Investigation of focusing properties of photovoltaic module concentrator in a wide temperature range

In the current work properties of a solar radiance concentrator with Fresnel lens made of Elastosil RT604 silicon made by Wacker have been investigated. The dependence of concentrator focal distance on temperature has been determined. Impact of variation of temperature-dependent concentrator focusing properties on the magnitude of short current of photovoltaic submodule has been determined by direct measurements using solar simulator. Using formalized model of modules based on the studied concentrator and solar cells with three and six $p$–$n$-junctions dimensions of a solar image in a wavelength range corresponding to an absorption profile of individual $p$–$n$-junctions has been calculated for the temperature range 10–60$^\circ$C. It has been concluded that in the case of three $p$–$n$-junctions the minimum size of solar image at focal plane was 4.7 mm with the distance between the concentrator and solar cell being equal to 106.25 mm, and in the case of six $p$–$n$-junctions, the minimum size was 4.8 mm with the distance between concentrator and solar cell being equal to 106.5 mm.