Tracing indoor contaminant release location based on local mean residual-life-time of air

Abstract

Even in case ventilation system is operating in optimal fashion, indoor air quality could be varied depending on the indoor contaminant release occasions. Thus, accurate and rapid identification of contaminant source locations in indoor environment is critical for occupants’ health as well as building safety and integrity. This study presented a novel method to locate indoor contaminant source using local mean residual-life-time (LMR). Based on the theoretical definition of LMR, a characteristic quantitative relationship between the LMR at source location and the contaminant concentration profile of a room was derived and assessed through two stages of studies: experimental and numerical explorations. In the experiments, by changing contaminant release location under limited condition, the LMR at the source location and the contaminant concentration profile of a test chamber were measured. Then, the outcomes were examined to verify whether the derived equation was established in the chamber. Computational Fluid Dynamics (CFD) technique was also used to make up for the experimental limitations. CFD simulations were carried out to analyze the validity of the equation in response to different release locations of the contaminant in a more complex physical environment by obtaining high-resolution information. Both experimental and numerical results showed that the presented equation was well established and could be used to locate indoor contaminant source even in non-ideal situation or in complicated spaces.