To develop solutions toward higher power generation sustainability, a hybrid power cycle is proposed and analyzed in this dissertation work. The hybrid cycle is based on a supercritical carbon dioxide Brayton power cycle but with two heat input sources, solar and fossil fuel. The environmental emissions of the proposed cycle are zero. To validate the proposed hybrid cycle, the dissertation work is divided into three parts. The first part is to evaluate the thermodynamics of the hybrid by conducting a study based on the first law of thermodynamics. The study revealed that the hybrid is compatible and can provide the required power generation targets. It also revealed that the hybrid has massive heat losses in the coolers as it loses up to 45% of the cycle energy input. Hence, it is recommended to exploit the energy losses by integrating the hybrid with a bottom cycle to produce power or freshwater. The second part of the research involves a dynamic analysis of one of the main cycle units, its recuperator. The recuperator is designed as a countercurrent tube and shell heat exchanger. The dynamic study revealed that CO2 properties are influenced by small fluctuations in mass flowrate on the hot side and temperature changes on the cold side of the heat exchanger. Hence, it is vital to develop a better understanding of the parameters affecting the dynamic behavior of the recuperator. In addition, control systems and cycle equipment design should consider both steady and unsteady state conditions. The third and final part of the research is focused on the economics of the hybrid cycle. This part of the research involves the energy, exergy, and economical attributes of the cycle. The exergoeconomic study is conducted to reveal the cycle's energy losses and propose appropriate improvements to acquire better efficiency, higher outputs, and minimize losses and cost.
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Doctor of Philosophy (Ph.D.)
College of Engineering and Computer Science
Mechanical and Aerospace Engineering
Length of Campus-only Access
Doctoral Dissertation (Campus-only Access)
Alenezi, Abdurrahman, "Dynamic and Exergoeconomic Analysis of a Hybrid Supercritical Carbon Dioxide Brayton Cycle" (2020). Electronic Theses and Dissertations, 2020-. 323.
Restricted to the UCF community until December 2025; it will then be open access.