Bidirectional irradiance transposition based on the Perez model

The model coefficients can be adjusted locally based on multiple datasets of diffuse and global irradiance on tilted and horizontal planes. In this paper, we present a different approach to adjust the coefficients, by using only measurements of global irradiance on tilted and horizontal planes from a tropical climate site, Singapore. A complete set of mathematical solutions to the inverse problem, i.e., irradiance transposition from tilt to horizontal, is also proposed. The data can then be used to generate irradiance maps from in-plane irradiance measurements at photovoltaics (PV) systems. Such maps provide relevant information for PV grid integration.