Browsing by Author "Al-Hamed, Khaled H. M."

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Analysis and optimization of fuel cell based integrated powering systems for clean rail applications
(2019-08-01) Al-Hamed, Khaled H. M.; Dincer, Ibrahim
In this thesis, proposals of novel integrated fuel cell powering systems for cleaner railway applications are presented and analyzed thermodynamically. Both energy and exergy analyses are conducted on these systems for such an application to evaluate and compare them thermodynamically, in terms of their power outputs capabilities and energetic and exergetic efficiencies. Next, parametric studies on each of the proposed integrated fuel cell systems are provided to have a deeper understanding of the operation of these systems under various conditions. This understanding can help us in the optimization of exergetic efficiency and packaging feasibility of the systems in a locomotive. A newly introduced method of multi-objective optimization is implemented to optimize the integrated systems in terms of exergetic efficiencies, power split for space reductions, and hydrogen production rate. Lastly, economic and environmental justifications are given through a case study of a duty cycle of a passenger train. Fuel costs and CO2 emissions of these proposed integrated systems are compared to the current technology of diesel-electric engines used in railways of Canada. The thermodynamic analysis shows that these systems can reach high energetic and exergetic efficiencies of 80.06% and 77.55%, respectively for methane-based solid oxide fuel cell systems, while ammonia-based systems have the values of energetic and exergetic efficiencies of 61.20%, and 66.30%, respectively. Fuel costs of passenger train operation, using these proposed systems, are significantly reduced compared to diesel-electric engines. The most efficient system is system 3 and has a brake specific fuel consumption of 0.08902 kg kWh-1, whereas a typical diesel-electric engine has a value of 0.2318 kg kWh-1.
Modeling and experimental investigation of renewable energy and ammonia-based systems for carbon capturing and useful outputs
(2022-04-01) Al-Hamed, Khaled H. M.; Dincer, Ibrahim
This thesis work focuses on developing ammonia-based carbon capturing systems that produce useful chemical outputs to offset the energy penalty typically imposed by implementing a carbon capture retrofitting to a power plant. These systems have been investigated through models that are based on exergy and economics tools. The motivation, and the objectives of this work are mentioned. Next, a thorough literature review of the topic of ammonia-based carbon capture systems is provided here to identify the gaps in knowledge. This review concluded that there is a significant lack in experimental investigations of ammonia-based carbon capture systems that are powered by renewable energy sources. Also, the direction of future carbon capture systems is moving towards co-producing of useful and valuable chemicals to offset the costs of operating such systems. By knowing this, renewable energy and ammonia-based carbon capturing systems that produce ammonium bicarbonate are developed and described. Thermodynamic models of the present carbon capturing systems are established using the energy and exergy tools. After that, exergoeconomic models are explained for these systems. Results of the simulation work show that the use of an electrochemical ammonia synthesizer has 13.3% lower energy requirements compared to the use of a proton-exchange membrane electrolyzer and the Haber-Bosch process for ammonia synthesis. The cost of producing ammonium bicarbonate is almost 16% of the market price of this chemical commodity. This indicates that the developed carbon capturing system are financially feasible to produce monetary value.