Plus energy office building - Subproject 3: Austria's biggest plus energy office building

In course of the refurbishment of the Vienna University of Technology (Univercity 2015) Austria´s biggest plus energy office building is going to be built. This project intends to demonstrate not only the technical but furthermore the economical feasibility of plus energy office buildings. Within this building the plus energy concept is fulfilled by optimizing the power consumption of the whole building and the installation of Austria´s largest facade integrated photovoltaic plant.

Short Description

This project is a sub project of the flagship project "Plus energy office building".




Austria's largest plus-energy-office building situated on Getreidemarkt is now in completion and the relocation of the staff is going to take place in August 2014. The building offers 700 working spaces. The entire building has a net floor area of 13.500 m² and 11 storages.

Goal of the project was to accomplish the plus-energy-standard on a primary energy level on the site of the building including office computers and servers. The coverage of the primary energy demand is accomplished with the photovoltaic system, the usage of thermal discharge from the servers and the energy recovery from the elevators.

The central point for reaching the plus-energy-standard of the office building was the extreme reduction of the energy demand for all sections and components in the building, from heating to cooling and also for the office computers and smaller electric components. 9.300 components out of 280 categories in the project were registered, optimized and approved by the science team.

The following graphic differentiates between university usage and standard office usage of the entire building. In the university usage in opposition to the standard office usage highperformance simulation computers are being used.

To accomplish the plus-energy-standard for the office building the following points were realized in the project.

  • optimized passive house envelope
  • core ventilation for automatized night ventilation and lower cooling demand
  • highly energy efficient building services

    • double rotary heat exchangers for more efficient recovery of moisture and to prevent humidification and dehumidification
    • high insulated distribution pipes (heating 6/3, cooling 3/3)
    • thermal activation of building structures (activated screed for heating and cooling)
    • cooling machine with SEER > 9
    • ventilation system and air ducts with minimal pressure drops, no heating and cooling coils
    • demand-actuated ventilation system
  • LED-lighting with 110 lm/W
  • 24 V grid for higher energy efficiency and centralization of power adapters
  • energy efficient office computers, kitchen appliances and servers

    • stepwise exchange concept for existing computers of the institutes
    • transfer of the simulation computers from the working space to the server room for centralized and efficient cooling
  • energy production: photovoltaic system on the roof and in the facade

    • total power: 328,4 kWp
    • roof: 97,8 kWp
    • facade: 230,6 kWp, largest building integrated photovoltaic system in Austria
  • energy production: usage of thermal discharge from the servers and usage in the thermal activation system, coverage of the greater part of the building's heating energy demand
  • energy production: elevator better then energy demand class A with energy recovery and weight reduction

The building achieves 983 points with the building certification TQB.

Results from this project are already realised by TU Vienna for all 5.500 employees: efficient 10 W computers, powering off of all existing phones at night etc. Technical aspects from this project are going to be transferred on upcoming projects from the TU Vienna, like LED lighting, the renovation standard etc.

Project Partners

Project management

Schöberl & Pöll GmbH

Project or cooperation partners

Contact Address

Schöberl & Pöll GmbH
Lassallestraße 2/6-8
A-1020 Wien
Tel.: +43 (1) 726 45 66