Development of setting methods to control outdoor ventilation airflow rate in office buildings

Ventilation is essential for the health and comfort of building occupants. It is particularly required todilute and/or remove pollutants emitted by occupants' metabolism and activities. The concentration of metabolic CO2 is well correlated to metabolic odour intensity. Therefore CO2 concentration can beefficiently chosen as an indoor air quality index when occupants are the main source of pollution inside the buildings. This paper presents the results of a research work conducted to adjust and compare five advanced techniques based on CO2 level measurement in order to adapt ventilation extractor fan speed to the intermittent occupation of an office. An experimental one-zone cell called Hybcell was chosen to compare these five control technologies (i.e. on/off, proportional integrative regulator, fuzzy logic control, analytical control function, and radio frequency identification) under the same conditions.A method was developed to define the setting parameters of a proportional integrative and a fuzzylogic control regulator of an extract fan. Criteria based on control precision, command stability andglobal air exchanged were then established for the final evaluation. The results revealed fine controlaccuracy. They showed a good stability with a reduced and simplified setting period for the developed methods compared to current controllers.