Patent ID: 8915295
Filing Date: 2014-12-23
Classification: F24F

Abstract:
1. A method for controlling a bypass damper in a zoned HVAC system, the method comprising: (a) flowing conditioned air from an HVAC unit to a plurality of zones and a bypass duct including the bypass damper, wherein the bypass damper has an open position, a closed position, and a plurality of partially open positions; (b) flowing a portion of the conditioned air through the bypass duct and the bypass damper, the conditioned air flowing through the bypass damper having an actual flow rate; (c) determining the actual flow rate of the conditioned air flowing through the bypass damper in response to measuring the pressure differential across the bypass damper; (d) calculating a recirculation ratio equal to the ratio of the actual flow rate of the conditioned air flowing through the bypass damper to a nominal flow rate of conditioned air generated by the HVAC unit; (e) comparing the calculated recirculation ratio to a maximum recirculation percentage; and (f) at least one of (1) adjusting the position of the bypass damper in response to determining that the calculated recirculation ratio exceeds the maximum recirculation percentage and (2) maintaining the position of the bypass damper in response to determining that the calculated recirculation ratio does not exceed the maximum recirculation percentage.