Analysis of Measured Irradiance from Experiment of Diffuse Irradiance Shadowing

Abstract

Photovoltaic technology is constantly evolving and its supply is increasing in various regions. Especially, as installation technology of solar panel is developed and efficiency increases, installation is increasing in a complex area with many shadows. Therefore, it is necessary to study the shadow effect caused by the complex objects in the surroundings such as buildings and trees. An experiment of measuring diffuse irradiance with shadowing blocks is designed in this study. The objectives of this experiment is to quantitatively measure and analyze the change in irradiance by the shadowing blocks. Shadowing blocks are designed to make blocks having an equal area, the angular blocked area in sky dome, from the view of solar radiation meters but different distances. Calibration of the measured data from two solar radiation meter and the preprocessing methods are devised and applied. Tendency and variance of data are analyzed and patterns are derived. The results show a linear pattern of the transmittance according to the distance from shadowing objects in few meters. The proposed transmittance model is expected to increase the accuracy of approximately 10% in diffuse irradiance calculation.