CH-12-020 (RP-1335) -- Installation Effects on Air Outlet Performance, Part II: Field Air Outlet Throw and Pressure Loss Performance Difference from Ideal PDF

This paper is based on findings resulting from ASHRAE Research Project RP-1335.

Building air distribution terminal system designers and system installers require accurate quantitative information on the diffuser throw and pressure loss performance of the installed system to achieve optimum efficiency and levels of human comfort. This research project, covered in three papers, establishes the diffuser baseline performance and then determines the field installation adjustment values. The first paper covers baseline performance. This paper documents the field conditions difference in throw and pressure loss from ideal conditions of six types of ceiling diffusers, each with three different inlet sizes at three different inlet velocities. The third paper covers differences in sound generation from ideal conditions. Full scale laboratory testing of typical field installation variations was completed with variations in damper installation, duct approach angle, duct type, duct vertical height above the diffuser, and close coupling duct installation. A predictive model was developed and used to create a set of look-up tables that can be used to easily predict how the installation configuration would affect diffuser performance compared to published data. The results in this report can be used to determine the corrections for throw and pressure loss for field conditions from baseline results.