PO-86-01-2 -- Fan Energy Use in Variable Air Volume Systems PDF

Fan energy consumption in variable air volume (VAV) systems is affected by both the technique used to control the flow rate and the control algorithm used. In this paper a simulation study is made of a "standard" 10,000 square foot building. Three flow-control techniques -- system dampers, inlet vane control, and variable speed control -- are considered along with two types of control algorithms: proportional (P) and proportional-integral (PI). A relationship is derived for the relative power consumption under P and PI control. Fan power consumption in the example building is calculated for five locations, two types of fan (backward-inclined centrifugal and vaneaxial), the three control techniques, and the two control algorithms. Significant differences are found in annual energy consumption for the different cases.

Units: I-P