Abstract
A concentrator photovoltaic (CPV) system which can reduce the power generation cost of PV system has been developed and assessed for commercialization. An early-type CPV module consists of 20 pairs of dome Fresnel lenses the geometrical concentration ratio of which is X550 and three junction solar cells (InGaP/InGaAs/Ge). We had carried out a field test of the early-type CPV module to evaluate the power generation, the efficiency, and other characteristics from 2004. The Fresnel lenses had never been washed until 2012 were washed and some characteristics of the CPV module were compared in before and after cleaning the lenses. Before the cleaning, many micro particulate dust included 46wt.% of C was on the lenses. Its number density decreased from 600mm-2 to 230mm-2 with cleaning the lenses. However, some characteristics of the CPV module such as I-V curve, FF and electricity efficiency were not changed by cleaning the lenses. The influences of yellow sand (Asian dust) which decreased the direct irradiance and covered on the lens surface from some deserts in interior of East Asia did not continue persistently. This is because, any dirt would not cover easily on the lenses surface, since the CPV module was moved to track to the Sun, and it had the dome-shaped Fresnel lenses which had smooth surface.
