How to verify that outside air is modeled with zero flow

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Hi friends,

How to verify that outside air is modeled (in eQuest) with zero flow in both
the Baseline and Proposed Case during unoccupied periods when fans are
cycled on to meet unoccupied setback temperatures?

And how to model it in eQuest actually?

I got this comment from the reviewer in one of our projects.

Thanks in advance.

Neeraj Arora

neeraj arora's picture
Joined: 2011-09-30
Reputation: 0

Hi Neeraj,

To model this in eQuest you would go to the air-side system -> fans -> night cycle control and set night ventilation to unavailable and fan cycle to the appropriate control scheme.

If you want to confirm this setup using the outputs from eQuest, I believe you will need to set up hourly reports for the systems and take a look there. To my knowledge, it doesn't show up explicitly in the .sim file. As a first approximation, you could check the SS-K report, and see if there is any difference between "temperature between outdoor & room air all hours" and "temperature difference between outdoor & room air fan off hours" which could suggest whether there is some sort of difference between "all hours" and "fan off hours" in the eyes of the model.


Alex.Blue's picture
Joined: 2013-02-14
Reputation: 0

I think the way to do this is to set the night fans to cycle on any and set an OA Schedule (like so):

[cid:image001.png at 01CE0AB8.31F6EF50]
Takes the U-name of a SCHEDULE that contains hourly values of the ratio of minimum outside air flow to supply air flow. Values in the MIN-AIR-SCH vary from 0.0 (no outside air flow; economizer inactive if specified) to 1.0 (100% outside air flow). A value of 0.001 actives the economizer. A value of -999 returns the hourly value to MIN-OUTSIDE-AIR or to the program's calculated minimum outside air value (found on report SV-A for the SYSTEM or for each zone for zonal systems). During a warmup period, this schedule is normally set to zero and can then be set to -999 during other hours to allow the specified or calculated ventilation minimum damper position to be used. Note that schedules are ignored in the design routines; therefore, the minimum ventilation air desired for design must be specified either at the zone or system level.

[cid:image002.png at 01CE0AB8.31F6EF50]

Vikram Sami, LEED AP BD+C

Sami, Vikram's picture
Joined: 2011-09-30
Reputation: -1