# A Holistic Approach for Design and Assessment of Building-Integrated Photovoltaics Systems
## 3 Customized PV Modules Software Analysis
### Irradiance on the Window Surfaces  
The first result of the software was obtained after providing the geographic and climatic data. PVSITES provides qualitative and quantitative data of the annual average irradiance value (kWh/m\({}^{2}\)) for all surfaces in 3D scenes. This value allows the evaluation of the solar energy potential in each area. Figure 7 shows the irradiance on the facade surface, where the solar windows will be integrated. Color profiles help to visualize the average irradiance ranges, where the darkest corresponds to the minimum (Black--0 Wh/m\({}^{2}\)) and the lightest to the maximum (White--590 Wh/m\({}^{2}\)). On average, the irradiance of solar  
Figure 5: Case study SketchUp design. Figure 6: SketchUp design. windows is 187 Wh/m\({}^{2}\), which is 95.7% lower than the average irradiance (4410 Wh/m\({}^{2}\)/d) of a roof without shading in Medellin [13]. This result identifies the strong decrease of irradiation in the perpendicular surface on the horizontal (less exposure to the direct rays of the sun), and it is also affected by the shadows of nearby buildings. The software has an extensive library of commercial BIPV products, with technical characteristics determined by the manufacturer. In this case, monocrystalline panels with an average yield of 199.36 W/m\({}^{2}\) were included. These data were obtained from a proprietary panel design, not from commercial sources. The primary purpose of a proprietary design is to take advantage of the maximum useful area available for solar windows. Figure 8 shows the integration of the modules in the building facade. Once the BIPV system is configured at the desired location in the 3D model, the next step is to select the inverter. The software allows the selection of different configurations for the installation, and it has the option to include custom configurations. For the case study, a 600 W Soladin inverter with a Maximum Power Point Tracker (MPPT) was selected. Subsequently, the wiring of the BIPV system was carried out, which is an important aspect in the design and installation stages, as the energy efficiency and costs of the system depend on it. The wiring design depends not only on the number and position of the interconnected modules but also on the inverter connection. To facilitate the wiring task, PVSITES proposes different wiring scenarios, always seeking to minimize conductor losses. Results from the installed project were extracted from a microinverter (WVC300-230 VAC), which takes and updates the obtained hourly power outputs into the data cloud for the whole of 2019. At the same time, the project was evaluated in the software fixing the self-made PV modules. Despite the efficiency of the PVSITES, it is not possible to forecast any unexpected event that might affect the deviation of the results. Weather  
Figure 7: Irradiance on the facade surface. profiles were taken from average statistics in Medellin. However, since it is a large city, weather conditions may differ from neighborhood to neighborhood. In addition, the modules were customized, and they may also have plausible differences compared to the computer simulation. The monthly energy production of the 400 Wp BIPV design is presented in Figure 9, having an average generation/month of 7.39 kWh, a maximum in July of 9.2 kWh and a minimum in December of 5.6 kWh. These values represent the perceived savings from installing the BIPV system in the windows, reducing consumption from the electrical grid. When comparing this generation with the average monthly consumption of 152 kWh/month for a family home of four people in Medellin [33], the BIPV solar system supplies 4.86% of the energy of the house, which represents a decrease in the energy bill of USD 1.9/month, considering an electric energy cost of 0.16 USD/kWh for residential users, according to data consulted on 2 October 2019 [34].