André Mermoud

Infrared sky radiation in Geneva

Abstract Continuous measurements of sky radiation have been performed in Geneva for more than two years. We present here some results, and we show that the radiative earth-sky deficit is correlated to the clearness of the day as evaluated from the amount of solar radiation reaching the ground. The corresponding model allows to determine the sky temperature within 2–3°C, with respect to ambient temperature, diffuse and global solar radiation. These results can be of help when computing energy balances involving sky radiation, especially in buildings and solar energy fields.

Validation of the PVSyst Performance Model for the Concentrix CPV Technology

The accuracy of the two‐stage PVSyst model for the Concentrix CPV Technology is determined by comparing modeled to measured values. For both stages, i) the module model and ii) the power plant model, the underlying approaches are explained and methods for obtaining the model parameters are presented. The performance of both models is quantified using 19 months of outdoor measurements for the module model and 9 months of measurements at four different sites for the power plant model. Results are presented by giving statistical quantities for the model accuracy.

Software Modeling of FLATCON© CPV Systems

This paper describes an approach of making the FLATCON® CPV technology compatible with standard photovoltaic simulation software like PVSYST and INSEL in order to facilitate yield estimations for potential power plant sites. Due to the use of triple‐junction cells, the FLATCON® CPV module efficiency is more sensitive to changes in the solar spectrum than the efficiency of an average single‐junction flat plate module. Besides that, the concentrating optics show a temperature dependency. These effects result in a non‐linear component in the short circuit dependency on the direct normal irradiance. By means of introducing a “Utilization Factor”, deduced from both measured data and theoretical considerations, these CPV peculiarities can be considered in standard software tools and transferred to other locations without the need of overly complex measurements or algorithms.