Qualitative Modelling of the Natural Ventilation Potential in Urban Context

The two objectives of natural ventilation in buildings are the improvement of indoor air quality and thermal comfort. The methodology proposed hereafter provides an assessment of the natural ventilation potential for indoor air quality, while taking into consideration the other objective. More precisely, requirements on comfort impose the appropriate ventilation strategies to be applied for each given meteorological situation. On the basis of these strategies, the methodology evaluates the appropriateness of a given location to natural ventilation. After a historical introduction (Chapter 1), the statement of the problem (Chapter 2) and a review of the state of the art (Chapter 3), Chapter 4 presents a novel methodology to assess the natural ventilation potential starting from its driving forces (wind-induced and buoyancy-induced pressures) and from its constraints (noise pollution and atmospheric pollution), which applies multicriteria analysis. The method uses the results of the atmospheric simulation model Lokal-Modell (LM, described in section 3.4). The related software tool, developed within the European project Urbvent, and tested against real cases, is presented as well. Chapter 5 gives a view of the results of an atmospheric mesoscale model, referred to as Finite Volume Model (FVM), that includes an urban module (described in section 3.6) allowing to compute the effects of the urban tissue on meteorological parameters. This model has been adapted as part of this work to use the outputs of the above-mentioned Lokal-Modell (LM) as boundary conditions. (To this end, previous works utilized NCEP/NCAR Reanalysis data, with an original spatial resolution 40 times lower than LM in latitude, 25 times lower in longitude and 6 times lower in time.) iii