EuroSun2008-5

Quantification of the impact resistance of solar thermal collectors and. photovoltaic-modules against severe hailstorms

Stefan Mehnert*, Matthias Rommel, Stefan Brachmann, Joseph Steinhart, Thorsten Siems,
Anne-Marie Behringer, Georg Mulhofer, Korbinian Kramer, Johannes Scherer

Fraunhofer Institute for Solar Energy Systems ISE, Heidenhofstrafle 2, D-79110 Freiburg, Germany
Corresponding Author, stefan. mehnert@ise. fraunhofer. de

Abstract

Damages caused by severe thunderstorms are dramatically increasing in recent years and it can be assumed that this trend will continue within the climatic change. A survey of the most common thunderstorms in Europe shows that associated climatologically secondary phenomena like hail have likely the same or actually in some cases even a higher potential for damage than their primary wind phenomena. Current studies report an increasing of severe hailstorms in the European Union (EU). It must be assumed that severe hailstorms will become one of the most pressing problems posed to society by severe thunderstorms, mainly in the summer season. The enormous financial losses caused by hailstorms each year in moderate climate regions will further increase. This fact results in the basic necessity to perform some representative studies to quantify the impact resistance of solar thermal collectors and photovoltaic-modules against severe hailstorms. The benefit of such studies will be the mitigation of the threat of physical conditions posed by hailstorms, a better basis of information for the insurance industry for the assessment and the coverage of severe hailstorms, and last but not least to back up essential guidelines given from the EU to ensure the sustainable growth.

Keywords: quality assurance, impact resistance, severe Hailstorms

1. Introduction

The Fraunhofer ISE developed a new testing facility to simulate hail impacts with ice balls with the objective to perform impact resistance tests of solar thermal collectors and PV-modules according to the valid standards. This testing facility has recently been set-up and gives us the possibility to perform experimental research as well as the possibility to perform tests commissioned by the industry. This paper describes the background of the relevance of impact resistance test procedures for the quality assurance of solar thermal collectors and PV-modules. Furthermore, this paper compares and assesses the different requirements of the testing procedures within the currently valid European and international standards.