On the dust-equivalent series resistance of a photovoltaic concentrator

A new concept for treating the effects of dust on the electrical performance of photovoltaic concentrators is presented in the paper. The dust concentration in the atmospheric air around the concentrator is measured continuously during the test period. The rate of dust accumulation on the concentrator surface is determined. The concentrator performance degradation, as a result of dust accumulation, is related to the amount of dust accumulated per unit area of the collector surface (in g/m2) rather than the exposure time. It has been shown that major reductions in the short-circuit current and the efficiency are observed for dust accumulations up to 5.4 g/m2. The accumulation of dust on the photovoltaic concentrator causes a successively larger `rounding¿ of the I/V characteristic at constant incident direct normal radiation intensity and constant cell temperature. This effect is equivalent to an increase in the internal series resistance of the concentrator. This dust-equivalent series resistance increases with increasing dust accumulation.