The chapter "Thermal Design and Optimization" from the book "Thermal System Design" by Adrian Bejan, George Tsatsaronis, and Michael Moran covers the fundamentals and advanced topics in thermal system design. It begins with an introduction to the design process, including project management, documentation, and the importance of understanding the problem. The chapter then delves into thermodynamics, modeling, and design analysis, providing a comprehensive overview of the first and second laws of thermodynamics, control volume concepts, and property relations. It also discusses exergy analysis, heat transfer, and the application of these principles in various systems such as thermal insulation, fins, electronic packages, and heat exchangers. The economic analysis section addresses cost estimation, revenue requirements, and profitability evaluation. Finally, the chapter explores thermoeconomic analysis and optimization techniques, including cost-optimal exergetic efficiency, optimization of heat exchanger networks, and analytical and numerical optimization methods. The chapter concludes with appendices that provide additional resources, including variational calculus, economic models, property data tables, symbols, and conversion factors.The chapter "Thermal Design and Optimization" from the book "Thermal System Design" by Adrian Bejan, George Tsatsaronis, and Michael Moran covers the fundamentals and advanced topics in thermal system design. It begins with an introduction to the design process, including project management, documentation, and the importance of understanding the problem. The chapter then delves into thermodynamics, modeling, and design analysis, providing a comprehensive overview of the first and second laws of thermodynamics, control volume concepts, and property relations. It also discusses exergy analysis, heat transfer, and the application of these principles in various systems such as thermal insulation, fins, electronic packages, and heat exchangers. The economic analysis section addresses cost estimation, revenue requirements, and profitability evaluation. Finally, the chapter explores thermoeconomic analysis and optimization techniques, including cost-optimal exergetic efficiency, optimization of heat exchanger networks, and analytical and numerical optimization methods. The chapter concludes with appendices that provide additional resources, including variational calculus, economic models, property data tables, symbols, and conversion factors.