Bedroom ventilation performance in daycare centers under three typical ventilation strategies

With increasing reliance on daycare centers for early childhood development, ensuring healthy environments in semi-enclosed baby beds for napping is crucial, given infants' vulnerability to air pollutants and their inability to control surroundings. Despite concerns about indoor air quality, research on bed-level ventilation conditions remains scarce. This study investigates the performance of three ventilation strategies (mixing ventilation (MV), displacement ventilation (DV), and personalized ventilation (PV)) in enhancing air quality at bed level in daycare center bedrooms. Using a full-scale setup representing a typical Dutch daycare bedroom, ventilation performance was evaluated by examining CO₂ dispersion and inhalation for 12 breathing thermal baby models sleeping in 12 beds, considering two sleep positions and ventilation rates. A total of 58 strategically located CO₂ sensors enabled a thorough understanding of CO₂ levels at inhalation and both the bed and room scales. The findings reveal the superior performance of PV, followed by DV and MV, with significantly different inhaled CO₂ concentrations per baby: 1713 ppm (MV), 1104 ppm (DV), and 801 ppm (PV), though the mean in-bed values differed by less than 20 ppm among the modes. Thus, assessing ventilation performance of various ventilation strategies necessitates examining inhaled air quality. Sleep positions and ventilation rates significantly influenced MV and DV modes' performance. Importantly, PV demonstrated energy-saving potential by achieving comparable inhaled air quality at lower ventilation rates. These findings have practical implications for designing occupant-centric ventilation systems in daycare center bedrooms and effective CO₂ monitoring in semi-enclosed spaces.