Variable-volume exhaust system

An exhaust system for exhausting air from a space, the exhaust system comprising:

• a variable-volume exhaust air moving system comprising at least one fan comprising an inlet and an outlet;
• a duct connected to the inlet;
• an outlet nozzle having a variable cross-sectional outlet area, the outlet nozzle fluidly connected to the outlet, wherein the outlet nozzle comprises:
• a housing comprising a plurality of straight side portions and a plurality of curved end portions connecting the straight side portions, wherein the plurality of straight side portions and the plurality of curved end portions connecting the straight side portions define a discharge area;
• and
• a pair of blades disposed in the discharge area and at least partially defining the variable cross-sectional outlet area, wherein the curved end portions are spaced apart from the blades at both a top and bottom of the blades so as to define a separation, and wherein the separation between the pair of blades and the plurality of curved end portions is configured to allow debris to pass through the separation and out of the exhaust system;
• a selectively operable bypass damper fluidly connected to the inlet;
• a sensor for detecting at least one of a pressure condition and a flow condition in the exhaust system;
• and
• a control system for controlling the at least one fan, the outlet nozzle, and the bypass damper, based at least in part on a signal sent from the sensor.