Clear sky global solar irradiance on tilt angles of photovoltaic module in Perlis, Northern Malaysia

The performance of a photovoltaic (PV) is highly influenced by its orientation and its tilt angle with the horizontal, due to the fact that both the orientation and tilt angle change the amount of solar radiation reaching the surface of the PV module. This paper presents a calculation of tilt angle and global solar irradiance on PV module in Perlis, Northern Malaysia. A mathematic method is used to calculate tilt angles and clear sky global solar irradiance, which depend on latitude and day number. The clear sky global solar irradiance consists of beam, diffuse and reflected solar irradiance. The tilt angles and clear sky global solar irradiance change every day in a year and analyzed. The monthly average beam, diffuse, reflected and clear sky global solar irradiance are shown and analyzed in this paper. The tilt angles of PV module in Perlis, Northern Malaysia are -17.16° to 29.74°. The positive, zero and negative tilt angles indicate that the PV module is facing south, on horizontal surface and north, respectively. The monthly average beam solar irradiance give a highest value compared with the diffuse and reflected solar irradiance. The average monthly beam solar irradiance of a year is, 968.36 W/m², diffuse and reflected solar irradiance are 88.22 W/m², and 4.70 W/m², respectively. Based on global solar irradiance of a year, Perlis has a big global solar irradiance potential, its average is 1019 W/m². These data show that the clear sky global solar irradiance can be used for certain application, especially in PV power generation.