NA-2253 -- An Analysis of the Performance of Room Air Distribution Systems

This is paper number six in a series which describe the results of an experimental program to determine how various parameters affect the air distribution performance of different types of air distribution systems. Earlier papers presented preliminary results for ventilating ceilings, conetype circular ceiling diffusers, high sidewall grilles, sill grilles, ceiling slots, and light troffer diffusers, under various conditions of air flow rate and room loads (Refs 1, 2, 3, 4, 5). In these papers the Air Distribution Performance Index (ADPI) was demonstrated to be a valid single number rating index for the performance of air distribution systems. In this paper an analysis of the performance of the air distribution systems will be based on a newly defined "center-line" ADPI and how it is affected by the ratio of jet-throw distance divided by room characteristic length. This "center- line" ADPI is considerably easier to measure under normal laboratory conditions or in the field than is the previously used "whole-room" ADPI which essentially requires the use of a full scale research laboratory. Also included is information on room' average velocity as a function of the velocity at the outlet.