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.
Summary
Individual Glass Solutions
for Modern Building Skins
Frank Schneider, Dr.-Ing., Director R&D
OKALUX GmbH, Germany, info@okalux.de, www.okalux.de
Today glass often plays a central part in the design of building skins. Therefore demands on such
glazing become progressively complex and manifold. Depending on the respective environment,
the occupancy and other relevant parameters individual solutions have to be developed. To
optimize energy consumption of the façade, the insulating capacity, the sun protection and the
solar energy transmittance have to be adjusted carefully according to particular boundary
conditions. Translucent insulating materials (TIM), various systems for sun and energy control and
individual design inserts allow a wide range of innovative possibilities for green buildings of the
future.
Keywords: Insulating Glass, Sun Control, Energy Consideration, Individual Design
1 Introduction
Rising energy standards and peoples growing ecological awareness in terms of energy consumption
and CO2 emissions require new developments in the field of the building´s services facilities as well as
the building´s façade. Nevertheless, today the technical limits in the field of the Thermal Insulation are
very limited. Improvements may be achieved by exotic materials like translucent Silica-Aerogels [1].
Such nanoporous granulates prevent convection and conduction within the gas phase. Thus, an
Insulation Glass Unit filled with such a material achieves a thermal transmittance of U < 0.3 W/(m²K).
Evacuated glass units may once achieve even lower values. But a durable vacuum insulating unit with
such U-values is not available at the moment due to various technical problems of keeping the vacuum
durable.
Hence, a key development in the field of thermal insulation is very limited. Therefore, it is more
effective to taken the thermal and solar parameters into account to optimize the building´s overall
energy consumption. Even with an excellent thermal insulation glass buildings tend to overheat during
the summer. Considering the fact, that cooling a room by air-conditioning requires approximately
double the energy than rising the temperature about the same value, it is often more effective to design
a suitable shading system than to reduce the thermal insulation to some percentages. The physical
properties, especially the Insulating Capacity, the Visual Light Transmittance and the Total Solar
Energy Transmittance have to be fitted carefully, depending on the individual boundary conditions to
achieve an optimal performance.
Beside solar-control coatings, integrated blinds or metal meshes with optical properties can be used to
obtain the required shading coefficient. In addition, such solutions create an individual design of the
buildings envelope. As the technical parameters of the Insulating Glass Units often do not differ much,
such design issues become more and more important.
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