Assessment of Finest Tilt Angles and Adjustment Intervals for Maximizing the Utilization of PV Radiation on Solar Panels: A Case Study

ABSTRACT

The tilt angle of a solar photovoltaic (PV) panel is a key factor that determines the amount of electrical energy output from the panel. Some previous research works recommend approximate number of yearly tilt angles and adjustment intervals for countries located around the tropical latitude but similar recommendation for equatorial regions like Lagos metropolis in Nigeria and other coastal cities is lacking. Thus, this study presents an estimation of the maximum monthly average PV radiation on an adjusted panel and the optimum values of the pane tilt angles, using Lagos as a case study. Both physical measurements and constrained non-linear optimization technique modeled in MATLAB/Simulink are used. The diffused and reflected radiations were included along with the clearness index of the atmosphere for greater accuracy. From the results obtained, a seven-step adjustment interval of tilt angles comprising January to August and September to December (a combination of monthly and seasonal adjustments) is proposed as optimal adjustment intervals for solar panels located in Lagos metropolis. After the optimization process, the maximum radiation energy correlating with the optimum tilt angles were gotten for all the seven adjustment intervals and the average annual energy was estimated at 1555.3 kWh. The effectiveness of the proposed approach was checked and justified by comparing the results with that of daily adjustment of panel tilt angle. These results will be an effective source of information to designers of solar energy in equatorial regions.

Keywords — declination angle; optimum tilt angle; solar angles; solar irradiation; solar photovoltaic

module