4180 (RP-849) -- Selection of Cold Air Diffusers PDF

The subject of this paper is the selection of diffusers for cold air distribution systems. The paper provides a description of the different types of diffusers used to produce cold air jets followed by an introductory model of jet mixing. The three main design parameters for any type of diffuser, including cold air diffusers, are the room characteristic length, the throw, and the separation distance. This paper covers the dependence of the throw, entrainment, and separation distance of cold air jets on discharge conditions. The design procedure detailed in this paper uses optimum values of these parameters for diffuser selection. A design example is given that illustrates the determination of the throw and the separation distance of a cold air jet based on the diffuser size, type, and discharge flow conditions.

Units: Dual