The performance of a representative number of pyranometers which are commonly being used for solar collector testing similar applications was investigated.  Experiments were conducted on both indoors and outdoors. Laboratory investigations from different places were compared.  The results allow an assessment to be made of the overall accuracy of global irradiance measurements associated with the comparison of thermal performance data in solar energy applications.

This report summarizes the progress made by Task participants in developing characterization equations and test methods for various types of collectors. In particular, it shows how a simple generic model can be used to describe different collectors operating over a wider range of conditions than normally covered in standard tests.