Characterization of non-isothermal flows typical of built environments in a laboratory scale model. Part I – Experiments with 3D PIV

Built environments are major energy consumers worldwide and their efficiency is recognized as a key factor for the sustainable development of modern societies. Consequently, pressure has been put on researchers and engineers to make recourse to all available tools to improve such efficiency. A contribution to this goal is the gathering of experimental data viewing a comprehensive understanding of the involved transport phenomena. The present work addresses this issue by presenting a set of experimental data acquired with the 3D PIV technique and a set of profile thermocouples, which allow characterizing the velocity and temperature fields in a laboratory model (scale 1:30) of an office room, with a thermal resistance mimicking an occupant. An improved version of the moving average methodology is used to eliminate spurious vectors from the experimental data. Two ventilation strategies (mixing and displacement) are tested. Results for mixing show that the high momentum of the inlet flow promotes a homogeneous temperature field due to a large recirculation zone formed downstream the buoyant plume above the heat source. This plume constitutes however an aerodynamic barrier hindering the mixing process in the zone below the inlet grille (upstream the plume). Displacement results evidence the existence of a short-circuit flow between the inlet and outlet grilles. This undesirable phenomenon generates recirculation zones that promote a homogeneous temperature field, and not the aimed thermally stratified one. This may provoke discomfort to the occupant. The present data set is of capital importance to validate CFD results in built environment flows.