Interview with architect Nadia Vontobel

Maximizing the generation of winter electricity

April 27.2022

Architect Nadia Vontobel

Master of Science ETH in Architecture, Swiss Federal Institute of Technology, Zurich, Switzerland
In 2019 she established her own company Nadia Vontobel Architekten GmbH

If you had to choose three key words to describe the Sol’CH project, which ones would you pick?

BiPV, winter energy, overall architectural concept.

In the Sol’CH project, what is the role of PV? How is PV related to the building concept and architecture?

The Winter Plus Energy Building Sol’CH is consistently designed to achieve energy efficiency and energy production.

The starting point for the design was the concept that every newly built facade and roof surface could be used to generate electricity in addition to its function as the building envelope. At the same time, there was the architectural requirement to create a homely house that would blend well into its surroundings with its integrated photovoltaics. Consequently, the optimal use of solar energy was taken into account at an extremely early stage in the development of the programme and of the formulation of the building structure, and this has played a decisive role in shaping the architecture. The orientation of the building, the pitch of the roof and the recesses of the building volume are optimized to the maximum with regard to the generation of electricity, but at the same time take into account the existing outdoor qualities of the site. The matt and dark surface of the PV facade with its anthracite and brown tones contributes to a harmonious integration into the surrounding landscape.

The consistent use of all facade and roof surfaces in the practically fog-free Poschiavo, in combination with the ideal orientation and roof pitch of 35 degrees, results in considerable electricity production, especially in winter and the transitional period. An unusual feature of the Sol’CH project is the exploitation of the north facade and the steep north roof, which strengthens the overall architectural expression of the volume and at the same time, contributes to optimising electricity production.

How important is the relationship between architecture and technology?

The interplay between architecture and technology is a very essential point in the Sol’CH project. Both on a conceptual level as well as in the expression of the residential building, an attempt was made to find a balanced and meaningful relationship between these two aspects. Many elements are based on both technical and architectural considerations, which have influenced each other.

What was the most challenging aspect to manage?

One of the major challenges was the development of architecturally convincing solutions with regard to surfaces, mounting and connection details. In order to find out what is technically and creatively possible today, consultations were held with many different manufacturers of PV modules from Switzerland, Austria and Germany at an early stage of the planning process.

The entire building envelope, as well as all building openings, windows, etc., required a high degree of accuracy, which placed the highest demands on the companies involved, especially in terms of coordination.

Was there anything that particularly surprised you during the duration of the project? Do you have a favourite memory?

It surprised me that the market for customised PV cladding is still in its early stages, especially how few PV manufacturers were even willing and able to offer customised PV modules at an affordable price.

A special moment was when the scaffolding was taken down and the complete building envelope became visible for the first time.

How do you plan to integrate photovoltaics in your next projects? Do you favour a certain technology or type of application?

I would like to integrate photovoltaics into my future projects and apply it over as large an area as possible. It makes sense that surfaces that are newly built and suitable for this purpose should also be used for electricity production.

Nowadays, PV roof surfaces are already quite common. But if we also want to promote winter energy and exploit the full potential of solar energy, we must also increasingly exploit facade surfaces. I am convinced that, in principle, architecturally high-quality facades can be realised through PV modules.

I have no specific preference for a particular technology. In my opinion, it is important to remain open to all innovations. I am curious to see where the technological development will lead in the next few years.