Displacement ventilation system

In many countries, the mixing ventilation system (hereinafter referred to as MV) is the most common and widely used system in office buildings for decades, even after the development of the displacement ventilation system (hereinafter referred to as DV). It is believed that DV has better ventilation efficiency compared to MV. However, DV could have problems such as vertical temperature difference in the occupied zone, horizontal temperature distribution, and performance in the heating mode.

Worldwide concern has been focused on the airborne disease of the COVID-19 pandemic. This study investigated the effect of the limited space air stability on the mechanism of SARS-CoV-2 spreading in the interpersonal breathing microenvironment using an unsteady computational fluid dynamics (CFD) method. A validated numerical model was employed to simulate the transient SARS-CoV-2 releasing process from normal breathing activity. The computational domain was divided into an interpersonal breathing microenvironment and the rest macroenvironment.

Wall-mounted air conditioning systems including window-type and split-type air conditioners are widely used in Asian countries. However, these systems blow cold air directly into the working space perpendicular to the mounted wall and may make people affected by these air conditioners experience discomforts such as draught and uneven temperature distribution. Now a wall-mounted air conditioning system is expected to effectively implement the displacement ventilation system for space cooling and cold draught avoiding.