Assessment of the optical efficiency of a primary lens to be used in a CPV system

This article summarizes experimental methods to evaluate the performance and to assess the efficiency of a lens that will be used as primary optics in a concentrating photovoltaic system comprising multijunction solar cells. The methods are classified into two groups: those intended to quantify the transmission losses and those that estimate the size and shape of the light spot. In addition, the optical efficiency definition is reviewed and a systematic procedure to evaluate it is proposed.