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:

http://www.hicarquitectura.com/2011/03/cukrowicz-nachbaur-architekten-st.html

http://www.passivhausprojekte.de/projekte.php?detail=1711&keyword=gerold

Passive House Comment on Shay's Blog

Passive House Criteria

Critical publication review:Traditional, state-of-the-art and future thermal building insulation materials and solutions – Properties, requirements and possibilities (Bjørn Petter Jelle a,b,∗ )

In this article the Jelle outlines the advantages and disadvantages of thermal building insulation materials. He investigated traditional, state-of-the-art and possible future materials. The table attached compiles all of the various properties, requirements and possibilities analysed. This table is intended as a reference table and a learning tool for insulation materials and will be updated over the course of my studies.

Currently there is no single material that is capable of fulfilling all requirements. The new materials being introduced have their limitations, and Jelle stresses the importance of knowing these.

Jelle notes how recent studies point out that insulation of buildings is more cost-effective than the creation of renewable energies. It makes good fiscal sense to take account of these advances and for investment to be put into thermal products.

Thermal background in brief:

The main key property of thermal building insulation materials are the thermal conductivity (W/(mK)) and a low thermal transmittance U-value (W(m²K)).

Traditional insulation materials:

Traditional thermal insulating materials were robust with respect to perforation vulnerability and flexibility. They generally have a thermal conductivity value of between 30 and 40 mW/(mK). However this increased with an increase in moisture content.

State of the art insulation materials:

The author is most impressed with vacuum insulating panels (VIPs) and Aerogels. VIPs can achieve a thermal conductivity of between 3 and 4 mW/(mK) when in good condition. However, vacuums have a problem with maintaining their thermal conductivity over a long time period (vacuum can be lost with air and moisture penetration due to diffusion). Perforations also create an increase in thermal conductivity to 20mW/(mK).

Aerogels can achieve a thermal conductivity of as low as 4mW/(mK) at a pressure of 50 mbar. Aerogels conductivity does not increase over time, and perforations present no problem. As Aerogels can be manufactured in a translucent state this may mean that their application may be considered for projects where clients may be willing to pay higher costs.

Future Materials:

Currently the Nano insulation materials (NIM) solution seems to be the best high performance, low conductivity thermal material for the foreseeable future.

Dynamic insulation materials (DIM) and NanoCon also show good potential, due to their thermal insulating properties and their good load-bearing properties respectively.

Conclusion:

The author concludes that NanCon, the theoretical insulating material is the most desirable solution. I think that the DIM shows the most potential for global use due to the fact that its thermal properties can be altered in relation to the geographical climatic conditions.

The Passive House Standard is a standard that is global. It has been well discussed that Ireland does not require the very high standards set out by the Passive Institute. There may be an option to build using materials that have the potential to reach the standard when needs arise, but are of a much lower standard than needed in mainland Europe.

If the properties of the DIM (for thermal adaptability), NIM (Nano Insulation Materials: for strength and thermal conductivity), and the Phase Change Materials (PCM: these change from solid to liquid when heated and then when cooled release the energy used as heat back into building thereby keeping internal temperature constant), while also having a material that could adapt to moisture content, we would have the ideal solution. 


Link to the table of Insulating materials


Link to "Traditional, state-of-the-art and future thermal building insulation materials and solutions – Properties, requirements and possibilities"

The Passive House: A method rather than a building style (author: Dr Wolfgang Feist)

The Passive House standard is a universal standard for the construction of low energy buildings. The Passive House standard can be adapted for different regions throughout the world. Although regions might have differing climates, the principles of passive house will remain the same.

The main aim of the Passive House is to reduce living costs through energy efficiency, and to create a comfortable, efficient, living environment. The standard specifies that the peak heating load is not to be above 10w/m^2. This is because below this level the mechanical heat recovery ventilation system (MHRV) can be simplified and used as space heating, thus reducing costs as a separate heating system is no longer required. The MHRV’s function is also to maintain good indoor air quality.

Achieving a heating load of ≤10w/m² will be relatively easy in a warmer climate, but would need more consideration and planning in a colder climate. Achieving a “Zero Energy House” is not as desirable in economic terms, as the investment needed to increase construction standards to zero energy is much greater that the return on investment in the operation of the building. Also the environmental impact of a Passive House is so low as to be considered negligible.

Some rules of thumb:

• Comfort should be considered. A good indoor climate can easily be achieved using the standard.

• Simpler affordable solutions in relation to present building practices should be used.

• It is acceptable to minimise energy demands using conventional sources rather than aim for a “Zero Energy House”

• Insulation is recommended in all climates.

• Shading is needed in all climates that have high levels of solar radiation.

• Heat recovery is needed in all climates. This is also needed to maintain comfortable indoor air-temperatures and humidity levels.

• Using very low energy MHRV systems is very important.