[Equest-users] Summary of issues modeling DOAS in eQUEST

[Kendra Tupper]

I'm about to set up an eQUEST model with a DOAS with chilled beams, and I
wanted to be aware of all the issues with DOAS before I start.

1) Can you model OA economizers with a DOAS? I thought this would work if
you specify the economizer model on the AHUs that are pulling OA from the
DOAS. However, I tried this and the hourly output reports for OA cfm
indicate the economizer is not working.

2) Can you model Demand Control Ventilation with a DOAS? My guess is no
because the DCV sensors would be placed in the dummy zones or in the return
air stream from the dummy zones (which have no people). One potential
workaround would be to create a fractional schedule for the OA based on the
occupancy schedules in the zones served by the DOAS. Has anyone tried this
with success?

3) I understand that you cannot model heat or energy recovery on a DOAS
because the EA stream is from the dummy zones (at the supply temp of the
DOAS). In the past, I have exported hourly RA temps from occupied zones and
performed hourly spreadsheet calcs to determine the savings. Any other
workarounds that folks know of within eQUEST?

Thank you!

Kendra Tupper, PE, LEED AP
Senior Consultant
Built Environment Team

Rocky Mountain Institute  |  T  303-567-8641 |  F  303-245-7213  |
www.rmi.org
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