Analytical and experimental analysis of optimal tilt angle of solar photovoltaic systems

Performance of PV panel depends on the tilt angle of the panel with respect to the horizontal plane. The tilt angle determines the amount of solar insolation on panel surface and intern determines quantity of energy collected. Conventionally the best tilt angle is equivalent to latitude of the location at which panel is installed. The value of optimal tilt angle at defined location depends on local atmospheric condition, altitude of region, movement of sun etc. So the value of optimal tilt angle varies over each month. In this paper the values of optimal tilt angle over each month for a PV panel installed in Kerala, India (9.55°N, 76.81°E) was theoretically estimated using geographic factor method, clearness index method and declination angle method. The results showed that the gain in the amount of solar radiation throughout the year received by the PV panel mounted at monthly optimum tilt angles with respect to seasonal optimum angles and tilt angle equal to latitude were 3.4% and 7%, respectively. The theoretically estimated values of optimal tilt angles are used as a base for experimental investigation. Experimental investigation was done for three months and it is found that the geographic factor method is the best method among three methods.