CFD study of the air distribution and occupant draught sensation in a patient ward equipped with protected zone ventilation

Effective ventilation in general hospital wards is important for controlling the transmission of airborne infectious agents that may cause respiratory diseases. Recently, a new ventilation concept called protected occupied zone ventilation (POV) has been shown to have the ability to improve the quality of inhaled air compared to that of traditional ventilation strategies. This study numerically investigates the percentage of people dissatisfied due to draught close to the health-care worker (HCW) and patient in a single-bed isolation room equipped with POV. The CFD validation results showed that out of the three examined turbulence models, the SST k-omega models predicted the velocity and temperature profiles agreeably according to the experimental findings. The SST k-omega model was further used to visualize the airflow distribution in the patient ward and investigate the influence of the supply velocity and temperature on the draught risk. Supply velocities of 1.0, 1.5 and 2.0 m/s did not exceed the suggested comfort criterion of 20% even at lower supply temperatures. The draught risk at ankle level of the sitting patient exceeded the maximum allowed value at supply velocities of 2.5 and 3.0 m/s at both lower and higher supply temperatures.