La Cité du Design rappresenta l’anello di congiunzione tra il patrimonio industriale della città e gli investimenti nella creazione, ricerca e formazione per il futuro. Questa nuova istituzione riunisce in sé la École supérieure d’art et de design, la Saint-Etienne International Design Biennial e il Vocational Training Centre. Il progetto ha comportato il restauro di una serie di edifici storici e la realizzazione di nuovi edifici come il “Platine” (200x32 m), la torre Osservatorio (alta 31 m), due giardini e la Place d’Armes, uno spiazzo pubblico.

L'Osservatorio è stato il primo elemento ad essere edificato nel 2006, rivolgendo l’attenzione all'interazione tra architettura, programmi futuri, accoglienza del pubblico e opportunità del sito. Situata lateralmente al Bâtiment de l'Horloge, questa torre, assemblata in situ, ha svelato da subito il progetto alla popolazione Saint Etienne, offrendo una prospettiva nuova in città e diventando un importante punto di riferimento, identificabile con la Cité du Design.
L'Osservatorio, che sorge nel cuore della Cité, sconvolge l’apparente simmetria delle strutture e la gerarchia visiva tra la facciata e le aree di produzione. Domina dall’alto gli altri edifici e con la sua altezza, che ha consentito, durante tutta la fase di cantiere, di osservare dall’alto l’intero processo di costruzione, ha assunto ora il ruolo definitivo di punti panoramico.

Il Platine è un “laboratorio climatico” la cui pelle, configurabile in diverse maniere, avvolge differenti attività, tra cui spazi espositivi, un auditorium, l’agora, una serra, una mediateca e una biblioteca. Questa pelle è modulata nei vari spazi in funzione delle esigenze di luce e microclima. La struttura del Platine è una sorta di traliccio, formato da una maglia tridimensionale di profili metallici di dimensioni minime, basati su un modulo di 2,10 m, che sono al tempo stesso sia tetto sia pareti. L'omogeneità e la distribuzione delle forze in tutte le direzioni generano una struttura non gerarchica - un openspace privo di qualsiasi sostegno strutturale intermedio. Viste dall’interno, le dimensioni minime dei profili segnano il confine tra interno ed esterno.

Il Platine è concepito come un unicum, in cui ogni parte interagisce con l'ambiente, e in cui ogni elemento è al tempo stesso il risultato e il determinante di altri fattori. Il progetto regola con precisione gli ambienti climatici interni e tende all'indipendenza energetica. La successione delle diverse aree all'interno del Platine, tutte climaticamente indipendenti fra loro, è caratterizzata da pareti divisorie chiamati filtri. Garantiscono sia la protezione acustica sia la stabilità climatica di ogni singola area, come, ad esempio, nella serra. I due layer dell’involucro sono coinvolti nella regolazione del microclima. Lo strato esterno dei vari pannelli è in grado di modulare gli input in aree diverse a seconda delle esigenze; filtra la luce, la assorbe e la trasforma in energia, regolando anche l'aria e gli scambi di calore.
Sulle superfici interne, ventilazione naturale, riscaldamento e raffrescamento tramite un sistema reversibile di riscaldamento/raffrescamento a pavimento, e uno strato a bassa remissività nella parte inferiore aumentano il comfort termico degli occupanti. Il layer a bassa emissività delle pareti interne permette all'energia dissipata dai sistemi di riscaldamento/raffrescamento a pavimento di essere riflessa, come uno specchio termico. Sotto il Platine è stato realizzato un sistema geotermico, attraverso l'attivazione ‘termica’ di pali di fondazione, l'uso di pozzi canadesi per il pre-condizionamento dell'aria e gli scambi d'aria tra le zone per ridurre il consumo energetico.

I pannelli modulari triangolari che compongono la facciata del Platine integrano facilmente in un unico coerente sistema l'energia prodotta dagli elementi, compresi i pannelli fotovoltaici. Molte cellule sono collegate tra loro in un modulo solare fotovoltaico, che può assumere diverse configurazioni e inserirsi in un pannello di tipo triangolare. L'energia prodotta è reintrodotta nella rete globale e contribuisce a ridurre il carico sui centri di produzione e fornitura di energia elettrica.

120 mq di superficie esterna sono riservati all’installazione di pannelli sperimentali, ispirati al principio della fotosintesi, costituiti su un lato da uno strato di biossido di titanio coperto da un colorante chiamato “sensibilizzante" e sull'altro lato da una soluzione elettrolitica. Quando un raggio di luce colpisce il colorante, un elettrone viene espulso. Tutti gli elettroni liberati attraversano l’ossido, sono raccolti sul bordo della cella e, quindi, direzionati verso un circuito esterno.

Il rivestimento del Platine regola non solo il microclima, ma anche l’illuminazione, modificando gli angoli per bloccare la luce. La luminosità varia in funzione delle condizioni esterne e delle esigenze interne fornendo un'illuminazione artificiale controllata nelle aree espositive o in quelle con esigenze di elevata illuminazione, come la serra o l'Agorà.



Located on the Manufacture Natio¬nale d’Armes site in the heart of the Saint Etienne historical complex, the Cité du design brings about a conjunc¬tion between the industrial heritage of the city and investment in creation, research and training for the future. This new institution brings together the École supérieure d’art et de design, the Saint-Etienne International De¬sign Biennial and a Vocational Training Centre; the invitation to its architec¬tural design implies, then, respect for patrimonial continuity and historical legitimacy endorsing cohesion of all these activities.
Programme articulation
The project was designed based on major elements of the site – the Han¬ging Gardens, the Place d’Armes, the Bâtiment de l’Horloge, the Ateliers and the Grande Usine – and a new connecting element, the structure of a slender building, the Platine. This is thought of as the articulation between the hierarchical figure and the site’s heritage discontinuity and the conti¬nuous matrix required by the institu¬tional programme. It facilitates cross-connections between the centres of a non-hierarchical network and pro¬vides covered public transit, hosting the most open activities of the Cité du design. Indeed, this monospace brings together the communicative activities in the Agora, the exhibition halls, the auditorium and the material library. A place of merging and irrigation for the site, relative to the town, its exact po¬sitioning in the area makes it function as an inner street, interfering as little as possible with the visibility of the Bâ¬timent de l’Horloge and allows visual integration with the Place d’Armes and the town centre as well.
Observatory
The project scope and ambition led to a partial sequencing of openings, back to back, including the celebrations of the Saint-Etienne International Design Biennial. In 2006, the Observatory emerged as the first element to be established, directing the interaction between architecture, future programs, public reception and opportunities of the site. Aside from the Bâtiment de l’Horloge, this tower, assembled on site, made the project known to Saint Etienne’s population by offering a novel perspective on the town and becoming a notable landmark, identifiable with the Cité du design.

Located at the junction of different areas of the Manufacture, the Observatory shatters the apparent symmetry of the structures and the visual hierarchy between the façade and the production areas. Overlooking the other buildings, its elevation lets the process of building the Cité du design be observed throughout the construction period. Today it has assured its place as a lookout.

Gardens
Nature's "work in progress" has ac¬companied the evolution of the lands¬cape work of the Gardens. Having lost their use, they were abandoned. After a diagnosis of the state of the trees and an analysis of the characteristics of the two historic gardens, it was decided to retain their identities. Today, the sandy soil of the North Garden is endowed with an occupational basis which meets its many uses; the South Garden, designed as a large lawn with standing trees, is characterised by a contempla¬tive atmosphere

Structure of the Platine

The structure of the Platine is a kind of latticed unit , formed by a three dimensional mesh consisting of metallic profiles of minimum size and based on a 2.10 m frame. It becomes both the roof and walls. The homogeneity and distribution of forces in all directions generate a non-hierarchical structure – a monospace free of any intermediate support.

Seen from inside, the minimal dimensions of the profiles transform the structure into a vibration marking the boundary between the interior and the exterior

Interclimatic Laboratory
The Platine is designed as a whole, where each part interacts with its en¬vironment, and where each element is both the result and the determinant of other factors. The technique extends to the sides and the basement, leaving the space created as free and open as possible. Its climatic design precisely regulates the climatic environments and tends to energy independence.
The succession of different areas wi¬thin the Platine is marked by partition walls called filters. They guarantee both acoustical protection and in¬dividual climatic stability, as in the example of the Greenhouse.
The climatic design varies according to the area. This climate gradation allows interior conditions to be adapted to needs without having to treat the en¬tire volume of the Platine. However, the zones are themselves interactive, for example, the pre-conditioned air from the Greenhouse is taken for the benefit of the winter aeration of the attached zones.
The two layers of the envelope are in¬volved in climatic regulation. The outer layer of the various panels can modu¬late the inputs into the different areas according to their needs. It filters the light, absorbs and transforms it into energy, and also regulates air and heat exchanges.
On the interior surfaces, natural ven¬tilation, heating and cooling via a re¬versible heating/cooling floor, and a low emissivity (low E) layer on the un¬derside of the envelope increase occu¬pants' thermal comfort. The low emis¬sivity layer of interior walls enables the energy dissipated by the heating/coo¬ling floor to be reflected, like a thermal mirror.
Under the Platine a geothermal energy system is implemented, via thermal activation of foundation piles, use of Canadian well for pre-conditioning of fresh air and air exchanges between zones to reduce energy consumption.


Geothermal energy and Canadian wells
Geothermal energy consists of two combined networks: the first, a field of twenty-four probes in a double U with a length of 100 ml each, provides avai¬lable energy of 130 kW; the second, a field of piles (1st in France), composed of recovery loops in the one hundred foundation piles (tubes set in the rein¬forcing bar cages) of the Platine buil¬ding, giving available energy of 80 kW.
The heat pump provides 290 kW of available power to the heated floor.
A heat transfer fluid circulates in the two networks to recover energy avai¬lable in the ground and is collected to the local heat pump. In winter, these two networks also serve for heating by the heated floor; in summer for cooling with the cooling floor of the Platine building.
The French Environment and Energy Management Agency (ADEME) and the energy provider Électricité de France (EDF), with the support of the Scien¬tific and Technical Centre for Buil¬ding (CSTB), will conduct an energy follow-up over two years. To do this, ten energy meters, five electricity me¬ters, probe equipment and metering on the piles have been implemented. The ground temperature around two piles at different depths is recorded to follow the temperature change throughout the seasons.
A Canadian well is used to treat the air. To make this technology as economical as possible, the crawl space under the Platine is enclosed and can therefore assure this function

Skin
The Platine's envelope, consisting of 14,000 equilateral triangles of 1.20 m per side is a graduated and reactive skin: modulation between opaque and clear, insulated or interclimatic, open or closed, reflects and accompanies the various cycles and interactions of the Cité du design.
In order to achieve the differentiated ambiences and performances for each space of the Platine, the types of mo¬dules are combined according to their characteristics.
The choice of glazing type allows a dis¬tribution of natural light depending on the use of the premises. Thermal qua¬lities of the panels permit the climatic quality of the envelope to be modula¬ted according to unplanned criteria of the premises.
The opportunity to integrate solar pa¬nels (photovoltaic and experimental) in the skin of the Platine will allow so¬lar energy production, as well as deve¬lopment and testing of innovative solar energy materials.
The skin reacts continuously to changes in climate. It may also be given new functions. In the longer term, the panels may be replaced or modified to be adapted to changing needs or to ex¬pand the areas of experimentation

Photovoltaic panels
The modular triangular panels which make up the façade of the Platine easi¬ly integrate into one coherent system the energy producing elements, inclu¬ding photovoltaic panels. Photovol¬taic solar energy is a renewable form of energy which produces electricity by transforming a part of the solar ra¬diation with a photovoltaic cell. Many cells are connected together in a solar photovoltaic module which can take different configurations and fit into a standard triangular panel. The energy produced is reinjected into the global network and contributed in its scale to reduce the load on production centres for fossil energy supply of electricity.

Experimental panels
120 m² of the surface is set aside for installing experimental panels, which may evolve or be replaced following technological advances. Currently these are proposed photosynthesis panels.
These cells are inspired by photo¬synthesis and consist of a titanium dioxide layer on one side covered with a dye called a "sensitizer" and on the other side with an electrolytic solution. When a light ray strikes the dye, an electron is ejected. All the electrons re¬leased cross the oxide, are collected at the edge of the cell and then are direc¬ted to an external circuit.

Light
The Platine skin not only regulates cli¬mate but also lighting, by changing the angles for blocking the light. The lu¬minosity reacts to outdoor conditions and inside needs. The panels provide controlled lighting in exhibition areas or areas with high light levels, such as the Greenhouse or the Agora.

Infoscape
A guidance system for the Cité du de¬sign was developed to give access to a better use of information provided by the various actors of the Cité and its external partners. The navigation pa¬rameters extend beyond the Cité site limits and provide more direction in space, respond to enterprise communi¬cations problems, and bring together the data from the Vocational Training Centre.

Furnishings
The Cité du design furnishings were designed around four types of space use within a broader reflection about the autonomy and interaction in the work zones :
- Collective type (hive):
performance zone for routine tasks where each has their own space iden¬tified within the larger whole.
- Concentrated type (cell):
production area requiring a space for individual reflection allowing a high degree of concentration.
- Interactive type (den):
Work area for organization for short and intense times with a high degree of interaction between people.
- Spontaneous exchange type (club):
informal area for exchange and inte¬raction with a high degree of flexibi¬lity in the use of space to be suitable to different interaction configura¬tions between people.
The debated has been carried out not only on each of the types, but also on the interfaces and transitional zones, and the traffic patterns which exist between them. This way of un¬derstanding the space is coherence with opportunities of surfaces and volumes which the architecture of¬fers the Cité. The choice of furniture has been done to create this type of operation and to optimize the use of space. Certain elements have even been invented to initiate the creation of these areas and better integrate them into this particular representa¬tion of space (including cubicles).