Multizone modeling of pressure difference control analyses for an infectious disease hospital

Infectious disease hospitals must maintain pressure differences among rooms to direct the airflow toward the negative pressure isolation ward (NPIW) to prevent the spread of airborne pathogens. However, their values cannot be maintained easily in dynamic situations, especially when the door to the isolation room is open. There is a lack of guidelines for how to cope with this situation. A variable air volume (VAV) damper is set in the exhaust duct of the NPIW attempts to achieve active control by VAV but is often set to deliver constant air volume (CAV) because of a lack of confidence in its controllability. In this study, models based on a real infectious disease hospital are built and verified by the multizone model on Modelica. An appropriate active pressure difference control strategy for VAVs in NPIW is explored and it is applied in a floor of hospital model to analyze the influence of pressure differences among multiple rooms by VAV operation. The results show that the pressure difference deviations can be reduced by 9.98%-25.73% for different leakage paths of the isolation room with this control strategy. The pressure differences among hospital are stable during the VAV operation in the usual dynamic scenario. The airtightness of the door at zones junctions and external windows needs to be reduced to strengthen their anti-interference ability of pressure difference. This study fills the gap of guidelines and provides a reference for the application of VAVs for active pressure difference control in infectious disease hospitals.

Automated summary

In this study, models based on a real infectious disease hospital were constructed and verified by the multizone model on Modelica. An appropriate active pressure difference control strategy for VAVs in NPIW was explored and applied in a hospital floor model to analyze the impact of pressure differences among multiple rooms by VAV operation. The results showed that pressure difference deviations could be reduced by 9.98%-25.73% for different leakage paths of the isolation room with this control strategy. The study emphasizes the importance of reducing airtightness at zone junctions and external windows to enhance their ability to resist pressure difference interference.