Environmental parameters assessment of a new diffuser for air cooling/heating system: Measurements and numerical validation

Air distribution of HVAC systems is the most popular type used in the building sector, having a relevant impact on indoor air quality and occupant wellness. Many types of research developed optimal solutions for the HVAC system’s design, focusing on specific components of the distribution system, on the airflow and geometry of ducts, on the size of ducts, on the shape and position of air diffusers. However, few works in literature proposed a globally experimental and simulation analysis of an air distribution system with a variable mass flaw rate. Along this line, the presented research investigates the potentialities of a new ceiling diffuser, installed in an exhibition room. This system provides a variable mass flow rate thanks to its configuration, providing adequate thermal comfort. A warm wall is chosen as the heating system. Several tests are carried out, six for cooling and two for heating with different volumetric air rates and supply air temperature of the diffusers. The combination of two methods, the measurement campaigns and the computational fluid dynamics (CFD) technique represent a suitable approach to examine the thermal indoor environment. In general, results show a strong capability of this diffuser to provide a uniform temperature and velocity field inside the room. Moreover, experimental and numerical data are significantly comparable with an average deviation of 1% for the velocity and lower 1% for the temperature, guaranteeing an optimal distribution of the understudy environmental parameters on the vertical and horizontal planes.