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The building, which dates back to the early 1980s, was brought up to date in terms of design and technology. The main focus of the renovation is the renewal...
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Die Mobiliar Renovation
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Marcus Wyss
Head of Real Estate at Die Mobiliar
“From the very beginning it was clear that we wanted to renovate with the future in mind“.
Upgrading the facades

The building, which dates back to the early 1980s, was brought up to date in terms of design and technology. The main focus of the renovation is the renewal of the building services and the design and technical modernisation of the office environment as well as the central rooms: reception, break rooms and cafeteria. Another focal point was the complete renovation of the façade, which gives the building a new, distinctive and unmistakable appearance. The glass slats are equipped with photovoltaic cells on the south-facing facades and are motor-controlled to adjust according to the position of the sun. They represent an innovative design element and simultaneously serve to provide shade and energy.
In terms of urban planning, the façade concept with the louvres creates a calming effect on the building, which is already relatively complex due to its shape. These vertically positioned lamellas adjust to the position of the sun. The thin-film cells are semi-transparent, so that there is sufficient shading, but a certain amount of transparency remains between the slats and even through the slats.

Upper floor architectural plan.

New outdoor lounge area.

Die Mobiliar (Schweiz) building in Bern before the retrofit.

Building characteristics
  • Building typology
    Administrative
  • Construction type
    Retrofit
  • Year of construction
    Late ’80, renovation 2013-2017
  • Energy reference surface
    12384 m²
  • Energy index
    n/a
  • Energy labelling
    Minergie-P BE-588-P
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Architect Daniel Meyer
GWJ Architektur AG
“For the implementation of the client's vision, we were inspired by established elements, which we interpreted in a new combination“.
Energy
Active solar surface 455m² 1384m²
Active solar surface ratio <50% <50%
Peak power 76 kWp 74 kWp
Building skin application Flat roof Sun shading
Storage
Energy production
0
kWh
Source: GWJ Architektur AG
Self-consumption
40%
Building skin
  • Application
    Standard modules are laid on a metallic support system.
  • Description
    The production of the facade system is supplemented by crystalline photovoltaic modules on the flat roof.
  • U value
    n/a
  • Fastening system
    Continuous fixing system (aluminium tracks).
  • Other

Aerial view of the building.

  • Application
    Thin film glass louvres (slats).
  • Description
    Concrete walls insulated with a layer of mineral wool.
  • U value
    n/a
  • Fastening system
    n/a
  • Other
    The facade recess is straightened, which not only improves the urban space, but also moves the statics behind the insulation level.

The cables were integrated into the construction parts so that they are not visible.

Amorphous silicon thin film photovoltaic semi-transparent modules.

  • Application
    Windows and sun shading glass louvres.
  • Description
    Triple glazing with aluminium frame.
  • U value
    n/a
  • Other
    The PV-glass slats with amorphous cells thin-film cells provide a solar protection element with a transparency of about 20%, which is approximately the same g-value as a textile sunshade.

Since most photovoltaic cells based on silicon thin-film tent to be violet-brownish in colour, this was the colour integrated into the facade design.

In terms of urban planning, the facade concept with the louvres creates a calming effect on the building allowing it to blend smoothly with the existing urban fabric.

BIPV module
  • Manufacturer
    Antec Solar GmbH
  • Cell technology
    Amorphous silicon
  • Front glass type/customization
    8mm tempered (extra clear) + 3.2mm PV + 8mm tempered. Transparency about. 20%.
  • Cell colour
    Violet-brown
  • Dimensions
    Type 1 –> 2370x450mm, Type 2 –> 2570x450mm,
    Type 3 –> 3030x450mm, Type 4 –> 2080x450mm
  • Specific power
    About 57 Wp/m²
  • Specific weight
    n/a
Technical details

The building has a highly insulating building envelope with corresponding triple IV glazing which go considerably further than a normal Minergie facade. The louvre façade not only serves as sun protection, but also produces electricity on the facades that are well exposed to the sun. The glass slats are storey-high and 45 cm wide, they are motor-controlled and adjust to the position of the sun.

Projection
Hotspot image
Vertical section
Hotspot image
Costs
  • Total cost of the facade
    8,300,000 CHF (source Beri Müller Partner GmbH)
  • Price per m³  
    n/a

The glass slats are storey-high and 45 cm wide, they are motor-controlled and adjust to the position of the sun.

Parties involved
  • Owner
    Die Mobiliar (Switzerland)
  • Architect
    GWJ Architektur AG
  • Engineer
    Emch + Berger AG
  • Facade planner
    Buri Müller Partner GmbH
  • Photovoltaic consultant
    Ingenieurbüro Hostettler
  • Curtain wall elements manufacturer
    Colt International (Schweiz) AG
  • Building physics
    Gartenmann Engineering AG
  • Photo
    Kaspar Martig
Awards and recognitions

  • Publications


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