# Power Prediction of Bifacial Si PV Module with Different Reflection Conditions on Rooftop
## 4 Conclusions  
In this paper, we propose a modeling method to estimate the amount of irradiance on the rear side of the module, as the output power of the bifacial photovoltaic module changes according to the composition of the rear side environment. The output power was confirmed through experiments. Depending on where the solar module is installed, the direct and diffuse components of the irradiance are different, and, because of the rotation of the earth, it receives different levels of solar irradiation depending on the current date. Therefore, it is necessary to predict the amount of irradiance on the rear side of the module considering the position, environment, and time of measurement. Previously, the bifacial module was evaluated by comparing the output power amount of the rear side to that of the front side. In this paper, we predicted the output amount depending on the rear side environment. From the prediction based on the modeling proposed in this paper, the error rate was confirmed to be within a maximum value of 5% and average value of 1.84%, which allows it to be used in theoretical prediction. It is obvious that the rear environment should be taken into consideration when installing the bifacial module because the output amount is measured differently depending on the albedos of the mono-facial modules and the bifacial modules. Because it is efficient to use a solar module with a high efficiency output in a narrow terrain, the proposed model will be useful in predicting the efficiency achieved by applying a bifacial module to water-based photovoltaics or BIPV in the future. To accurately predict the output at low irradiation as well as the high solar irradiation through the output obtained through the modeling, the elements of weather affecting humidity and reflection are additionally required in addition to albedo, direct irradiation and scattered irradiation. Recently, installation of floating Photovoltaic has been increasing. As the reflection of irradiation from the water surface occurs, the positive influence of the installation with the bifacial photovoltaic can be expected. We are confident that this research will contribute to zero energy construction by designing systems based on bifacial PV module with high performance ratio when applying solar power in a microgrid environment, which is the future energy network. Figure 23: Output comparison between transparent and white back sheet on Exp. 6. **Author Contributions:** [PERSON] developed her own primary model for power prediction of bifacial Si PV Module in Rooftop using view factor. [PERSON], [PERSON] and J.H.C. added experimental methods at the test site (rooftop of department of engineering building at Konkuk University) with different albedos. H.K.A. integrated the design of systems based on bifacial PV modules with respect to the application to BIPVs, FPVs and MPVs (Marine PVs) for microgrid to grid connected networks. **Funding:** This research was supported by the New and Renewable Energy Technology Program of the Korea Institute of Energy Technology Evaluation and Planning (KETEP), granted financial resources by the Ministry of Trade, Industry and Energy, Republic of Korea (No. 20183010014260). **Acknowledgments:** To the memory of Dr. [PERSON] who devoted himself to the PV industry and research. **Conflicts of Interest:** The authors declare no conflict of interest. **Nomenclature**