Re: [EnergyPlus_Support] PlantFlowResolver error -- "Branch flow rates out of bounds"

["Josh K" <jeemang@xxxxxxxxx>]

Hi Richard/Brent;

I double checked, and the heating coils are on ACTIVE branches that are in
parallel with a demand bypass branch. Any other suggestions as to what might
be the problem?

Thanks,

Josh





On Feb 4, 2008 9:12 AM, Griffith, Brent <brent_griffith@xxxxxxxx> wrote:

>   Check that the hot water coils are on a plant loop branch with "ACTIVE"
> control and that there is a bypass in parallel with them.
>
> ________________________________
>
> From: EnergyPlus_Support@xxxxxxxxxxxxxxx<EnergyPlus_Support%40yahoogroups.com>
> [mailto:EnergyPlus_Support@xxxxxxxxxxxxxxx<EnergyPlus_Support%40yahoogroups.com>]
> On Behalf Of josh_miarch
> Sent: Saturday, February 02, 2008 4:57 PM
> To: EnergyPlus_Support@xxxxxxxxxxxxxxx<EnergyPlus_Support%40yahoogroups.com>
> Subject: [EnergyPlus_Support] PlantFlowResolver error -- "Branch flow
>
> rates out of bounds"
>
> I'm attempting to simulate a large, multizone building, and I'm
> encountering the following warning message:
>
> ** Warning ** PlantFlowResolver: Branch flow rates out of bounds, for
> Plant Loop=PLANT, Branch=514_COMPUTER_FC_HEATING_COIL_BRANCH
> ** ~~~ ** Conditions should be: 0.000 <= 1.517E-002 <= 0.000
>
> Over the course of an annual simulation, there are enough of these
> warnings (>30 000) to result in a fatal error that crashes the
> simulation.
>
> The branch in question is the heating coil branch for a
> PACKAGEDTERMINAL:AIRCONDITIONER object. Both the coil and the
> PACKAGEDTERMINAL:AIRCONDITIONER are available when these warnings are
> occurring.
>
> I've noticed that this error tends to occur largely in the shoulder
> seasons, when there is a relatively large amount of heating required
> in the morning (as there are relatively low external temperatures, and
> the zone thermostat switches from the the night set-back temperature
> of 16 C to 20 C), and then cooling required later in the day (as the
> combination of higher exterior temperatures and high internal gains
> adds heat to the zone). Although the load on the heating coil is
> relatively large in the morning and the PTAC object doesn't have a
> field for specifying max HW flowrates, the flow that I am seeing to
> coil is definitely reasonable, which makes this error more perplexing...
>
> Any help would be greatly appreciated.
>
> Josh
>
> [Non-text portions of this message have been removed]
>
>  
>



-- 
Josh Kjenner, EIT, LEED AP
Manasc Isaac Architects Ltd.
10225 100 Avenue :: Edmonton, AB T5J 0A1
780.429.3977


[Non-text portions of this message have been removed]



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