Solar Spectrum Prediction and Comparison With Measurements

Concentrator photovoltaic systems that use multijunction cells can suffer from suboptimal performance due to changes in the solar spectrum. Performance improvements may be achieved through tailoring the spectral response of cells to a given location. Reliable spectral data for the site of installation is required for this and is often unavailable or costly to obtain. Measurements of the solar spectrum have been taken at the University of Cyprus, alongside detailed environmental parameters. Simulations of the spectrum in the same location have been performed using the SMARTS program and a variety of different environmental data sets. The output of the model has been compared with the real data over the same time period using the metrics of direct normal irradiance (DNI) and average photon energy (APE). Good agreement has been found between the modeled and the measured data. Seasonality is observable in both the measured and simulated APE values, and ambient temperature is found to be a reasonable indicator of this variation.