Abstract: A noise reduction curb for use as an interface with a rooftop air conditioning unit by forming a base upon which the air conditioning unit rests and is mounted on a roof of a building. A noise reduction supply air duct is oriented in the longitudinal dimension of the air conditioning unit and has a supply air inlet fluidly coupled to the supply air source and a supply air outlet fluidly coupled directly to the supply ducts in the building. The supply air inlet is longitudinally displaced from the supply air outlet and is separated therefrom by a flow turbulence reducing substantially straight duct section. A noise reduction return air duct is oriented in the lateral dimension of the air conditioning unit and has a return air inlet fluidly coupled directly to the return air ducts in the building and a return air outlet fluidly coupled to the air conditioning unit. The return air inlet is laterally displaced from the return air outlet.

Abstract: A two section damper assembly and method of use is disclosed for avoiding stratification of cooled air in an air conditioning system. The damper assembly is especially adapted for use in variable air volume air conditioning systems that include an economizer. During the economizer mode of operation, the building in which the air conditioning system is installed is cooled at least partially with outside air as opposed to cooling solely by mechanical means and the volume of air that is required may be relatively low. The variable two section damper assembly ensures that an adequate volume of cooling air is taken in and that there is adequate velocity of the outside air and return air to ensure mixing of the outside air with the return air in order to avoid the stratification of the supply air that can occur. The damper assembly is variable in the size of the opened area and in the direction that the individual vanes of the damper assembly are set.