OctagonOffice: Excellent working environment

Even from the outside, the OctagonOffice in Wachtberg-Villip near Bonn attracts special attention. But its interior qualities are similarly impressive, since the innovative headquarters of the software company TETRA Computersysteme GmbH is an energy-plus office complex built to the passive house standard, making it particularly climate- and user-friendly.

The zero emissions and carbon neutral OctagonOffice came into being in 2009, having taken just three months to plan and six months to build. The managing director of TETRA Computersysteme GmbH, which uses the building as its head office, was responsible for the overall planning. As an energy-plus passive house, the innovative office building produces more energy with its photovoltaic system than the company consumes on site. The OctagonOffice implements numerous other measures to save energy and increase the comfort of its workforce.

Engine for progress:

  • heating required: only ten kilowatt-hours per square metre / year
  • optimised thermal efficiency
  • aesthetic architecture
  • controlled ventilation with heat recovery
  • pleasant indoor climate all year round without the need for air conditioning

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Photo: TETRA Computersysteme GmbH

The OctagonOffice: the thermally-optimised, octagonal architecture is distinctive here, with the thermally decoupled “ears” attached on the northeast and northwest sides; these accommodate technology and storage facilities and also support the patios on the upper level. The photovoltaic system with battery storage, which covers the whole roof area, generates enough power, on balance, to supply the entire energy requirements of the building. 

Maximum thermal efficiency, pleasant indoor climate all year round

The office building requires just ten kilowatt-hours per square metre per year to heat and thus clearly undercuts the strict limits of a passive house by five kilowatt-hours. This is due to the fact that the OctagonOffice is aligned in the optimum position to the sun and is very well insulated with triple-glazed windows.

A controlled ventilation system with heat recovery and an upstream geothermal heat exchanger further reduce the residual heating requirement. This means that the indoor climate is pleasant all year round without the need for air conditioning.

Minimal electricity consumption and high reliability

In order to minimise its electricity consumption, the IT company implemented an intelligent LED lighting design, installed an energy-saving IT infrastructure and purchased other super-efficient equipment. Furthermore, a building automation software system, which was developed in-house, records, visualises and controls all electrical usage.

The electricity requirement is more than covered by a photovoltaic system with a nominal capacity of ten kilowatts. In addition, a battery storage system makes the building completely independent in terms of energy supply in the summer and the storage facility can even keep the company operating for around three days in the winter.

Rapid amortisation and a high-quality working environment

If you think that all this effort is extremely expensive, you are wrong. The additional costs of three to five per cent are hardly higher than normal for the OctagonOffice. The investment pays for itself within a short time and saves costs in the long term. What is more, an energy-plus passive house like the OctagonOffice is also architecturally attractive; and all the employees reap the benefit of the office work stations, which are flooded with light and have an optimal temperature all year round.

Photo: TETRA GmbH

"It is not a problem of recognition, but a problem of implementation. Energy-efficient buildings are by no means uncharted technological territory, which would allegedly demand a substantial amount of research. We simply cannot allow the excuses that it is too expensive and too complicated to go unchallenged. These excuses are more indicative of a lack of knowledge and hostility towards innovation on the part of the planners and designers involved in the construction, than they are based on reservations substantiated by facts."

Claus P. Baumeister, Managing Director TETRA GmbH

Partners and sponsors

  • TETRA Computersysteme GmbH