Historic Otto Wagner Area to Become a Positive Energy District

They think big and positive in Austria.

Steinhof
Steinhof asylum, 1932.

 Walter Mittelholzer / Wikimedia Commons

Zero energy buildings are so 2020; in Austria, they talk about positive energy, and not just buildings; they are building positive energy districts (PEDs) or "urban areas that are able to meet their own energy needs by optimizing building infrastructure, maximizing efficiency in every area of energy consumption, and implementing innovative business models." And not just for new construction; a consortium of the Central European University (CEU), TU Wien – Institute of Architecture and Design, LANG consulting, the OeAD-Wohnraumverwaltungs-GmbH, and Schöberl & Pöll GmbH is proposing to turn the vast former psychiatric hospital in Vienna designed by Otto Wagner into a PED. Part of the site is going to become the new home for the Central European University, which was founded by George Soros in Budapest and has been forced to leave Hungary; it is headed now by Canada's Michael Ignatieff.

When the complex opened in 1907, it was a sensation. Kyle Walker writes that "seen from the south, the asylum’s 60-odd buildings appear to merge, presenting a continuous facade of white walls and glistening windows crowned by an onion-shaped golden dome.... Crowned by its church, Steinhof’s white walls and imposing facades evoke a modernist city on a hill: rational and ordered, but also bright and healthy."

Lloyd Alter with Gunter Lang
Lloyd Alter with Gunter Lang in Vienna, 2017

The challenge is to retain and restore those sensational buildings while bringing them up to the Positive Energy standard, without it costing the earth. Günter and Markus Lang of LANG Consulting Passive House experts and members of the consortium, told Treehugger that the building complex currently is heated via a district energy system with hot water supplied from a waste-to-energy plant, which is in need of significant investment. If they take that money and stick it into energy efficiency and a photovoltaic system on the roof, they can make the buildings energy-positive for just 9.66% more investment upfront, but which quickly gets paid back in energy savings.

Energy savings
Schöberl & Pöll GmbH

According to the project description in the guide to positive energy districts,

"By adapting the layout of the buildings to the practical needs of their users, and optimising all trades, including operating equipment, the total energy consumption can be reduced by around 90% compared to simply carrying out maintenance renovation ('baseline scenario'). The energy balance for the site is positive within the accepted range of variation. Additional energy requirements can be met using locally sourced energy."
Window renovations
via LANG Consulting

Renovations of historic buildings to this kind of standard can be expensive and difficult, especially with a list of planned interventions like this:

  • Insulation of the roofs and the floor slabs as well as internal insulation of the outer walls
  • Optimization of the box windows and installation of sun protection between the sashes
  • Minimization of thermal bridges
  • Optimization of the airtightness in the renovation of existing buildings
  • Highly efficient ventilation systems with heat and moisture recovery
  • Highly efficient hot water preparation and use of flow-optimized fittings
  • Heating and cooling via efficient surface systems
  • Installation of a highly efficient lighting system
  • Use of highly efficient energy-consuming devices in all areas of use
  • Installation of photovoltaic systems on the roof surfaces
Wall Section
via LANG Consulting

You can see the calcium silicate board insulation has to return on the floors, ceilings and interior walls to cut down on the thermal bridging. Life would be so much easier (and costs so much lower) if one could just wrap the building in insulation, as is done so often, but would destroy the historic character of the buildings; this is why renovations can be so tough.

But this is the kind of thinking we need if we are going to deal with the climate crisis: work at a district level, not with individual buildings. Think positive; give back more than you take. Fix what we've got; the greenest building is the one already standing. Last words to Professor Dr. Diana Ürge-Vortsatz of CEU:

"This project demonstrates that protected historic monuments – the last unconquered territory in the building sector – can be turned into energy producers rather than energy consumers. We believe this to be the final gasp for carbon-emitting buildings. It is now up to all of us to switch Europe’s building stock to being climate neutral. The landmark opportunity to refurbish a protected monument into an energy plus district is a world-first."
View Article Sources
  1. Walker, Kyle. "Modernism, Heal Thyself." Public Books, 2019.