In Saint-Mand, the reconstruction of a complex of public institutions under the jurisdiction of the Ministry of Environment, Sustainable Development and Energy has been completed: in accordance with the name of the ministry, the project was carried out with an emphasis on sustainable development. The goal was not only to combine the headquarters of the National Institute for Geographic Information and Forestry of France (Institut Géographique National) and the Center for Meteorology (Météo France) into a multifunctional complex, but also, by revitalizing the surrounding area, to stimulate the process of its renewal.
The Météo France building (in the diagrams - "A") with an area of 14,200 m2 was built in 2012 and did not require intervention, while the IGN building (in the diagrams - "B") was decided to be reconstructed: as a result, while maintaining the existing total area, the depth of the new the building has decreased to 18 m, and the area of the facades - by 30%. A more compact structure made it possible to make the interior lighter and more comfortable, improving the illumination and insolation of the lower floors, and on the outside - to lay out a large garden that unites both buildings: together with the "green" roof and terraces, the area of greenery increased by 200%. In addition, the increased distance between the buildings allowed building A to function as usual during the renovation work of its neighbor.
Offices, workshops, a restaurant and a medical center, which constituted the primary functional program of the new building, were supplemented by a multimedia library, a music room, a darkroom and three sports halls, and large terraces have the potential for additional useful spaces.
Offices range from separate offices for one or two people to large open spaces. Stretching along the glazed north and south facades, they are deeper on the south side: this optimizes the natural lighting of the premises. In the central part of each floor there is a recreational space, where conference rooms, cafes, bathrooms, informal work areas are located: this arrangement allows to improve communication between the "north" and "south".
The external appearance of the Meteorology Center is played out in the wooden facade elements of the IGN building, the pitch of which is almost identical (1.35 m in "A" and 1.37 in "B"), which gives the complex integrity and creates a recognizable image for these state institutions. The façade module is a one-piece frame made of glued spruce measuring 1.40 x 6.54 m with inserted opening window frames, “ventilation” pine sashes and stainless steel wall screens. Each of 535 of these modules weighs 500 kg and accommodates two floors in height, and two modules make up the minimum office cell. Tests for air, wind, moisture permeability and acoustic properties showed results higher than those required by theoretical calculations: 4th class of air permeability, 7A - waterproof, C2 - windproof.
In total, the building uses several types of facade modules: two "office" modules, differing in the presence or absence of ventilation flaps; fully glazed, increased height - for the first floor; non-glazed - for loggias and lined with opaque enameled glass - for the top, behind which the green spaces of the roof are hidden. It took 6,000 hours and 250 m3 of glued timber, 1,600 m2 of stainless steel screens, 3,000 m2 of glazing, 387 blinds to protect the south side from overheating, to erect 5,400 m2 of a facade with a total value of € 726 / m2.
The architects wanted to achieve a visual unity of internal and external spaces, but in most cases, energy-efficient glazing has a mirrored outer surface, which separates the building from its surroundings. To avoid this effect, glass was selected with the highest possible degree of transparency (solar factor - 37%, light transmittance - 68%) with thermal (heat transfer coefficient - 1.1 W / m²K) and acoustic (Ac = 33 dB) qualities that meet the energy efficiency requirements. …
To reduce operating costs in summer, the building is cooled by a passive ventilation system: in the windows of each office above the second floor there are "ventilation" sashes, when opened, the mechanical inflow system is automatically turned off, and four large heat extractors draw hot air out of the corridors. In winter, the air heated in the south is recovered and reintroduced into the premises. When the outside temperature rises to 12 ° C, the rotary damper automatically opens the "ventilation" flaps in the glazing of the central passage area.
To optimize energy consumption, a ground source pumping system is used, energy recovery double-flow ventilation units on hygroscopic rotary heat exchangers and glycol accumulators; the energy received from the solar panels installed on the roof is used to heat the water in the showers at the sports halls; green roofs reduce the heat loss of the building.
The street space is structured with large flower beds of geometric shapes that play up the relief of the site: together with a series of stairs, they create platforms with a different atmosphere, allowing 1600 residents of the complex to relax, communicate with colleagues, and hold a meeting in a pleasant atmosphere. The external appearance of the complex is changeable: large surfaces of mirrored facades and steel cladding reflect colorful plants of various shapes, depending on the season, wind fluctuations, and illumination.
The cost of this building, which meets the French THPE high energy efficiency standard, was about € 36 million, of which € 4.2 million is the cost of the facade.
