A@W Newsletter

Located not far from the railway station in Dijon's Arsenal eco-district, on the site of the former army equipment depot and the old Dijon flour mills, the Elithis Arsenal Tower is a positive-energy development that is both exemplary and virtuous. It is the work of the architectural firm Arte Charpentier, which builds in France and also in Asia. "This project is the result of research and collaboration with the Elithis group, for whom we have worked for a long time. We built their first head office in Dijon. It was the first positive energy tertiary building in France. It's a 5,000 sq. metre building with 500 sq. metre floors that revolve around a central core", points out Antonio Frausto, associate architect and Director of Architecture at Arte Charpentier.

Supported by the city of Dijon, the Greater Dijon urban community (Dijon Métropole) and the Société Publique Locale Aménagement de l'Agglomération Dijonnaise (SPLAAD), the joint project by the Elithis group and Arte Charpentier is distinguished by its programme of 59 homes for first-time buyers in the Tower and 51 social housing units in the lower building. The Tower, recognisable from afar, illustrates a daring urban policy that highlights new processes in the design of collective housing, including bioclimatic precepts for cutting-edge references in sustainable development.

"We're in the Arsenal urban development zone, where the town planning was drawn up by AUC architects and town planners. From the outset, we have been in dialogue with them, as well as with the client and all the stakeholders. We composed the project with the tower and the social building. The two entities make up a positive energy island, rather than a positive energy building", emphasises Antonio Frausto.

An architectural and energy feat

To achieve this architectural and energy feat, Arte Charpentier designed a building that produces more electricity than it consumes. The whole complex produces 136.9 kWh/year thanks to the photovoltaic panels on the roof of the building and also in the form of shaded areas at the heart of the block. The facades of the Elithis tower are a condensation of technology. The diamond facets have been designed to optimise energy production. New-generation photovoltaic panels are integrated into the architecture. Similarly, the external insulation of the walls, the treatment of thermal bridges and the choice of high-performance joinery reduce heat loss and capture free solar gain in winter. Good air permeability also helps to limit infiltration. Energy consumption can also be reduced by recovering heat from the greywater used in showers.

Antonio Frausto explains: "As part of our architectural approach, we reduced the north façade as much as possible to avoid heat loss. The soaring shape is due to this particular feature. This is a bioclimatic design, in which we studied the amount of sunlight and the position of the tower in relation to its surroundings." Another important factor was the price of the project. "The rental property market in Dijon is different from that in Paris or Geneva. We were able to complete the project at a cost of 1,400 euros per m². Today, a young worker's income is calculated to the nearest euro. Our aim was to use our know-how to ensure that the energy bills of our homes were as low as possible.”

The architects carefully studied the orientation of the different façades. The envelope is punctuated by vertical panels of light grey powder-coated aluminium. While the bedroom windows follow a pronounced vertical pattern created by the aluminium frames, the facades on the east and west sides incorporate the large bay windows in the living rooms, providing an abundance of light. Thanks to the perforated sheeting module that slides randomly in front of the large bay windows and bedroom windows, the façades are dynamic. The panoramic lift on the west side and the external staircase on the east side not only offer plenty of light, but also a view through from the communal landing serving the flats. Residents can also monitor their energy consumption and, thanks to a home automation application compatible with smartphones, control heating, lighting, blinds and electrical sockets. The aim is to make users resilient in the face of rising energy costs.

A generator of community spirit

The architects have also given priority to community living and user comfort. Antonio Frausto explains that "the top level of the tower is a shared space". But this is not always the case. In some programmes, the top floors are chic duplexes or spaces reserved for a privileged few. "Here, we're talking about the social heart of the tower, where, in addition to a sports hall, there's a meeting room that can also be used as a sports hall. There are also two rooms opening onto the terrace and a semi-open space. All at the service of the residents, with a breathtaking view over the route des grands crus. To avoid increased energy consumption, this space has no heating. The roof is made up of photovoltaic panels, and the space below lives with the rhythm of the seasons. It's a space that's neither enclosed nor heated; it's like a winter garden suspended fifty metres above the ground, with a view of the surrounding area", concludes the architect.

The Elithis offices are grouped together in the base, which consists of a ground floor and two upper floors. The facades are aligned along Avenue Jean Jaurès, which opens directly onto the urban space. The facades are based on the same codes as those of the Tower. They are composed of large rectangles one storey high in glass and aluminium, alternating on each level. Elithis, with whom Arte Charpentier has worked on a number of projects over the years, and for whom the agency is building the first Elithis Tower in Dijon, decided to establish its head office in this part of the base. Elithis occupies an entire floor space that has been carefully fitted out by Arte Charpentier's in-house interior design team. This is a mark of confidence in the architects, with whom the company has successfully completed a project with a triple ambition: to live in the city differently, to make positive energy accessible to all and to make Greater Dijon a benchmark for sustainable development.

Originally written by Sipane Hoh

All pictures © Arte Charpentier