Occupancy-Based Control of Indoor Air Ventilation: A Theoretical and Experimental Study

Abstract

In this paper, the theoretical and experimental studies of the occupancy-based control of the ventilation are presented to demonstrate the practical usefulness of the occupancy-based scheme for real-time air ventilation control and energy saving. The CO2 concentration is widely used as an indicator of the pollutant contaminant in indoor air and it often changes with time on account of the number of occupants. With the proposed methodology, the number of occupants can be estimated from the real-time measurement of the CO2 concentration of the outdoor air and the indoor air. As known, not only occupants but also buildings themselves contribute to potential indoor-air-quality problems. ASHRAE Standard 62-1989R guideline gives the design ventilation rate based on both occupancy and building space. According to ASHRAE Standard 62-1989R, the estimated number of the occupants and the area of ventilation-controlled space are used to determine the design ventilation rate required for acceptable indoor air quality. This design ventilation rate allows the Heating, Ventilating and Air-conditioning system to produce the acceptable indoor air quality at efficient energy usage. The experimental results show the viability of the proposed method- controlling ventilation based on estimated occupants.