Control of sleep environment of an infant by wide-cover type personalized ventilation

With a validated computational fluid dynamics (CFD) program, we investigated the potential for a wide-cover type personalized ventilation (WCPV) system to reduce the risk of Sudden Infant Death Syndrome (SIDS) due to thermal stress, rebreathing of expired carbon dioxide and exposure to airborne pathogens for a sleep infant. The WCPV system was intended to minimize draft discomfort by blowing cooled air upward and then descending uniformly and slowly over a sleep infant's head. Two settings for personalized airflow were simulated: a spreading angle of 75° (WCPV-75°) and 35° (WCPV-35°) above the horizontal plane. Simulations demonstrated that a well ventilated comfort microenvironment could be maintained around the infant's head with air temperature varying between 19 and 22 °C and draft rate kept under 15%. For the infant with supine position, the average time for the air from both ambient and personalized ventilations to reach the infant's inhalation decreased by 29.3% with WCPV-75° and 89.0% with WCPV-35°. Moreover, the infant's exposure to the infectious influenza quanta from an adult standing aside the bed decreased by 54.3% with WCPV-75° and 80.4% with WCPV-35°. On the other hand, WCPV-35° could take 90.3% less time to deliver 26.6% more personalized air to the infant. For the infant with face-to-side sleep position, the WCPV would also improve the infant's microenvironment. A smaller spreading angle resulted in a much better performance, while a bigger spreading angle led to a better “wide-cover” effect.