Design and Development of an Experimental Photovoltaic System

The world faces many challenges today and the distributed photovoltaic (PV) systems for local high-efficiency generation of electricity from sunlight seem to be one of the good solutions, but most of the population live in crowded urban environments, which creates a number of limiting factors. This study focuses on the design and implementation of an experimental photovoltaic installation in Ruse, Bulgaria, which allows the investigation of the impact of these factors on the efficiency of urban PV plants for optimization and education purposes. Initially, the goals towards the research facility are defined and the design and implementation of the installation is presented, including the orientation and positioning of the PV park, its schematic, and the key characteristics of the equipment used. Next, the first full year of operation of the research facility is analyzed by examining its energy generation profile. The winter months have about 6 times lower energy yields than the best summer ones and about 4-5 times lower on average compared to those for the other 3 seasons. This is due to the nearby buildings and trees, which create different shadows over the different seasons. The daily energy generation period during the winter is more than twice as short in comparison to that for the other seasons, while the peak daily winter energy yield is about $30 \%$ lower. The yearly energy yield per 1 kW peak installed PV panels is $1131.75 \mathrm{kWh} / \mathrm{kW}$, while the Global Solar Atlas suggests that the specific photovoltaic power output for Ruse is $1360.2 \mathrm{kWh} / \mathrm{kWp}$. The obtained exploitation results indicate that the experimental installation fully complies with the stated goals and allows investigating a number of urban scenarios.