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Re: [EnergyPlus_Support] PlantFlowResolver error -- "Branch flow rates out of bounds"
Run the first 6 months of the year (or 3 months). Then run the other 6
months (or 3 months). Then append the csv's and sum the meter files.
Josh K wrote:
>
> Hey Richard;
>
> Just curious: although we ascertained a couple weeks ago that the
> PlantFlowResolver errors that were the subject of this email won't affect
> the accuracy of my simulation, I'm still having one problem: I get so many
> of them (>30000) on one particular heating coil during the course of an
> annual simulation that the only way I can get through a full year's
> simulation without it crashing is to use 1 hour as a minimum timestep. Is
> there a way to change this 30000 error threshold, or anything else you can
> think of that would allow me to run a simulation with shorter timesteps?
>
> Thanks,
>
> Josh
>
> On Feb 5, 2008 9:48 AM, Richard Raustad <RRaustad@xxxxxxxxxxxx
> <mailto:RRaustad%40fsec.ucf.edu>> wrote:
>
> > I just tested your input file by adding the pump inlet node volumetric
> > flow rate as a report variable. Then I corrected the code to eliminate
> > the plant flow resolver warnings. I found no differences in the answer.
> >
> >
> > Richard Raustad wrote:
> > >
> > > It appears from the output (csv) file that the PTAC water heating coil
> > > in zone 513_computer is operating. Please disregard these warnings
> > > unless you find good reason to suspect it affects the simulation
> > > results. From the report variables you selected, you did a very
> good job
> > > of troubleshooting the warnings. These report variables confirm
> the unit
> > > is operating correctly. I did not look closely at the plant loop
> to see
> > > if the warnings indicate a problem with the flow rate through the
> plant.
> > > To check the plant operation, report out all hot water coil (and
> bypass)
> > > outlet node flow rates and compare the sum of these to the hot water
> > > pump flow rate. Also compare pump water flow rate with the boiler (and
> > > bypass) flow rate.
> > >
> > > We will look into resolving this issue.
> > >
> > > Richard Raustad wrote:
> > > > You will have to upload your file so we can take a look.
> > > >
> > > > Josh K wrote:
> > > >>
> > > >> 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
> <mailto:brent_griffith%40nrel.gov><brent_griffith%40nrel.gov>
> > > <mailto:brent_griffith%40nrel.gov>
> > > >> <mailto:brent_griffith%40nrel.gov>> 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
> <mailto:EnergyPlus_Support%40yahoogroups.com><EnergyPlus_Support%40yahoogroups.com>
> > > <mailto:EnergyPlus_Support%40yahoogroups.com>
> > > >>
> > >
> <mailto:EnergyPlus_Support%40yahoogroups.com><EnergyPlus_Support%40yahoogroups.com>
> >
> > >
> > > >>
> > > >> > [mailto:EnergyPlus_Support@xxxxxxxxxxxxxxx
> <mailto:EnergyPlus_Support%40yahoogroups.com><EnergyPlus_Support%40yahoogroups.com>
> > > <mailto:EnergyPlus_Support%40yahoogroups.com>
> > > >>
> > >
> <mailto:EnergyPlus_Support%40yahoogroups.com><EnergyPlus_Support%40yahoogroups.com>]
> >
> > >
> > > >>
> > > >> > On Behalf Of josh_miarch
> > > >> > Sent: Saturday, February 02, 2008 4:57 PM
> > > >> > To: EnergyPlus_Support@xxxxxxxxxxxxxxx
> <mailto:EnergyPlus_Support%40yahoogroups.com><EnergyPlus_Support%40yahoogroups.com>
> > > <mailto:EnergyPlus_Support%40yahoogroups.com>
> > > >>
> > >
> <mailto:EnergyPlus_Support%40yahoogroups.com><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]
> > > >>
> > > >>
> > > >
> > >
> > > --
> > > Richard A. Raustad
> > > Senior Research Engineer
> > > Florida Solar Energy Center
> > > University of Central Florida
> > > 1679 Clearlake Road
> > > Cocoa, FL 32922-5703
> > > Phone: (321) 638-1454
> > > Fax: (321) 638-1439 or 1010
> > > Visit our web site at: http://www.fsec.ucf.edu
> <http://www.fsec.ucf.edu> <http://www.fsec.ucf.edu
> <http://www.fsec.ucf.edu>>
> > >
> > > UCF - From Promise to Prominence: Celebrating 40 Years
> > >
> > >
> >
> > --
> > Richard A. Raustad
> > Senior Research Engineer
> > Florida Solar Energy Center
> > University of Central Florida
> > 1679 Clearlake Road
> > Cocoa, FL 32922-5703
> > Phone: (321) 638-1454
> > Fax: (321) 638-1439 or 1010
> > Visit our web site at: http://www.fsec.ucf.edu <http://www.fsec.ucf.edu>
> >
> > UCF - From Promise to Prominence: Celebrating 40 Years
> >
> >
> >
>
> --
> 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]
>
>
--
Richard A. Raustad
Senior Research Engineer
Florida Solar Energy Center
University of Central Florida
1679 Clearlake Road
Cocoa, FL 32922-5703
Phone: (321) 638-1454
Fax: (321) 638-1439 or 1010
Visit our web site at: http://www.fsec.ucf.edu
UCF - From Promise to Prominence: Celebrating 40 Years
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