f|solar GmbH (Osterweddingen, Germany) now offers heat strengthened glass that is only 2mm thick and has general technical approval.

This was awarded by the German Institute for Building Technology in Berlin and is valid for five years. Heat strengthened and equipped with a robust and homogenous antireflection coating, “f|solarfloat HT” is optimally suited for use in glass-glass PV modules of the latest generation. As heat strengthened glass for the back of the modules, with holes for the electrical connections, “f|ecofloat T” is used. Especially interesting for module manufacturers: the technical approval also applies to sheets of glass with drilled holes, coatings and enamelling.

“Glass-glass photovoltaic modules have a particularly high yield stability and last for an extremely long time – they therefore provide additional value compared with traditional modules. Our 2mm thick glass types are ideal for both the front and the back of the modules,” f|solar GmbH managing director Thomas Keyser says.

Float glass process for consistently high quality

For building-integrated PV systems, glass of a reliably high quality is especially important – which is one of the reasons that this new type of solar glass is produced exclusively with an industrial float glass process. This ensures that a manufacturing tolerance of 2mm ± 0.05mm can be maintained. The float glass also has a very low defect density, which provides clear advantages for the processes that follow such as the creation of a particularly high level of tempering – an essential requirement for the strength of the glass-glass PV laminate. This is made possible by a modern tempering furnace that achieves top results in terms of flatness and bending tensile strength. With a typical bending tensile strength of 120 N/mm² the heat strengthened two-millimetre solar glass even exceeds the required norm for four-millimetre standard glass.

f|solarfloat HT is coated under vacuum conditions with a robust and homogenous mono-broadband antireflection coating and provides an energy transmittance (TePV) of around 94%. To increase the back glass reflection, the glass at the rear of the module can be ceramic screen-printed.