UTILIZING DIFFUSION THEORY TO PREDICT INDOOR OCCUPANY PATTERNS

摘要

Carbon dioxide concentration is an indicator of building occupancy that can be used to enhance energy efficiency. This research has developed a diffusion approach to modeling carbon dioxide levels in indoor air environments with limited airflow and sources of carbon dioxide. The diffusion model developed from this research has the potential to correlate carbon dioxide concentration with static occupancy levels which can lead to energy savings through a reduction in air exchange rates when low occupancy is detected. A two foot diameter spherical test chamber with three dual beam, infrared, carbon dioxide monitors mounded at its top, middle, and bottom is used to study carbon dioxide with limited convection and is used to benchmark the developed model. The model is then adapted to model a room operating in a restricted ventilation mode in the presence of a source of carbon dioxide. The extrapolated diffusion model is accurate to within twenty percent of the experimental results for restricted air flow rates. The diffusion model developed from this research provides a quick and effective method to correlate carbon dioxide concentration and occupancy patters and can provide an efficient alternative to present methods for a large number of cases.