The Campus Sanitaire et Social (CSS) is a university around health and social professions. This new construction is made up of two buildings: the administrative building (air-conditioned) and the teaching building (with natural ventilation, except for the CDI and the amphitheater).

The HEQ approach

The HQE approach is a global environmental approach which aims to lead to the realization of an architectural project:

• whose impact on the local, regional and planetary environment is minimal;
• whose impact on the comfort and health of its occupants is optimal.

This approach is facilitated by the use of a certain number of tools making it possible both to qualify the environmental quality of the project, to set quantitative and qualitative objectives to be achieved and to monitor the implementation of these objectives.

The HQE approach therefore constitutes a methodological contribution to the creation of a sustainable development architecture.

This approach is above all a “quality approach”. It can be described as "win-win-win", i.e. a winner for the owner or manager of a building, a winner for its users or occupants and, finally, a winner for the people living in its immediate environment. or distant.

This building aims to be a model in its tropical environmental quality approach applied to ventilation, materials and optimized natural light and greening (HQE type).

This building is a major component of the overall project of the city of knowledge, a link between the sites thanks to its openness, its transparency, the "green flow", a plant and pedestrian link open to all, which crosses it and its respectful layout. of the environment.

The health and social campus is designed for comfort of use, in the search for healthy atmospheres, suitable for concentration and study.

A well-thought-out control of consumption, architectural options for orientation, ventilation, optimized solar protection, the choice of eco-certified and sustainable materials, for an exemplary building in its tropical HQE approach.

Choices regarding the location of the Campus

The layout and morphology of the buildings of the Health and Social Campus result from a critical analysis of the bioclimatic and environmental constraints and potentialities of the site. Thus the north-south orientation of the buildings constitutes the best compromise between natural air conditioning and optimal solar protection , taking into account the site effect which influences the direction of the prevailing winds.

The complete separation of the two volumes makes it possible to economically satisfy the envelope requirements induced by each type of environment: natural air conditioning and artificial air conditioning.

The compactness of the administrative building, by minimizing the exchange surfaces, makes it possible to avoid heat losses and therefore to promote sobriety of needs, while the slenderness of the teaching building offers the largest possible surface of openings to the trade winds, its location allowing it to overcome any mask effect at the same time as it eliminates the noise pollution caused by the classrooms.

Hygro-thermal comfort

Essential element of general comfort insofar as it can compromise the quality of learning if it is not treated in depth (one works and concentrates less efficiently in a building where it is hot), the thermal comfort of the building teaching, operating in natural ventilation, is obtained by the measures described below.

The measures directly concerning the heat treatment of the building are as follows:

Layoutof the land and treatment of the periphery of the buildings:

• treatment of the soil, more than 90% vegetated (with adapted and water-efficient species) to reduce the albedo, and minimize the bituminous surfaces that capture sunlight around the buildings;

These measures alone not only make it possible to create comfort by lowering the ambient temperature by 1 to 3°C on the outskirts of the buildings and therefore, consequently, in the buildings , but they also make it possible to create comfortable outdoor spaces conducive to relaxation and conviviality.

Optimization of solar protection of buildings:

Without solar protection, there is first of all no possible comfort in buildings when they are not air-conditioned and no minimization of air-conditioning loads when they are.
The designers carried out a fine-tuned optimization, building by building, facade by facade, using suitable and proven computer design tools (Ecotect, EnergyPlus, etc.) of the building's solar protection techniques and systems.

The general principles of sun protection are:

• roofs (which can receive up to 7 kWh/m².day in very sunny weather): thermal insulation (in polystyrene with a minimum thickness of 5 cm) and revegetation of the roof (administrative building and caretaker's accommodation) to bring back the postman overall solar transmission of the roof at less than 1%, this value going further than proven and known requirement levels such as those of the RTG 2020;
• glazed vertical walls equipped with light-coloured sunscreens sized according to the orientation;
• for the teaching building, an over-roof was placed for insulation and ventilation, as well as solar protection calculated according to the orientations (atrium, sun visors, etc.).

All of these measures lead to an overall objective of reducing the percentage of solar energy incident on the building transmitted inside it by less than 1.5%, i.e., under extreme sunshine conditions, less than 0.15 kWh/m2-day is still an average transmitted power of less than 6 W/m2 of surface area. This level places the buildings at an overall level of solar protection more than twice as efficient as the level of requirements of the RTG 2020.

Optimization of natural ventilation in the teaching building and the caretaker's accommodation:

After the solar protection limiting the thermal contributions, the thermal comfort in the teaching building and the housing of the caretaker will be created by the ventilation of the premises which makes it possible on the one hand to evacuate the internal loads and, on the other hand, to create a air speed on the occupant lowering the temperature felt by the latter by up to 4°C .

An excellent natural ventilation capacity of the buildings is allowed:

• qualitatively and conceptually : through classrooms in the teaching building, respective position of ventilation inlets-outlets, modularity of openings (ventilation by frames) leading to control of directional flows and speeds;
• in terms of sizing : the porosity (percentage rate) downwind of the least effective aeraulics (thermal breeze during the day) will be increased to values higher than the specifications of the RTG 2020 and allowing a homogeneous air circulation and an effect venturi.

For periods without wind or when the wind speed is insufficient to ensure comfort in non-air-conditioned areas, this can be obtained by means of ceiling fans.

Energy balance

The use of renewable energies, and in particularsolar photovoltaic is a key point of the project.
Having obtained, thanks to the quality of the envelope, the equipment and the surroundings, a low-energy campus, we can complete our Négawatt approach (sobriety, efficiency, renewable) by installing on the roof of the teaching building, ideally facing south at 16°, a photovoltaic field of up to 90 kWp for a maximum of around 760 m² in self-consumption calculated to meet more than 100% of the energy needs of buildings.

This installation will make it possible to make use of the sunshine 365 days a year, the electricity being produced and consumed directly by the building or injected into the network "over the sun", on a permanent basis (more details in the "Energy" section) .