Energy-efficient air quality control in school classrooms

The aim of the present work is to maximize indoor environmental quality (IEQ), in particular air quality, and energy performance in schools, when having different ventilation alternatives combined with carbon dioxide feedback. In this effort, trial measurements and energy simulations were conducted to predict and compare the indoor environmental and energy performance in an otherwise similar school building. A literature review was performed on indoor air quality (IAQ). Reported ventilation in literature and CO2 data strongly indicates that ventilation is inadequate in many classrooms. A survey assessment was performed over a period of five weeks. Concurrent measurement of window open state, CO2 concentration, temperature, and outside environmental conditions were taken. In addition, classroom occupancy levels and classrooms energy usage were recorded. Statistical probabilistic and regression models of the proportion of windows open were performed. A simulation model was created in IDA-ICE-4 to reproduce energy demands. Occupant window opening behavior showed to have a significant impact on both classroom indoor air quality and building energy use; To improve indoor air quality in schools, CO2 feedback was show to be an effective and useful low-cost tool, especially in naturally ventilated classrooms, but although ventilation is significantly improved through behavioral change in windows opening behavior, the fresh air rate is still insufficient to maintain good air quality all time during the full school day. Results show that in cold weather CO2 feedback has a negative impact on energy. It was found that cooling in summer can have detrimental effects for air quality.