Question-and-Answer Resource for the Building Energy Modeling Community
 | 1 | initial version |
It looks like the Fan:ZoneExhaust object has an input field where you can specify a schedule to affect the max flow rate. This may not be the ideal situation, but that is a fan object where you can set a schedule to specify fan speed at each time step. For that process, it may be easier to create an external schedule file with flow speed values for each timestep, then use the Schedule:File object to have your E+ file read it in.
Looking over the Fan:ComponentModel object, there does seem to be input fields related to VFD. Namely, input fields for VFD Efficiency Type (calculate efficiency based on Power or Speed), Maximum Output Power of VFD Motor, VFD Motor Input Power Sizing Factor, and VFD Efficiency Curve (uses operational Power or Speed, depending upon value entered in "VFD Efficiency Type" input field). You may want to consider including some kind of analysis with these capabilities, since they are specifically for VFDs with fans. The E+ Engineering Reference doc makes two references to VFD data in the Air System Fans Section (search for the term "VFD" on that page) for justifying how these capabilities were incorporated into the tool.
