Ventilation control of IAQ, thermal comfort and energy conservation by CO2 measurement.

The use of indoor carbon dioxide levels is a good method for controlling indoor air quality in office buildings. The measured CO2 is used to determine the amount of outdoor air needed to purge air contaminants and to obtain the desired CO2 indoors. Two floors of a commercial building in Montreal were used in the study. Since both floors were identical in architectural layout, type of work being done, and in population density, and since they had identical yet separate ventilation systems, one floor was used as a control, and the other was modified to include a CO2 and temperature control system. The strategy complies with the requirements of the ventilation, indoor air quality, and thermal comfort standards. The discomfort that did exist was due to HVAC system repairs. It also performs the ventilation service in an energy effective manner, with an annual saving of 12%, and a payback period of 0,4 years. However, the occupants' perception of their working environment does not reflect the measured results. They perceived that their productivity is proportional to their perception of the indoor environment. The DCV floor occupants complained significantly more of their indoor environment than the occupants of the other floor.