a fan having a fan intake and a fan exit downstream from the fan intake, wherein the fan is configured to draw air into the fan intake and propel the air downstream through the fan exit;

a housing having a housing inlet configured to be coupled to the fan exit and a housing outlet downstream from the housing inlet;

an air straightener, adjacent to the housing inlet, having an annular array of honeycomb apertures that surround a center cut-out and streamline the air that flows downstream, and a solid cover that plugs the center cut-out and blocks the air; and

an air guider mounted inside the housing adjacent to the housing inlet, the air guider having a conical shape with a base adjacent to the solid cover, and an apex opposite the base that points towards the housing outlet, wherein the air guider has a first diameter that tapers from the base to the apex to define a peripheral volume surrounding the air guider that serves as a tunnel, and wherein the air guider is configured to reduce air turbulence of the air when propelled from the housing inlet to the housing outlet.