The whole building envelope has a homogeneous appearance thanks to glass elements used as cladding and tiles. Both the facade and the roof are fully covered with PV elements...
Grosspeter Tower
Architect Andreas Kaufmann
``Just as we started the design of the facade a significant development within the solar power market was made (N.B. custom made modules)``.
The solar skyscraper

Grosspeter Tower’s height and architecture makes it one of the city’s most striking buildings. Its shape comes from the concept of two interlocking volumes, which present themselves in a different form from every angle. The project provides mixed-use with offices and a hotel, according to the “core and shell” principle, a basic fit-out and a tenant fit-out. The very stringent quality requirements in the building’s overall concept also result in an excellent eco-efficient footprint. A borehole heat exchanger array provides the heat-pump system and cooling unit with geothermal energy. Photovoltaic surfaces are integrated into the facade and on the roof. Grosspeter Tower is an sober and elegant example of the successful symbiosis of solar techniques and architecture.

The building was designed following the core (staircases and installation shafts) and shell (building envelope) principle.

View of the indoor space.

The facade is half window, half integrated photovoltaic system.

Building characteristics
  • Building typology
    Administrative and commercial (mixed)
  • Construction type
  • Year of construction
  • Energy reference surface
    20,300 m²
  • Energy index
    44.5 kWh/m²a (heating, cooling and electricity)
  • Energy labelling
Active solar surface 770 m² 4800 m²
Active solar surface ratio >75% >50%
Peak power 100 kWp 440 kWp
Building skin application Flat roof Cold facade
Energy production
kWh (roof and facades)
Source: Solaragentur, Solar Preis Publikation 2017
Building skin
  • Application
    Standard modules are laid on a metallic support system.
  • Description
    Flat roof insulated with 16 – 24 cm of mineral wool.
  • U value
    0.12 – 0.18 W/m²K
  • Fastening system
    Aluminium stands
  • Other

The roof photovoltaic installation has a power capacity of 100 kWp.

  • Application
    PV cladding integrated in a cold facade
  • Description
    Concrete walls insulated with 20 cm of mineral wool.
  • U value
    0.18 W/m²K
  • Fastening system
    Continuous fixing system (aluminium tracks)
  • Other
    Prefabricated concrete and steel frame construction.

The solar module sizes vary widely: around 450 different, customized and customer-specific thin-film solar module types were used in all opaque facade surfaces of the skyscraper.

  • Application
  • Description
    Triple glazing with aluminium frame.
  • U value
    0.91 – 0.97 W/m²K
  • g value
  • Other
    Venetian blinds, perforated.

The windows are all full-height.

Within the six-storey base are a hotel, conference rooms and office spaces.

BIPV module
  • Manufacturer
    Nice Solar energy & Sto AG.
  • Cell technology
  • Front glass type/customization
    No coloured print, but structured front glass (Albarino T)
  • Dimensions
    450 different sized (average dimension 1.4 m²)
  • Specific power
    110 Wp/m²
  • Specific weight
    32 kg/m²
Technical details

The supporting structure is made of flat concrete slabs which form the skeleton of the structure and are insulated with a layer of mineral wool. Thin-film photovoltaic modules are integrated into all facade elements. There are more than 450 different types of PV facade elements to match the width and height of the facade panels. All facade components are in aluminium, steam-tight on the inside and rain-tight on the outside, at the bottom these elements are positioned on a continuous angular profile made of steel, they are fixed sideways and at the top are fixed with dilating punctures inserted in the shell construction. The sun protection is mounted outside.

  • Total cost of the building
    120 millions CHF
  • Price per m³  

The building is close to the main transport axes.

Parties involved
  • Owner
    PSP Real Estate AG
  • Architect
    Burckhardt+Partner AG, lead architect: Andreas Kaufmann.
  • Construction management
    Dietziker Partner Baumanagement AG
  • Photovoltaic Installer
    Planeco GmbH
  • Photovoltaic consultant
    energiebüro® ag
  • Facade installer
    Hevron SA
  • Photo
    Adriano Biondo
Awards and recognitions
  • Schweizer Solarpreis 2018 – New buildings

    Bavarian Architecture Award for building integrated solar technology 2017

    Prixforix 2018, Award for the most attractive facade in Switzerland, 3. prize

    sun21 Faktor-5 Jury prize 2018

  • Publications
    TEC21 Nr. 24–25 June 2017
  • Other
    Please refers also to Burckhardt+Partner AG online project description: