Draft:Cameleon Woluwe building

The eco-built store Cameleon Woluwe, opened in 2009 in the commune of Woluwe-Saint-Lambert in Brussels and rewarded with numerous awards, has become a reference at European level in terms of eco-built buildings. The designers of this 17,000 m2 surface area wanted to make it an exemplary building in terms of sustainable architecture and energy performance, to offer a space of natural comfort, in harmony with the environment. The use of technologies and materials that respect nature reflects this desire: natural ventilation of the free cooling type, ecological materials, optimal insulation, solar panels, natural lighting, green roof. This innovative building saves tons of CO 2 compared to a classic modern building.

Genesis
The history of the building probably began around ten years before its completion. Jean-Cédric van der Belen, sponsor of the work, before calling on the chosen architect, Charly Wittock , was inspired by many innovative ideas seen elsewhere. He observed a lot of green roofs in Iceland in the late 1990s. Then it was in Denmark, where he often went because he had opened a store there, that he was seduced by the idea of pleasant canteens for employees and, above all, daycare centers integrated within companies, to encourage child-parent employee contact. Italy then had a strong impact. In Tyrol, we can recognize the influence of Matteo Thun 's Vigilius Mountain Resort (Memphis Group), while Tuscany has had an influence with its green walls.

Inspirations and references
The main leitmotif was “less is more”, an adage of the architect Mies van der Rohe, leading figure of the Bauhaus, a movement which will deeply permeate the Cameleon building. Stair railings are a particular reference to this. The rational use of spaces and materials define the ambition of the project. The office spaces, located on the top level, provide working comfort and natural light. Raw concrete asserts itself as a material that is as practical as it is aesthetic. For the purposes of constructive efficiency and maintenance, and like the Pompidou Center in Paris, all the techniques are visible. This allows the modification and replacement of equipment (electrical cables, pipes, etc.) without degradation of other layers of durability, with a minimum impact on the use of the building.

For Jean-Cédric van der Belen, one thing was clear in terms of choice in his desire for a model building in terms of sustainable development: "Everything had to make sense. No artifice, no concessions!" To the point that there were moments of tension: "Sometimes I changed my mind about certain initial options, and that may have annoyed my colleagues, but we managed to stay within the budget." "The objective was not to make an investment in dressing at the end of the project, but rather to integrate environmental constraints throughout the design and development work." .

Ecological and coherent approach
"The project owner is at the basis of the ecological approach for the new Cameleon building. His long-term vision, his contagious enthusiasm, his strength of persuasion and his desire to make the project a model of ecological sustainability have given the building an undeniable character."

A collaboration between Cameleon, the AWAA architecture office, the Catholic University of Louvain and its spin-off Matriciel (sustainable architecture design and consultancy office) was set up in order to integrate the environmental dimension into each stage of the design, development and implementation of the project.

"In this spirit, the first meeting with the architects even before the definition of the architectural program consisted of a training session on environmental issues with the team from the Architecture Research Unit of the Catholic University of Louvain (architecture and climate). This training allowed the company's managers and architects to be aware of the concrete implications for the environment of all the decisions to be made and thus to integrate an environmental dimension into each choice." Matriciel's support also enabled good educational communication for visitors to the building. This global and multidisciplinary approach allowed the project to be resolutely innovative.

The architect Charly Wittock will summarize this collective dialectic by saying “''the project was built by constantly questioning ourselves, us as architects and our client as a user. All the 'basic rules of business' have been called into question''."

Site implementation
"By staying in Brussels, Cameleon has chosen to be socially responsible", noted one of the three elected politicians present at the launch of the project in 2008" . While many companies established in the capital were in the process of relocating to reduce their costs, Cameleon's desire was to locate the store in the Brussels Region in order to facilitate access to public transport users, cyclists and pedestrians. Within the company, the mobility policy aimed to encourage staff to travel to work by carpooling, public transport or by bicycle. "Caring about the environment also means integrating into your neighborhood and participating in a city project", affirmed Jean-Cédric van der Belen, founder of Cameleon, sponsor of the project.

As the press already pointed out after its public presentation, it was a question of creating a building that was daring from every point of view. "An innovative crossroads between industry, architecture and ecology, the project also aims to "societal" . More than a store, a meeting place, family and friendly."

Employees, visitors and local residents can thus benefit from the cafeteria and terraces which are accessible even outside the store's opening days, a municipal kindergarden for 39 children (partnership with the Municipality of Woluwé-Saint-Lambert ) as well as as many green spaces. In addition, the central staircase of the store is designed as stands that can be converted into a 250-seat performance hall in the evening.

All these societal dimensions convinced politicians to support the project from the outset. "Permits issued in record time (6 months) and the collaboration of numerous public organizations (in bulk: Region, municipality, SDRB, SRIB and ABE)."

Orientation
The orientation of the building was studied to optimize its exposure to the sun depending on the seasons. As an example, here are some elements carried out:


 * the facades of the crèche are deliberately exposed to the morning sun to benefit from natural warming before the arrival of the children.
 * the glazed openings to the south are designed to avoid creating a greenhouse effect and therefore having to cool the building; the south-facing glass facades are protected by sunshades and exterior shutters.
 * the inclination of the wooden sunshades has been studied to break the rays of the summer sun, high on the horizon (risk of overheating in summer) and to let the low rays of the winter sun pass through (need for heating in winter).

This common sense approach, the basis of the design of all buildings since antiquity, has only been possible thanks to simulation software, given the shortening of design time in our societies.

Insulation and heating
"Reducing your ecological footprint and saving energy requires, above all, building insulation. Aware of the impact of poor insulation on the environmental quality of the entire project, we have seriously studied all the parameters favorable to efficient and environmentally friendly insulation. The result is more than satisfactory: the level of overall thermal insulation of the building (K) is 26, well below the regulatory standard for buildings in Brussels of K55-65", according to Fabrice Derny, environmental advisor UCL-Matriciel.

This large store, a relatively compact building, was designed to limit heat loss (thermal bridges), or even to recover it, as for example in offices. The wall materials are either sandwich concrete with thick layers of insulation or high-efficiency double glazing (K1.1).

In winter, the basic heat supply is provided by a pellet boiler. Two high-performance backup condensing boilers (gas) have been provided in the event of extreme temperatures.

Ventilation and cooling
Visitors and lighting being the two main sources of heat which most of the time require continuous cooling and ventilation of commercial buildings - summer and winter - and traditional systems ( air conditioners/air conditioning ) being very energy-intensive and polluting, the Here too, the project designers chose to use a more ecological alternative.

The large metal ceiling fans, recovered, contribute to the overall concept of free cooling. A principle of natural cooling based on a play of air circulation and the storage of nighttime coolness during hot periods, an ingenious process which already existed in Ancient Egypt and which is still the subject of practical application today. The process matured through meetings and research. The principle is based on the use of the coolness of the night: a current of air is created thanks to a mechanical window opening system. Thanks to its strong thermal inertia, concrete stores this freshness and releases it during the day. Air circulation is naturally amplified by the chimney effect of the skylight which induces an entry of fresh air at the bottom of the building and an exit of hot air at the top.

In its educational sheets intended for architects and professionals in the construction sector, Bruxelles-Environnement has developed one on free-cooling by intensive ventilation. The quote from the Cameleon building comes back under thirteen aspects in its implementation as an exemplary building.

The optimal performance of this type of system is based on the combination of various parameters (coherent design) thus making it possible to facilitate the circulation of air in the building and to limit additional heat gains. These parameters are found both in the design of the building itself - namely the orientation in relation to the wind and the sun, the insulation, the height of the ceilings, the creation of skylights (natural lighting), and the protection against direct rays of the sun (sunshades) - as well as in the choice of materials (concrete, green roof) and equipment (lighting, computer equipment).

Finally, the comfort temperature limits are revised by defining a temperature difference relative to the outside, rather than a fixed temperature (generally 18°C in classic projects, even during heatwaves). The idea is to adapt to seasonal temperatures, as an energy-saving act. Considerations which allowed the Cameleon building to become the "first large textile store in Europe without the need for air conditioning".

Natural lighting
Given that lighting in a retail business is a very energy-intensive area, the Cameleon building was designed to let in as much daylight as possible (skylights and windows), and certain ceilings and walls were painted white. to reflect the light. The performance of the equipment (energy-efficient lighting fixtures, light sensors, dimmer to adapt the lighting, motion detectors) and the centralized management of lighting installations makes it possible to considerably reduce energy consumption and heat input.

The combination of natural lighting and intelligently designed adaptive devices gives a special atmosphere to those who visit the interior of the building. “We breathe, in this large vessel where the sunshade panels are designed to stop the burning rays of the zenith, while allowing the grazing light to penetrate during the winter months. (…) During the day, the thick concrete walls of the structure restore the coolness accumulated during the night inside. The opening of mobile panels in the roof is managed by sensors which react to the sun as well as to raindrops.

Energy autonomy
The use of solar energy as part of this project not only aimed to reduce the environmental impact of the building and increase its energy autonomy but also to promote the use of these technologies. Thus, the project includes a field of photovoltaic cells with a projected production of 14,000 kWh per year (installation of 18,000 W peak), or the average annual electricity consumption of four Brussels households. Hot water for the nursery and the concierge is provided by a solar thermal installation (water heating by the sun's rays). According to experts linked to the project, thanks to the innovative concept of the building, over a period of thirty years, 7,250 tonnes less CO2 will be saved, compared to a classic modern building.

Wind power was also considered from the start, but this aspect ultimately proved inconclusive given the difficult management of winds in the urban environment.

Construction site and selection of materials
Measures have been taken to reduce nuisance for local residents during the construction site, such as the use of prefabricated concrete panels, which leads to a reduction in transport, construction times and waste. The project lasted only eighteen months.

Measures have been taken to reduce nuisance for local residents during the construction site, such as the use of prefabricated concrete panels, which leads to a reduction in transport, construction times and waste. The project lasted only eighteen months.

All the materials in the project were chosen based on their life cycle, namely the energy required for their manufacture, transport, use and recycling. The walls are made of sandwich concrete (prefabricated) because this material generates little pollution - during its manufacturing in the factory and its use on the site - and is 98% recyclable, which made it possible to limit the execution time of the site and thus the nuisance for the neighborhood In addition, this type of material has the advantage of being easily dismantled.

Most structures are made of locally sourced wood treated with natural products. However, the use of certified exotic wood for frames, which is more resistant, has sometimes been necessary in order to avoid chemical treatment or to extend the life of the material. In order to compensate for the use of wood in the project, plots of native species were replanted in the Ardennes (1,200 trees). In addition, to save on materials, certain structures (wood, concrete, etc.) were deliberately left visible. All glues, paints and solvents used are of natural origin - this choice also takes into consideration the health of occupants and visitors. When the choice was possible, the project designers opted for "ecological alternatives" for certain installations. For example, elevator and escalator chains do not require lubricating oil. A large part of the interior furniture and internal structural elements come from recycling channels (thrifted furniture, recovery of parts of buildings or planes, etc.).

Water and waste management
An industrial recycling dock has been provided for the treatment of waste generated by the commercial activity of the building. Organic waste is thrown into compost.

In order to avoid unnecessary consumption of drinking water, the building is supplied by a double water network (rainwater/city water).

Thus, in addition to being equipped with water savers, the toilets are connected to rainwater recovery tanks.

The green roof also allows the retention and evapotranspiration of rainwater, thus helping to avoid clogging of public sewers and flooding.

Vegetation and biodiversity
Throughout the project (design, development and construction), the concern to reduce or compensate for the impact of the construction of the building on the surrounding nature (fauna and flora) was truly present. The project sponsor requested that existing trees be preserved as much as possible during construction. The 2,000 m2 of roof are covered with a plant substrate (green roof, meadow type) while the various facades are covered with climbing plants. Particularly abundant vegetation during the hottest months of the year, both a source of natural freshness and a carbon sink.

Around the site, native species have been planted, some of which are threatened with decline, as well as species likely to form a habitat for butterflies.

At the same time, a project to conserve populations of owls in the region between Sambre and Meuse was set up in partnership with a nature protection association. “In this same spirit of innovative and civic approach, one of its administrators, Augustin Wigny, asked Natagora ESM to install around twenty nest boxes around the perimeter of the building. The result was not long in coming..."

Beehives in town?
On the green roof, three hives had been installed to demonstrate that it is possible to produce quality honey, varied, rich, without pesticides, in the city. Cameleon appealed to the non-profit organization Apis Bruoc Sella. “Yes, it is possible and desirable, said Marc Wollast, beekeeper responsible for this association raising awareness of the environment and biodiversity using bees. This is possible because bees are not aggressive and can easily coexist with city dwellers. This is desirable because bees play a fundamental role in the reproduction of nature. Plus, bees love the city! Bees may be less sensitive to urban air pollution than to that of agricultural pesticides. In the city, bees produce up to three times more honey than in the countryside!» In 2011, annual production was already almost 400kg. A portion was collected with Cameleon employees and offered to customers and store partners.

In 2016, Cameleon's hives are part of the experimental project of BeeOdiversity, a social entrepreneurship start-up at "environmental purpose", to collect indices allowing the analysis of biodiversity and pollution at the regional level.

Urban farm
Between 2015 and 2023, at the initiative of Jean-Patrick Scheepers, promoter of Peas & Love, the roof of Cameleon will be occupied by an impressive collective vertical vegetable garden system, allowing some 200 cooperators to come and harvest vegetables from their micro- plots. This ambition to colonize large flat roofs that are sufficiently strong has gained momentum since then, notably with seven projects in Paris. Unfortunately, the two Brussels farms (Woluwe and Uccle) were declared bankrupt at the beginning of 2023.

A textbook case for eco-construction
In 2009, journalist Steve Polus said: "This living building is, in itself, an applied lesson in eco-construction technology, but with touches that humanize it. Entire internal walls are made of raw reclaimed wood, the wall of a meeting room comes from a piece of the fuselage of an Airbus, portholes included, 1920 store furniture and old glass doors, with their handles. copper, interact with factory metal lockers and Kartell chairs."

A point of view already shared today by Adel El Gammal, secretary general of the European Energy Research Alliance ( EERA ) in Brussels. Indeed, this expert who is also a professor at the Free University of Brussels (ULB) regularly cites the Cameleon Woluwe building in his courses and conferences. As he pointed out in December 2024, "this building was quickly considered as an interesting reference for students in the field of eco-construction. Indeed, the global and multidisciplinary consideration of environmental issues, from the initial phases of the building's design, the bold choice of materials used, as well as its entire production process, demonstrate a visionary approach to time of its construction and constitute a remarkable model of eco-design/construction. It also highlights the underlying societal thinking which largely contributed to the relevance and socio-economic solidity of the project.; more than fifteen years after its implementation, this building remains at the cutting edge, despite criteria which are changing quickly and becoming much more restrictive."

The Cameleon building has thus demonstrated its capacity to adapt over time. Pascale Switten summed up with sufficient distance: "They were once again visionary by building the first eco-built commercial building in Europe in 2009 in Woluwé. Moreover, they have won several awards for this building internationally and locally. (…) They really wanted to have the most sustainable building possible."

Prizes and awards

 * Mapic Awards (Cannes) 2009 "Best Sustainable Retail Development of the year" (best sustainable business development of the year)
 * Declared "Exemplary building in energy and eco-construction" by the government of the Brussels-Capital Region, 2009.
 * Mercury Prize 2009 (Fedis) "The most successful commercial space in Belgium" ( 1st prize)

The Fedis jury, chaired by the visionary architect and urban planner of green cities, Luc Schuiten, based itself on three criteria to award the Mercurius Prize: architecture, sustainability and integration into the environment. Cameleon was selected from around thirty candidates based on these criteria: "The brand new building is an example in terms of aesthetics, respect for the environment and integration into a district of Woluwe-Saint-Lambert."

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 * Bauhaus
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 * Luc Schuiten