is one of the first passive houses build in Austria - it was completed in 2001.
It originates from a disused exhibition stand and has been transformed into a detached family home.
The remarkable building is 15m in diameter and offers 140m2 of living area.
The client brief demanded the construction of a passive house standard at no additional expense above the cost for a general house build. Further the recycling and reuse of all items contained in the original exhibition stand was encouraged. As a result even bookshelves where constructed from the previous internal partition and exhibition panels.
Energy Concept:
The compact building form is equiped with a high insulating thermal envelope including high performance windows. It is designed and constructed airtight and free from thermal bridges and employs a low-tech concept, whereby the complete mechanical ventilation with heat recovery and warm water production is housed in a compact unit within the bathroom.
Energyperformance data are shown below:
- Heating requirement: QH = 13,7 kWh/m²a
- Heat load: PH = 11,4 W/m²
- Blower Door Test: n50 = 0,40 1/h
Building Concept:
The building envelope is made up of lightweight timberframe construction.
Exterior Wall: U-value: 0.1 W/(m2K)
(Wall construction from inside to outside):
2.5 cm gypsum plasterboard, 2-layered; 10.0 cm mineral wool between upright wooden members; --- vapour barrier
1.6 cm oriented strand board; 30.0 cm TJI joists with mineral wool; 1.6 cm diffusible wood fibreboard; --- Wind-proof fleece
2.4 cm battens; 3.0 cm counter-battens; 2.4 cm larch formwork rough-sawn untreated
Roof: U-value: 0.08 W/(m2K)
Roof construction from bottom to top:
4.0 cm tongue-and-groove fire-protection cladding, untreated on glue-laminated girders load-carrying stucture --- Difunorm Vario; 33.0 cm mineral wool roof insulation panels;
1.2 cm 3-layered polymer bitumen sheeting root-resistant; 20.0 cm XPS CO2 foamed - world premiere
1.5 cm dimpled sheet with fleece; 8.0 cm substrate; extensive greening
Floor: U-value: 0.12 W/(m2K)
Floor slab from bottom to top: 30.0 cm recycled demolished concrete
12.0 cm XPS CO2 foamed; 25.0 cm foundation slab steel-fibre reinforced; 0.5 cm humidity insulation
18.0 cm mineral wool between height-adjustable distance floor construction; 3.0 cm OSB sealed
Windows: Uw-Value installed: 0.78 W/(m2K)
Entrance Door: 0.62 W/(m2K)
Clever Solutions:
- The intake air is preheated by a supplementary heating register 30 m ground heat exchanger at a depth of 1.5 – 2.0 m
- Reserve heating 1 emergency 2 kW bioethanol-fired stove of max. 2 kW, free-standing in the living room, without chimney. Annual consumption of high-proof alcohol 11 litres!
- 100 % green electricity for power demand.
Ecological evaluation:
Extensive ecological study results: Compared to a standard energy saving house, the tenfold savings were achieved for: consumption of resources, life cycle assessment of all building components, freight volume, greenhouse gas emissions, surface sealing (green roof), no use of chemical greenhouse gases.
Are Circular Designs becoming the Future of Housing Design?
The Advantages:
Strength: Round is the strongest, indeed the optimal shape, whether it be the trunk of a tree, or a reed of grass in nature - or the whole earth... . round is a more effective form... a more hurricane, earthquake and tornado resistant home.
Energy Efficiency: All of natures creatures instinctively rely on the round shape for warmer shelter. A bird's egg, its nest, a rabbit den - all are proof that it takes less wall area to enclose an equally sized round, than a square or rectangular space. As such, a round house uses at least 30% less outer wall area than an identically-sized conventional house.
Here is a 7 min video about a possible circular shaped future and its benefits:
http://vimeo.com/5457265
Conclusion:
The circular design concept is definitely futuristic and offers efficiencies in several areas such as automated production, resource efficiency and thermal performance. In the context of building a sustainable future economy it might be worth keeping in mind. However, with regard to the 'Passivhausscheibe' I would say what for a great achievement and pilot project for sustainable construction as a whole.
Low impact not only during its lifecycle but also during the construction stage is heroic and moreover does not cost extra. Today it sometimes is cheaper to buy something new than reusing or recycling stuff. This idiocy has to end, but is written in another chapter anyway.
Generally a round building form seems ideal to catch sunlight and presents the best surface area - volume ratio, but additional costs from tailor-made solutions (as required from circular buildings) might be counter-efficient in terms of cost. Due to the fact that the base construct to this building was an existing structure which has been utilised in the most efficient way, it is certainly a successful project.
From a visit to Straffan Co. Kildare and the talk with architect Fergal O'Malley of Timbertech Homes, I learned that many Irish clients do not want to abstain from an 'open fire' place. So they invest all the time and energy to build an airtight passive house and after the blower door test, they open up the previously sealed fireplace. A really good alternative solution for those who like to play with fire is the ethanol burning fireplaces. There are hundreds of manufacturers I like this one: www.vauni.com/ just to check out and probably worth of spreading around the news that you can have both:
an open fire and an airtight house.
Regards,
Henrik
