### Optimum Tilt Angle at Tropical Region

*S Soulayman -  Higher Institute for Applied Sciences and Technology, Damascus P. O. Box 31983, Syrian Arab Republic
W Sabbagh -  National Energy Research Center, Damascus,, Syrian Arab Republic
Published: 15 Feb 2015.
Citation Format:
Article Info
Section: Original Research Article
Language: EN
Full Text:
Statistics: 1016 987
Abstract

: One of the important parameters that affect the performance of a solar collector is its tilt angle with the horizon. This is because of the variation of tilt angle changes the amount of solar radiation reaching the collector surface. Meanwhile, is the rule of thumb, which says that solar collector Equator facing position is the best, is valid for tropical region? Thus, it is required to determine the optimum tilt as for Equator facing and for Pole oriented collectors. In addition, the question that may arise: how many times is reasonable for adjusting collector tilt angle for a definite value of surface azimuth angle? A mathematical model was used for estimating the solar radiation on a tilted surface, and to determine the optimum tilt angle and orientation (surface azimuth angle) for the solar collector at any latitude. This model was applied for determining optimum tilt angle and orientation in the tropical zones, on a daily basis, as well as for a specific period. The optimum angle was computed by searching for the values for which the radiation on the collector surface is a maximum for a particular day or a specific period. The results reveal that changing the tilt angle 12 times in a year (i.e. using the monthly optimum tilt angle) maintains approximately the total amount of solar radiation near the maximum value that is found by changing the tilt angle daily to its optimum value. This achieves a yearly gain in solar radiation of 11% to 18% more than the case of a solar collector fixed on a horizontal surface.

Keywords
Optimum tilt, orientation, mathematical model, tropical region

Article Metrics:

1. Aja, O. C., Al-Kayiem, H. H., Abdul Karim, Z. A. (2013) Analytical investigation of collector optimum tilt angle at low latitude. AIP J. Renewable Sustainable Energy, 5, 063112; http://dx.doi.org/10.1063/1.4829434
2. Diaz, F., Ngo, J., Pascual, M., Planes, A., Chua, A. (2014) Enhanced energy conversion performance of Philippine photovoltaic panels through tilt angle adjustments: A mechatronics approach. Philippine Science Letters, 7(1): 7-12.
3. Duffie, J.A., Beckman, W.A. (1991) Solar Engineering of Thermal Processes, 2nd edn. Wiley, New York.
4. Eke, A. B. (2011) Prediction of optimum angle of inclination for flat plate solar collector in Zaria, Nigeria. Agricultural Engineering International: CIGR Journal, 13, Manuscript No. 1840.
5. El-Kassaby, M.M. (1988) Monthly and daily optimum tilt angle for south facing solar collectors; theoretical model, experimental and empirical correlations. Solar and Wind Technology5(6),589–96. http://dx.doi.org/10.1016/0741-983X(88)90054-9
6. El-Kassaby, M.M., Hassab, M.H. (1994) Investigation of a variable tilt angle Australian type solar collector. Renewable Energy 4, 327–332. http://dx.doi.org/10.1016/0960-1481(94)90036-1
7. Idowu, O. S., Olarenwaju, O. M., Ifedayo Odesola, I. (2013) Determination of optimum tilt angles for solar collectors in low-latitude tropical region. International Journal of Energy and Environmental Engineering , 4:29, 1-10.
8. Kamanga, B., Mlatho, J. S. P., Mikeka C., Kamunda, C. (2014) Optimum Tilt Angle for Photovoltaic Solar Panels in Zomba District, Malawi. Journal of Solar Energy, 2014, Article ID 132950, 9 pages. http://dx.doi.org/10.1155/2014/132950
9. Ng, Kh. M., Adam, N. M., Inayatullah, O., Ab Kadir, M. Z. A. (2014) Assessment of solar radiation on diversely oriented surfaces and optimum tilts for solar absorbers in Malaysian tropical latitude. International Journal of Energy and Environmental Engineering, 5:5, 1-13.
10. Nijegorodov,N., Devan, K.R.S., Jain, P.K. (1997) Atmospheric transmittance models and an analytical method to predict the optimum slope on an absorber plate. Renewable Energy, 4, 525–530. http://dx.doi.org/10.1016/0960-1481(94)90215-1
11. Oko, C.O.C., Nnamchi, S.N. (2012) Optimum Collector Tilt Angles For Low Latitudes, The Open Renewable Energy Journal, 5, 7-14.
12. Qiu, G., Riffat, S.B. (2003) Optimum tilt angle of solar collectors and its impact on performance. International Journal of Ambient Energy, 24, 13–20. http://dx.doi.org/10.1080/01430750.2003.9674898
13. Skeiker, K. (2009) Optimum tilt angle and orientation for solar collectors in Syria. Energy Conversion and Management 50, 2439–2448. http://dx.doi.org/10.1016/j.enconman.2009.05.031
14. Soulayman, S. (1991) On the optimum tilt of solar absorber plates. Renewable Energy, 1(3-4), 551-554. http://dx.doi.org/10.1016/0960-1481(91)90070-6.
15. Soulayman, S., Sabbagh, W. (2014) Comment on ‘Optimum tilt angle and orientation for solar collectors in Syria’ by Skeiker, K. Energy Conversion and Management, Available online 1 November 2014. doi:10.1016/j.enconman.2014.10.023
16. Stanciu, C., Stanciu, D. (2014) Optimum tilt angle for flat plate collectors all over the World – A declination dependence formula and comparisons of three solar radiation models. Energy Conversion and Management 81, 133–143. doi:10.1016/j.enconman.2014.02.016
17. Uba, F. A., Sarsah, E. A. (2013) Optimization of tilt angle for solar collectors in WA, Ghana. Pelagia Research Library, Advances in Applied Science Research, 4(4):108-114.
18. Waziri, N. H., Usman, A. M., Enaburekhan, Babakano,J. S. A. (2014) Determination of Optimum Tilt Angle and Orientation of a Flat Plate Solar Collector for Different Periods in Kano. Scirj, 2, 2014 Edition, ISSN: 2201-2796.