Long-term performance of photovoltaic modules at different tilt angles and orientations

In the present study, the performance of mono-crystalline silicon type PV modules has been investigated theoretically at different tilt angles and orientations. The annual performance was predicted using a Fortran computer subprogram constructed based on the analysis and connected to TRNSYS simulation program. The subprogram was experimentally verified at different meteorological conditions and design parameters in a previous study by the authors based on the meteorological conditions of Cairo (Egypt). It is found that the optimum value of yearly maximum output energy (i.e. yearly output energy at maximum power point) can be obtained from PV modules oriented facing south with a tilt angle in the range of 20/spl deg/ to 30/spl deg/. Besides, the yearly maximum output energy of the PV modules mounted at different tilt angles and orientations is obtained as a fraction of its optimum value at optimum tilt angle and orientation.