Outlook

It is primarily the innovative projects and prototypes—which do not fall within the remit of approved types of application in Germany—that are expanding the design spectrum. Transparent and high-modulus adhesives, in particular, are

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FIG. 18—Tensile test specimen in the testing machine at —25 °C.

opening up new fields of application for load bearing adhesive joints in glass structures, with point, linear, or planar adhesive joint geometries. Other adhe­sive systems such as epoxy resins, polyurethanes, or acrylates represent alterna­tives to the silicones traditionally used. Investigating the options for gluing glass to other materials and assessing the durability of such joints can lead to new types of structure and a wealth of opportunities in the medium-term.

Beside the use of adhesives for glass in building applications, options for developing the use of adhesives in solar technology and intensifying the use of that technology are being investigated more and more. These include current topics such as integrating PV elements into facades as part of the “Spitzencluster Solarvalley" project (www. solarvalley. org). Together with facade fabricators,

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FIG. 19—Construction of a facade for generating electricity.

solutions with a high aesthetic quality are drawn up based on various construc­tion principles, the planning process is optimized, and attention-grabbing dem­onstration projects devised. As part of this, both opaque and semi-transparent PV elements for facades with and without a ventilation cavity plus new fixing systems should be developed.

The range of designs permits a fundamental analysis of the additional loads due to PV elements which result from new applications in various types of fa­cade. Specifications drawn up based on this ease the development of the tech­nology. Beside the respective requirements placed on the modules, e. g., dimensions, weight, stability, and yield; architectural aspects and electrical safety issues are taken into account in the development of suitable jointing

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FIG. 20—Bonded Photovoltaic system facade, Manz Automation, Reutlingen, Germany (Hank und Hirth Freie Architekten;photo: Oliver Starke).

methods, e. g., adhesives, standardized mounting methods, and optimized ca­bling variants.

In this joint project, the Institute of Building Construction is responsible for the overall management of the scientific side and assists in the facade develop­ment by the industrial partners. One primary objective is the further develop­ment of adhesives for facade construction. Experimental proof obtained from small-scale specimens right up to full-size prototypes supports the validation. Rules for applications in accordance with building legislation are developed on the basis of the results of tests and practical experience gained with systems already in place.

Acknowledgments

The writers are grateful to all project partners and supporters who enable the diverse tests within the scope of the various research projects.