Optical investigation of a sun simulator for concentrator PV applications

Abstract

In photovoltaics (PV), sun simulators are used to reproduce outdoor conditions in a lab environment such as irradiance level, light uniformity and spectral distribution. Concentrator (C)PV applications additionally require the sun simulators to provide rays with an angular distribution similar to that of the sun rays. However, different factors in CPV sun simulator setups make it difficult to achieve the perfect sun like angular distribution. This is mainly caused by the unavailability of appropriate light sources. Therefore, we investigated in this work, to which deviations such a non-ideal light source can lead and which impact is expected at the measurement of a CPV module. For this, two ray tracing models are presented - one for the simulation of natural sunrays, another one for the simulation of sun simulator conditions. The models are validated based on measurements and subsequently used to simulate the impact on a typical CPV module with silicone-on-glass Fresnel lenses. Here, significant deviations to outdoor conditions are found.

Challenges in the design of concentrator photovoltaic (CPV) modules to achieve highest efficiencies

“…The requirement for the irradiance intensity and spectral irradiance is commonly achieved using illumination with a flash light on the focal spot of a paraboloidal mirror and measuring during a short period of a few milliseconds. [231][232][233][234] Absolute irradiance level is determined by means of a reference device similar to the measured module (typically, a calibrated mono-module is used as reference sensor), while the spectral conditions are determined by means of component cells and SMRs parameters. 235,236 The method is limited by the size of the mirror.…”