# Experimental Investigation of the BIPV System under Sanluurfa Meteorological Conditions
## 2 Materials and Methods  
### Experimental Design and Setup  
In this study, the aim was to evaluate the performance of BIPV systems under the meteorological conditions of Sanlurfa. The experimental setup was established at Harran University's GAP-YENEV Research and Application Center. The design of the PV panels and the experimental setup is shown in Figure 1. The width, length, and height of the building structure where the experimental setup was located were 1.98 m, 2.96 m, and 2.45 m, respectively. The BIPV experimental setup shown in Figure 1 was designed to determine the electrical energy that can be generated from three different facades, namely east, roof, and south. There are a total of four PV panels in the BIPV system. Figure 1: External design of the experimental setup. Two of these panels consist of bifacial and monofacial panels located on the south facade to be compared under the same conditions. The panel closer to the east facade on the south side is the bifacial panel. The panels on the south facade are positioned approximately 11.5 cm away from the wall. The wall surface behind the bifacial panel is covered with aluminum foil. The 11.5 cm gaps between the panel and the wall were sealed with transparent material. Thus, sunlight was allowed to reach the rear surface of the bifacial panel. In addition, monofacial PV panels of the same capacity were placed on the east facade and the roof of the experimental setup. Thus, it became possible to comparatively observe the electrical production effects on different facades. The technical specifications of the panels used in the experimental setup are provided in Table 1.  
The bifacial panel used on the south facade of the BIPV experimental setup was glass-glass and had semitransparent properties. Thus, the solar radiation hitting the bifacial panel passes through to the back wall. The solar radiation that reached the back wall was reflected thanks to the reflective surface coating on the wall. Thus, a higher amount of radiation was directed to the back surface of the bifacial panel. Energy production values were measured on all facades of the established BIPV system. For this purpose, the electrical circuit shown in Figure 2 was established. As can be seen from the figure, the PV panels are connected to the Hoymiles brand MI-1500 model microinverter using DC cables. The microinverter converts the incoming direct current to alternating current and transfers it to the grid. To record the amount of electrical energy produced by the panels, the micro inverter is connected to the Hoymiles brand Data Transfer Unit (DTU) device via its own Wi-Fi. The micro inverter calculates the amounts of both power and electrical energy produced by each panel separately and sends it to the DTU device. The DTU records the amount of electrical energy produced by the micro inverter every 15 min. It transfers the recorded data to the cloud system, and access to the data can be achieved wherever there is an internet connection. To measure the amount of radiation received by the PV panels, an Eko brand MS-602 model pyranometer was placed on each facade. The data from these pyranometers were collected in a HIOKI brand data logger (Figure 2).