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A new building with a tensile roof: Although the textile architecture used for the new Energy Efficiency Center in Würzburg still seems exotic, the undulating roof forms are also reminiscent of a rolling landscape.
© ZAE Bayern, Foto: Petra Högelmeier
Interview with Thomas Rampp to mark the inauguration of the Energy Efficiency Center

With its new institute building, the ZAE Bayern research institute wants to demonstrate and further research a whole raft of innovative technologies.
© ZAE Bayern, Foto: Petra Högelmeier

Interior of the textile membrane roof with a transparent and translucent membrane for utilising daylight.
© ZAE Bayern, Foto: Petra Högelmeier

“But certainly not a cabinet of technological curiosities”

The Energy Efficiency Center in Würzburg was officially inaugurated last Friday.  The ZAE Bayern research institute is moving into the new building, with which it wants to demonstrate and further research a whole raft of innovative technologies. The most striking feature of the new building is its textile roof. In combination with special ceiling elements, innovative membrane films enable daylight to penetrate into the building and at the same time create a controllable, intermediate climate zone. Thomas Rampp is the architect. In the BINE-Interview he talks about the challenges and opportunities presented by technological innovations for architecture.

BINE Information Service: Mr Rampp, what strikes you the most when you stand in front of the almost completed building?

Rampp: The current visualisation possibilities enable you to anticipate much of the building’s impact in advance. In the end you stand in front of the building and think – yes, that’s it. The building looks exactly how it was visualised on the computer.

So there are mostly no surprises these days?

Rampp: Yes that’s true, but it is only when you see the actual building that you really appreciate its overall size and proportions. The Energy Efficiency Center has fortunately turned out to be somewhat more delicate than was expected during the planning. The gently curving roof membranes give the building a lighter touch. It is astonishing how varied the building appears in different weather conditions and during the course of the day. You can see how the building uses passive solar effects.
The building needs sunlight. The play of light and shade created by the numerous cantilevered building elements and the shine and shimmer of the white, sail-like roof skin are shown to particularly good effect. It is a gently undulating roof landscape, which a lot of people like.

The building developer wanted to create a flagship building for technology. Does “form follows technology” apply in this case?

Rampp: Architecture should not be a motley collection of technologies, not even with a flagship building for a research institute. We wanted to deploy new technologies here, but certainly not a cabinet of technological curiosities. However, “form follows technology” is not completely wrong, and I could add that “form follows the path of the sun”, since the building makes considerable use of passive solar effects. As with established solar architecture, it is about using the sun to the best possible effect to achieve good visual and thermal comfort in the building.
Nevertheless, wherever possible we have tried to use the synergy effects between different technologies or infrastructural requirements. For example, the water storage tanks required in the Energy Efficiency Center for fire protection purposes are also activated as a thermal storage system as part of the building’s energy system. Another example is the roof of the plant room. It is not allowed to have a membrane roof for reasons concerned with the building regulations. In clear summer nights we sprinkle the concrete roof with water so that it acts as a heat sink for cooling the entire building.

What are the unique challenges when furnishing buildings with tensile roofs?

Rampp: Actually there are more opportunities than challenges. Hyperbolic surfaces – in other words membranes curved and tensioned in two opposing directions – achieve considerable stability. You can even walk around on them. At the same time we also consider these forms to be harmonious, elegant and pleasing. They remind us of a rolling landscape. The tension that is contained with these forms is also very appealing.

And how weather-resistant are these membranes?

Rampp: These days, the membranes normally have a guaranteed lifespan of twenty years. However, the service life of these membranes is presumably considerably longer. If you take a look at the first building of this kind, which was constructed in the USA in 1973, the membranes are still in a reasonable condition today. The materials are UV-resistant and durable.

How much potential does textile architecture have?

Rampp: The Energy Efficiency Center is probably more of an exception as a building type, since membrane roofs and textile facades cannot compete so quickly in central Europe with the single-leaf, monolithic construction method. That’s why I particularly envisage two application areas for textile architecture: special buildings without any considerable thermal requirements, for example stadia or airport terminals, and the roofing over of courtyards and atria. In addition there are all the building structures in which industrial prefabrication provides the decisive advantage in the construction process. The significantly reduced construction times are interesting for areas where it is very complicated to build in-situ.
In future it will also be conceivable to use membranes in refurbishing buildings. The MESG research project is currently investigating the contribution that can be made by hyperbolically tensioned membranes. The project is concerned with the use of double-skin facades and house-in-house concepts for refurbishment.

Which of the innovative technologies installed in the Energy Efficiency Center will soon be ready for use in practice?

Rampp: First of all it should be mentioned that in order to comply with the building regulations we had to obtain individual building approval for many of the construction elements and components used in this new-build scheme. Proving the fire-resistant properties of the film membranes turned out to be particularly challenging and complex. But we were ultimately successful. But if you are asking which of the technologies installed here are already ready for use …

…in other words for widespread use in new-build schemes and refurbishment…

Rampp: …then I can think of several technologies: vacuum insulation is already market-ready – there are various providers and a competitive market with interesting solutions. Vacuum insulation becomes particularly interesting in cost terms when little space is available for high quality insulation.
The heating and cooling ceiling elements developed by us also have considerable potential. As a thermally effective PCM material, they contain salt hydrates instead of paraffin and are therefore also safe in fire protection terms. In addition the elements also use graphite, which as a new material for buildings improves the dynamism of the thermally active ceiling elements.
In addition I can think of the radiation and evaporative cooling for the flat roofs. That is low-tech and also interesting for cooling solar modules. This enables the building to be cooled in the night and the solar power modules during the day.

And what is the case with vacuum glass

Rampp: Vacuum-insulated glass would of course be highly interesting. We wanted to install this kind of glazing but unfortunately it was not yet available. We will have to wait and see whether the technological problems will be solved during the next few years.
A nice development is emerging with the window frames and facade systems: we have installed wonderfully slim window and facade profiles with very high thermal insulation. The ideas stem from the research at the ZAE Bayern research institute; the product was supplied by a major facade system provider.

What costs are entailed by a building full of new technologies?

Rampp: The Energy Efficiency Center cost 11.5 million euros to build. That really isn’t very much for this type of building. Maintaining the budget framework was certainly an amazing achievement. In contrast to some public buildings there was no funding disaster. Of course compromises had to be made: for example there is linoleum instead of parquet flooring.
Together with the building developer, it has also been possible to foster the commitment of the mostly regional firms. The companies sense that they can create an impressive reference project on their own doorstep. The regional roots of the companies offer nothing but advantages. They want to supply something decent. That is also sustainable in socio-cultural terms.



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Energy Efficiency Center
New building of the research institute
ZAE Bayern

Research project MESG
Membrane constructions for the energy-oriented refurbishment of buildings

Lang Hugger Rampp Architects
Architecture of the Enercy Efficiency Center

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BINE-Projektinfo 8/2012