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 Study of Concentration Characteristics of Linear Fresnel Reflector System

선형 프레넬 반사판 시스템의 집광 특성에 대한 수치해석 연구

  • Lee, Hyun Jin (School of Mechanical Systems Engineering, Kookmin Univ.) ;
  • Kim, Jong Kyu (Solar Thermal Laboratory, Korea Institute of Energy Research) ;
  • Lee, Sang Nam (Solar Thermal Laboratory, Korea Institute of Energy Research)
  • 이현진 (국민대학교 기계시스템공학부) ;
  • 김종규 (한국에너지기술연구원 태양열연구실) ;
  • 이상남 (한국에너지기술연구원 태양열연구실)
  • Received : 2015.05.07
  • Accepted : 2015.09.29
  • Published : 2015.12.01
Download PDF
⟨ Previous Next ⟩

Abstract

In this study, we numerically investigated the concentration characteristics of a linear Fresnel reflector system that can drive a solar thermal absorption refrigeration system to be installed in Saudi Arabia. Using an optical modeling program based on the Monte Carlo ray-tracing method, we simulated the concentrated solar flux, concentration efficiency, and concentrated solar energy on four representative days of the year - the vernal equinox, summer solstice, autumnal equinox, and winter solstice. Except the winter solstice, the concentrations were approximately steady from 9 AM to 15 PM, and the concentration efficiencies exceed 70%. Moreover, the maximum solar flux around the solar receiver center changes only within the range of $13.0{\sim}14.6kW/m^2$. When we investigated the effects of the receiver installation height, reflector width, and reflector gap, the optimal receiver installation height was found to be 5 m. A smaller reflector width had a greater concentration efficiency. However, the design of the reflector width should be based on the capacity of the refrigeration system because it dominantly affects the concentrated solar energy. The present study was an essential prerequisite for thermal analyses of the solar receiver. Thus, an optical-thermal integration study in the future will assist with the performance prediction and design of the entire system.

고일사 지역인 사우디아라비아에서 태양열로 구동하는 흡수식 냉동 시스템 개발을 염두에 두고, 본 논문에서는 태양을 추적하는 선형 프레넬 반사판 시스템의 집광 특성을 수치해석 하였다. 몬테카를로 광선추적법을 기반으로 하는 광학 프로그램을 통해 집광 열유속, 집광 효율, 집광 에너지를 일년을 대표하는 춘분, 하지, 추분, 동지 날짜에 계산하였다. 동지를 제외하면, 9 시에서 15 시까지는 집광 성능이 일정한 가운데, 집광 효율도 70% 이상으로 높게 나타났다. 이 시간대에서 흡수기 중심 20% 영역에 모이는 최대 열유속은 하지 때 약 $13.0{\sim}14.6kW/m^2$ 범위에서 변했다. 집광 시스템의 설계 인자 중에서 흡수기 설치 높이, 반사판의 폭, 반사판 사이의 거리가 집광 효율을 조사해 보면, 흡수기 설치 높이는 반사판의 폭에 관계없이 5 m 에서 최적의 성능을 나타냈다. 반사판의 폭이 작을수록 집광 효율이 좋지만, 반사판의 폭은 집광 되는 에너지에 직접적으로 비례하기 때문에 냉동 시스템의 용량에 맞추어 설계가 필요하다. 본 연구는 흡수기의 열전달 해석의 중요한 선행조건이므로 향후에 광학-열전달 연계된 해석을 통해 전체 시스템의 성능을 예측하고 설계하는데 활용할 수 있을 것이다.

Keywords

References

  1. International Energy Agency (IEA) Report, 2010, Technology Roadmap: Concentrating Solar Power, (http://www.iea.org/publications/freepublications/publication/csp_roadmap.pdf)
  2. Lovegrove, K. and Stein, W., 2012, Concentrating Solar Power Technology: Principles, Developments and Applications, Woodhead Publishing, Cambridge, UK.
  3. Garcia, P., Ferriere, A. and Bezian, J. J., 2008, "Codes for Solar Flux Calculation Dedicated to Central Receiver System Applications: a Comparative Review," Solar Energy, Vol. 82, pp. 189-197. https://doi.org/10.1016/j.solener.2007.08.004
  4. Siegel, R. and Howell, J. R., 2002, Thermal Radiation Heat Transfer, 4th ed., Taylor & Francis, New York.
  5. Mahan, J. R., 2002, Radiation Heat Transfer: A Statistical Approach, J. Wiley, New York.
  6. Montes, M. J., Rubbia, C., Abbas, R. and Martinez- Val, J. M., 2014, "A Comparative Analysis of Configurations of Linear Fresnel Collectors for Concentrating Solar Power," Energy, Vol. 73, pp. 192-203. https://doi.org/10.1016/j.energy.2014.06.010
  7. Lee, H. J., Kim, J. K., Lee, S. N. and Kang, Y. H., 2011, "Heat-Flux Analysis of Solar Furnace Using the Monte Carlo Ray-Tracing Method," Trans. KSME B, Vol. 35, No. 10, pp. 989-996. https://doi.org/10.3795/KSME-B.2011.35.10.989
  8. Lee, H. J., Chai, K. K., Kim, J. K., Lee, S. N., Yoon, H. K., Yu, C. K. and Kang, Y. H., 2014, "Optical Performance Evaluation of a Solar Furnace by Measuring the Highly Concentrated Solar Flux," Energy, Vol. 66, pp. 63-69. https://doi.org/10.1016/j.energy.2013.04.081
  9. Belhomme, B., Pitz-Paal, R., Schwarzbozl, P. and Ulmer, S., 2009, "A New Fast Ray Tracing Tool for High-Precision Simulation of Heliostat Fields," J. Sol. Energ. T. ASME, Vol. 131, paper 031002.
  10. He, Y.-L., Cui, F.-Q., Cheng, Z.-D., Li, Z.-Y. and Tao, W.-Q., 2013, "Numerical Simulation of Solar Radiation Transmission Process for the Solar Tower Power Plant: From the Heliostat Field to the Pressurized Volumetric Receiver," App. Therm. Eng., Vol. 61, No. 2, pp. 583-595. https://doi.org/10.1016/j.applthermaleng.2013.08.015
  11. Buie, D., Monger, A. G. and Dey, C. J., 2003, "Sunshape Distributions for Terrestrial Solar Simulations," Solar Energy, Vol. 74, pp. 113-122. https://doi.org/10.1016/S0038-092X(03)00125-7
  12. Hottel, H. C., 1976, "A Simple Model for Estimating the Transmittance of Direct Solar Radiation through Clear Atmospheres," Solar Energy, Vol. 18, No. 2, pp. 129-134. https://doi.org/10.1016/0038-092X(76)90045-1
  13. Lee, H. J., Kim, J. K., Lee, S. N. and Kang, Y. H., 2015, " Numerical Study on Optical Performances of the First Central-Receiver Solar Thermal Power Plant in Korea," J. Mech. Sci. Technol., submitted.
  14. Lee, H. J., 2014, "The Geometric-Optics Relation Between Surface Slope Error and Reflected Ray Error in Solar Concentrators," Solar Energy, Vol. 101, pp. 299-307. https://doi.org/10.1016/j.solener.2013.12.035