The Maison du Bâtiment
Energy Solidarity
Sustainable construction
Energy efficiency
A positive-energy building for Energy Solidarity®
Associating the construction of positive-energy buildings and the renovation of existing buildings
Anticipating the French heating regulation “RT 2020” which, after 2020, provides for the implementing of “Bâtiments à Energie POSitive” or “BEPOS” (Positive Energy Buildings), EIFFAGE has been developing its own positive energy concept applied to both new construction and renovation.
Priority is given to reducing the energy needs of the building through its bioclimatic design, the compactness and inertia of its shape, the treatment of its envelope and its façades. The residual energy needs are then handled with, as a function of the potential of the territory, exclusive use of local renewable energies.
In a rationale of analysis of the life cycle of the building, the "embodied energy" corresponding to the energy use and greenhouse gas generation during the construction phase is taken into account in the choices of construction processes and materials.
Each building is characterized by a specific set of uses and an architectural shape which affect its energy and economic performance. The Phosphore teams therefore developed two BEPOS approaches on buildings that are different in all ways except that they are both old and remarkable.
- The "high-tech" approach is applied to The Maison du Bâtiment, a very tall building of the 1960’s, requiring a particularly substantial technological exterior treatment and consequently a new sophisticated programming.
The Phosphore teams want to prolong the working life of the building while going beyond the BEPOS standards planned for 2020 for new construction. This ambitious choice will amortize the embodied energy expended for its construction. All of the energy needs specifically for the operation of the Maison du Bâtiment, limited to a minimum, are covered by the production of local renewable forms of energy.
In terms of uses, the south and west façades, which have good exposure, will welcome service sector and sports activities, public services and restaurants, and housing units. An upscale hotel occupies the northeast part.
- The "low-tech" approach is applied to the so-called "Restos du Cœur" building, a compact construction representative of the industrial architecture of the early 20th century, requiring more modest technology and adapted to the maintaining of its social objective.
By conserving the historical façades of this industrial building, EIFFAGE is once again carrying out energy rehabilitation, but now by integrating different architectural and use constraints.
Alongside the initial function of social solidarity there are programs for housing, public services and service sector activities housed within an extension made with a mixed concrete/wood structure.
Thermal solar and photovoltaic panels are installed on the inclining roofs facing south. Panes of photovoltaic glass are arranged on the south and west façades and supplement the residual needs of the building.
Wood, preferred for structures and façades, reduces the environmental footprint of the building.
Pooling and balancing energy consumption and production on the scale of a block
Each building, according to its nature, dimensions and orientation, has a different profile and potential in terms of energy performance. While new constructions allow for the production of more energy than they consume, most existing buildings have a limited potential for energy renovation and will always be net consumers. Moreover, some new constructions that are less well situated or that are subject to major architectural or use constraints will not achieve the conditions necessary for BEPOS (Positive Energy Building) performance.
The Phosphore teams chose to rule out the individual approach, judged to be counterproductive, in favor of a systemic approach to Energy Solidarity®.
- Cost of the renovation of each existing construction is optimized through the neighboring positive energy building.
- Energy consumption and production achieve equilibrium on the scale of the block and the neighborhood.
Applying the principle of Energy Solidarity®, the Maison du Bâtiment exchanges heat and electricity with the new building called the “Hive”. This system equilibrates energy consumption and production on the scale of Haguenau Square.
