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Session: System design and optimization II
Session starts: Tuesday 08 October, 09:00
Presentation starts: 09:00
Room: Ruys & Rijckenvorsel Zaal

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Santiago Suarez de la Fuente (University College London)
Alistair Greig (University College London)

Abstract:
The predictions of CO2 atmospheric concentrations by 2050 are between 480 ppm to 550 ppm with increases of temperature from 0.5 to 2.5°C; shipping contributes in 3.3% of the total human CO2 emissions (1). It is therefore important to start generating green and intelligent solutions based on new strategies and technologies, which will help to follow a green agenda in shipping. The biggest source of energy losses in a ship is found in the propulsion system (1). This study focuses on analyzing and working with the concept of heat management for waste heat energy from the exhaust gas. Using waste heat recovery systems to make shipping more efficient represents a good area of opportunity from an academic and industrial point of view. Organic Rankine Cycles have been applied in land based systems before, showing improvements in performance when compared with traditional Rankine cycle (2–4). However, their use in ships has been limited, offering an important area of opportunity to be considered (5,6). The proposed ORC waste heat recovery system is modelled with a typical ship main propulsion, slow speed diesel engine installed after the turbo compressors in the exhaust gas system. The energy recovered from the exhaust gas flow will be transformed via the thermodynamic cycle into electricity which will help to cover the ship demand. By doing this there will be a fuel consumption reduction, hence decreasing the emissions of CO2 and other greenhouse gases. A code generated explicitly for this purpose will show the behaviour of different working fluids appropriate for the chosen scenario at each stage of the thermodynamic cycle. With this it is possible to demonstrate that a simple ORC can be more effective than a water based Rankine cycle, challenging previous research and common standards for the industry. This research project will provide new knowledge on thermodynamics and waste heat recovery systems with a simulation model to enable the use of accurate information to experiment for ship design and identify new areas of opportunity and improvement. The presentation will include the relevant literature that anchors the research, its strengths, weaknesses and gaps. Then, it shows a quantitative comparison that uses the first and second thermodynamic laws and pinch point analysis. With those tools a consistent and unbiased decision-making model is elaborated for ships operating under different and changing conditions. That will allow identification of areas of improvement of thermodynamic technologies. Benefits of this research are threefold. From the academic perspective it increases the knowledge on thermodynamics and behaviour of waste heat recovery systems in challenging environments. From the industrial point of view it will find areas of opportunity for ship design attractive to the consumer and in a cost efficient basis. For the society in general, it represents a possibility of environmental friendly transportation that helps to reduce CO2 emissions.