Transactions of the Korean Society of Mechanical Engineers B (대한기계학회논문집B)

The Korean Society of Mechanical Engineers (대한기계학회)
권호 표지
DOI QR코드

DOI QR Code

Numerical Analysis of Heat Transfer in Multichannel Volumetric Solar Receivers

다채널 체적식 태양열 흡수기에서 열전달 수치해석

  • Lee, Hyun-Jin (Solar Thermal and Geothermal Center, Korea Institute of Energy Research) ;
  • Kim, Jong-Kyu (Solar Thermal and Geothermal Center, Korea Institute of Energy Research) ;
  • Lee, Sang-Nam (Solar Thermal and Geothermal Center, Korea Institute of Energy Research) ;
  • Kang, Yong-Heack (Solar Thermal and Geothermal Center, Korea Institute of Energy Research)
  • 이현진 (한국에너지기술연구원 태양열지열센터) ;
  • 김종규 (한국에너지기술연구원 태양열지열센터) ;
  • 이상남 (한국에너지기술연구원 태양열지열센터) ;
  • 강용혁 (한국에너지기술연구원 태양열지열센터)
  • Received : 2011.05.17
  • Accepted : 2011.08.25
  • Published : 2011.12.01
Download PDF
⟨ Previous Next ⟩

Abstract

The current study focuses on the consistent analysis of heat transfer in multichannel volumetric solar receivers used for concentrating solar power. Changes in the properties of the absorbing material and channel dimensions are considered in an optical model based on the Monte Carlo ray-tracing method and in a one-dimensional heat transfer model that includes conduction, convection, and radiation. The optical model results show that most of the solar radiation energy is absorbed within a very small channel length of around 15 mm because of the large length-to-radius ratio. Classification of radiation losses reveals that at low absorptivity, increased reflection losses cause reduction of the receiver efficiency, notwithstanding the decrease in the emission loss. As the average temperature increases because of the large channel radius or small mass flow rate, both emission and reflection losses increase but the effect of emission losses prevails.

본 연구는 태양열 발전에 사용하는 공기식 다채널 체적식 흡수기의 일관성 있는 열전달 해석에 초점을 두고 있다. 이를 위해 흡수 소재 물성과 채널 형상 변화의 영향을 몬테카를로 광선추적법에 기반한 광학 모델과 전도, 대류, 복사를 고려한 1 차원 열전달 모델에 동시에 반영하였다. 광학 모델 결과는 채널 반경 대비 길이의 형상비가 매우 커서 대부분의 태양 에너지는 15 mm 이내의 짧은 길이에서 흡수됨을 증명하고 있다. 복사 열손실 분류를 통해 채널의 낮은 흡수율에서는 방사 손실은 줄지만 반사손실이 증가하여 흡수기 효율이 감소하는 것을 보였다. 큰 채널 반경이나 작은 질량 유량으로 인해 흡수기 평균 온도가 상승할 때, 방사 손실과 반사 손실 모두 증가하지만 방사 손실의 영향이 더 큰 것으로 나타났다.

Keywords

References

  1. Romero-Alvarez, M. and Zarza, E., 2007, Handbook of Energy Efficiency and Renewable Energy, Taylor & Francis, Taylor & Francis, New York, Chapter 21.
  2. Fend, T., Hoffschmidt, B., Pitz-Paal, R., Reutter, O. and Rietbrock, P., 2004, "Porous Materials as Open Volumetric Solar Receivers: Experimental Determination of Thermophysical and Heat Transfer Properties," Energy, Vol. 29, pp. 823-833. https://doi.org/10.1016/S0360-5442(03)00188-9
  3. Agrafiotis, C. C., Mavroidis, I., Konstandopoulos, A. G., Hoffschmidt, B., Stobbe, P., Romero, M. and Fernandez-Quero, V., 2007, "Evaluation of Porous Silicon Carbide Monolithic Honeycombs as Volumetric Receivers/Collectors of Concentrated Solar Radiation," Sol. Energ. Mat. Sol. C., Vol. 91, pp. 474-488. https://doi.org/10.1016/j.solmat.2006.10.021
  4. Pitz-Paal, R., Hoffschmidt, B., Bohmer, M. and Becker, M., 1997, "Experimental and Numerical Evaluation of the Performance and Flow Stability of Different Types of Open Volumetric Absorbers under Non-Homogeneous Irradiation," Sol. Energy, Vol. 60, Nos. 3-4, pp. 135-150. https://doi.org/10.1016/S0038-092X(97)00007-8
  5. Xu, C., Song, Z., Chen, L, and Zhen, Y., 2011, "Numerical Investigation on Porous Media Heat Transfer in a Solar Tower Receiver," Renew. Energ., Vol. 36, pp. 1138-1144. https://doi.org/10.1016/j.renene.2010.09.017
  6. Carotenuto, A., Ruocco, G. and Reale, F., 1991, "Heat Exchange in a Multi-Cavity Volumetric Solar Receiver," Sol. Energy, Vol. 46, No. 4, pp. 241-248. https://doi.org/10.1016/0038-092X(91)90069-9
  7. Carotenuto, A., Reale, F., Ruocco, G., Nocera, R. and Bonomo, F., 1993, "Thermal Behavior of a Multi- Cavity Volumetric Solar Receiver: Design and Tests Results," Sol. Energy, Vol. 50, No. 2, pp. 113-121. https://doi.org/10.1016/0038-092X(93)90082-Y
  8. Carcia-Casals, X. and Ajona, J. I., 1999, "The Duct Selectivity Volumetric Receivers: Potential for Different Selectivity Strategies and Stability Issues," Sol. Energy, Vol. 67, Nos. 4-6, pp. 265-286. https://doi.org/10.1016/S0038-092X(00)00076-1
  9. Bai, F., 2010, "One Dimensional Thermal Analysis of Silicon Carbide Ceramic Foam Used for Solar Air Receiver," Int. J. of Therm. Sci., Vol. 49, pp. 2400-2404. https://doi.org/10.1016/j.ijthermalsci.2010.08.010
  10. Siegel, R. and Howell, J. R., 2002, Thermal Radiation Heat Transfer, 4th ed., Taylor & Francis, New York, pp. 371-390.
  11. Byun, D. Y., Lee, C. J. and Chang, S. Y., 2004, " Radiative Heat Transfer in Discretely Heated Irregular Geometry with an Absorbing, Emitting, and Anisotropically Scattering Medium Using Combined Monte-Carlo and Finite Volume Method," Trans. of the KSME(B), Vol. 28, No. 5, pp. 580-586.
  12. Lee, H. J., Kim, J. K., Lee, S. N. and Kang, Y. H., 2011, "Heat Flux Analysis of a Solar Furnace Using the Monte Carlo Ray-Tracing Method," Trans. of the KSME(B), in press. https://doi.org/10.3795/KSME-B.2011.35.10.989
  13. Lee, H. J., Kim, J. K., Lee, S. N. and Kang, Y. H., 2011, "Concentrated Solar Flux Modeling for the Heat Transfer Analysis of Multi-Channeled Solar Receivers," J. of the KSES, in press. https://doi.org/10.7836/kses.2011.31.4.041

Cited by

  1. Thermal characteristics of a volumetric solar absorption system vol.38, pp.5, 2013, https://doi.org/10.1002/er.3063