energy consumption is expected to be insignificant. A full description of the model equations, calculation procedures, and other assumptions used in the simplified UFAD cooling load design tool are presented by Schiavon, et al.14 Design Tool Description A B A spreadsheet-based calculation procedure to predict the design cooling load and airflow rate for both interior and perimeter zones of a typical multistory office or other commercial building using underfloor air distribution has been developed. The tool allows the user to select from four different plenum configurations that represent a range of design practice. Figure 3 shows schematic and plan views of two of these options: Figure 3a: Series plenum configuration. Figure 3b: Reverse series plenum configuration. series and reverse series. Both represent an open plenum design that serves the interior and perimeter supply air from the air handler is first delivered to the interior zones of the conditioned space. In the series configuration, portion of the plenum, where it gains some heat, and then www.info.hotims.com/30919-59 www.info.hotims.com/30919-110 66 ASHRAE Journal September 2010