Measuring factors influencing performance of rooftop PV panels in warm tropical climates

The integration of photovoltaic (PV) panels and green roofs, which is a system known as green roof integrated photovoltaics (GRIPV), can provide mutual benefits such as improving the conversion efficiency of the PV panels and reducing the incident solar irradiation on the vegetation. Although previous studies have quantified the increase in the output power of PV panels in these systems, there is a need for experimental research to characterise the influence of several factors on system performance. Accordingly, this work presents an experimental study that seeks to describe the influence of three factors on the performance of PV panels in warm tropical climates: height of installation (25, 50, 75, and 100 cm), type of roof (green-vegetated and concrete), and air velocity (0, 1.15, and 2.10 m/s). The results obtained indicate that concrete roofs slightly increase the surrounding air temperature up to 100 cm above the surface, but this effect is not observed on green roofs. In addition, a PV panel installed at heights between 50 and 75 cm on a green roof can generate up to 1.3 +/- 0.4% more energy than one installed on a concrete roof. Finally, increasing the air velocity from 0 to 2.10 m/s on either surface can produce up to 2.0 +/- 0.4% more energy per day from each PV panel.