knowledge of ship systems, in order to evaluate the different energy flows. The identification of main producers, consumers and waste flows, allowed by the application of the method, leads to the suggestion of a number of possible improvements guided by the improved knowledge of the ship's energy system.
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| 3. |
- Baldi, Francesco, 1986, et al.
(författare)
-
Energy and exergy analysis of ship energy systems - the case study of a chemical tanker
- 2014
-
Ingår i: 27th ECOS, International Conference on Efficiency, Cost, Optimization, Simulation and Environmental Impact of Energy Systems. - 9781634391344
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Konferensbidrag (refereegranskat)abstract
- Shipping is already a relevant contributor to global carbon dioxide emissions, and its share is expected to grow together with global trade in the coming years. At the same time, bunker prices are increasing and companies start to feel the pressure of growing fuel bills in their balance sheet. In order to address both challenges, it is important to improve the understanding of how ship energy consumption is generated, through a detailed analysis of its energy systems. In this paper, a method for the analysis of ship energy systems is proposed and applied on one year of operations of a chemical tanker, for which both measurements and mechanistic knowledge of ship systems were available. Energy analysis applied to the case-study vessel allowed comparing different energy flows and therefore identifying system components and interactions critical for ship energy consumption. Exergy analysis allowed instead identifying main inefficiencies and evaluating waste flows. This last information was then processed in order to estimate the potential for waste energy recovery under different conditions. Results showed that propulsion is the main contributor to ship energy consumption (70%), but that also auxiliary heat (16.5%) and power (13.5%) needs are relevant sources of energy consumption. The potential for waste heat recovery is relevant, especially in the exhaust gas, which contains an exergy flow sized 18% of engine power output.
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| 4. |
- Baldi, Francesco, 1986, et al.
(författare)
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From Energy Flows to Monetary Flows - An Innovative Way of Assessing Ship Performances Through Thermo-Economic Analysis
- 2012
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Ingår i: International Association of Maritime Economists Conference (IAME 2012 Taipei)..
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Konferensbidrag (refereegranskat)abstract
- Recent events concerning world economy, environmental policies and resources depletion have grown a large interest in the matter of reducing energy consumption. Unfortunately, even if several cost-effective measures could bring to sensible reductions in fuel consumption, shipping industry is often much reluctant to act in this direction. It is in the opinion of the authors, based on recent studies on the subject (Johnson, 2012),(Johnson, 2011), that a primary reason for this behavior lays in the lack of clear and effective tools for including these matters in the decision making processes. Therefore, the aim of this paper is to propose a new and innovative methodology for improving communication between technical and management departments of a shipping company when dealing with ship fuel consumption analysis. This will be done by making use of Sankey diagrams as graphical support and by converting energy flows to monetary flows, thus showing how energy is being used by different components or wasted to the environment in a much tangible manner. A case study will be presented in order to support the analysis with numerical values.
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| 5. |
- Larsen, Ulrik, 1972, et al.
(författare)
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Design and optimisation of organic Rankine cycles for waste heat recovery in marine applications using the principles of natural selection
- 2013
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Ingår i: Energy. - : Elsevier BV. - 0360-5442. ; 55, s. 803-812
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Tidskriftsartikel (refereegranskat)abstract
- Power cycles using alternative working fluids are currently receiving significant attention. Selection of working fluid among many candidates is a key topic and guidelines have been presented. A general problem is that the selection is based on numerous criteria, such as thermodynamic performance, boundary conditions, hazard levels and environmental concerns. A generally applicable methodology, based on the principles of natural selection, is presented and used to determine the optimum working fluid, boiler pressure and Rankine cycle process layout for scenarios related to marine engine heat recovery. Included in the solution domain are 109 fluids in sub and supercritical processes, and the process is adapted to the properties of the individual fluid. The efficiency losses caused by imposing process constraints are investigated to help propose a suitable process layout. Hydrocarbon dry type fluids in recuperated processes produced the highest efficiencies, while wet and isentropic fluids were superior in non-recuperated processes. The results suggested that at design point, the requirements of process simplicity, low operating pressure and low hazard resulted in cumulative reductions in cycle efficiency. Furthermore, the results indicated that non-flammable fluids were able to produce near optimum efficiency in recuperated high pressure processes.
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