The test case ADNBATI, a benchmark on natural ventilation in a room

A common case of simplified nocturnal ventilation strictly induced by natural convection is submitted to different numerical models of heat and fluid flow in buildings. The methods range from analytical formulae to Direct Numerical Simulation, via nodal models, zonal models and numerical simulations on coarse grids. Agreement is acceptable (±20%) for flow-rates, but a strong scatter occurs on the cooling rates (average values). Mesh refinement seems to be crucial for determining average velocity and temperature fields.