The effect of tilt angle and orientation of Photovoltaic (PV) modules on the performance of Stand-alone Photovoltaic Electricity Generation Systems (SPVEGS) for rural electrification was investigated in this study. In order to have maximum irradiation converted into electricity, both the tilt angle and orientation of the PV surface should be optimum. It is found that the total irradiation captured on a tilted surface mounted in Ipoh, Malaysia can be maximized by positioning the PV modules at the monthly optimum tilt of βoptimum = φ-δ, facing North (γ = 180°) for the months April to August and facing South (γ = 0°) for the rest of the months throughout the year. The total irradiation on a tilted surface calculated in this study considered the beam, diffuse and reflected components of the radiation on a tilted surface. The total irradiation incident on surfaces tilted at β = φ, β = 0° and β = |φ-δ| were also investigated. A gain of 6.4 and 6.1%, respectively is achieved by positioning the PV modules at the monthly optimum tilt and orientation as compared to keeping them fixed throughout the year at horizontal (β = 0°) or at latitude (β = φ). PV modules maintained at a monthly tilt of β = |φ-δ| with South facing orientation at all times accounted for a loss of approximately 5.3% in total tilted irradiation as compared to tilting the PV modules to βoptimum with North and South facing surfaces. This indicates that the orientations of PV modules are equally as important as tilt angles.
Prashanthini Sunderan, Adibah Mohd Ismail, Balbir Singh and Norani Muti Mohamed, 2011. Optimum Tilt Angle and Orientation of Stand-Alone Photovoltaic Electricity Generation Systems for Rural Electrification. Journal of Applied Sciences, 11: 1219-1224.