Outdoor simultaneous testing of four types of photovoltaic tracked modules

Abstract

Photovoltaic (PV) systems implemented in the built environment must fulfill supplementary design restrictions related to the limited available space and to architectural integration, thus the need for increased output is a must and tracking, whenever possible, represents a feasible solution. Tracking significantly enhances the amount of solar radiation on the module, including infrared radiation which contributes to their heating and influences the conversion efficiency. These efficiency variations are different, mainly depending on the modules' type (materials). The paper analyses the conversion efficiency of four types of commercial photovoltaic modules (amorphous, mono- and polycrystalline silicon, and CuInS2 (CIS)), simultaneously tested in two in-field setups: on a tracked PV platform and fixed tilt at 45°. The input global radiation and the outdoor temperature are correlated with the variation in the conversion efficiencies, outlining significant differences and the advantages of thin film (CIS) modules. A novel criterion is proposed to evaluate the results: the relative efficiency loss based on the actual and the nominal conversion efficiencies.