sizing return air flow for an autosized supply air flow - follow up for return air flow greater then 90%

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I have a few zones where the FX must be greater than the outside air venting. OA is between 6-8% supply air flow.
I am trying to automate the return air flow to equal that of supply flow less outside air. Is there anyway to set FX to equal outside air flow?

What I have tried, without success, is to set Return-cap-ratio equal to (supply-OA)/supply.
Such as, (Local("SUPPLY-FLOW")-ChildRef("OUTSIDE-AIR-FLOW"))/ Local("SUPPLY-FLOW").

Do supply-flow and outside-air-flow need to be entered numbers to achieve?
I am trying to autosize supply flow based on 20F coil-to-space temp so I do not want to enter a number there.

Thanks for the insight.



Message: 3
Date: Mon, 11 May 2009 12:47:43 -0700 (PDT)

Kevin Kyte's picture
Joined: 2011-09-30
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