TITLE:
Solar Receivers Optimum Tilt Angle at Southern Hemisphere
AUTHORS:
Soulayman Soulayman, Alhelou Mohammad, Nouredine Salah
KEYWORDS:
Southern Hemisphere, Optimum Tilt, Energy Gain, High Latitudes
JOURNAL NAME:
Open Access Library Journal,
Vol.3 No.2,
February
29,
2016
ABSTRACT: One of the important parameters that affects the performance of a solar
collector is its tilt angle with the horizon. This is because 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
should be orientated towards the Equator with a tilt equal to latitude, valid
for high latitudes region? Thus, it is required to determine the optimum tilt
for Equator facing collectors. In addition, the question may rise: how much adjustments
of Equator facing solar collector tilt angle is reasonable to do during a year?
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 in the high latitudes zone in the Southern
Hemisphere, 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 up to 1.8 times of the
case of a horizontal surface while the daily gain reaches 60 times
approximately. Moreover, general formulas are proposed for predicting daily
optimum tilt angle and optimum tilt angle over any number of days.