A method to identify the point source of indoor gaseous contaminant based on limited on-site steady concentration measurements

Abstract

Identification of potential contaminant sources in buildings is an important issue for indoor pollutant source control. In this paper, a method based on the characteristics matrix derived from the transport governing equation is proposed, and the procedure to identify the contaminant source is presented. Compared with the methods in the literature, the new method is more suitable for the identification of steady point contaminant sources because it only requires limited on-site concentration measurement data without historical information. As a demonstration case, a 2D room with a known flow field validated by the experiment in the literature is selected. A steady point source is presumed at a certain point and the concentration field is calculated by computational fluid dynamics (CFD). Then the concentration data at the specified sampling points are used to identify the source position. Without the measurement error, the method can work well when the concentration measurement data at only two sampling points are given. However, when concentration measurement errors are considered, sampling points need to be increased to improve the identification accuracy. For the simulated 2D case, nine sampling points are sufficient for acceptable accuracy when the relative measurement error is 10%. Effects of positions of the source and the sampling points, and the uncertainty of the flow field simulation on the identification results, as well as the limitation of the method are also discussed.