Numerical sensitivity analysis of the tracer gas decay method coupled with the Kalman filter in a two-zones dwelling.

• The Kalman decay method in suited to multizone's applications. • The Kalman method is 40% more accurate than the 2-points decay method. • The in-situ Kalman decay method has an uncertainty of 20% maximum. • The formulation of the Kalman decay method's uncertainty is given. The measurement of a natural airflow-rate is already challenging. It is often realised thanks to the decay method. Dealing with multi-zone naturally ventilated buildings is even more challenging as multi-zone's applications prevent from using single-tracer gas methods. A method has already shown its ability to measure the global airflow-rate of a multi-zone passive stack dwelling. It is based on the Kalman filter applied to decay methods implemented quasi-simultaneously in each outlet room of a dwelling. This paper presents a numerical sensitivity analysis of the so-called "Kalman decay method". Formulations of the global uncertainty are drawn depending on parameters involved in the analysis. It allowed improving the accuracy, compared to the conventional 2-points method, from 8 to 48%. If the sensor is placed near the outlet, an accuracy between 8 and 20% can be achieved. The main influential parameter is occupation in living rooms of the dwelling during the test, but its effect on the global uncertainty of the Kalman decay method is 20% lower than on the conventional 2-points method. [ABSTRACT FROM AUTHOR]