International Journal of Applied Science and Engineering
Published by Chaoyang University of Technology

Tian Pau Chang1

Department of Computer Science and Information Engineering, Nankai University of  Technology, Nantou 542, Taiwan


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Resulting from the shortage of fossil fuels, solar energy plays a more and more important role in power supply in future. The amount of radiation flux incident upon a solar collector is mainly affected by the installation angle. Proper design of a collector can increase the irradiation received. In this paper, the optimal angle in Taiwan is calculated according to three different radiation types, i.e. the extraterrestrial radiation, global radiation predicted by empirical model and ten-year observation data from 1990 to 1999. Some differences among them are analyzed considering the geographic and climatic factors. The results show that the angles calculated from the extraterrestrial and predicted radiations are simply latitude-dependent and thus can be well determined, but the angles estimated from observation data vary from location to location and are generally flatter than those from other two radiation types. It tells us that the collector must be installed with a flatter tilt angle when it works in a cloudy or pollutant environment.

Keywords: Solar radiation; Solar collector; Clearness index; Optimal tilt angle

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  1. [1] Saraf, G. R., and Hamad, F. A. W. 1988. Optimum tilt angle for a flat plate solar collector. Energy Conversion and Management, 28: 185-191.

  2. [2] Gopinathan, K. K. 1991. Solar radiation on variously oriented sloping surfaces. Solar Energy, 47: 173-179.

  3. [3] Soulayman, S. S. H. 1991. On the optimum tilt of solar absorber plates. Renewable Energy, 1: 551-554.

  4. [4] Nijegorodov, N., Devan, K. R. S., Jain, P. K., and Carlsson, S. 1994. Atmospheric transmittance models and an analytical method to predict the optimum slope of an absorber plate, variously orientated at any latitude. Renewable Energy, 4, 5: 529-543.

  5. [5] Gunerhan, H., and Hepbasli, A. 2007. Determination of the optimum tilt angle of solar collectors for building applications. Building and Environment, 42: 779-783.

  6. [6] Yakup, M. Ab. H. M., and Malik, A. Q. 2001. Optimum tilt angle and orientation for solar collector in Brunei Darussalam. Renewable Energy, 24: 223-234.

  7. [7] Shariah, A., Al-Akhras, M. A., and Al-Omari, I. A. 2002. Optimizing the tilt angle of solar collectors. Renewable Energy, 26: 587-598.

  8. [8] Chow, T. T., and Chan, A. L. S. 2004. Numerical study of desirable solar-collector orientations for the coastal region of South China. Applied Energy, 79: 249-260.

  9. [9] Chen, Y. M., Lee, C. H., and Wu, H. C. 2005. Calculation of the optimum installation angle for fixed solar-cell panels based on the genetic algorithm and the simulated-annealing method. IEEE Transactions on Energy Conversion, 20, 2: 467-473.

  10. [10] Liu, B. Y. H., and Jordan, R. C. 1963. The long-term average performance of flat-plate solar energy collectors. Solar Energy, 7, 2: 53-74.

  11. [11] Markvart, T. 2000. “Solar Electricity”. second edition, John Wiley&Sons Ltd. 5-18.

  12. [12] Hottel, H. C. 1976. A simple model for estimating the transmittance of direct solar radiation through clear atmospheres. Solar Energy, 18, 2: 129-134.

  13. [13] Liu, B. Y. H., and Jordan, R. C. 1960. The interrelationship and characteristic distribution of direct, diffuse and total solar radiation. Solar Energy, 4, 3,: 1-19.

  14. [14] Page, J. K. 1977. “The estimation of monthly mean value of daily short wave irradiation on vertical and inclined sur-facesfrom sunshine records for latitudes of 60°N to 40°S. BS32”, Department of Building Science, University of Sheffield, UK.

  15. [15] Chang, T. P. 2008. Performance evalua-tionfor solar collectors in Taiwan. Sub-mittedto Energy.


Accepted: 2008-10-30
Available Online: 2008-11-01

Cite this article:

Chang, T.P. 2008. Study on the optimal tilt angle of solar collector according to different radiation types. International Journal of Applied Science and Engineering, 6, 151–161.