[Equest-users] eQuest - FCU with DOAS

[Grando, John]

One further question that has been bothering me.  How would you set up ERV with the DOAS?  I've seen some posts from the archives but none are too clear.  The return air temperature of the DOAS appears to be too low to use an ERV on. Any suggestions?

 
John Grando LEED AP
 

-----Original Message-----
From: James Hansen [mailto:JHANSEN at ghtltd.com] 
Sent: Monday, March 01, 2010 11:16 AM
To: Marcus Eliason; equest-users at lists.onebuilding.org
Subject: Re: [Equest-users] eQuest - FCU with DOAS

I haven't had a chance to look at your .inp file, but when you are creating a DOAS system, make sure that you at least do the following:

1) Make sure the fan schedule is forced off at night and setback times.
2) Make sure the throttling range for the dummy zone thermostat is at least 4 degrees (I usually use 6).
3) Make sure that the heating/cooling schedules that the dummy zone follows are set to something like 120 degrees cooling and 20 degrees heating after hours, just to make sure that a call for heating/cooling doesn't show up in your report, and mess up the unmet load hours.


Just looked at your file:  you need to specify some sort of minimum OA control or minimum air schedule for the FCUs (I think).  Right now nothing shows up.

Also, why is the DOAS system serving so many "dummy" zones?  I *think* your DOAS system is EL1 Sys1 (SZRH), yet it is serving 20+ zones.  I'm confused...

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-----Original Message-----
From: equest-users-bounces at lists.onebuilding.org [mailto:equest-users-bounces at lists.onebuilding.org] On Behalf Of Marcus Eliason
Sent: Monday, March 01, 2010 11:04 AM
To: equest-users at lists.onebuilding.org
Subject: [Equest-users] eQuest - FCU with DOAS


Hello,

I am trying to model a building with FCUs and a DOAS to deliver outdoor air to the individual zones.  I have put in the dummy zones for the DOAS system, modeled as a single air handler with chilled and hot water coils. I have changed the walls of the dummy zone to air walls, specified the DOAS to get OA flow as sum of all zones and for the FCUs to get OA from the DOAS.  When I run the model, I get a lot of unmet hours corresponding to the dummy zones and the DOAS system.  I have tried but cannot seem to turn off the return air path for the DOAS (since it is 100% OA) and have specified the minimum OA fraction for the DOAS as 1.  I am not sure if the unmet hours means that my DOAS is not adequately cooling the OA load or if it something else.
Also, my "pump & aux" energy in the model seems very high for a building that only has 3 pumps.  Can someone familiar with modeling DOAS shed any light on what might be causing some of these problems.  I have attached the .inp and .pd2 files for reference.

Thanks,

Marcus Eliason



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