Cité du Design, St. Etienne, France

Cité du Design

The project is designed around the banqueting hall of the former national arms factory. Built at a lower level and with a slightly convex shape, this structure is a combination of a variety of areas: construction resources centre, greenhouse, library, cafeteria, reception area, exhibition rooms, auditorium, amphitheatre.
The key feature of the energy concept is the innovative design of the building envelope. It's multifunctionality allows a natural ventilation, thermal comfort through thermal protection of the zones, visual comfort via the management of natural light and a part of the energy production. The basement of the building elegantly integrates an earth duct which pre-conditions the air distributed into the various zones. The energy performance of the project is completed by a geothermal thermodynamic system.
The building envelope functions in two ways. Besides thermal protective properties the various panels of the external layer enable a modulation of the luminous and solar contributions in the various zones according to the ad hoc needs. The outer skin does not only filter light, it also allows its absorption and its conversion into energy besides regulating the exchanges of air and heat. The natural ventilation of the building, the heating and cooling via reversible active slabs as well as an interior layer of the envelope with low emissivity (low-E layer) on the interior walls makes it possible to increase the thermal comfort of the occupants. The layer with low emissivity of the interiors walls makes it possible to reflect the energy dissipated by the heating/cooling slabs, like a thermal mirror, allowing an increase in perceived thermal comfort of the occupants. A geothermal system using foundation piles is used as energy source.