The building

The 'Plus-Energie-Bürohochhaus' (Plus-Energy Office High-Rise Building) is one of the eight buildings on TU Wien's Getreidemarkt campus which have been refurbished or rebuilt as part of the TU Univercity 2015 project. However, turning a 1970s tower block into a modern plus-energy building was not without its challenges.


TU Wien's Plus-Energy Office High-Rise Building can be found in the eastern corner of the university's Getreidemarkt campus. It essentially consists of two components – one adjacent building and the actual eleven-storey tower block. Refurbishment turned out to be the only option for the project due to legal restrictions preventing any new building from being so high.

The project team

The tower block refurbishment project's team consisted of the following members, making it no different from any other construction project in this regard:

  • Owner: Federal Real Estate Company (BIG)
  • User: TU Wien Rector's Office – TU Wien Buildings and Technology (GuT)
  • General contractor: Work group of architects Hiesmayr-Gallister-Kratochwil
  • Various expert planners as part of the general planning team

The team also receives scientific and research support from:

  • Professor Bednar – Building Physics and Sound Insulation research team at TU Wien
  • Schöberl & Pöll GmbH, Building Physics and Research
  • Other specialists and consultants

Thanks to strong cooperation between all those involved in the project who showed great enthusiasm for their research and a passion for innovation, it was possible to develop the world's first-ever 'Energy-plus' office tower block from the existing building. As this project required concurrent, integral planning in a fast-changing environment, transferring knowledge and maintaining a clear overview was crucial, meaning those involved were required to communicate well, put their advocacy skills into practice, and to project manage proactively.

Initial situation

The approx. 55 m-high building was constructed in the 1970s and had an energy consumption of around 803 kWh/(m²BGF.a) (primary energy, non-renewable).


It housed a main auditorium (lecture theatre), a library, offices and labs with its around 8000 m² of floor space and was home to the Faculty of Technical Chemistry, hence its former nickname 'Chemiehochhaus', or 'the chemistry block'.


A large number of the rooms were used as labs, which required there to be a suitably powerful ventilation system; this was housed on the top storey of the building.



Situation after the refurbishment

Over the course of the refurbishment, a new user moved into the building – the Faculty of Mechanical and Industrial Engineering, with the previous users moving their labs to the newly built 'Lehartrakt'.

The rooms which used to be labs have now become offices, while the 11th floor which housed the ventilation system is now home to the 'TUtheSKY' function room, and provides wonderful views of Vienna.

All storeys of the building were fitted with energy-efficient technology as part of the refurbishment. The 'Plus-Energy-Office High-Rise Building' research project covers the office areas of the building and part of the building's technology, as well as the server room in the basement (shown in green in the illustration above). All the diagrams and information presented here relate to this area.


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