Efficiency characterisation of various ventilation configurations.

The study concerns the ventilation of a parallelepiped shape room by means of several systems whose supplying and extracting methods differ, so the different thermic conditions applied to limits. To qualify the efficiency of each of these systems in relation with the various current criteria, we carried out measurements by means of a tracer gas, both with a transitory and a permanent flow. At the same time, numerical simulations were carried out by means of a CFD code which solves the equations of the fluids mechanic, material and heat transfers associated with flows. These calculations results, after measurements validation, enable to accurately know the air movements in the ventilated room as well as the tracer gas concentrations distribution in the tested configurations. From these calculation results, was also demonstrated how the complex behaviour of each of these ventilation systems can be characterised owing to the possibility of identifying it to a simple model, using a reduced number of parameters. These typical parameters can in turn be used to implement the system performance evaluation criteria. These criteria allow to compare the various studied ventilation systems and class them in performance order. It can be seen that this classification can be modified depending on the selected criterion as well as the chosen ventilated area. The study results equally show the interest of the use of numerical simulation together with experiments, thus extending the range of results in order to generalise conclusions.