Air diffusion performance index of high sidewall line diffuser in a room with perimeter heating load

The purpose of this study is to evaluate the effect of the perimeter heating load about the air diffusion performance index (ADPI) and propose a selection guide for proper line diffuser when perimeter heating load exists.

A high sidewall line diffuser was installed into a test room following the ISO standard 5219. The velocity and temperature distributions and the ADPI values are obtained numerically with 12 cases when the air flow rates are 425, 730 and 950 CMH and the heating loads are 0, 25, 50 and 75 percent of the total heating load, 2,143 W.

The ADPI decreases according to the increases of the flow rate on every heat load ratio of the present study except 0.75 with the line diffuser installed at the high sidewall. And we produced ADPI curves when the sidewall heating load exists or not in the same air flow rate and supply conditions. From that, it is possible to assume that the throw length guarantees more than 80 percent of ADPI with heating load on the wall.

Further work by the authors is focusing on making of database of various other diffusers which are generally used in the field.

This paper provides a modified selection guide for proper sidewall line diffusers to field engineers when perimeter heating load exists on the walls.