| dc.description.abstract | The strict environmental regulations for the marine sector directed the research studies and industries to develop solutions in compliance with new goals of promoting efficiency and decreasing emissions. Among the solutions, alternative fuels such as hydrogen, ammonia, and methanol can be a solution to comply with the emission reduction objectives. Indeed, fuel cells are introduced as a promising candidate which are compatible with alternative fuels for converting the stored chemical energy to electrical power onboard. The new solutions raised challenges for the researchers and designers to deal with cost, reliability, sustainability, life cycle, lifetime, and performance. However, the mathematical models and simulators can evaluate the new concepts in the early steps of the design to estimate the performance and help propose practical concepts.
Simulation and modeling are powerful tools that facilitate predicting the system’s performance and responses. Modeling a vessel as a complex system is a challenging endeavor because of encompassing different subsystems with various domains and dynamics with coupled interactions. The detail of capturing the interactions of the components and overall performance is known as fidelity and, depending on the simulation purpose and expected accuracy, affects the models’ computational and development effort. System-level models provide a comprehensive understanding of the overall system behavior and responses with a reasonable computational burden.
The new solutions for the power plant provide various choices and uncertainties about the performance regarding the configurations, components’ size, and operations strategies. The proper models with size and configurations flexibility framework enable evaluating different concepts for the power plant with new power suppliers such as fuel cells. Indeed, integration of the power plant with the vessel model provides a full-system simulator to study the system behavior in different maneuvering and environmental conditions to find the proper size, optimum operation strategy, testing, designing, and assessing the feasibility. The full-system vessel simulator encompasses different models with different disciplines developed with various modeling methods to be integrated. As an efficient approach, co-simulation provides a solution to integrate the different models to build a full-system simulator.
This work mainly contributes to developing a full-system simulator with real-time capabilities by developing fuel cell-fed power plants and integrating the developed vessel model and propulsion systems of NTNU bond graph model library. Firstly, the PEMFC and SOFC with system-level fidelity, size flexibility, and auxiliary components are modeled for the marine application. Secondly, the battery, DC converters, low- and high-level controllers, power management system, and energy management system are modeled to develop a DC hybrid power system with average-based assumptions for the electrical components. Thirdly, the developed power plant is integrated into the vessel model and propulsion system of an offshore supply vessel from the marine NTNU library with a co-simulation approach. The integration aims to analyze various power plant configurations in different realistic operations. Lastly, different power plant concepts from ship design companies for an offshore supply vessel are investigated in the dynamic positioning and cruising operations to study the performance of each configuration. The proposed models and simulations have size and configuration flexibility for further case studies and developments. | en_US |
