Modeling Natural Ventilation in Refugee Healthcare Shelters

Ventilation is imperative in combating airborne viruses such as SARS-CoV-2. In refugee camp healthcare shelters without mechanical ventilation systems, natural ventilation can be used to lower transmission risk. With the goal of investigating the mitigation of airborne viral concentration while also evaluating thermal comfort, we performed computational fluid dynamics (CFD) simulations to model flow, temperature, and exhaled aerosol dispersion inside a refugee camp healthcare shelter. Lacking field measurements, we used a building thermal model to solve for the CFD boundary conditions. Three recommendations can be made from the results. First, for the climate conditions considered here, ventilation should be maximized at any time of day: in the day the amount of ventilation has little impact on thermal comfort, and at night maximizing ventilation both minimizes viral concentration and improves thermal comfort. Second, window openings should be aligned with the prevailing wind direction to maximize ventilation; if the wind is 60° off-normal, ventilation rates are on average 33% less than when the wind is normal to the windows. Third, infectious patients should be placed next to leeward windows if possible, so that exhaled viral particles are drawn outside and diluted.