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Geneva, Switzerland

Velum Sky (Campus Biotech)

Sweco UK was appointed by Roxbury as part of the design team to support the development of sustainable building design, which includes an innovative fin solution to allow natural ventilation within the occupancy spaces for this office/laboratory development Velum Sky in Geneva.

The project will deliver best in class sustainable design with a focus on the end-user’s wellbeing and is set to achieve one of Switzerland’s first BREEAM Outstanding Certificates and energy consumption is targeted at 70 kWh/m²/annum, to meet the UKGBC’s Paris Proof Target.

Geneva, Switzerland
Type of project
Next generation sustainable building
Design architect

Challenge and scope

Our challenge was to Provide a sustainable building design which met the client’s and local authority’s expectations on the excellent view out to Lake Geneva along with a visually appealing building which fits in with the surroundings.

Sweco worked on the early-stage design as part of a wider project team, with design architects CP3 in Switzerland and building service consultants in Germany – using advanced building optimisation techniques via parametric modelling. The design concept agreed with the planners was for a glazed design, with an innovative ‘breathing’ fin façade unlocking sustainable ventilation.



The key target parameter – based on the energy target of 70 kWh/m² per annum – was set in order for machine learning AI software to provide guidelines on building design. The results indicated the cooling load was the dominant source of energy consumption and solar gains outside of the winter season at various times and days, causing the energy consumption to the peak. The fabric heat loss also caused significant energy consumption during the winter months. The next challenge was to establish the natural ventilation design, where the operation does not interfere with the external shading, for example, external windows.


As the direct outcome of our analysis, natural ventilation strategy was deemed essential to reduce energy consumption by the mechanical cooling system. Our solution was therefore to review the application of innovative external shading designed by the German designer and simulate the performance using thermal modelling. The external blinds were investigated to be able to limit peak solar gains to 20 to 30 W/m², when in full operation, i.e. covering the entire windowpane.

Innovative strategies for buildings used to achieve reduced emissions – like the cutting-edge ‘breathing building’ fin façade at Velum Sky – not only help protect the environment by reducing the need for mechanical ventilation, but can be core to achieving occupant wellbeing in the the workplace too.

Monika Potomska Senior Sustainability Consultant

The application of the innovative external shading drastically reduced cooling loads of the building and also, increased percentage of days the building can be in natural ventilation mode. So the operation of natural ventilation did not interfere with the external shading, such as external windows, we introduced the concept of an external fin-based ‘breathing building’ and results were promising, providing win-win situation on all counts.

This breathing building concept using external fins to the building was championed by Sweco at Bloomberg London, which afforded us insights into functionality through ongoing post-occupancy evaluation. The objectives were to establish fin orientation against the probable annual wind direction and creation of fin’s contour to maximise outside air intake and deflect the air to avoid discomfort to the occupants.

The resulting design for Velum Sky is set to be best in class in Switzerland, with a holistic, sustainable solution but functionally providing clients with the high-class Grade A speculative office space.

Key expertise

  • Design for Performance
  • Natural Ventilation Design
  • Biophilic and Ecology
  • Thermal Modelling and Façade Optimisation
  • Computational Fluid Dynamics
  • BREEAM Certification
  • Well Standard Certification
  • Embodied Carbon Analysis
  • Circular Economy Design