Hu, Chehao (2018-08). Light Pipe Design for Solar Concentrator. Doctoral Dissertation. Thesis uri icon

abstract

  • This dissertation includes three main sections: 1. Planar waveguide solar concentrator 2. Modeling light pipe scattering loss 3. Trade-off of the concentrator design. All of the simulations are accomplished by Zemax, TracePro, and Matlab. Each of this three software has their own advantages, for example, Zemax is handy to trace rays as several different conditions, TracePro has many professional built-in tools (e.g., Solar simulator), and Matlab allows more freedom of simulation. In the first section, we discuss the first design of the planar waveguide solar concentrator in this world proposed by Karp, a design made by Liu that improves the Karp's first design, and a new design that satisfy the fabrication requirements. This new design achieves 30% of total harvesting efficiency under the low-DNI condition, 1000X concentration, 99.98% geometric efficiency, and 0.9? of acceptance angle. In the second section, we go through the scattering loss of a light pipe and propose a new model to calculate the average scattering loss of a light pipe by the given RMS slope (m) of the surface. We demonstrate the RMS slope is a better indicator to represent the characteristics of a rough surface. In the last section, we propose a new structure which improves the design shown in the first section, but the fabrication issues are not taken in to account. This structure has an extra lens above the waveguide to parallel the rays that enter the waveguide. By doing so to alleviate loss caused by HR coating and surface roughness. We also discuss the tradeoffs of using a compound parabolic concentrator and linear concentrator.
  • This dissertation includes three main sections: 1. Planar waveguide solar concentrator 2. Modeling light pipe scattering loss 3. Trade-off of the concentrator design. All of the simulations are accomplished by Zemax, TracePro, and Matlab. Each of this three software has their own advantages, for example, Zemax is handy to trace rays as several different conditions, TracePro has many professional built-in tools (e.g., Solar simulator), and Matlab allows more freedom of simulation.
    In the first section, we discuss the first design of the planar waveguide solar concentrator in this world proposed by Karp, a design made by Liu that improves the Karp's first design, and a new design that satisfy the fabrication requirements. This new design achieves 30% of total harvesting efficiency under the low-DNI condition, 1000X concentration, 99.98% geometric efficiency, and 0.9? of acceptance angle.
    In the second section, we go through the scattering loss of a light pipe and propose a new model to calculate the average scattering loss of a light pipe by the given RMS slope (m) of the surface. We demonstrate the RMS slope is a better indicator to represent the characteristics of a rough surface.
    In the last section, we propose a new structure which improves the design shown in the first section, but the fabrication issues are not taken in to account. This structure has an extra lens above the waveguide to parallel the rays that enter the waveguide. By doing so to alleviate loss caused by HR coating and surface roughness. We also discuss the tradeoffs of using a compound parabolic concentrator and linear concentrator.

publication date

  • August 2018