Role of HVAC System Configuration on Probable Flow Path of Airborne Pathogens in a Patient Room
ASHRAE Annual Conference, Denver, CO, 2013
CFD models are developed to evaluate the impact of various HVAC design configurations on the airflow patterns, temperature distribution, and resulting thermal comfort of occupants, and on the probable flow path of airborne particles released from the patient’s face. These analyses indicate the linear diffusers combined with high supply air flow rates (high air change rates) can cause strong recirculation and entrainment (induction) flows in the room. Depending on the location of the return the airborne particles released from the patient’s face can get entrained back into the supply air stream and can eventually spread into the entire room. However, this study indicates placement of a return grill right behind the linear supply diffuser over the patient’s head can potentially provide ready flow path to airborne particles to exit out of the room without significant recirculation and entrainment back into the supply stream. This study demonstrates that a careful evaluation of the HVAC configuration can help in gaining the insight and optimizing the flow path of air to obtain the desired combination of occupant thermal comfort and the best possible hygienic conditions in patient rooms.