Monday 19 December 2011

St. Gerold Community centre, Austria by the architects CUKROWICZ NACHBAUR ARCHITEKTEN

The building is a community centre based in Vorlarberg, in Austria. It won second prize in the Passive House non-residential awards in 2010. It is based in St. Gerold, a small village. The area has put in place different sustainable initiatives (for example the nomination of the region as a biosphere park) to try to enhance the awareness and identity of the population. It is a proclaimed aim of the region to reach autarky (self-sufficiency) in terms of energy not later than 10 years from now.

Image of the surrounding landscape
The playground
This was the brief for the building, to be completely self-sufficient. What is so interesting about this building is how it blends into the landscape, which is very much in keeping with the idea of autarky. Unlike many Passive House designs, it responds to the landscape and uses the geometries of the landscape to create complexity in the design. The building uses both existing flat surfaces, and created surfaces (the playground) to make the building itself a gateway between the two. Set openings create differentiated spatial situations with different views to the surrounding landscape. 

Image of the building in context of the site
 It is a four-story timber building, which in itself is unusual. All of the construction units are wood and come from forests in the local area. The building is deemed to be nearly self sufficient. The building includes a kindergarten, playgroup, village shop, multi-purpose room and a room for local government functions.

Floorplans of the building
All parts of the house are made of solid wood; the surfaces are made from untreated native white pine. All the thermal insulation is made by sheepswool and wood fibre insulation. All construction units (construction, façade, windows, floors, walls, ceilings and furniture) are from massive wood (silver fir) and derive mainly from forests in the local area. They were inserted completely untreated.
All aspects of the building were proved ecological in terms of:
Content of primary energy
Global warming potential
Acidification


Interiors of the building
The area of the building is 571 m² net, and the energy area according to PHPP is 528 m². The building uses controlled ventilation with heat recovery. The energy supply is a combination of geothermal, internal heat gains and passive solar gains. A small power station uses the large decline in the landscape of 800m for drinking water as well as the creation of electricity.

Project Summary:

Site area: 2045 m².

Building area:  571 m² net.

Energy area according to PHPP: 528 m² 

Construction: Mixed construction (mainly timber) 

Air-tightness:
n 50 = 0.5 / h 

Ecological aspects:
PVC-free, CFC free, HCFC-free, tropical wood-free, heavy metal free 

Heating energy:
14 kWh / (m² a) calculated according to PHPP 

Heat Load:
16 W / (m) is calculated according to PHPP 

Primary Energy Consumption:
120 kWh / (m² a) Living for heating, hot water, supplies, and household electricity calculated using PHPP 

Construction costs:
4,275 / m² for Treated Floor Area

Ventilation:
The building uses Heizbösch, rotary exchanger 
Controlled ventilation is used,
 with controlled CO2, and passive heat recovery of 75% efficiency and an upstream earth heat exchanger 

Heating:
Heating the incoming air, the air flows over wood displacement diffusers in the room. 
Heat dissipation is controlled by the individual room control.
 
In summer the convectors cool down the air with energy source ground collectors and borehole heat exchangers.

Hot water:
Circulation pipes for the distribution of domestic hot water via the heat pump, storage, container steel ST 37.2, installed in the tank - Hydrax BW-861 water heater hygiene V4A Ne. 1.4571, capacity 46 litres, including Legionella-Certification 
Product: Hardware Forstner 6923, Type: HWS BM-080 WP
 


Exterior wall:
There are different exterior wall structures and most of the structures are of wood construction. Below is a sample of the constructions:
timber formwork / battens
 
vapour barrier
 
4 cm battens / insulation felt (040)
 
2.5 cm diagonal formwork
 
32.5 cm wood / insulation Isocell (039),
 
2.5 cm diagonal formwork
 
wind paper
 
There is additionally reinforced concrete exterior wall that is ventilated, and exterior walls with photovoltaic elements
The averaged value of all exterior wall surfaces against outside air is a U-value = 0.139 W / (m² K) 

Basement Ceiling/ Floor plate:
Wood belt 
24 cm insulation (040)
 
moisture barrier / concrete
 
blinding layer
U-value = 0.162 W / (m² K) 

Roof:
Again there are different roof structures and most of the structures.
Below is a sample of the constructions:
depicted wood construction with a significant share of the total U-value
 
roof seal (Sarnafil)
 
wood planking
 
40 cm cross layer and insulation Isocell (040)
 
wood planking / vapour barrier
 
The averaged value of all roof surfaces U-value = 0.11 W / (m² K) 

Windows:
Messrs. Hartmann Hartmann window wood 
white pine solid wood
 
U
 w -value = 0.78 W / (m² K) 

Glazing:
3-fold glazing with stainless steel edge joint,
Guardian 6/18/6/18/6 argon filled U: 0.53 W / (m² K)
Guardian 6/16/6/16/6 argon filled U: 0.64 W / (m² K) 
U g -value = 0.6 W / (m² K), g-value = 48% 

Conclusion:
This building is certainly an ideal poster building to promote the Passive House Standard. It is both beautiful and functional. The architects have taken great care to minimise the impact on the surrounding landscape and to create a space that the locals can be proud of.

The four storey timber frame structure is very impressive, and should be encouraged in order to minimise the use of steel. The fact that the buildings embodied energy was considered, and that all of the wood used was taken from the surrounding landscape is to be commended. The buildings global warming potential is very low, both during the construction and operation phase.

The large expansive windows take great advantage of the surrounding views while also maximising solar gains. The shuttering on the west façade is seamlessly integrated into the façade, and the solar gains are controlled without compromising the aesthetic. The plan is box-shaped, which is the optimum layout to prevent heat-losses through the perimeter wall. However, the complexity within the elevations, and the use of the natural level changes on site, make for a much more interesting building.

The idea of autarky is something positive for consideration. It is going to be of more relevance in the future when oil prices rise to unaffordable levels. It is clear from this project, that the Passive House standard has a large role to play in creating self-sufficient buildings and homes. The fact that this building is completely independent in terms of energy and water resources means that there is more certainty in terms of its future cost. It was certainly worth investing in these energy efficient methods as the returns on investment in terms of cost and energy security will be great in the future. 


References:

1 comment:

  1. Dear Eimear,

    the presented building is a beautiful building from the internal view. I like the light colour of the silver fir. From the external I find the building very 'massive' and 'edgy' and cannot really follow your thought of the buildings response to the landscape. However, the idea behind it, to not only create a community center with local materials that will be running on low operating cost in the future, but in fact seeing the 'greater picture' for the community by enhancing the awareness and promoting the identity of the population, leads to a successful beginning of their long term objectives. On a worrying note I have to say to leave the exposed timber untreated might have worked fine in the past. Latest reports from Sweden show that timber houses suffer greatly from global warming and wetter climate.

    Eimear, as mentioned earlier, it is a beautiful building, fully passivhaus certified, build from local materials and has its own water and power supply - is there room to improve? Well spotted and informative blog post. Have a good christmas! Henrik

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