At the Intersolar trade fair, SCHOTT Solar and BASF are presenting a new roof-integrated photovoltaic concept based on the SCHOTT ADVANCE Series.
The concept employs only two parts: a specially developed, multi-functional pan made from the BASF resin Ultramid B High Speed and a frameless double-glazed module from SCHOTT. The product has been designed for large roof areas on industrial or agricultural buildings and is very light and easy to install.
The new roof-integrated photovoltaic (PV) concept based on the SCHOTT ADVANCE Series that Schott Solar will present for the first time at the Intersolar Europe in June 2011. Photo: BASF - The Chemical Company, 2011
Roof-integrated lightweight plastic pan with multiple functions
The one-piece plastic pan, which can be installed directly on the roof substructure of a building in place of conventional roofing, combines several functions and employs a new fastening method.
Tool-free installation of the PV module
After the plastic pan has been fastened to the roof substructure at four points, the only remaining step is to insert the rugged double-glazed module into the pan's precision mounting system and secure it in position by means of an integrated latch. The PV module from the SCHOTT PROTECT Series employs proven double-glazing technology for reliable protection against rain, hail and other adverse weather conditions. To ensure safe handling of the double-glazed module, handles that are also made from Ultramid are provided on the back. This makes it easy to carry the PV module, place it on the integrated support edges of the plastic pan and simultaneously secure it at all four attachment points quickly and without the need for tools by sliding the module into the latching mechanism on the pan (Click & Go). Moreover, the new bayonet connection and screw-free attachment to the pan provide automatic tolerance compensation. The pan itself is stackable, thus minimizing shipping volume.
Rain channels, back ventilation and cable channels included
Channels integrated into the pan ensure that rainwater drains away easily. Additional channels in the pan's structure facilitate the installation of electrical cables. Thanks to the large opening in the center of the pan, the plastic part of the 1.7 m² photovoltaic module weighs only 8 kg and has adequate back ventilation. As with a classical roof tile, specially designed edges permit overlapping with adjacent modules, providing further protection against rain.
Plastic and part design
The approximately 1.2 m x 2.0 m plastic pan presented a challenge for the engineering resin (polyamide) and the part design: the long flow paths and sometimes thin walls require an easy-flowing resin in order to produce the part by means of conventional injection molding. For this reason, the application development engineers at BASF recommended Ultramid B High Speed, one of the new especially easy-flowing grades in the polyamide 6 range. The good flow characteristics of the resin, in conjunction with the opening in the pan, also help to reduce manufacturing costs: it can be processed on injection molding machines with a lower clamping force.
An additional benefit of the special Ultramid grade for this part is its toughness. To withstand the strong solar radiation, the resin must furthermore exhibit high strength even at elevated temperatures as well as exceptional UV resistance and resistance to weathering. In terms of fire behavior, UltramidB High Speed satisfies the criteria required for such construction applications (material class B2).
Doubly beneficial PV module
The dimensions of the double-glazed PV module, which has been designed for large roof areas, combine exceptionally good product characteristics with a high efficiency per unit area. The integrative solution ensures a considerable reduction in the number of steps necessary for installation. Working direction during roofing is left to the roofer. The ease of handling provided by the built-in handles permits use of frameless double-glazed modules, thereby preventing the accumulation of dirt on the surface.