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
5 comments:
Henrik,
Very interesting choice. The round house is an unusual design - one wonders will it ever be widely used in the building industry.
The u values and air tightness look impressive and the reuse of the old building's materials is commendable.
The open ethanol burning fire is a good idea but I see in the vauni website it still does emit some small amounts of CO2.
Finally looking at the roof of the building, I'm not sure I'd fancy mowing the lawn up there! Awkward getting the lawnmower up! Ha ha.
An informative, well structured blog.
Well done.
Shay
@Shay
Hi Shay, thanks for your refreshing comment.
Yes, the ethanol is still producing CO2, but a properly designed MVHR unit will be able to cope with the additional fresh air demands. At least you can avoid the draft of a chimney and maintain a balanced inhouse climate.
Shay, I know its a hard time at the moment. Do you really want to skip the fees for your golf club membership - or why do you want to cut the lawn on top of the roof? :)
Hi Henrik
Found your blog post to be an interesting read. The house in question is an impressive Passive House that seems to instil good sustainable values.
Interesting to see the shape of the house and I think it will become a more common type of construction into the future taking advantage of solar gains at all times of the day.
As I mentioned, I liked to see the sustainable/recycling side of things in this project reusing as many materials as possible.
The U-values and air tightness results are all impressive easily meeting Passive house standards.
The fireplace is very innovative and provides the house with a nice effect. Are these ethanol fuelled fires expensive to run?
On a lighter note maybe to make the house more sustainable a few sheep could be put on the roof and there would be no need for lawn mower ha.
Interesting case study Henrik.
Regards
John
Dear John,
I am happy to read your comment which is ending with a very amusing and creative idea. Always wanted to have a few sheep.. And the sheep in turn would produce biomass and wool insulation.
Bioethanol cost between €1,70 - €5 a litre, depends on where you buy. The occupants of the house said there are using 11 l/per year!
It is interesting that the brief stipulated a Passive House Standard house with no additional cost above the cost for a general house build. I wonder is this a general house build that would have to be bespoke anyway due to the curved nature of the building? In general a Passive House is 10% more expensive to build than an average house. Usually an average house would use standardised sized elements in the design, thus the difference in price, as they would be using mass-produced items. However in this design, I think that this statement misrepresents the house as being inexpensive, when in fact the curved nature of the house probably makes it expensive to begin with, so making it passive didn’t make that much difference!
I do agree that round is a good shape in terms of shelter. The analogy of the egg etc. is used to good effect. However, I do not feel that it is practicable for the present living environment that has to be divided up into separate useable spaces. A circular plan on its own is good, but when put into practice it is questionable. Certainly this would put the cost up also as all furniture etc. would have to be bespoke.
In terms of the re-use of old materials, I agree that that is something that is to be commended. Unfortunately, if you are to re-use existing materials in a circular house, “down cycling” is inevitable. As was mentioned in your blog, old elements of the panelling from the exhibition villa were only used for bookshelves, perhaps if the house had used traditional geometries, they could have been used as panelling again, and saved the production and purchasing of new panels.
The video you have posted is great! I do think that there is scope for circular buildings in the future when production processes move on, but it will take time. This will also involve a change in mind-set of the general public, and alteration of their living habits. It was a great video with lots of interesting ideas for the architects out there, although I don’t know how I feel about the possibility of living under water!
Well done!
Eimear
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