Prediction of Photovoltaic Power Output Considering Weather Conditions

A reasonable construction of photovoltaic (PV) system would be possible if the electrical output from the PV can be predicted accurately from weather data before the construction. The electrical output can be calculated theoretically from the voltage-current characteristics equation for a silicon solar cell, if the solar irradiance and the cell temperature are known. However, it is not easy to predict the cell temperature because it depends on several physical and environment factors; in particular, it is difficult to estimate a heat transfer from PV surface to surrounds. In this study, firstly, we confirmed that the electrical output can be predicted accurately by a modified equation of traditional voltage-current characteristic equation when the irradiance and the cell temperature are given. Secondly, we estimated the average heat transfer coefficient from PV surface as a function of wind speed using the experimental data on the PV system obtained in this study and compared it with three kinds of data in references. As a result, the estimated values agree with the references’ results in their accuracy of the data.