How do I model Active Chilled Beams?

In order to model an active chilled beam, you need simply to set up the equivalent of a DOAS plus fan-coil system with no fan or heating coil at the zone level. Then add a proportional controller to maintain the induced flow from the room into the coil (with the primary flow) at a fixed multiple of the primary flow.

The ApacheHVAC system file in the Related Documents section provides an example of this. This file is archived in the .zip format, which you can open with WinZip if you do not have WinRar. If you wish to run the attached system, you'll need to have at least version 6.1.0.1 of the IES VE installed. You will also, as enabled in this version for all ApacheHVAC users, need to use the Acquire prototype HVAC systems action in the VE-Gaia System Prototypes & Sizing workflow to bring in a set of HVAC-specific profiles referenced by this sample system (as is the case for all prototype systems). When your project profiles database includes profiles with names such as HVAC CP3 - Cooling (Midband: Sys 5-9 Clg Coil SAT), you'll know you have completed this step correctly and, once rooms are assigned to it, you can run the sample system.

Alternatively, if you wish this to be autosizable, you'll need to modify the pre-defined system 9 (DOAS + Fancoil) that is brought in via the system prototypes S button in ApacheHVAC. This also requires the HVAC-specific profiles to be brought in by the Acquire prototype HVAC systems action.