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St. Francis Church has been transformed into a PEB building with a 221% energy efficency that may be run CO2-neutral. Built in 1989 and...
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St. Francis Church Refurbishment
  • Address
    Bachtelstrasse 13, 8123 Ebmatingen ZH, Switzerland
  • Location
    47°21’16” N  | 8°38’08” E
  • Altitude
    626 MAMSL
Image
Architect Daniel Studer
“PV and PVT look identical and may be applied in conjunction without compromising architectural unity“.
PV and PVT combined

St. Francis Church has been transformed into a “Plus Energy” building with an energy efficiency of 221% and zero CO2 emissions. Erected in 1989 and extended in 2008, the 2018 partial refurbishment, limited to the original building, included the insulation of roof and façades and a new heating system with heat pumps. Despite this, an architectural harmony was achieved for the entire building. South-west oriented prefabricated PVT-roof-elements incorporate absorbers and hydraulic tubes as well as additional insulation improving the existing roof structure, which was assembled in one day. The PV-roof oriented to north-east is made with the same PV-modules and architectural detailing as the PVT-roof. The new heating system’s COP is 6.8.

Plan of the ground floor.

South-east view with PVT roof.

PVT-roof under construction.

Building characteristics
  • Building typology
    Church
  • Construction type
    Retrofit
  • Year of construction
    1989 (original building) and 2018 (retrofit)
  • Energy reference surface
    1,072 m²
  • Energy index
    51.2 kWh/m²a (heating and electricity, ev. cooling)
  • Energy labelling
    –
Energy
Active solar surface 543m² –
Active solar surface ratio 100% –
Peak power 89.93 kWp –
Building skin application Solar tiles –
Storage n/a n/a
Energy production
0
kWh
Self-consumption
0%
Building skin

Roof

  • Application
    Solar tiles integrated in a pitched roof
  • Description
    Sloped timber roof insulated with 24 cm of mineral wool
  • U value
    0.16 W/m²K
  • Fastening system
    Eternit Integral II, punctual fixing system (timber tracks)
  • Other
    PVT and PV using identical modules

Facade

  • Application
    –
  • Description
    –
  • U value
    –
  • Fastening system
    –
  • Other
    –

Glass surface

  • Application
    Windows and skylights
  • Description
    Triple glazing with wooden frame
  • U value
    0.70 W/m²K
  • g value
    0.47
  • Other
    Refurbishment, just glazing was changed while still using existing framing

Mounting of the BS2 PVT solar roof element onto the existing roof.

PV-roof (left) and PVT-roof (right) under construction.

BIPV module
  • Product
    Eternit Integral II
  • Manufacturer
    Eternit AG / SI Module GmbH
  • Cell technology
    Mono-crystalline
  • Cell colour
    Black
  • Front glass type/customization
    Transmission-optimised solar glass (2×3.2 mm ESG) with anti-reflective coating
  • Dimensions
    1300x880x12mm
  • Nominal power
    190 Wp
  • Specific power
    166 Wp/m²
  • Module weight
    11 kg
  • Specific weight
    9.62 kg/m²
BIPVT element
  • Product
    BS2 Solardach
  • Manufacturer
    BS2 AG / PV-Modules: Eternit AG
  • Cell technology
    Mono-crystalline
  • Cell colour
    Black
  • Front glass type/customization
    Transmission-optimised solar glass (2×3.2 mm ESG) with anti-reflective coating
  • Dimensions
    Roof element 2610x8710x310mm; PV module 1300x880x7.5mm
  • Nominal power
    Thermal 480 Wp; electric 190 Wp
  • Specific power
    Thermal 430 Wp/m²; electric 166 Wp/m²
  • Module weight
    Element weight depends on construction; PV module 19.5 kg
  • Specific weight
    PV module 17 kg/m²
Technical details

The roof areas are completely covered with photovoltaic modules. Whereas the northern side was built conventionally onsite, the southern roof area was entirely prefabricated including the hydraulic system for the integrated PVT in eight wooden elements and installed in one day. It was possible to use the same modules, with only slightly varied connection details, for both the roof with the conventional in-roof photovoltaic system and for the roof with the PVT system (hybrid). The roof edges and the eaves are identical, resulting in a very uniform architectural design.

  • Visit the details page
  • Video of the roof construction
Projection
Hotspot image
Vertical section
Hotspot image
Costs
  • Total cost of the building
    Refurbishment: 1,200,000 CHF
  • Price per m³  
    n/a

The original edge of the roof had to be redesigned due to the insulation increase of the roof area.

Parties involved
  • Owner
    Röm.-kath. Kirchgemeinde Egg
  • Architect
    Daniel Studer, dipl. Arch. ETH SIA, Hüttenmattweg 19, 5213 Villnachern, www.studerarchitekt.ch
  • Research partner
    BS2 AG, Brandstr. 33, 8952 Schlieren – W+P Engineering AG, Zweierstr. 129, 8003 Zürich
  • Photovoltaic Installer
    Winsun AG, Beeschi Mattenstr. 2, 3940 Steg VS
  • Photo
    Daniel Studer – Bildschirmfoto
Awards and recognitions
  • Schweizer Solarpreis 2019 – Plus Energy Buildings

    European Solar prize 2019 – Owners and operators of renewable energy installations

  • Publications
    Erneuerbare-Energien-2019-1 S. 14ff;

    Solaris #03 2019 S. 31;

    Zürich Oberländer/Anzeioger von Uster 22.3.2019 S. 9

  • Acknowlegments
    Interreg V-A “BIPV meets History”

     

    Operation co-financed by the European Union, European Regional Development Fund, the Italian Government, the Swiss Confederation and Cantons, as part of the Interreg V-A Italy-Switzerland Cooperation Program for the Project “BIPV meets history. Value-chain creation for the building integrated photovoltaics in the energy retrofit of transnational historic buildings” (ID n. 603882).

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