1997 Fiscal Year Final Research Report Summary
Development of energy conversion system of highly concentrated solar energy transmitted by an optical fiber
| Project/Area Number |
08555050
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| Research Category |
Grant-in-Aid for Scientific Research (A)
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| Allocation Type | Single-year Grants |
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| Section | 展開研究 |
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| Research Field |
Thermal engineering
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| Research Institution | Tohoku University |
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Principal Investigator |
NAITO Hitoshi Tohoku University, Graduate School of Engineering, Research Associate, 大学院・工学研究科, 助手 (40270813)
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| Co-Investigator(Kenkyū-buntansha) |
OKA Toshiharu Ishikawajimaharima Heavy Industry, Co.Ltd, Researcher, 研究員
YUGAMI Hiroo Tohoku University, Graduate School of Engineering, Associate Professor, 大学院・工学研究科, 助教授 (60192803)
SAITOH Takeo Tohoku University, Graduate School of Engineering, Professor, 大学院・工学研究科, 教授 (80064161)
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| Project Period (FY) |
1996 – 1997
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| Keywords | Solar Energy / Optical Fiber / CPC / Solar Energy Transmission / Concentrated Solar Energy |
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| Research Abstract |
The solar energy concentration system, coupled with an optical fiber, enables us to use highly concentrated solar energy at the desired place regardless of the position of a solar concentrator. We can use it as a heat or light source. This system is also useful for space applications. However, solar energy density decreases from at the end of the optical fiber according to its numerical aperture. To overcome this problem, we are investigating the CPC (Compound Parabolic Concentrator)coupled to the exit of an optical fiber. This method is capable of increasing the solar energy density.
We have constructed the system, which was composed of the auto-tracking parabolic concentrator, the optical fiber bundle, and the CPC.A heat flux was measured and transmission efficiency was evaluated. The transmission efficiency distribution in the optical fiber was not uniform and was very low compared to the theoretical one. It was due to the degradation of the surface and edge of each fiber. As for CPC,we have experimentally confirmed that the solar energy density from CPC increased 3.67 times as that of an optical fiber bundle output. This result coincides with the theoretical one. If the optical fiber bundle works as well as that of theoretical one and the direct solar insolation is 800W/m^2,900W/cm^2 of concentrated solar power density at the output of CPC can be obtained. This value is sufficient to provide energy to latent heat thermal storage system, in which LiF and LiF/CaF_2 are used as phase change materials.
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