Occupancy density and benefits of demand-controlled ventilation in Norwegian primary schools

One hundred and fifty-seven classrooms for fourth form pupils were inspected at 81 randomly selected schools in Oslo, Norway. Primary school classrooms in Oslo have on average 22 occupants present, while the maximum capacity is 30. Classrooms are typically used 4 h daily for normal school activities. The corresponding ventilating air volume and energy use has been analysed for three ventilation strategies: (a) constant air volume [CAVI, (b) CO2 sensor based demand-controlled ventilation [DCV-CO2], and (c) infrared occupancy sensor based demand-controlled ventilation [DCV-IR]. DCV-CO2 and DCV-IR reduce the energy use due to ventilation in the average classroom to 38% and 51%, respectively, compared to the corresponding energy use for a CAV system operating with full airflow from 7:00 am to 5:00 pm. (c) 2005 Elsevier B.V. All rights reserved.