We experimentally study the thermal conductance of single-tube and loop heat pipes for a solar collector. The evaporator of the heat pipe is 1 m long, 6 mm in diameter and has 30° inclination. The thermal conductance is defined as the heat transfer rate divided by the temperature difference between the evaporator-wall and the condenser-wall. Effects of heat transfer rate, saturation temperature of the working fluid, liquid filling ratio, inclination angle, and position of the evaporator on the thermal conductance are examined. We found that the thermal conductance of the 30°-inclined loop heat pipe with an upper-evaporator is 40–50 (W/K), which is 1.8 times higher than that of the vertical loop type and 3 times higher than that of the single-tube type. Thus, the inclined loop heat pipe is preferable for a solar collector. There is an optimum liquid filling ratio. When the liquid filling ratio is too small, a dry-out portion appears in the evaporator. When the liquid filling ratio is too large, the liquid flows in the condenser to decrease heat transfer area. Also we numerically analyze the thermal conductance of a vertical loop heat pipe.
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ASME 2012 International Mechanical Engineering Congress and Exposition
November 9–15, 2012
Houston, Texas, USA
Conference Sponsors:
- ASME
ISBN:
978-0-7918-4523-3
PROCEEDINGS PAPER
Study on Heat Transfer Characteristics of Loop Heat Pipe for Solar Collector
Shota Sato,
Shota Sato
Kobe University, Kobe, Hyogo, Japan
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Shigeki Hirasawa,
Shigeki Hirasawa
Kobe University, Kobe, Hyogo, Japan
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Tsuyoshi Kawanami,
Tsuyoshi Kawanami
Kobe University, Kobe, Hyogo, Japan
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Katsuaki Shirai
Katsuaki Shirai
Kobe University, Kobe, Hyogo, Japan
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Shota Sato
Kobe University, Kobe, Hyogo, Japan
Shigeki Hirasawa
Kobe University, Kobe, Hyogo, Japan
Tsuyoshi Kawanami
Kobe University, Kobe, Hyogo, Japan
Katsuaki Shirai
Kobe University, Kobe, Hyogo, Japan
Paper No:
IMECE2012-86260, pp. 1573-1581; 9 pages
Published Online:
October 8, 2013
Citation
Sato, S, Hirasawa, S, Kawanami, T, & Shirai, K. "Study on Heat Transfer Characteristics of Loop Heat Pipe for Solar Collector." Proceedings of the ASME 2012 International Mechanical Engineering Congress and Exposition. Volume 7: Fluids and Heat Transfer, Parts A, B, C, and D. Houston, Texas, USA. November 9–15, 2012. pp. 1573-1581. ASME. https://doi.org/10.1115/IMECE2012-86260
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