Offering sound comfort and energy performance to the EcoCity in Champs-sur-Marne

In Cité Descartes in eastern Paris, a new EcoCity aims for architectural innovation, a better quality of life and energy performance. EPA Marne, a public urban development agency, initiated this project as part of France's City of Tomorrow program, supported by the Investment Plan for the Future. This local stakeholder is rising to the challenge of creating a pleasant and open living space, developed near railways. Partners such as Elithis and Urban Practices, Linkcity, Bouygues Bâtiment IDF, RATP and the CSTB are collaborating with EPA Marne to develop suitable innovations.

The public urban development agency of Marne-la-Vallée wants to develop the urban spaces located alongside the regional express train line (RER A), close to the station of Noisy-Champs. This 100,000 sq.-meter area will accommodate various types of buildings: housing, offices, services, etc. > Watch a video of the project

Energy strategy of the neighborhood

Key challenge: designing the neighborhood's energy system with a comprehensive approach to the neighborhood's energy needs, before launching the call for tenders which will be split into several sectors of buildings. This is precisely the approach taken by EPA Marne, seeking optimal supply solutions thanks to proposals from the consulting firms Elithis and Urban Practices and the experts of the CSTB.

The three partners analyzed the possibility of pooling energy solutions across the entire neighborhood. In concrete terms, this would include a water loop serving all of the buildings, to which each building's heat pump would be connected. The objective with such a combined system is to optimize energy consumption at the source when there is simultaneous demand for hot and cold water.

Energy simulation with Dimosim

Right from the beginning, the developer chose the Dimosim solution to enable such an analysis. This dynamic calculation and simulation software, developed by the CSTB, studies energy flows at the scale of a neighborhood. The technical results provide decision-making support to the developer.

Currently, the CSTB is calculating the energy requirements of each future building. Dimosim offers a vision of the energy demand, through a color graph and an hourly curve for each building, over a one-year period. By superimposing the demand of all of the buildings, the CSTB calculates the hot and cold water needs for the whole neighborhood. In this way, it analyzes the relevance of a shared supply solution, and can pre-size it.

Next step in 2017: using Dimosim to simulate the future EcoCity equipped with a combined system. The aim is to carry out the technical characterization of the system (production and storage). Next, the consumption calculations will predict the energy savings generated over time (in comparison with a standard system). This will serve as a baseline for the developer, who wants to calculate the initial investment and the payback period.

Solutions for acoustic and vibration comfort

The study of the future neighborhood also includes the treatment of the acoustic and vibration nuisances caused by the nearby railway. In order to provide pleasant living conditions, EPA Marne and Linkcity wanted to limit the impact of the airborne noise and underground vibrations impacting the residential buildings near the railway, when trains go by.

In 2016, the CSTB worked with all of the partners to imagine and design innovative solutions in three forms:

  • buried vibration protection mechanisms;
  • noise control systems at low levels, close to the railway;
  • using facades to counteract outdoor noise.

In order to assess their suitability, the CSTB uses its expertise and advanced prediction and calculation software, including Mefissto for the calculation of vibration impact.

Simulation of vibrations with Mefissto

Mefissto simulates vibrations in flooring and the level of structure-borne noise experienced by occupants in buildings. This makes it possible to assess the vibration reduction of different solutions, such as a dual wall installed near underground levels.

Before running the simulations, the CSTB and RATP carried out extensive on-site measurement and analysis work and then built a realistic model of the ground. They worked with partners to take account of the implementation constraints and offered viable, reproducible solutions, in the preliminary design phase.

Next step: in 2017, the CSTB and project partners will complete their exploration of the technical and economic performance of several solutions to provide the project teams with the information they need to make a decision.

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