advanced building skins 14 | 15 June 2012 - lamp.tugraz.at - Graz ...

Prof. Dr.nat.techn. Oliver Englhardt
Institute of Building Construction
Graz University of Technology
Copyright © with the authors. All rights reserved.
Bearing Capacity of Thin Film Photovoltaic
Modules – Differences in the Safety Levels
Summary
Jens Schneider, Johannes Kuntsche, Jonas Kleuderlein
Technische Universität Darmstadt, Germany, www.iwmb.tu-darmstadt.de
The increasing use of thin film photovoltaic modules and the increasing occurrence of damages
raise the question about a sufficient safety level for the glass-glass-modules used at present. This
paper compares the experimental determination of the load-bearing capacity used in the solar
industry according to IEC 61646 and a calculative method according to the German structural
design standard for glass structures (DIN 18008). Substantial differences in the safety level are
pointed out. Moreover, the load case „temperature“ can become relevant for the structural design
because of the high solar absorption of the modules. This influence is currently not regulated in the
standards. For typical installation situations, a calculative consideration of this load case is
discussed.
This article was published in CHALLENGING GLASS 3 – CONFERENCE ON ARCHITECTURAL AND
STRUCTURAL APPLICATIONS OF GLASS, TU Delft, June 2012.
Keywords: Photovoltaic, Safety level, Temperature
1 Introduction
The use of photovoltaic (PV) modules is growing more and more due to falling prices of the modules
and governmental subventions. In 2010 Germany produced more than 11 billion kilowatt hours of
electricity by photovoltaic systems according to the Federal Ministry for Environment, Nature
Conservation and Nuclear Safety (BMU) [1]. This represents an increase by 77% compared to 2009.
Figure 1: Damage pattern in thin-film PV modules with glass-glass assembly
This is accompanied by the rising occurrence of damages at installed modules (Figure 1). Especially in
thin-film modules with glass-glass assembly (Figure 2) increased cases are noticed, where, due to
glass breakage, the modules lose their function as a power supplier and also become problematic due
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