Anomalies in practical solar photovoltaic installations and tilt angle optimization

The study deals with analyzing the performance of solar photovoltaic (SPV) collectors due to error in tilt angle of mounting structures. Usually fixed angle structures are fabricated to hold the SPV modules. With mistake during fabrication of mounting structures, SPV modules are held at erroneous tilt angles. This error in inclination angle results in reduced electrical power yield from modules. The measure of power loss due to this error is huge in large power plants. SPV installations are exposed to varying conditions in field which are difficult to exactly simulate using tools. Thus results recorded from hardware experimental setup in field are used for analysis. The study involves experimental analysis to evaluate the percentage of electrical power yield deterioration from SPV modules due to anomalies in the construction of mounting structures. Calculation of optimal tilt angle depends on the geographical location and declination angle of the earth. For Bengaluru, calculated annual mean optimal tilt angle is 78°. Identical 40W modules oriented towards true south are used for experiments. Experiments were conducted for four different tilt angles (+5°, -5°, -10°, +10°) and the power output were measured against the reference module held at optimal tilt angle. Nearly ≥10% error can be found for ±5° variation of tilt angle. The power difference between the modules fixed at annual mean tilt angle and monthly tilt angle is also analyzed from measurements over four months.