The use of air in optimizing design or renovation of nZEB Buildings – VENISE

There are three barriers to overcome. The first is methodological type. Indeed, the proposed methodology (global optimized design focused on the use of air) has never been applied or very little so far. The second issue concerns the technology as it is to develop and implement innovative technology solutions with optimized components. The last barrier is economic since the cost of investment and operation of the proposed solutions have to be competitive in order to meet different purposes. To do this, the first part of the project will be dedicated to a functional analysis of the building described as a complex energy system. This will not only describe the functions, but also the coupling between functions and determine the actual or potential role of air. The proposed methodology is based on energy modeling of buildings. Thus, a state of the art on models available and those that it will necessary to develop will be carry out. Once the state of the art produced and the models developed, sensitivity analysis will be conducted to simplify the problem which will be subject to optimization. The latter should determine optimal solutions to meet different objectives under various constraints. Some solutions will then be characterized and tested throughout the building under real operating conditions. The expected results include physical systems, models and optimization methods.

Currently and after 18 months of operation of the project, the main results consist of: 1- Market review of existing multifunctional air systems and their functions. 2- Analysis of field operation of multifunctional air systems 3- Definition of objectives and constraints with respect to the functions of ventilation, heating, cooling and DHW 4- Definition of renovated and new building case studies namely single-family houses, apartment blocks, office buildings and education buildings. Concerning modeling, all pertners of the project use the software MODELICA/DYMOLA. A first modeling and optimization approach for multifunctional air systems was carried out either considering a system defined a priori or by seeking to optimize the composition of the initial system (type and numbr of components, components array...)

The middle-term perspective consists of the optimization of the multifunctional air systems with respect to two objectives namely the minimization of overall energy consumption and maximization of the use of environmental resources. The results of the optimization phase will be used to define and develop three prototypes (office buiuldings and dwellings). Then field tests will be carried out using ULR and CSTB experimental buildings.

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The objectives of Title 1 of the Law "Grenelle 2" related to improving energy efficiency in buildings, and reducing their energy consumption and carbon content, are extremely demanding and do produce lower energy requirements. The need to reduce energy consumption is causing a profound reassessment throughout the building sector. The current design methods, mainly based on technical and economic optimization function by function, will not achieve these targets optimally. Combining powerful and expensive equipment for each function will not produce a low overall energy consumption. In addition, energy-efficient buildings offer the opportunity for air control to attain a new level of relevance. Air, despite its poor thermodynamic properties, has undeniable advantages (ubiquity, fine control with low power ...) when the energy requirements and power usage are reduced.

This new context thus opens new avenues of research. The vision, not function by function but all simultaneously, focusing on air to satisfy the different regulatory needs by making the most of synergies between functions and the coincidence between the needs and availability of renewable resources. With this goal we propose to tackle this project. This involves developing a new design approach based on a multi-criteria method of optimization tailored to different segments of the building, and to extend the range and technical solutions to satisfy the demands of BEPOS and nZEB buildings.

The consortium brings together a university laboratory, an industrial laboratory, two research centres, a consultancy, a manufacturer and an architect, all with recognised competencies in the area of energy efficiency in buildings. The project is fully aligned with the second theme of the RFP, and specifically the sub-theme 2.3, "multi-physics modelling, dealing with interior environments, comfort, environmental quality (noise and air quality) along with energy efficiency" with the proposed methodology, and the sub-theme 2.4, "Innovation in construction and renovation" due to the technologies that will emerge.