An Analysis of Methods for Deriving the Constituent Insolation Components From Multipyranometer Array Measurements

Abstract

A multipyranometer array (MPA) is a static platform of solar sensors designed to “untangle” the beam, diffuse and reflected portions of the total solar radiation. Over the past four years, a series of weather stations located throughout Colorado has used MPA’s to record insolation. This paper compares the beam radiation derived from an MPA with that measured by a nearby tracking pyrheliometer. Three different diffuse sky models as well as uniform and specular foreground reflectance models are used in the analysis. The ability of each model to predict the actual beam radiation is tabulated. Finally, two novel methods for deriving the beam component without the use of sky models are presented, along with a comparison with the conventional models.