Energy Efficiency of Photovoltaic Panels Depending on the Step Resolution of Tracking System

Abstract

The article presents an energy analysis of a 3.5 kWp photovoltaic installation placed on a two-axis tracking system, depending on resolution of step tracking system, that tracks apparent position of the Sun on the celestial sphere. Measurements were taken during July and August, months with similar solar radiation intensity. During the first month, the tracking system changed the spatial orientation of the photovoltaic panels with a frequency of 20 minutes, while in the second month the resolution of the tracking step was 120 minutes. The total energy production by the photovoltaic installation cooperating with the tracking system was 589.5 kWh and 579.85 kWh, for a tracking step resolution of 20 and 120 minutes, respectively. The monthly difference between the two analysed periods does not exceed 1.7%. However, when analysing the days with the highest energy production – exceeding 28 kWh/day, the photovoltaic installation which changed its spatial orientation with greater frequency produced 309.83 kWh, and with a smaller one 259.88 kWh. In the case of sunny, cloudless days, the difference in the efficiency of both solutions is equal to 19%. During days with lower solar radiation, the efficiency of the photovoltaic installations was similar. It can be concluded that increasing the step resolution of the tracking system increases energy production on sunny, cloudless days. It should be taken into account that increasing the frequency of changing the position of photovoltaic panels increased energy consumption by tracker motors from 2.48 kWh to 3.75 kWh, which constitutes 13.2% of the energy gain obtained over the entire tested period, but less than 1% during days with the highest amount of solar radiation.