The office building was built in 1999 and enlarged several times during recent years. A comprehensive renovation was decided in 2007. The focus of this refurbishment was primarily on solar architectural aspects. These included insulation and tightness of the building envelope, mass storage optimization, summer comfort, sunscreen planning and of course the internal comfort (natural light, indoor air quality, organic materials, ...). This was related to the heating demand of a Passive house (heating demand = 15 kWh/m²y). The objective of the efforts was to have the own office building representing a model for innovative building solutions and as a test case. The project was designed and planned by Siegfried Manschein and Gregor Högler, the implementation was done by the employees of the company Manschein GmbH. The "Ohnergiekonzept" stands for a equalized energy balance for heating and cooling as well as the 100 % utilization of solar potential. Through simulation of glazing, sunscreens, lighting and daylight quality the energy consumption was further optimized.
Due to the refurbishment the heating demand has been reduced by 86 % and the primary energy consumption by 82 %. 100 % of the electricity consumption is covered by the PV system.
- External walls - 0.18 W/m²K
- Roof - 0.12 W/m²K
- Windows - 0.6 W/m²K
- Optimisation of the building envelope (insulation, airtightness, windows, cold bridges, thermal mass)
Building services - HVAC:
- Mechanincal ventilation with heat and cold recovery
- Heating: solar thermal heating system, ground source heat pump
- Cooling: free cooling (night time ventilation), passive cooling (ground source), solar cooling
- PV (42 m²)
- solar thermal system (32 m²)
- ground source heat pump (720 m² soil collector)
- use of daylight
- external shading
- storage mass substitution with PCM-material to lower temperature peaks during summer
- Monitoring of energy consumption
- Use of simulation tools when planning the building
Acronym of the case
Especially the solar cooling system had problems in the beginning, which could be reduced or solved until now.
The effects of the ventilation system like the night time ventilation and the reached indoor air quality are highly appriciated by the employees. Whenever the ventilation system has been turned off without the knowledge of the employees this has been noticed quickly.
Within the first two years the systems have been expanded with additional innovations and measures like increase of the brine temperature through solar increase of low temperature level, re-cooling of the solar cooling system through the soil collector and implementation of a CO2 sensor in the ventilation system.
Finally it can be said that the expectations concerning economy, ecology and comfort have been met and exceeded.
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