Floor Heating with Displacement Ventilation: An Experimental and Numerical Analysis

The effect of floor heating combined with displacement ventilation (DV) on thermal indoor environments and indoor air quality (IAQ) was studied by means of CFD. The numerical model was validated with experimental data. A typical office room was simulated, and one of the occupants was considered to be the contaminant source. The CFD model reliably simulated air velocities and temperatures. Also ventilation effectiveness values were coherent with experimental data. The model made it possible to understand the effect of the downdraft from a cold window on the dissemination of contaminant in the room. Although ventilation effectiveness at seated breathing height was always higher than one, it was not possible to visualize a defined contaminant stratification in the room. Only when the windows were not assumed to be cold, a clearly stratified flow pattern could be detected. The numerical model was then used to simulate different kinds of contaminant sources, under the same boundary conditions. It was found that DV does not guarantee a better IAQ than full mixing when contaminant sources are not linked to heat sources, even when floor heating is used. Contaminants produced by powerful heat sources require high ventilation flow rates to guarantee high values of ventilation effectiveness.