US Patent 11802710 Article and method for determining airflow

A method for measuring outside airflow and return airflow is provided for an air handling system that includes an outside air inlet, a mixed air chamber, a return air inlet, a supply air outlet and a supply fan having a Supply Airflow Station with a fixed area, wherein the mixed air chamber is separated from the outside air inlet via a damper having a plurality of first damper slats. The method includes determining if the Temperature Differential (TD) between the Outside Air and the Return Air is greater than 10° F., where if the TD is greater than 10° F., then determining a position of the first damper slats, and referencing a reference table to identify the percent of outside airflow into the outside air inlet (CFM